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Biomedical subjects

G Otero

Publications and source records attributed to G Otero.

18 recordsLinked to original sources
PubMed2007

The marine sphingolipid-derived compound ES 285 triggers an atypical cell death pathway.

The isolation of new molecules from marine sources opens the door to their possible therapeutic use against tumors and other pathological conditions. Indeed, we recently defined the cytotoxicity of ES 285, obtained from the clam Mactromeris polynima, and its affects on the cells microfilament but not the microtubule network. Considering the analogy between ES 285 and sphingosine-related lipids, we wondered whether ES 285 might affect the activity of PKC at the intracellular level. While we anticipated that ES 285 might inhibit PKC, it turns out that in contrast it serves to activate PKC at the cellular level. Indeed, like other sphingosine-related lipids, ES 285 induces the phosphorylation of MARCKS. Additionally, we further examined the cytotoxicity of ES 285 to elucidate the molecular mechanisms through which this compound triggers apoptosis. When the influence of ES 285 on "cell death markers" was assessed, it became clear that ES285 activates caspase 3 and 12, and that it modified the phosphorylation of p53. In contrast, ES 285 does not affect other pathways widely implicated in regulating cell survival/apoptosis, such as JNK, Erks or Akt. Thus, these data suggest that ES 285-triggers an atypical cell death program when compared to other sphingosine-dependent apoptosis pathways.

Alkanes↗
PubMed2003

EEG and behavioral changes following neurofeedback treatment in learning disabled children.

Neurofeedback (NFB) is an operant conditioning procedure, by which the subject learns to control his/her EEG activity. On one hand, Learning Disabled (LD) children have higher values of theta EEG absolute and relative power than normal children, and on the other hand, it has been shown that minimum alpha absolute power is necessary for adequate performance. Ten LD children were selected with higher than normal ratios of theta to alpha absolute power (theta/alpha). The Test Of Variables of Attention (TOVA) was applied. Children were divided into two groups in order to maintain similar IQ values, TOVA values, socioeconomical status, and gender for each group. In the experimental group, NFB was applied in the region with highest ratio, triggering a sound each time the ratio fell below a threshold value. Noncontingent reinforcement was given to the other group. Twenty half-hour sessions were applied, at a rate of 2 per week. At the end of the 20 sessions, TOVA, WISC and EEG were obtained. There was significant improvement in WISC performance in the experimental group that was not observed in the control group. EEG absolute power decreased in delta, theta, alpha and beta bands in the experimental group. Control children only showed a decrease in relative power in the delta band. All changes observed in the experimental group and not observed in the control group indicate better cognitive performance and the presence of greater EEG maturation in the experimental group, which suggests that changes were due not only to development but also to NFB treatment.

Behavior↗
PubMed2001

[Pseudo acute pancreatitis: a syndrome mimicked by a multiple parasitic duodenitis. Analysis of 7 case].

INTRODUCTION: The aim of this presentation was to analyze a clinical syndrome characterized by repeated episodes of upper abdominal pain, markedly increased levels of both total amylase and lipase, but with normal values of pancreatic isoamylase. Besides, with the lack of morphologic changes of the pancreatic gland, either by ultrasound, abdominal tomography, or Nuclear Magnetic Resonance. MATERIAL, METHODS AND RESULTS: Five female and two male patients, with an average age of 51 +/- 3 were studied. All had been diagnosed as having acute edematous pancreatitis (ranson score < 3). Laboratory tests had disclosed eosinophilia (5-30%); total amylasemia (1547 +/- 398 UA/l); lipasemia (857 +/- 499 UBL/L); normal pancreatic isoamylase (72 +/- 18 UA/L). Upper endoscopy showed nonspecific signs of duodenitis sometimes with duodenal erosions. Collection studies, pre and post Sorbitol, disclosed an unexpected multiple parasitic infestation, e.g.: giardias, ascaris, amoeba, hymenolepis nana. This finding was always suggestively associated with abundant sludge (bilirrubinate cholesterol and oxalate crystals). All patients, after having been submitted to the appropriate antiparasitic medication, were rapidly relieved of their symptoms and remained free of episodes of abdominal pain. CONCLUSIONS: When the fact that all our patients had normal pancreatic isoamylase levels and lack of any morphologic distortion of the pancreatic parenchyma is associated to the notion that total amylase and lipase may have as a source the gastrointestinal mucosa, it appears as a logical inference that the clinical syndrome here discussed is indeed primarily a reflection of an extrapancreatic disease, essentially of parasitic duodenitis.

Acute Disease↗
PubMed2000

Specific EEG frequencies at specific brain areas and performance.

In this study it was shown that in adults, the frequency characteristics of EEG preceding stimuli that were followed by incorrect responses were different from the characteristics of EEG preceding stimuli that were followed by correct responses. In the recording during three different tasks that explore different neuronal networks, higher values of current preceding incorrect performance in those areas directly related to the task were found in frequencies within the delta (1.56 and 3.12 Hz) and beta bands (13.26, 14.04, 14.82, 15.6, 17.16 and 17.94 Hz), suggesting that these frequencies signal inhibition. Frequencies within the alpha band (9.36 and 12.48 Hz) showed greater energy preceding correct responses in task-specific areas, supporting previous results observed in children.

Adult↗
PubMed2000

[Autonomic nervous system and pancreas. (Analysis of the influence of different types of autonomic denervation in glandular regeneration phenomena and the interactions of the exocrine-endocrine-Axis)].

The present tests, in male Wistar rats, center around the trophic and functional changes of the pancreatic gland (R G), both exocrine and endocrine, induced by different types of autonomic nervous interruptions. First Group of Tests: Following one year celiac ganglionectomy (CG), nonpancreatectomized (Non-Pt) rats showed, basally, in blood, a drop of glucose (G), without changes of insulin (I). At autopsy, the CG animals showed an increase of the pancreatic we weight, of the total protein, of the RNA but not DNA. In the Pt. 95% rats, superimposing CG triggered, on the one hand, a drop to control values of the raised G blood levels, and on the other, a rise of I Besides, in feces, a rising of chymotrypsin concentration. At autopsy, in the PG, an increase of total protein and of RNA. Second Group of Tests: CG, after 6 months, induced, in blood, both basally and a 2 h glucose tolerance test, significant opposite enzyme activities changes in respect to C. Indeed, as amylase (A) was increased, that of lipase (L) was depressed. When alcohol feeding (AF) was superimposed to CG rats, a reversal of the L values was observed. The latter reached levels significantly higher those of the C. In in-vitro tests, the isolated islets of CG disclosed to release more I to the bath medium than those of the C animals. Third Group of Tests: Analyzing, in conscious animal, the L excretory changes in the basal bile pancreatic secretion (BB-PS) induced by chronic (2 months interruption of the autonomic nervous innervation of the PG, it was found that CG, truncal vagotomy (V), the association of CG + V, peri-Vaterian duodenotomy (PV-D), but not bilateral splachicectomy (Spl), inhibit, significantly the L output. It was also shown that superimosing AF to the V or CG + V animals reverted to C values the I depressed levels. In acute interruptions (24 h) of the autonomic nervous innervation of the PG: CG, V, P. V-D, the depression in the BBPS is highly significant, more than 40%. From these three sets of experiments it is concluded that: Firstly, CG increases the regenerative and functional capacity of both the exocrine pancreas. This is distinctively evident when the secretory mass is reduced like in the Pt. 95% series of animals. CG probably exerts its effects suppressing the releasing of some negative reins: adrenergic, pepdidergic (galanin). Secondly, CG evokes modifications of the normal Islet-pancreon inter-relationships. The rising of A and the drop of L in blood elicited by this type of autonomic nervous interruption probably reflects an increased release of I by the Langerhans islet. Thirdly, CG, the same as V. CG + V and P.V-D, but not Spl, depress the intrapancreatic cholinergic tone. This might by at the basis of the depression of L excretion in the BB-PS. The reversion to C Through the coupling of chronic alcohol intoxication to the autonomic decentralized PG would be a reflection of an increased sensitivity to ethanol of the intrapancreatic ganglionic neurons. The augmented acetylcholine release at the nerve terminal would lead to a high intrapancreatic cholinergic tone that, in the end, might be at the basis of the reversal changes induced in the autonomic decentralized PG by the chronic ethanol intoxication.

Animals↗
PubMed1999

Elongator, a multisubunit component of a novel RNA polymerase II holoenzyme for transcriptional elongation.

The form of RNA polymerase II (RNAPII) engaged in transcriptional elongation was isolated. Elongating RNAPII was associated with a novel multisubunit complex, termed elongator, whose stable interaction was dependent on a hyperphosphorylated state of the RNAPII carboxy-terminal domain (CTD). A free form of elongator was also isolated, demonstrating the discrete nature of the complex, and free elongator could bind directly to RNAPII. The gene encoding the largest subunit of elongator, ELP1, was cloned. Phenotypes of yeast elp1 delta cells demonstrated an involvement of elongator in transcriptional elongation as well as activation in vivo. Our data indicate that the transition from transcriptional initiation to elongation involves an exchange of the multiprotein mediator complex for elongator in a reaction coupled to CTD hyperphosphorylation.

Cell Division↗
PubMed1999

A novel histone acetyltransferase is an integral subunit of elongating RNA polymerase II holoenzyme.

The elongator complex is a major component of the RNA polymerase II (RNAPII) holoenzyme responsible for transcriptional elongation in yeast. Here we identify Elp3, the 60-kilodalton subunit of elongator/RNAPII holoenzyme, as a highly conserved histone acetyltransferase (HAT) capable of acetylating core histones in vitro. In vivo, ELP3 gene deletion confers typical elp phenotypes such as slow growth adaptation, slow gene activation, and temperature sensitivity. These results suggest a role for a novel, tightly RNAPII-associated HAT in transcription of DNA packaged in chromatin.

Acetyltransferases↗
PubMed1998

Relationship of specific EEG frequencies at specific brain areas with performance.

This study shows that incorrect responses are preceded by different EEG characteristics than correct responses, and that these differences appear in specific brain regions that participate in each particular task. EEGs were recorded in children during three different tasks: color discrimination (CDT), verbal working memory (VWM), and word categorization task (WCT). EEG segments previous to the presentation of the stimulus were analysed. Incorrect responses were preceded by lower EEG power values at 7.8 Hz in posterior temporal and right parietal leads in CDT, 8.59 and 9.36 Hz in frontal areas in VWM, and 10.72 Hz in the left hemisphere in WCT. In the former task > 1.56 Hz power in frontal areas prior to an incorrect response was also observed.

Alpha Rhythm↗
PubMed1997

Altered processing of precursor transcripts and increased levels of the subunit I of mitochondrial cytochrome c oxidase in Syrian hamster fetal cells initiated with ionizing radiation.

Treatment of Syrian hamster fetal cells (SHFC) with ionizing radiation resulted in the establishment of 21 transformed cell lines. Relative to unirradiated controls, cells from early post-irradiation passages (p.3) showed marked morphologic alterations, increased growth rate and extended life span, and they were contact-inhibited and not tumorigenic in nude mice, although they became tumorigenic after extended passaging in culture (p. > 30). Differential mRNA display analyses of normal cells (84-3) and radiation-initiated cell lines at early passage showed that the latter contained increased steady-state levels of the precursor (4-fold) and mature (1.7-fold) transcripts of the mitochondrial (mt) gene encoding the subunit I of cytochrome c oxidase (CO I). These molecular alterations were consistently observed in 57% of the irradiated (HDR) cell lines, and were stably maintained during continuous passaging (p. > 50). Further analyses of one of these cell lines (HDR-3) demonstrated that the accumulation of CO I precursor transcripts was the result of mRNA stabilization and increased replication and/or amplification of the mt DNA. Radiation-initiated cells contained elevated levels of the CO I protein, showed a 75% reduction in cytochrome c oxidase (CO) activity, and a 5-fold increase in the concentration of hydrogen peroxide secreted into their culture medium compared with cells with no alterations in CO I mRNA processing. Our findings suggest that alterations in mt CO I processing may play a role in the neoplastic conversion of mammalian cells by ionizing radiation.

Animals↗
PubMed1996

Increased manganese superoxide dismutase activity, protein, and mRNA levels and concurrent induction of tumor necrosis factor alpha in radiation-initiated Syrian hamster cells.

The levels of the antioxidant enzyme manganese superoxide dismutase (Mn-SOD) are frequently decreased in tumor cells and increased in normal cells upon treatment with ionizing radiation. We studied Mn-SOD at different stages during the neoplastic conversion of radiation-initiated Syrian hamster embryo HDR-3 cells. Mn-SOD activity and the concentration of Mn-SOD protein and mRNA increased gradually during the malignant transformation of HDR-3 cells after radiation exposure; fully neoplastic cells showed greater Mn-SOD levels than preneoplastic and normal 84-3 cells. Inhibitors of superoxide (SO) anion production (thenoyltrifluoroacetone and rotenone) decreased the concentration of Mn-SOD mRNA, raising the possibility that the generation of SO radicals participated in the upregulation of Mn-SOD in cells transformed by exposure to radiation. We observed an increase in the concentration of tumor necrosis factor alpha (TNF alpha) in HDR-3 cells relative to mock-irradiated cells. Together with the observation that TNF alpha stimulates the production of SO by mitochondria and increases the level of Mn-SOD mRNA in other experimental systems, our results suggest that as normal 84-3 cells undergo malignant transformation induced by ionizing radiation they produce TNF alpha, to which the cells respond by increasing the concentration of Mn-SOD mRNA and protein and the activity of the enzyme.

Animals↗
PubMed1994

[Primary tuberculosis of the penis].

Presentation of one case of primary tuberculosis of the penis which presented as a skin ulcer. The need of preparing a good clinical history, with special emphasis on sexual habits, as well as the convenience of taking a biopsy for diagnosis and further treatment is analyzed.

Adult↗
PubMed1993

Activation of phospholipase D participates in signal transduction pathways responsive to gamma-radiation.

Early responses of mammalian cells to ionizing radiation include the activation of a protein kinase C implicated in the regulation of gene expression, the stimulation of tyrosine kinase activities, and the enhancement of phosphatidylinositol turnover. In the present report we show that clinically relevant doses of gamma-radiation (2 Gy) stimulate phosphatidylcholine hydrolysis in human squamous carcinoma cells. Radiation induced the accumulation of intracellular [3H]choline and the simultaneous increase in [3H]myristoyl-phosphatidic acid, followed by a small increase in the levels of [3H]myristoyl-diacylglycerol. Furthermore, in the presence of ethanol, gamma-radiation stimulated the appearance of [32P]phosphatidylethanol, an indicator of phospholipase D transphosphatidylation activity. These data demonstrate for the first time that phospholipase D activation participates in signaling pathways in response to gamma-radiation.

Carcinoma, Squamous Cell↗
PubMed1993

[Bladder fibroma. Report of a case].

Analysis of one case of benign vesical primitive connective tumour, with pathoanatomical description of vesical fibroma. The interest of this case rests on its rarity and uncertain origin, still subject to controversy. The paper presents the tumour's clinical history, pathological anatomy, therapeutical approach and prognosis.

Female↗
PubMed1993

[Antimicrobial prophylaxis in urethrocystoscopy. Comparative study].

Instrumentation of lower urinary tract is a predisposing factor for the development of urinary infection. Incidence of infective complications following urethrocystoscopy has been evaluated in a multicenter, prospective, comparative and randomized study in 2,284 patients, who had a previous negative urine culture. Patients were randomized into two groups: one to be used as control and the other one to received antimicrobial prophylaxis prior to instrumentation (ceftriazone, 1 gr intramuscular). Clinical and microbiological responses were evaluated at 48-72 hours and 4 weeks after cystoscopy. Symptomatic bacteriuria was observed in 10.2% of patients in the control group and in 2.5% in the prophylaxis group (p < 0.000); asymptomatic bacteriuria in 3.02% and 1.52% (p > 0.05) and irritative syndrome with sterile urine in 2.93% and 2.60% (p > 0.05), respectively. Thus, the use of prophylaxis reduced the incidence of infective complications in these patients.

Adolescent↗
PubMed1975

Polarity coincidence correlation coefficient and signal energy ratio of the ongoing EEG activity. II. Brain tumors.

The asymmetry of the EEG in 35 patients with brain tumor was analyzed using a special purpose computer which provided two measures: Polarity Coincidence Correlation Coefficient (PCC) and Signal Energy Ration (SER). Significant differences were found between this group and a control group of normal subjects. A discriminant function was calculated using both measures and gave an overall separation accuracy of 87% in the sample studied. It was concluded that the method described offers great utility in routine screening and diagnosis of brain tumors.

Adolescent↗
PubMed1975

Polarity coincidence correlation coefficient and signal energy ratio of the ongoing EEG activity. III. Cerebral vascular lesions.

The EEG symmetry of 65 patients with different kinds of cerebrovascular disorders was analyzed using the Polarity Coincidence Correlation Coefficient (PCC) and the Signal Energy Ratio (SER) measurements. Significant differences were found between the pathology group and a control group of normal subjects for both measures. A discriminant function was applied for both values with an overall accuracy of 80%. It is concluded that since the method does not require an experienced electroencephalographer it may be useful for the diagnosis of cerebrovascular pathology and for screening purposes.

Adolescent↗