Biomedical subjects

R Insausti

Publications and source records attributed to R Insausti.

58 records · Page 4Linked to original sources

PubMedDate not supplied

[Senescence process of mnesic centers: a study in humans and rats].

The age-related neuronal changes in mnemonic centres were studied in 37 human and 36 rats (Wistar) brains. The age of the brains (without cerebral alterations) was uniformly distributed along the lifespan (16-86 years in humans and 1-36 months in rats). The results showed parallel changes in humans and rats. The neuronal loss oscillated between 3 and 64%, mean 32%. Neuronal death was a continuous process, although there were differences according the centres, for instance, the higher loss was found in the first half of life in the cortex entorhinalis and hippocampus (rat), and the contrary happened in the dorsolateral and basomedial nucleus of amygdala. In other centres, e.g., mamilla body, basal nucleus of Meynert etc. the loss was quite uniform. The modification in nuclear size showed 3 different phases: there was an initial period in which the nuclear area decreased, a second period with an increase and, in the last period, there was a stabilization in humans and a conspicuous decrease in rats. The nuclear enlargement is interpreted as result of the loss of redundance in nervous centres and the stabilization or atrophy as a consequence of loss of the neuronal plasticity.

Adolescent↗

PubMedDate not supplied

[Production and characterization of a monoclonal antibody that selectively marks the astrocyte population in the central nervous system].

The development of a monoclonal antibody that selectively labels the astrocitic population of the central nervous system in the three species tested (human, monkey and rat) is described. The tissue used as immunogen consisted in a sector of the human hippocampus (CA1) from a brain removed shortly after death. The neuropathological examination in this case revealed an congophilic angiopathy. The tissue was frozen until homogenezation and intraperitoneal injection in 8 weeks old BALB/C mice, after which lymphocytes from the spleen were fused with NS-1 myeloma cells devoid of the enzyme Hypoxantine Guanine Phosphoribosyl Transferase (HPGT (-)) following standard procedures. The resulting hybridomas were tested by ELISA assays, immunofluorescence and immunohistochemical (PAP and ABC) techniques. The monoclonal antibody obtained was identified as an IgM and the Western blot analysis indicated that it recognizes a protein of 43,000 dalton. Immunohistochemistry was performed in 30 or 50 microns sections of human temporal lobe perfused through the carotid arteries with a mixture of 4% paraformaldehyde and 0.02% picric acid. Monkey tissue (sectioned at 50 microns) was obtained from a brain with the same fixation. Rat tissue followed the same protocol, although better results were seen after shifting to 1% paraformaldehyde and 1.25% glutaraldehyde (sections were 30 microns thick). Paraffin embedded human tissue (fixed in either 10% buffered formalin or in 4% paraformaldehyde) was also tested. All immunoreactions were intensified in a solution of osmium tetroxide and thiocarbohydrazide. The monoclonal antibody gave best results at a dilution of 1:50-100, where it gave a sharp labeling of both fibrous and protoplasmic astrocytes up to the most delicate processes, both in white and the grey matter. Rat tissue fixed in only 4% paraformaldehyde resulted in less optimal labeling, mostly restricted to limiting glia and Bergmann glia. The other fixation protocol (1% paraformaldehyde and 1.25% glutaraldehyde) gave a labeling comparable to monkey and human tissue. Paraffin embedded tissue was positive and similar to that obtained in frozen tissue, only when used the 4% paraformaldehyde fixation, but not when it was fixed in 10% formalin. Therefore, this monoclonal antibody has high specificity for the astrocitic population in the nervous system of mammals and it can be useful in a variety of studies of the normal and pathological situations of the nervous system.

Aged↗

PubMedDate not supplied

[Quantitative volumetric analysis of the hippocampus, amygdala and entorhinal cortex: normative database for the adult Portuguese population].

INTRODUCTION: Atrophy of the hippocampus, amygdala and entorhinal cortex can be found in neurodegenerative diseases, head trauma and epilepsy and are expressed by means of volume reductions. The ability to detect these changes quantitatively depends on accurate comparisons with normative databases. AIM: To present standard magnetic resonance imaging (MRI) volumes of the mesio-temporal lobe structures and an objective statistical methodology for contrasting pathological states. SUBJECTS AND METHODS: Volumes of the right and left hippocampi, amygdalae and entorhinal cortex were measured from MRI in 34 right-handed healthy volunteers, aged 19-52 years. Data were normalized for the individual variation in total intracranial volume. Reproducibility was confirmed by intra/inter-observer tests. The statistical analyses included asymmetry comparisons, correlations between volumes and tests to assess the influence of age, gender and general morphometry (body mass index and height). For each volume, we further defined a normative interval by means of 99% confidence ellipses, accordingly to Hotteling's method. RESULTS: Right-left asymmetry in the volumes of the hippocampus and entorhinal cortex was a normal finding. Structures located in the right hemisphere were larger than the left by a small but statistically significant amount. No asymmetry was found in the amygdala. There was no correlation in-between these volumes. Gender differences were exclusively noted in the absolute amygdala volumes (male > female) but were eliminated by the normalization procedure. No effect of age or morphometry was seen in the absolute or normalized volumes (except for a milder correlation between hippocampal volumes and height). Confidence ellipses were built for every structure and provided a precise reading of the data. Particularly, it allowed for a clear distinction of pathological asymmetries and bilateral cases. CONCLUSION: These normative volumes serve as a reference for the assessment of pathologic groups within similar age-range. The use of a single graphic representation simplifies the clinical interpretation and enhances the precision of the results.

Adult↗

PubMedDate not supplied

[The entorhinal cortex (hippocampal formation) in aging and Alzheimer's disease. Neuroanatomical interpretation].

This paper deals with the neuronal changes shown by the entorhinal cortex in aging (30 cases) and in Alzheimer's disease (17 cases). In both instances, changes show a neuronal loss (measured as an index of cortical atrophy). The entorhinal cortex more closely related to polymodal association cortex hardly shows any variation with age, while Alzheimer cases present very intense neuronal loss. This pattern is interpreted taking into account the present knowledge about the connectivity of the entorhinal cortex and the remainder of the hippocampal formation and their role in memory processing.

Adolescent↗