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P Amat

Publications and source records attributed to P Amat.

At least 19 recordsLinked to original sources
PubMed2006

Purified allergens vs. complete extract in the diagnosis of plane tree pollen allergy.

BACKGROUND: Plane tree pollen allergy is a clinical disorder affecting human population in cities of Europe, North America, South Africa, and Australia. OBJECTIVE: To compare IgE-reactivity of the natural and recombinant forms of two major plane allergens, Pla a 1 and Pla a 2, with the reactivity of Platanus acerifolia pollen extract. METHODS: Forty-seven patients with P. acerifolia allergy, 15 of them monosensitized, and 24 control subjects were included in the study. Natural Pla a 1 and Pla a 2 were purified by standard chromatographic methods and recombinant proteins were expressed in Escherichia coli. Skin prick test and determination of specific IgE were performed with commercial P. acerifolia extract and natural and recombinant purified allergens. RESULTS: Pla a 1 and Pla a 2 were responsible for 79% of the IgE-binding capacity against P. acerifolia pollen extract. A high correlation has been found between the IgE response to nPla a 1 (R = 0.80; P < 0.001) or nPla a 2 (R = 0.79; P < 0.001) vs. P. acerifolia extract as well as between natural and recombinant Pla a 1 (R = 0.89; P < 0.001). Skin testing showed no significant differences between extract and nPla a 2, whereas a higher reactivity was found with nPla a 1. In contrast, rPla a 1 revealed markedly reduced sensitivity in comparison with extract by skin prick test and specific IgE. The sensitivity of the mix Pla a 1+Pla a 2 was 100% and 87.5% for monosensitized and polysensitized patients, respectively, with no false-positive reactions detected. Conclusion Pla a 1 and Pla 2 are sufficient for a reliable diagnosis of P. acerifolia in most patients and induce comparable skin test reactivity as a whole extract.

Adolescent↗
PubMed2004

Microinjection of urocortin 2 into the dorsal raphe nucleus activates serotonergic neurons and increases extracellular serotonin in the basolateral amygdala.

The intra dorsal raphe nucleus (DRN) administration of corticotropin releasing hormone (CRF) inhibits serotonergic (5-HT) activity in this structure, an effect blocked by antagonists selective for the type 1 CRF receptor (CRF1). The DRN has a high density of the type 2 receptor (CRF2), and so the present experiments explored the impact of CRF2 activation within the DRN on 5-HT function. The intra-DRN administration of the selective CRF2 agonist urocortin 2 (Ucn 2) dose dependently increased 5-HT efflux in the basolateral amygdala, a projection region of the DRN. Intra-DRN Ucn 2 also increased c-fos expression in labeled 5-HT neurons. Both of these effects of Ucn 2 were completely blocked by intra-DRN antisauvagine-30 (ASV-30), a relatively selective CRF2 antagonist. These data suggest that CRF1 and CRF2 activation within the DRN affect 5-HT neurons in opponent fashion. Implications of these results for understanding the behavioral effects of CRF and other CRF-like ligands are discussed.

Amygdala↗
PubMed2003

[Contribution of a functional orthopedic splint to the treatment of Class II malocclusions].

The numerous therapeutic, psychological and functional benefits that derive from using a two-stage approach to the treatment of Class II malocclusions can sometimes be partially offset by difficulties stemming from the choice of technique: patients may be reluctant to wear cumbersome appliances which, when they are worn, can interfere with speech production, the quality of therapeutic improvement may be reduced by undesirable dento-alveolar responses to orthopedic forces, treatment results may turn out to be unstable at the final finishing stage and continuation of treatment at the time of the appearance of the young adult dentition may be jeopardized. The author has designed a new appliance, a functional orthopedic splint whose slim design largely eliminates these problems. Suitable for use in a variety of techniques, this easily worn device greatly reduces unwanted dento-alveolar responses as it stimulates desirable functional improvement and gives orthodontists much improved control of their treatment of Class II malocclusions.

Adolescent↗
PubMed2000

A second look at the barriers of the medial basal hypothalamus.

The cell bodies of hypothalamic secretory neurons are localized in areas protected by the blood-brain barrier (BBB), whereas their axon terminals are localized in the median eminence, which lacks a BBB. This implies a complex barrier system, allowing neurons of the central nervous system to secrete into the blood stream without making the BBB leaky. In the present study, three experimental protocols were applied to clarify certain relevant aspects of the barriers operating in the medial basal hypothalamus of the rat. We established that the milieu of the arcuate nucleus is exposed to both the ventricular and the subarachnoidal cerebrospinal fluid (CSF). The median eminence milieu, the perivascular space of the portal vessels, and the subarachnoid space appear to be in open communication; also, beta2-tanycytes establish an efficient barrier between the median eminence milieu and the ventricular CSF. Similarly, beta1-tanycytes establish a lateral barrier, separating the intercellular space of the median eminence from that of the arcuate nucleus. We also found that the glucose transporter I (GLUT I), a BBB marker, is localized throughout the whole plasma membrane of beta1-tanycytes, but is missing from beta2-tanycytes. Expression of GLUT I by tanycytes progressively develops during the first postnatal weeks; while the degree of damage of the arcuate nucleus by administration of monosodium glutamate, at different postnatal intervals, parallels that of the GLUT I immunoreactivity of beta1-tanycytes. An explanation is offered for the selective destruction of the arcuate neurons by the parenteral administration of monosodium glutamate to infant rats.

Aging↗
PubMed1999

Lateral evaginations from the third ventricle into the rat mediobasal hypothalamus: an amplification of the ventricular route.

In this work we report the existence of several evaginations extending out of the third ventricle within the mediobasal hypothalamus of the rat. In coronal sections, these evaginations appear as very narrow canaliculi integrating a canalicular system, which increases the contact surface between the ventricular lining and the nervous tissue. Consequently these evaginations enlarge the ventricular route for the transport of active principles present in the cerebrospinal fluid, such as (neuro)hormones and neurotransmitters. The mediobasal hypothalamus includes the arcuate nucleus and the median eminence (both involved in neuroendocrine mechanisms and in the regulation of pituitary function). A possible implication of our finding is that the neuroactive substance-containing ventricular cerebrospinal fluid may reach the intercellular spaces of the surrounding neuropil of the arcuate nucleus. According to literature these substances cross the ependyma of the lateral wall of the infundibular recess of the third ventricle. We suggest that such substances might also pass through the ependymal lining of the canalicular system, which displays the same ultrastructural characteristics as the rest of the ependyma of the lateral wall of the third ventricle. Therefore, the arcuate neurons may be influenced not only by synaptic inputs (afferent fibers) but also by non-synaptic diffusion neurotransmission (by means of neuroactive substances present in the cerebrospinal fluid).

Animals↗
PubMed1999

Lectinhistochemistry and ultrastructure of microglial response to monosodium glutamate-mediated neurotoxicity in the arcuate nucleus.

In this study we describe the most relevant morphological features of the microglial reaction that takes place in the arcuate nucleus (AN) after neurotoxic injury induced by a single subcutaneous injection of monosodium glutamate (MSG) in neonatal rats. The time course of the reaction was evaluated by lectinhistochemistry. Microglial/macrophagic cells were labelled with the lectin obtained from Lycopersicon esculentum and with B4 isolectin from Griffonia simplicifolia. The microglial response was also studied by ultrastructural observations. The histochemical study revealed the presence of few reactive microglial cells at 6 h post-injection. These cells were intensely stained and had a globular morphology but contained no neuronal debris inside them when observed under the electron microscope. At 12 h post-injection, the number of microglial cells had increased and, at the same time, intense phagocytic activity was observed ultrastructurally. The microglial reaction peaked at 24 and 36 h post-injection, when the number of microglial/macrophagic cells was maximum, although the ultrastructural observations showed that at 36 h the amount of debris ingested by macrophages was decreased with respect to animals sacrificed at 24 h. Finally, at 4 days after neurotoxic injection the number and morphology of microglial cells were similar to those observed in the control rats. The ultrastructural study also revealed the existence of microglial cell mitosis in the territory of the AN together with a strong increase in the number of supraependymal cells resembling macrophages in the third ventricle during the lesion. Our data demonstrate that activated microglial cells initially extend throughout the damaged territory, but from 24-36 h onwards they are especially patent in the ventrolateral portions of the AN.

Animals↗
PubMed1998

Ultrastructural features of rat arcuate nucleus neurons during pregnancy.

The ultrastructure of the arcuate nucleus was studied in Sprague-Dawley rats sacrificed at 7, 10, 14 and 20 days of gestation, using conventional techniques of electron microscopy. Our results revealed an increase in granular filamentous bodies and whorled bodies that appear in arcuate neurons as early as on the 7th day of gestation. A further increase of these structures was showed by day 10 and, especially, by day 14. In the arcuate nucleus of rats sacrificed on day 14 of gestation, some compact, homogeneous and very large (up to 5.5 microm diameter) granular filamentous bodies may be seen both in neuronal bodies and in dendrites. In some neurons of arcuate nucleus of these gestational phases (days 10 and 14), besides the whorled bodies dense-core vesicles were found. Neurons with cilia were occasionally observed, and some neuronal bodies were in close apposition and joined by intercellular bridges. Open synapses were observed during all the gestational phases. The smallest number of these synapses was seen in the arcuate nucleus of rats sacrificed on day 14 of gestation.

Animals↗
PubMed1995

Giant granular filamentous bodies in the cytoplasm of arcuate nucleus neurons of castrated rats.

We have performed an ultrastructural and quantitative study of granular filamentous bodies (GFBs) present in the cytoplasm of some arcuate nucleus neurons of rats of both sexes castrated at one month of age and sacrificed one or three months later, as well as untreated and sham-operated animals of the same ages. GFBs appear as round or ovoid cytoplasmic inclusions of granular-filamentous texture and generally lack a limiting membrane; their sizes vary from 0.7 to 2.8 microns (average 1.7 microns). GFBs are present more frequently in the perikarya, but they also occur in dendrites. In rats of both sexes castrated at one month of age and sacrificed three months later a noticeable finding was the presence of some giant GFBs, whose major axis could reach up to 6 microns. The nomenclature, the origin and the possible significance and function of GFBs are discussed.

Animals↗
PubMed1994

Transependymal diapedesis: reality or speculation?

The present study attempts to describe the possible origin of certain elements situated inside the infundibular recess of the third ventricle, such as supraependymal cells and Herring bodies, together with the way in which they reach the ventricular lumen. We used albino Sprague-Dawley rats and cats of both sexes sacrificed at different ages. The results point to the possible existence of a transependymal diapedesis of some Herring bodies and supraependymal cells into the infundibular recess.

Animals↗
PubMed1993

Hypersensitivity to mustard seed.

Two patients were studied. Both underwent a thorough clinical evaluation, including a comprehensive physical examination. Both were also prick tested for inhalants, pollens, and food (including fruit). A nasal provocation test, serum immunoglobulins, total IgE serum, specific IgE serum, and a histamine release test were also carried out. The results of all these tests were positive to mustard seed.

Adult↗
PubMed1992

[Morphologic substrates of the ventricular route of secretion and transport of substances in the tubero-infundibular region of the hypothalamus. Ultrastructural study].

Ultrastructural studies of the ependyma of the tuberoinfundibular region of the rat hypothalamus have revealed the existence of intraventricular axonal endings and of cytoplasmic blebs and bulbs that project from the apical surface of the ependymal cells to the ventricular lumen. All these structures account for the processes of ependymal apocrine secretion and the neuroventriculocrinia, and hence the release of biologically active substances into the cerebrospinal fluid (CSF). These substances contained in the CSF must act on the nervous nuclei of the tuberoinfundibular region, such as the arcuate nucleus, which is very important in the neuroendocrine regulation of the anterior pituitary gland. Dilated intercellular spaces among neighbouring ependymocytes of this region, small intraependymal cisternae and, in particular, a lateral prolongation of the infundibular recess, which courses through the nervous tissue between the arcuate nucleus and the median eminence from the vertex of the lateral angle of the infundibular recess, may be the route followed by the CSF from the third ventricle to the tissue compartment of the tuberoinfundibular region. Also studied are the cisternae of the region and the relationships of these with the lateral prolongation of the infundibular recess. Some of these cisternae may be filled by the CSF through the prolongation. In this way, the tissue compartment of CSF would be enlarged, and hence the ventricular route for the secretion and transport of biologically active substances would be potentiated.

Animals↗
PubMed1992

The ependymal surface of the fourth ventricle of the rat: a combined scanning and transmission electron microscopic study.

The morphological features of the ependymal surface and supraependymal elements of the fourth ventricle of the rat were examined by scanning electron microscopy (SEM) and by the transmission electron microscopy (TEM). The results confirm the following aspects: 1) The presence of supraependymal elements and microvilli in the ependymal territories, including the sites where the cilia completely cover the ependymal surface; 2) The existence of cilia with oval or spherical thickenings together with supraependymal bulbs similar in size to those of the larger ciliary swellings; 3) Identification of the long supraependymal fibres with intermittent fusiform dilations observed under the SEM with the nerve fibres seen under the TEM; 4) The existence of intraventricular axodendritic synapses.

Animals↗
PubMed1991

Myelinated Herring bodies in the median eminence of the cat.

An electron-microscopic study was carried out on the median eminence of cats during post-natal development. From the moment of birth (observations performed 12 hours later) Herring bodies were seen in the fibrillary layer of the median eminence. At 45 days after birth, myelinated nerve fibres could be observed, some of them containing neurosecretory granules. The number of myelinated fibres in the median eminence increased with age and at 90 days some Herring bodies appeared surrounded by myelin sheaths; these mainly contained neurosecretory granules and a few mitochondria.

Animals↗
PubMed1990

Quantitative and ultrastructural alterations in the lamina propria and Sertoli cells in human cryptorchid testes.

A quantitative and ultrastructural study was performed on biopsies of human cryptorchid testes to investigate lesions in the lamina propria and Sertoli cells. Prepubertal cryptorchid testes (1-9 years of age) were classified into four groups: Type 1, testes with minimal lesions; Type II, testes with a moderate decrease in tubule diameter and spermatogonal number; Type III, testes with Sertoli cell hypoplasia and a marked reduction in tubule diameter and spermatogonal number; and Type IV, testes with Sertoli cell hyperplasia and a variable reduction in spermatogonal number. An increase in thickness of the lamina propria was found in Type II and III testes from 5 years of age onwards. These testes also showed a decrease in both the average number of peritubular cells per cross-sectioned tubule and in the average nuclear volume of these cells. Most of the postpubertal cryptorchid testes from 13- to 18-year-old youths presented a prepubertal pattern suggestive of delayed testicular maturation. Postpubertal testes from 19- to 27-year-old men were classified into three types: Type A testes showed complete spermatogenesis, mature Sertoli cells and no lesions in the lamina propria; Type B testes showed isolated spermatogonia, mature Sertoli cells, and a marked thickening of the lamina propria; and Type C testes showed isolated spermatogonia, hyperplasia of immature Sertoli cells, and a slightly thickened lamina propria. Maturation of the lamina propria was always associated with maturation of the Sertoli cells. Thickening of the lamina propria was associated with peritubular cell alterations consisting of decreases in the nuclear volume (average and total per testis) of peritubular cells and increases in the number of these cells per cross-sectioned tubule. The three types of adult cryptorchid testes appear to be the postpubertal transformation of Type 1 testes (Type A), Type II and Type III testes (Type B), and Type IV testes (Type C).

Adult↗
PubMed1988

[Post-pneumonectomy bronchial fistula. Treatment by resection of the carina].

A technique for the surgical treatment of bronchial fistulae developed after pneumonectomy is presented. This technique, which resembles that of Abruzzini, consists of resection of the carina followed by tracheo-bronchial suture in a healthy area away from any purulent focus of infection. It is easy to perform and facilitates the treatment of thoracic empyema which is no longer maintained by the fistula.

Bronchi↗