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T Tuñón

Publications and source records attributed to T Tuñón.

At least 19 recordsLinked to original sources
PubMed2006

High promoter hypermethylation frequency of p14/ARF in supratentorial PNET but not in medulloblastoma.

AIMS: Medulloblastoma (MB) is the most common primitive neuroectodermal tumour (PNET) of the central nervous system. Although supratentorial PNET (sPNET) and MB are histologically similar, their clinical behaviour differs, sPNET being more aggressive than MB. The aim of this study was to determine whether sPNET and MB are genetically different entities. METHODS AND RESULTS: We investigated 32 PNET primary tumour samples (23 MB and nine sPNET) and four PNET cell lines, for the presence of CDKN2A homozygous deletions at exon 1-alpha of p16/INK4 and exon 1-beta of p14/ARF, and promoter hypermethylation of both genes. No homozygous deletion of either p16/INK4 or p14/ARF was demonstrated in any of the PNET primary tumour samples. Methylation of p16/INK4 was found in one of six sPNET and in one of 23 MB, while p14/ARF methylation was observed in three of six sPNET and in three of 21 MB. No methylation of p16/INK4 or p14/ARF was found in any of the PNET cell lines analysed. The three MB cell lines did not show p16/INK4 expression, and only the MB Daoy cell line (homozygously deleted at CDKN2A) presented loss of p14/ARF expression. CONCLUSIONS: Our results in this limited series of central PNET show that p14/ARF is frequently involved in PNET carcinogenesis, with a higher frequency, but not statistically significant, for sPNET than for MB.

Cell Line, Tumor↗
PubMed2005

Genetic heterogeneity in supratentorial and infratentorial primitive neuroectodermal tumours of the central nervous system.

AIMS: Medulloblastoma (MB), a kind of infratentorial primitive neuroectodermal tumour (PNET), is the most frequent malignant brain tumour in childhood. In contrast, supratentorial PNET (sPNET) are very infrequent tumours, but they are histologically similar to MB, although they present a worse clinical outcome. We investigated the differences in genetic abnormalities between sPNET and MB. METHODS AND RESULTS: We analysed 20 central PNET (14 MB and six sPNET) by conventional comparative genomic hybridization (CGH) in order to determine whether a different genetic profile for each tumour exists. Isochromosome 17q was detected in four of the 14 MB cases, but not in any sPNET. Gains at 17q and 7 happened more frequently in MB, and those at 1q in sPNET. Losses at chromosome 10 were detected only in MB, while losses at 16p and 19p happened more frequently in sPNET. A new amplification site, on 4q12, was detected in two MB. CONCLUSIONS: Central PNET are a heterogeneous group of tumours from the genetic point of view. The present and previous data, together with further results from larger series, might contribute to the establishment of specific treatments for supratentorial and infratentorial PNET.

Brain Neoplasms↗
PubMed2000

Single large-scale mitochondrial DNA deletion in a patient with encephalopathy, cardiomyopathy, and prominent intestinal pseudo-obstruction.

We studied a 62 year-old woman with a clinical phenotype characterized by encephalopathy, restrictive cardiomyopathy, and prominent intestinal pseudo-obstruction. Muscle morphology showed ragged red fibres with ultrastructurally abnormal mitochondrial whereas muscle respiratory chain was normal. Molecular genetics revealed the 'common deletion' in mtDNA, which represented 40% of total mtDNA. These data expand and confirm the wide clinical spectrum of mitochondrial disorders associated with single large-scale mtDNA deletions.

Cardiomyopathies↗
PubMed1998

Eosinophilic gastroenteritis and Anisakis.

BACKGROUND: The differential diagnosis of eosinophilic gastroenteritis (EG) includes, among other diseases, parasitic infections such as anisakiasis, which has acquired worldwide importance. METHODS: We reviewed all patients referred to our allergy service who had been diagnosed as having primary EG to determine the possible role of Anisakis simplex in the etiopathology of the disease. All patients (n = 10) were studied and diagnosed as having primary EG between 1989 and 1996, inclusive. Two different groups of subjects were used as controls: group A (149 subjects without digestive disorder) and group B (10 subjects with digestive disorder different from EG). Cutaneous prick tests were performed with the main foods, aeroallergens, and commercial extract of A. simplex. Total and specific serum IgE was measured in all patients. Gastric or gut histologic specimens were re-examined in five cases. RESULTS: Peripheral eosinophilia was detected in 40% of the patients with EG, and sensitization to A. simplex was detected in 80% of these. In both control groups, the rate of sensitization to A. simplex was 10%. Sensitization to A. simplex in EG patients with respect to control groups A and B showed odds ratios (OR) of 36 and 40, respectively. In one case, serialization of the histologic section allowed us to observe a whole Anisakis larva. CONCLUSIONS: Immunologic methods to detect specific antibodies against Anisakis should be used routinely before diagnosing EG as primary disorder. Preventive measures are of capital importance.

Animals↗
PubMed1995

The human entorhinal cortex: a cytoarchitectonic analysis.

The entorhinal cortex of man is in the medial aspect of the temporal lobe. As in other mammalian species, it constitutes an essential component of the hippocampal formation and the route through which the neocortex interacts with the hippocampus. The importance of knowing its architecture in detail arises from the possibility of extrapolating it to experimental findings, notably in the nonhuman primate. We have investigated the cytoarchitectonic features of the human entorhinal cortex by using as a base our previous study (D.G. Amaral, R. Insausti, and W.M. Cowan [1987] J. Comp. Neurol. 264:326-355) of the nonhuman primate entorhinal cortex. We prepared serial sections of the temporal lobe from 35 normal brains. Thionin- and myelin-stained series were made of all cases. Sections spaced 500 microns apart through the full rostrocaudal extent of the entorhinal cortex were analyzed. The human entorhinal cortex is made up of six layers, of which layer IV does not appear throughout all subfields of the entorhinal cortex. The overall appearance resembles that of the adjacent neocortex in lateral and caudal portions. In harmony with general structural principles in the nonhuman primate entorhinal cortex, our analysis supports the partitioning of the human entorhinal cortex into eight different subfields. (1) The olfactory subfield (EO), the rostralmost field, is little laminated. (2) The lateral rostral subfield (ELr), laterally located, merges with the laterally adjacent perirhinal cortex. (3) The rostral subfield (ER) is between EO and ELr, with better differentiation of layers II and III than EO. (4) The medial intermediate subfield (EMI) is located at the medial border. (5) The intermediate field (EI) is a lateral continuation of EMI; lamina dissecans (layer IV) can be best appreciated in this field. (6) The lateral caudal subfield (ELc) laterally borders on EI as a continuation of ELr. (7) The caudal subfield (EC) lies caudal to the beginning of the hippocampal fissure, with a distinctive, clear space (Vc) between layers V and VI. (8) The caudal limiting field (ECL) forms the caudal termination of the entorhinal cortex. Thus our parcellation of the entorhinal cortex in man is largely parallel to that arrived at in the monkey. This close homology provides a rational basis for the application to clinical problems of anatomical and functional information obtained in experimental work in nonhuman primates.

Adolescent↗
PubMed1995

Chronic alcoholism decreases neuronal nuclear size in the human entorhinal cortex.

The effect of chronic alcoholism in the neuronal nuclear area (karyometry) of the lateral entorhinal cortex at three rostro-caudal levels (rostral, intermediate and caudal) has been studied in 19 alcoholic subjects and in 15 aged-matched controls. Cases were distributed into three groups according to their age (29-44, 45-60 and 61-70 years of age). In the second group (45-60 years), the nuclear size in layers II and III of the caudal entorhinal cortex showed a very significant decrease compared to controls. The first group (29-44 years) also showed a significant reduction in size, while the third group presented the smallest differences. The presence of cirrhosis in the alcoholic group did not vary the observed results. Thus, chronic alcoholism significantly decreases the nuclear size in layers II and III of the lateral entorhinal cortex, and thus the entorhinal output to the hippocampus may be altered in alcoholism.

Adult↗
PubMed1995

Bilateral pallidostriatal necrosis caused by a wasp sting: a clinical and pathological study.

A previously healthy man developed an acute encephalopathy with coma after a single wasp sting on his chin. Brain CT showed bilateral pallidostriatal radio-lucencies. He died 72 hours after the sting with no evidence of primary cardiorespiratory failure or allergic reaction. Pathological findings were bilateral pallidostriatal necrosis and diffuse neuronal damage in the frontal, temporal, and parietal cortex. The neurotoxic effect of the poison, together with a hypersensitivity are the most likely explanations for this unusual encephalopathy.

Aged↗
PubMed1993

Calbindin D-28k and parvalbumin immunoreactivity in the frontal cortex in patients with frontal lobe dementia of non-Alzheimer type associated with amyotrophic lateral sclerosis.

The morphology and distribution of local-circuit neurons (interneurons) were examined, by calbindin D-28k and parvalbumin immunocytochemistry, in the frontal cortex (area 8) in two patients with frontal lobe dementia of non-Alzheimer type associated with classical amyotrophic lateral sclerosis (ALS), and in seven normal cases. The density of calbindin D-28k immunoreactive cells was dramatically reduced in ALS patients, but the density of parvalbumin-immunoreactive neurons was preserved. Decreased density of calbindin D-28k-immunoreactive neurons, which are mainly located in the upper cortical layers, may interfere with the normal processing of cortico-cortical connections, whereas integrity of parvalbumin-immunoreactive cells may be associated with the preservation of the major inhibitory intracortical circuits in patients with frontal lobe dementia.

Adult↗
PubMed1993

[Massive lower digestive hemorrhage caused by colonic ulcers secondary to cholesterol embolism].

Cholesterol crystal embolization has been considered an unusual entity with poor short term prognosis. However, it is an underestimated complication according to post-mortem findings. Patients have quite characteristic risk and precipitating factors which may be an aid to suspect the diagnosis. Gastrointestinal bleeding of different severity occurs in only 10% of patients with visceral embolization. We present the case of a patient with massive lower gastrointestinal bleeding secondary to several ulcerations in the hepatic flexure due to bowel cholesterol embolization.

Aged↗
PubMed1992

Parvalbumin and calbindin D-28K in the human entorhinal cortex. An immunohistochemical study.

Research is here reported on the distribution of immunoreactivities of the calcium-binding proteins parvalbumin and calbindin D-28K in the entorhinal cortex of normal human brains. Topographically, parvalbumin immunoreactive neurons were only seen in the lateral portion of the rostral entorhinal cortex, in continuity with the adjacent perirhinal cortex. The intermediate and caudal portions gave positive results along the mediolateral extension of the entorhinal cortex. The laminar distribution of parvalbumin immunoreactive neurons was similar throughout the entorhinal cortex. Heavy immunostaining, largely coincident with cell islands, was observed in cells and fibers in layer II, being densest in the deep half of layer III and more sparsely distributed in layers V and VI. Calbindin D-28K immunoreactivity was found throughout the entorhinal cortex. In contrast to parvalbumin immunoreactivity, calbindin D-28K was present from layer I up to upper layer III, the neurons being most numerous in the cell islands of layer II. These results show that rostromedial portions of the human entorhinal cortex contain calbindin immunoreactivity, but not parvalbumin, while the lateral, intermediate and caudal portions of the entorhinal cortex contain both calcium-binding proteins. As it is known that these two proteins belong to a subset of GABAergic neurons, we suggest that a topographical diversity in some of the cells may be responsible for inhibitory effects in the human entorhinal cortex. This proposed diversity might be relevant to the processing of information that the entorhinal cortex conveys to the dentate gyrus and receives from various components of the hippocampus, the subicular complex and other cortical and subcortical sources.

Calbindins↗
PubMed1992

Calbindin immunoreactivity in normal human temporal neocortex.

Calbindin immunoreactivity in the temporal neocortex was examined in 4 subjects with no neurological, metabolic or malignant disease. The brains were obtained between 1 and 4 h after death and rapidly fixed by perfusion with 4% paraformaldehyde through the carotid arteries, cut into slabs, cryoprotected and stored at -80 degrees C. Sections of the whole left temporal lobe obtained with a freezing microtome were processed free-floating with a well known monoclonal antibody against calbindin according to the peroxidase-antiperoxidase (PAP) method. Calbindin-immunoreactive (CaBP-ir) neurons were found to be local-circuit neurons (interneurons) mainly distributed in the upper cortical layers (layers I, II and III), and were categorized as small multipolar neurons with ascending dendrites ramifying in the molecular layer, small bitufted cells, pyramid-like cells in layer II, horizontal neurons in the molecular layer, multipolar neurons with long descending dendrites, and large double-bouquet cells, some of them exhibiting a very long dendrite with claw-shaped terminals in layer V. Less than 10% of all CaBP-ir neurons were localized in the remaining cortical layers. Pyramidal cells were only very weakly or not stained at all. In addition, CaBP-ir fibres formed a dense plexus in the molecular layer, and vertical bundles 8-10 microns thick and 500-600 microns long, separated by blank spaces 20-40 microns wide were distributed in layers III and V/VI.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Abnormal muscle and skin mitochondria in family with myoclonus, ataxia, and deafness (May and White syndrome).

A mother and two of her daughters had deafness and cortical reflex myoclonus; the mother also had mild truncal ataxia. Muscle and skin biopsy specimens revealed abundant ragged-red fibres and abnormal mitochondria. The son of one of the daughters had sensorineural deafness. Three other grandchildren were asymptomatic. The two daughters also had diabetes mellitus, hypertension and cardiomyopathy. Another daughter died of renal failure. The mother lost her hearing in her 70s, one daughter in her 30s, and the other daughter and the grandson in their 20s. The mother has had transient episodes (24-48 hours) of temporal disorientation, severe action myoclonus, and ataxia for about eight years. This is the first reported family with inherited deafness, myoclonus, and ataxia with mitochondrial pathology.

Adolescent↗
PubMed1991

Parvalbumin immunoreactive neurons in normal human temporal neocortex and in patients with Alzheimer's disease.

Parvalbumin-immunoreactive (PARV-ir) neurons were studied in the temporal neocortex of 4 normal subjects and in 7 patients with Alzheimer's disease (AD) whose brains were removed from the skull between 1 and 4 h after death and immediately fixed by perfusion through the carotid arteries to minimize pitfalls related to delayed tissue processing. Freezing microtome sections were immunostained free-floating for PARV using a well characterized monoclonal antibody diluted at 1:5000 and the peroxidase-antiperoxidase method. PARV-ir cells predominated in layers III, IV and V and were classified as bitufted cells and small, medium and large multipolar neurons according to their dendritic arbors. Immunoreactive cell processes surrounding the soma of neighbouring cells and immunoreactive vertical strings of buttons were consistent, respectively, with terminal axons of basket cells and chandelier neurons. The number of PARV-ir cells in the superior (T1), middle (T2) and inferior (T3) temporal gyri was variable from one case to another in both normal and pathological cases. Only 1 of 7 patients with AD had significantly reduced numbers of PARV-ir neurons, thus suggesting that PARV-ir cells in the neocortex are relatively resistant to degeneration in Alzheimer's disease.

Aged↗
PubMed1990

Neuronal alterations in patients with dementia: a Golgi study on biopsy samples.

Golgi-impregnated neurons in biopsy samples of the cerebral cortex (area 8) of patients with Alzheimer's disease (AD), Pick's disease (PD) and Creutzfeldt-Jakob disease (CJD), but not in control samples, have swellings in the proximal and mid regions of dendrites of pyramidal and non-pyramidal cells that differ from normal dendritic varicosities. Dendritic outgrowths, isolated or in clusters, and covered with spines occur only in neurons with reduced dendritic arbors mainly located in the vicinity of senile plaques. Degenerating pyramidal and non-pyramidal neurons, although distributed throughout the cerebral cortex in CJD and PD, predominate in layers II, III and VIb in patients with AD.

Adult↗
PubMed1987

Necrotising haemorrhagic encephalomyelopathy in an adult: Leigh's disease.

A 21 year old male, well-nourished and non-alcoholic, died after five weeks illness. He had suffered epileptic fits, bilateral internuclear ophthalmoplegia, bulbar and pontine paralysis, tetraparesia, ataxia and dystonia. A CT brain scan showed low density lesions of the striatum bilaterally. Post-mortem studies revealed pathological anomalies compatible with Leigh's disease, although the presence of haemorrhages and involvement of the mamillary bodies could also suggest Wernicke's encephalopathy.

Adult↗