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Biomedical subjects

P Peña

Publications and source records attributed to P Peña.

At least 19 recordsLinked to original sources
PubMed1998

The transcription factor GHF-1, but not the splice variant GHF-2, cooperates with thyroid hormone and retinoic acid receptors to stimulate rat growth hormone gene expression.

The rat growth hormone (GH) promoter was significantly activated in non-pituitary cells by the expression of unliganded trioodothyronine (T3) and retinoic acid (RA) receptors. Furthermore, a strong ligand-dependent activation was found in the presence of the pituitary-specific transcription factor GHF-1. When compared with GHF-1, the splice variant GHF-2 showed a decreased ability to bind the cognate site in the GH promoter. As a consequence, expression of GHF-2 had little stimulatory effect on the GH promoter and did not show cooperation with T3 or RA receptors even in the presence of ligands. Furthermore, over-expression of GHF-2 inhibited the response to T3 and RA in pituitary cells. These results show that alternative splicing of the GHF-1 gene gives rise to two isoforms that differ in their transactivating properties and in their ability to synergize with the nuclear thyroid hormone and retinoic acid receptors on GH gene expression.

Alternative Splicing↗
PubMed1997

[Viridans streptococci isolated from cerebrospinal fluid. Clinical significance of 9 cases].

Viridans streptococci (VS) are often isolated from cerebrospinal fluid (CSF). However, the significance of such isolates is poorly understood. In the present study we carry out a retrospective analysis of 9 patients in whom VS were isolated from CSF during a 1-year period at La Paz Hospital. Two patients (22.2%) had meningitis diagnosed through clinical, laboratory and bacteriologic findings. Both patients had predisposition diseases (previous difficult spinal tap, ventriculo-peritoneal shunt). The other isolations were considered as contaminants. Three patients (33.3%) with no VS meningitis had other different serious disease (sepsis without bacteriologic confirmation). VS are isolated with relative frequency from CSF, although they cause meningitis in less than one-quarter of the cases (those who have a predisposition disease). In the other cases, VS are isolated as contaminants of CSF and other disease should be search as cause of patient symptoms.

Adolescent↗
PubMed1997

Destructive herpetic whitlow in AIDS: report of three cases.

Herpes simplex virus infection in immunocompromised individuals, including AIDS patients, is characterized by its tendency for atypical presentations and unusual locations, often resulting in delayed diagnosis and treatment. Three HIV-infected patients who developed prolonged cutaneous lesions of the fingers are presented. These lesions were unmodified by previous antibiotic treatment, and rapidly progressed to the complete destruction of nail structures in two patients. Viral culture confirmed the diagnosis of herpetic whitlow in all cases, and treatment with oral acyclovir resulted in complete recovery. Surgical treatment was not necessary.

AIDS-Related Opportunistic Infections↗
PubMed1996

Hypophysial and extrahypophysial projections of the neurosecretory system of cartilaginous fishes: an immunocytochemical study using a polyclonal antibody against dogfish neurophysin.

Immunocytochemistry using antibodies against the neurohypophysial nonapeptides has given equivocal results regarding relevant aspects of the classical neurosecretory system of elasmobranchs. The lack of antibodies reacting with the elasmobranch neurophysins (Nps) has prevented the study of this neurosecretory system by Nps immunocytochemistry. This led us to purify Nps from Scyliorhinus canicula, and to use them to raise a polyclonal antibody. This antibody reacted strongly with the elasmobranch neurophysin neurons, revealing their most delicate and distant hypophysial and extrahypophysial projections. A detailed mapping of the neurosecretory system of five elasmobranch species (Etmopterus spinax, Squalus acanthias, Scyliorhinus canicula, Galeus melanostomus, Raja radiata) and one holocephalian species (Hydrolagus colliei) was performed. In elasmobranchs, the magnocellular neurophysin cells formed a distinct preoptic nucleus, whereas in Hydrolagus the immunoreactive cells were scattered. Distinct parvicellular neurophysin cells were present in the preoptic nucleus. In Raja the nucleus "O" contained parvicellular Nps-immunoreactive neurons. The findings at the pituitary level point to the possibility that neurophysin neurons, in addition to releasing nonapeptides into the systemic capillaries of the neural lobe, also participate in the regulation of the function of the rostral, medial and intermediate lobes of the adenohypophysis by a dual mechanism, i.e., a neurovascular pathway and a direct neural input. The extrahypophysial projections of the neurophysin neurons were highly developed to a degree not comparable to any other vertebrate group. The targets of these projections were located in the telencephalon, diencephalon and hindbrain. The evolutionary and functional implications of this phenomenon are discussed.

Animals↗
PubMed1996

[Epilepsy and dementia. An atavistic association].

We carried out a brief historical review as to the meaning of the association between epilepsy and dementia and of 'epileptic dementia'. We also reviewed the literature published in the last decade on this theme, analyzing whether chronic recurrence of epileptic fits brings about cognitive deterioration. We concluded by affirming that 'epileptic dementia' was a mixed bag containing numerous diseases and syndromes with symptoms of both. Only exceptionally could epileptic fits bring on cognitive deterioration and this usually only slight. A great many factors and not just recurrent epileptic fits determine cognitive prognosis in epileptics.

Cognition Disorders↗
PubMed1995

Analysis of the mitochondrial ATP synthase beta-subunit gene in Drosophilidae: structure, transcriptional regulatory features and developmental pattern of expression in Drosophila melanogaster.

We have cloned and determined the structure of the gene encoding the H(+)-ATP synthase beta subunit in two distantly related Drosophila species, D. melanogaster and D. virilis. The gene contains three exons that are extremely well conserved at the amino acid level, not only in the region encoding the mature protein but also in that encoding the leader peptide. Primer extension analysis indicates that the 5' untranslated region is extremely short, and reveals the presence of multiple initiation sites of transcription in both Drosophila species. The promoters of D. melanogaster and D. virilis H(+)-ATP synthase beta-subunit genes contain a conserved region surrounding the initiation transcription sites. Nucleotide sequence analysis has revealed the absence of canonical TATA and CCAAT boxes and the presence of several putative regulatory elements in both promoter regions, including GAGA, GATA and Ets binding sites. We have analysed the pattern of gene expression during D. melanogaster development. The mRNA is stored in oocytes, and activation of transcription takes place after 10 h of development. The expression of the nuclear-encoded H(+)-ATP synthase beta subunit is strictly coordinated with the expression of subunits 6 and 8 of the same complex that are encoded in the mitochondrial genome.

Amino Acid Sequence↗
PubMed1995

Composition of sulfited potatoes: comparison with fresh and frozen potatoes.

The content in moisture, fat, protein, carbohydrate, fibre and vitamin C was analyzed in three commercial types of potatoes: sulfited (treated with E223), frozen potatoes (pre-fried) and fresh potatoes (not processed). The composition of sulfited potatoes does not usually appear in food composition tables. Our results showed significant differences in the content of carbohydrates and fibre between sulfited and fresh potatoes. The content of vitamin C in sulfited potatoes, which is similar to that of frozen potatoes, was shown to be approximately half of that found in fresh potatoes.

Ascorbic Acid↗
PubMed1994

Bacteraemia caused by Campylobacter spp.

The genus Campylobacter has become increasingly recognised as the cause of various infections. Campylobacter jejuni and C coli cause acute gastroenteritis in man all over the world. C jejuni enteritis can lead to bacteraemia, but its actual incidence remains unknown. Seven cases of bacteraemia caused by C jejuni or C coli are reported, from the blood of seven patients: five immune deficient adults; a newborn baby; and a patient who had had abdominal surgery. Patients who develop diarrhoea as a result of Campylobacter infection are at risk of bacteraemia thereafter.

Adolescent↗
PubMed1993

The beta subunit of the Drosophila melanogaster ATP synthase: cDNA cloning, amino acid analysis and identification of the protein in adult flies.

The cDNA encoding the Drosophila melanogaster beta subunit of H+ ATP synthase has been cloned and sequenced. The predicted mature protein is highly homologous to the equivalent beta subunits of other organisms and is preceded by a signal peptide of 31 amino acids, that although not conserved at primary sequence level has the characteristics of leader peptides present in other mitochondrial proteins. We have raised polyclonal antibodies that specifically recognize the beta H+ ATP synthase subunit present in Drosophila melanogaster protein extracts. This is the first time that a gene of the ATP synthase complex has been characterized in the invertebrate phyla.

Amino Acid Sequence↗
PubMed1993

Mitochondrial DNA remains intact during Drosophila aging, but the levels of mitochondrial transcripts are significantly reduced.

It has been suggested that mutations accumulated in mitochondrial DNA during the aging process may be causally related to the decreased physiological response of the senescent organisms. We have quantified and evaluated the integrity of the mitochondrial genome during the life span of Drosophila melanogaster. Its amount remains fairly constant representing roughly 1% of the total DNA at all ages. Southern experiments have also revealed a high stability and integrity of the mitochondrial DNA (mtDNA). However, we have detected an important decrease in the steady-state levels of all mitochondrial transcripts investigated: 16 S ribosomal RNA (16SrRNA), cytochrome c oxidase, cytochrome b, and beta H(+)-ATP synthase subunit. These changes correlate with the shape of the life span curve, preceding the decrease in survival of the male flies used in the study, and at least in the case of 16SrRNA, is tissue-specific. Although mitochondrial DNA remains unchanged in heads, thoraces, and abdomens, 16SrRNA levels decrease more severely in heads and thoraces and much less conspicuously in abdomens. On the other hand, control non-mitochondrial transcripts investigated remain essentially unaffected. These results suggest that in Drosophila the main effect of aging on the mitochondrial genetic system is downstream from mtDNA itself. The decline in the levels of beta H(+)-ATPase transcript, nuclear-encoded, suggests that not only the mitochondrial machinery, but also the nuclear one involved in mitochondrial biogenesis, is affected during aging.

Aging↗
PubMed1992

First seizure in adults: a prospective study from the emergency department.

A prospective study of 98 consecutive adults with a first seizure to determine the most important etiological factors and the optimum diagnostics. 27 were thought to have cryptogenic seizures. Main causes of symptomatic seizures were: cerebral infarction, alcohol-withdrawal, CNS infections, tumors, vascular malformations, traumatism and miscellanea. Eight were infected by human immunodeficiency virus (HIV-1) representing 8.2% of all the patients with a first seizure and 20% of the 15-45-year age group. CT disclosed structural lesions in 33 cases. MRI in those with normal CT and no other explanation of seizure revealed additional lesions in 22.2%, but did not change management in any. We conclude that CT is essential in evaluation of adults with first seizure. MRI may be useful in selected cases. The HIV-infected now represent an important group with a first seizure.

Adolescent↗
PubMed1992

[The usefulness of two-dimensional echocardiography in the diagnosis of an interventricular aneurysm].

The ventricular septal defect (VSD) may close spontaneously in the first few years of life. The closure occurs by muscle's growth of the borders of the defect or by the appearance of an aneurysm of ventricular septum composed mostly by tricuspid tissue. We believe that the two-dimensional echocardiography is the best method to determine the mechanisms that take part in the aneurysm formation. The study was carried out on 58 patients with aneurysms of ventricular septum observed in 230 patients with ventricular septal defects. 29 were male and 29 were female patients. The mean age at the time of diagnosis of aneurysm was 30 months (range 1 month-13 years). Forty seven patients had a perimembranous ventricular septal defect (perimembranous inlet 29, perimembranous trabecular nine, perimembranous outlet nine and of mixed's type seven), muscular defect nine (muscular inlet seven, and muscular trabecular two) and VSD closed in two. The size of the defect was 0.47 +/- 0.2 cm (range 0.2-1.1). In 16 the defect was larger than 0.6 cm. Thirty two patients had associated anomalies. On study the aneurysm in relation with tricuspid valve leaflets: in 27 cases (46.3%), the aneurysm was entirely formed by tricuspid septal leaflets tissue (17 had perimembranous ventricular septal defect and seven muscular), in eight (13.6) the aneurysm had tricuspid valve leaflets and interventricular component of the membranous septum tissue (five perimembranous defect and two muscular) and in another 16 cases membranous septum tissue only. In 7 patients the origin of the aneurysm wasn't confirmed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Nosocomial bacteremia caused by Serratia marcescens: analysis of 44 cases].

We have evaluated 44 cases of Serratia marcescens bacteremia (SB). Most took place in surgical services (57%) and the ICU (34%). In one occasion, the cases developed as an epidemic outbreak. SB basically developed in patients with underlying diseases (neoplasia in 32%, heart disease in 16%, chronic bronchitis in 14% and miscellaneous in 20%) in whom some invasive procedure had been carried out (98%). The most common complication was septic shock. In 17 cases the infection was polymicrobial. The most common serogroup was 0:5 (41%). 98% of strains were resistant to cephalothin, 78% to ampicillin and 29% to tobramycin. The mortality rate was 39% and the most common cause of death was septic shock. The factors which adversely influenced prognosis were as follows, in order of decreasing importance: leukocytosis, thrombopenia, associated gram-positive infection, age older than 65 years, "non-typable" serogroup, unknown portal of entry, epidemic case and septic shock.

Adult↗
PubMed1988

Effects of colchicine on the hypothalamo-neurohypophysial system of chronically salt-loaded rats.

The effect of colchicine on the hypothalamo-neurohypophysial system of rats drinking 2% NaCl for 4, 6, or 90 days was investigated. Colchicine was injected at time 0 for the 4-day group and 48 h before sacrifice for the 6- and 90-day groups. Each experimental group was divided into two subgroups that were injected with 7 micrograms colchicine into either the cisterna magna or the lateral cerebral ventricle. The hypothalamo-neurohypophysial system was investigated immunocytochemically using an antiserum against both neurophysins (NPs) as primary antibody. The arginine vasopressin content of the neural lobe (NL) of rats salt loaded for 4 days and injected with colchicine on days 0 and 3 was determined by radioimmunoassay. The amount of immunoreactive NPs in the supraoptic nucleus, the paraventricular nucleus, and in the NL was decreased in salt-loaded rats. In salt-loaded rats injected with colchicine into the lateral ventricle, a substantially larger amount of immunoreactive NPs was present in these three areas. However, when colchicine was injected into the cisterna magna, only the supraoptic nucleus appeared loaded with immunoreactive NPs, while NPs were depleted from the paraventricular nucleus. In the NL of rats salt loaded for 90 days immunoreactive NPs were diminished markedly, and axon swellings (Herring bodies) had virtually disappeared. Colchicine treatment of these rats caused an increase of immunoreactive NPs in the NL approaching control values and a reappearance of a large number of axon swellings. Results similar to those obtained with immunohistochemistry for NPs were obtained when determining the arginine vasopressin content of the NL by radioimmunoassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Immunohistochemical investigation of the magnocellular peptidergic hypothalamo-neurohypophysial system of the rat chronically stimulated by long-term administration of hypertonic saline.

The hypothalamic supraoptic (SON) and paraventricular nuclei (PVN), median eminences (ME) and neural lobes (NL) of normally hydrated control rats (group 1), and of rats drinking 2% NaCl for 7 (group 2), 30 (group 3) or 90 days (group 4) were investigated using immunohistochemistry for neurophysins (NP), arginine vasopressin (AVP) or oxytocin (OXY). Animals from the 3 experimental groups showed equivalent decreased levels of immunoreactive NP in the SON and PVN, but the greatest decrease was in the SON. Dendrites of SON and PVN neurons became loaded progressively with immunoreactive NP, AVP and OXY as salt loading proceeded. In rats of group 2, axons leaving the SON and PVN showed a marked depletion of immunoreactive material. The latter was found mainly at the periphery of widely spaced axonal swellings, clearly contrasting with the small and narrowly spaced beads of the neurosecretory axons of control rats. In rats of groups 3 and 4, axons leaving the SON and PVN resembled those of control rats. In the ME of the animals in all experimental groups, the same degree of decrease of immunoreactive NP was observed. In rats of group 3, bundles of axons containing immunoreactive AVP and OXY frequently projected through the ependymal lining of the ME into the third ventricle. In the NL of all experimental animals, a marked decrease occurred in the amount of immunoreactive NP, AVP and OXY. The decrease of immunoreactive AVP, however, was more pronounced in rats of group 2 than in those of groups 3 and 4. The NL of rats in group 4 were approximately 80% larger than those of control rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗