Biomedical subjects

R Ferres-Torres

Publications and source records attributed to R Ferres-Torres.

At least 37 records · Page 2Linked to original sources

PubMed1990

Development of the median eminence in the male mouse. Karyometric effect of neonatal and prepuberal castration.

We have studied the karyometric development of the ependymocytes of the median eminence and ependyma adjacent of the arcuate nucleus in a control group of male albino mice from the 5th to the 160th postnatal day, and in other two experimental groups of animals that were castrated at two different days: the first and the 20th day of life. We have found differences in the spontaneous development of both ependymocytes showing the median eminence ependyma a more closely relationship to changes of gonadal hormone levels around puberty. In both zones, the response of the ependymocytes to neonatal castration was clearly more significative than that obtained after prepuberal castration, with lower values in the castrated animals than in the control mice. We suggest that this could be related to nervous and hormonal mechanisms.

Animals↗

PubMed1989

Aggregations of granule cells in the basal forebrain (islands of Calleja): Golgi and cytoarchitectonic study in different mammals, including man.

The granule cell islands in the olfactory tubercle (islands of Calleja) and the insula magna of Calleja are present in all species examined in this study: cat, rat, mouse, rabbit, hedgehog, monkey, man, and dolphin, displaying the same basic morphology. They appear as rather undifferentiated neurons with a poorly developed dendritic tree and a short unramified axon that does not leave the island. The larger islands and the insula magna are associated with medium-sized neurons often lying in cell-sparse core regions; they probably represent the efferent component of the islands. The distribution of granule cell islands in the olfactory tubercle varies from species to species: in the cat, they are restricted to the superficial cap regions; in the hedgehog and rabbit, they lie in cap regions and in the deep polymorph layer. In the rat, they are confined mainly to the deep polymorph layer, whereas in the mouse they extend through the three layers. In most species, the lateral islands form part of the cap regions, and they may receive fibers from the lateral olfactory tract. However, the consistent relationship between dwarf cells in the cap regions and granule cells seems to be a merely topographical one. The variable location of granule cell islands indicates that they are not related to specific cell types or cell groups in the olfactory tubercle, except to the large neurons in the hilus zones, which send their dendrites into the islands. Another close and constant relationship exists between granule islands and fibers of the medial forebrain bundle. The medial islands and the insula magna are the largest and most constant aggregations of granule cells. They are present even in the dolphin, which lacks lateral islands. Medial islands and insula magna are continuous in the hedgehog and the newborn kitten and seem to belong to a medial system of granule cells that is independent from the olfactory tubercle and from olfactory fibers. Aggregations of granule cells occur also outside the olfactory tubercle and the insula magna: in the hedgehog and the rabbit, clusters lie scattered in the n. accumbens. Distribution of granule cells outside the olfactory tubercle is related to ontogenetic development: in newborn kittens, granule cells extend from the subependymal layer of the lateral ventricle, where they probably originate, to the medioventral border of the hemisphere, and also distribute throughout the n. accumbens and the ventral pallidum. Thus, the granule cell territory is initially wider, and the original distribution is maintained in some species.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗

PubMed1989

Development of neuronal types and laminar organization in the central nucleus of the inferior colliculus in the cat.

The development of neuronal morphology and laminar organization in the central nucleus of the inferior colliculus has been studied with the different Golgi methods in kittens and cats of 1 day-2 years of age. The different Golgi methods used allowed us to selectively visualize the axonal or dendritic component of the fibrodendritic laminae. The characteristic lamination of the central nucleus defined by the fiber system of the lateral lemniscus is already present at birth. The axonal component of the laminae is constituted by parallel condensations of varicose terminals, myelinated axons, and preterminal fibers, oriented from ventrolateral to dorsomedial. The laminae are smaller in the dorsolateral edge of the nucleus. Neurons are classified mainly on the basis of their dendritic trees and the axonal ramification patterns. Three main types are distinguished: spinous disk-shaped neurons, aspinous to sparsely spinous disk-shaped neurons, and large or giant multipolar neurons. Our results suggest that the basic structures of the central nucleus--neuronal types and lamination of the lemniscal fibers--are already established at birth. The different neuronal types can be distinguished from the first days of life according to the ramification pattern of dendritic and axonal arbors. The characteristics of the different cell types, such as the density and distribution of dendritic spines, and the presence of varicose dendritic branchlets, are recognizable from the second week. At the end of the first month, neurons display an adult-like morphology, although the density of dendritic spines is higher than in the adult. Our morphological data can be related to the development of response properties in the inferior colliculus.

Aging↗

PubMed1989

The spiny stellate neurons in layer IV of the human auditory cortex. A Golgi study.

The spiny stellate neurons have been studied by the Golgi method in the auditory koniocortex and parakoniocortex of man. Spiny stellate cells are a consistent though not very common component of layer IV. They are not confined to specific sublayers but occur at all depths of layer IV, and also in layer IIIc. Spiny stellate cells in the auditory areas show a great variety of their dendritic arborization pattern. The presence of all intermediate forms between small pyramidal cells--which constitute the dominant cell type in layer IV and which display an extraordinary heteromorphism--and spiny stellate cells shows the close kinship between both neuronal types. The morphology and distribution of spines along the dendrites of spiny stellate neurons are similar to those of the small pyramidal cells of the same layer. The axons, which were impregnated only in their proximal portions, mostly descend, giving rise to recurrent ascending collaterals, but initially ascending axons do also occur. Spiny stellate neurons are present in the different cytoarchitectonic areas examined, and thus they are not confined to the auditory koniocortex.

Adult↗

PubMed1989

Effects of ethanol and propylthiouracil on hepatic iron and copper contents in the male albino mouse.

With the aim to analyze whether propylthiouracil (PTU) alters ethanol-induced changes in liver iron and copper contents, 40 male albino mice were equally divided into a control group, an ethanol-treated group, a PTU-treated group and an ethanol + PTU-treated group. Twenty animals were killed at the age of 85 days and 20 at the age of 180 days. Liver iron and copper contents showed a progressive, statistically non-significant increase both in the controls and in ethanol-treated animals. Liver iron contents was significantly higher in the 180-day-old alcoholic mice as compared with controls. Animals treated either with PTU or with PTU + ethanol showed liver iron levels in the normal range, markedly different from the ethanol-treated animals (P less than 0.005). Liver copper content of the ethanol-treated animals was higher (but not significantly) than that of the controls. Liver copper levels of the PTU + ethanol-treated animals were in the range of the ethanol-treated animals. Thus, PTU seems to revert an overload of ethanol-mediated iron of copper.

Alcoholism↗

PubMed1989

Direct projections from the medulla oblongata to selective cortical areas in the rat.

Injections of horseradish peroxidase into different cortical areas reveal that neurons located in the rostroventral medulla oblongata innervate restricted cortical areas: the anterior and posterior cingulate cortex and the insular cortex. Other cortical areas do not receive medullary projections. Neurons projecting to both the anterior and the posterior cingulate cortex lie scattered throughout a wide territory of the ventrorostral medulla, whereas neurons projecting to the insular cortex are restricted to more medial regions.

Animals↗

PubMed1988

Effect of propylthiouracil on liver cell development in the male albino mouse: protective effect against ethanol-induced alterations.

The aim of the present study is to analyze whether the addition of propylthiouracil reverts the influence of ethanol on the development of periportal and pericentral hepatocytes and their nuclei in male albino mice. Propylthiouracil-treated animals showed decreased cellular and nuclear areas when compared with the control animals, except for the 180-day-old animals, whose pericentral cells and nuclei were greater than those of the controls and exhibited fatty infiltration. Pericentral hepatocytes and nuclei of the ethanol-fed animals showed an increase of their sizes, especially in 180-day-old animals. In contrast, hepatocyte and nuclear sizes of the animals treated with both propylthiouracil and ethanol were similar to those of the control group, suggesting a protective effect of propylthiouracil against the ethanol-induced alterations.

Animals↗

PubMed1988

Development of the subfornical organ and area postrema of the male albino mouse. Karyometric effect of neonatal and prepuberal castration.

We have studied the karyometric development of the nuclei of the ependymal cells and neurons of the subfornical organ and the area postrema in the male albino mouse from the 5th to the 190th postnatal day. We have found similar patterns of development in both although the area postrema showed more significant postnatal oscillations than those of the subfornical organ, suggesting a more intimate chronological relationship to gonadal development. We have furthermore analyzed the development in two experimental groups: in the one animals were castrated at birth, in the other, castration was made on the 20th postnatal day. We have found that neonatal castration produced a significant decrease of nuclear sizes; this was more evident in the subfornical organ than in the area postrema in earlier stages of development while the response was similar in both at peripuberal ages. The response to prepuberal castration was similar in both organs.

Aging↗

PubMed1987

Effect of ethanol on liver cell-development in the male albino mouse.

The aim of this study is to determine the influence of ethanol on the development of periportal and pericentral hepatocytes and their nuclei, comparing it with the development of these cells and nuclei in a control, age-matched population. In male albino mice fed with 20% ethanol added to drinking water and sacrificed at day 25, 35, 85 and 180 of life haematoxylin-eosin stained liver specimens were studied with the aid of a LEITZ ASM semiautomatic autoanalyzer. The nuclear area of at least 25 hepatocytes with evident nucleoli was measured at each of 3 periportal and 3 pericentral fields. The area of the cells of the same fields was estimated by dividing the area of the fields by the number of hepatocyte nuclei present in them. Both cellular and nuclear areas of periportal and pericentral hepatocytes of the 25-day-old animals were smaller than those of age-matched controls. By contrast, the experimental group showed a striking increase both in cellular and nuclear size in the pericentral hepatocytes, but not in the periportal ones. Thus, ethanol seems to inhibit the initial growth of cells and nuclei; but, after maturation, it causes a marked increase not only in cellular size of pericentral hepatocytes, especially in 180-day-old animals, but also in nuclear size, already evident in the 35-day-old mice.

Age Factors↗

PubMed1987

Topographic organization of the karyometric response to neonatal castration of the male mouse in the paraventricular and ventromedial hypothalamic nuclei.

We have analysed the karyometric development of four topographic subdivisions of the paraventricular nucleus (rostral, medial, lateral and caudal) and three topographic subdivisions of the ventromedial nucleus (ventral, central and dorsal) of the hypothalamus in neonatally castrated male mice. Castration at birth produces a decrease of the nuclear sizes from the 10th to the 35th postnatal day, but after this age, no differences were detected in comparison with the sizes of the control male mice. Neonatal gonadal hormone deprivation also produces changes in the nuclear shape of the nuclei, that tend to be more spherical in both centres, as we could establish after the study of the form factor parameter (perimeter/area ratio). We have found differences in the response of both hypothalamic nuclei to neonatal castration and differences in the response of the topographic subdivisions of both of them.

Animals↗

PubMed1987

Afferent connections of the inferior colliculus in the albino mouse.

We have studied the afferent connections of the inferior colliculus of the albino mouse. Our results show: First, the afferent connections of the inferior colliculus in the mouse are similar to those of other species, however, some differences exist. Second, there is a different projection pattern to the dorsal cortex and the central nucleus of the inferior colliculus; the dorsal cortex receives fibers essentially from auditory centers, while the central nucleus also receives afferents from other structures not related to the auditory system. Third, an interesting parallel may be established between the connections of the inferior colliculus and those of the superior colliculus.

Afferent Pathways↗

PubMed1987

Effects of hormone deprivation on the karyometric development of the medial and lateral preoptic area of the male mouse. II. Hypothyroidism.

We have analysed the karyometric development of the medial and lateral preoptic area of the hypothalamus in two groups of experimentally hypothyroid male mice, from the 25th to the 160th postnatal day. In one group, animals were treated with propylthiouracil from birth until the day of sacrifice. In the second experimental group animals were treated only until the 35th postnatal day, and thereafter sacrificed at the 45th, 55th, 85th and 160th postnatal day. We compare the results of both groups of animals with a control group of male mice. Hypothyroidism did not alter the nuclear sizes of the medial preoptic area, but in the lateral preoptic area, values were significantly higher in the hypothyroid animals after the 55th day.

Animals↗

PubMed1987

Effects of hormone deprivation on the karyometric development of the medial and lateral preoptic area of the male mouse. I. Neonatal castration.

We have analysed the karyometric development of the nuclear neuronal sizes in the medial and lateral preoptic area of male albino mice castrated within 24 hours of birth. We have analysed six different age groups of animals: 10th, 20th, 35th, 45th, 55th and 85th postnatal day, and we have compared our results to those of a control group of male mice. Both hypothalamic areas respond to neonatal castration showing lower values of the nuclear sizes than those of the control group. The reaction of these areas to gonadal hormone deprivation at birth is more striking than that obtained after prepuberal castration of the animals, studied in a previous report. Neonatal gonadal hormone deprivation also produces changes of the nuclear shape of the nuclei towards sphericity.

Aging↗

PubMed1987

Effects of hypothyroidism on the karyometric development of pyramidal neurons of the hippocampus (CA1), area 6 and area 17 in the male mouse.

This study has examined the karyometric changes within pyramidal neurons of the hippocampus, motor area 6 and visual area 17 in a hypothyroid group of male mice treated with propylthiouracil, with or without interruption of treatment at the 35th postnatal day. Hypothyroidism resulted in decrease of nuclear size in the three areas before puberty and even after puberty in the hippocampus. Where the treatment was continued throughout the experimental period there was a progressive increase of nuclear size in both visual and motor areas.

Animals↗

PubMed1986

Direct projections from the reticular formation of the medulla oblongata to the anterior cingulate cortex in the mouse and the rat.

After injections of horseradish peroxidase into the anterior cingulate cortex of the mouse and the rat, labeled neurons were observed in different nuclei of the reticular formation of the rostral medulla oblongata: ventral part of the nucleus gigantocellularis, nucleus paragigantocellularis and nucleus lateralis reticularis. Other labeled neurons lay scattered outside the nuclear boundaries, often close to the ventral-most border of the medulla. The projection to the cingulate cortex is sparse, with rarely more than 3 cells per case, but constant. Injections into other cortical areas (visual, motor and somatosensory cortex) did not produce labeling in the medullary reticular formation.

Afferent Pathways↗

PubMed1986

Effects of hypothyroidism on the karyometric development of the paraventricular and ventromedial nuclei of the hypothalamus in the mouse.

We studied the karyometric development of 4 subdivisions of the paraventricular nucleus (rostral, caudal, medial and lateral) and 3 subdivisions of the ventromedial nucleus of the hypothalamus (ventral, central and dorsal) in a hypothyroid group of male albino mice treated with propylthiouracil with or without interruption of the treatment at the 35th postnatal day. Hypothyroidism produces an increase of the nuclear-size values of the paraventricular and ventromedial nuclei, and the continued treatment increases this effect. The caudal and the rostral subdivisions of the paraventricular nucleus show more significant changes of their nuclear sizes compared to the medial and lateral subdivisions. The ventromedial nucleus responds similarly to hypothyroidism in all its subdivisions.

Animals↗

PubMed1986

The commissural interconnections of the inferior colliculus in the albino mouse.

In the inferior colliculus of the mouse, 4 cell types project across the collicular commissure: small to medium sized spiny cells, small to medium sized spineless cells, medium sized sparsely spinous neurons and large cells. The axons of large cells give rise to a great number of ipsi- and contralateral collaterals terminating in nests of fine varicose fibers. The anterograde transport of HRP revealed that following injections into the central nucleus, the axonal terminals are arranged in a fixed, ipsi- and contralateral banding pattern across the central, pericentral and external nucleus irrespective of the location of the injection. On the contrary, the position of projecting cells varies with the location of the injection, though the area emitting commissural fibers is not completely homotopic to the injection site but subordinated to the axonal banding pattern.

Animals↗

PubMed1985

Effects of gonadectomy on the karyometric development of the ventromedial nucleus of the hypothalamus in the mouse.

We studied the karyometric development of 3 subdivisions (ventral, central and dorsal) of the ventromedial nucleus in male albino mice from the 5th to the 190th day of life. All subdivisions exhibited a similar development pattern. Another group of animals were castrated at the 20th day of life and examined from the 25th to the 85th day. The increase of the nuclear size at the 35th day and the decrease at the 85th day, observed in the control group, were not present after castration.

Animals↗