Biomedical subjects
Publications and source records attributed to F Sanchez.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Although the different vespid species of the genus Polistes are found all over the world, studies about allergy sensitization to these species have been made mainly in North America. We studied the specific IgE in a large group of sera from patients sensitized to Polistes dominulus (PD) and determined the crossreactivity with another important European Polistes (P. gallicus [PG]) and with five American relevant species of this genus: P. exclamans (PE), P. fuscatus (PF), P. metricus (PM), P. annularis (PAN) and P. apachus (PAP). Studies indicated that 96.7% of sera with IgE positive to PD were positive to PG. No case positive to just PG was found. The comparison of these two European species with the American relatives indicated that most cases were positive to all the insects although there were significant differences in the radioallergosorbent test (RAST) value. These results were confirmed by RAST inhibition studies, and indicate that although the European and American species are closely related, species specific allergenic differences exist. These data suggest that in vivo studies should be carried out in order to determine the sensitivity and specificity of the European venoms compared with the American species.
In order to establish whether osmotic stimuli induce variations in the contact regions among neurosecretory axons of the neural lobe of the hypophysis, adult Sprague-Dawley rats of both sexes were treated with furosemide, a diuretic drug. Contacts between adjacent membranes with no condensations of the axolemma but increase in their osmiophilia were observed. After treatment with furosemide interaxonal contacts were significantly increased (p < 0.01, in relation to control animals). Additionally, following treatment with furosemide, axo-axonic synapses among the axons of the neural lobe were found. These findings suggest the existence of interactions among activated neurosecretory axons of the neural lobe of the adult rat.
Natural resistance to infection with unrelated intracellular parasites such as Mycobacteria, Salmonella, and Leishmania is controlled in the mouse by a single gene on chromosome 1, designated Bcg, Ity, or Lsh. A candidate gene for Bcg, designated natural resistance-associated macrophage protein (Nramp), has been isolated and shown to encode a novel macrophage-specific membrane protein, which is altered in susceptible animals. We have cloned and characterized cDNA clones corresponding to the human NRAMP gene. Nucleotide and predicted amino acid sequence analyses indicate that the human NRAMP polypeptide encodes a 550-amino acid residue membrane protein with 10-12 putative transmembrane domains, two N-linked glycosylation sites, and an evolutionary conserved consensus transport motif. Identification of genomic clones corresponding to human NRAMP indicates that the gene maps to chromosome 2q35 within a group of syntenic loci conserved with proximal mouse 1. The gene is composed of at least 15 exons, with several exons encoding discrete predicted structural domains of the protein. These studies have also identified an alternatively spliced exon encoded by an Alu element present within intron 4. Although this novel exon was found expressed in vivo, it would introduce a termination codon in the downstream exon V, resulting in a severely truncated protein. Northern blot analyses indicate that NRAMP mRNA expression is tightly controlled in a tissue-specific fashion, with the highest sites of expression being peripheral blood leukocytes, lungs, and spleen. Additional RNA expression studies in cultured cells identified the macrophage as a site of expression of human NRAMP and indicated that increased expression was correlated with an advanced state of differentiation of this lineage.
In order to establish whether dopamine is involved in the regulation of immunocytochemical expression of VIP in pituitary cells, in vivo and in vitro studies were carried out on male rats after treatment with haloperidol and dopamine, respectively. In the in vivo studies, following intraventricular (third ventricle) administration of haloperidol, an increase in the total number of VIP-immunoreactive cells (p < 0.05) was observed; additionally, the cellular, cytoplasmic and nuclear areas were increased (p < 0.01). The in vitro studies demonstrated that dopamine induces a significant decrease (p < 0.05) in the total number of VIP-immunoreactive cells, which were smaller than the cells from the control dishes, because dopamine induces a significant decrease in their cellular, cytoplasmic and nuclear areas (p < 0.01). These results support the hypothesis that dopamine is a physiological inhibitor of pituitary VIP expression and suggest that dopamine modulates the auto- or paracrine effects of VIP in the rat pituitary.
The aim of this study was to assess the life quality of a group of patients who had undergone liver transplantation using (1) a psychological test to evaluate family relations, work activity, emotional state and social relationships; (2) the quantification of hospital dependence and degree of fitness for work. Included in the study were 32 patients using the following criteria: diagnosis of hepatic cirrhosis and minimum posttransplant follow-up of 6 months. The average age of the study population was 44.8 +/- 10.5 years; there were 23 males and 9 females, with an average follow-up of 15 months. The psychological test used was the Quality of Life Scale (QLS) which consists of 21 items each scoring from 1 to 6 points. The questionnaire was completed before transplantation by all the patients, and after transplantation by 32 patients at 6 months, 20 at 12 months and 12 at 24 months. Hospital dependence was evaluated by the number of admissions and number of days per admission. Lastly, we compared fitness for work before transplantation and at 1 and 2 years after transplantation. The QLS test showed a post-transplant improvement in the four aspects assessed, particularly in the personal aspects (emotions and family) (P < 0.001). Hospital dependence following liver transplantation decreased significantly compared with the pretransplant situation (P < 0.01). Finally, the post-transplant percentage of unfitness for work decreased with time, reaching a significant differences 2 years after transplantation (P < 0.05).
This study was carried out to compare the allergenic potency of Vespula germanica (VG) venoms extracted by different methods and commercially available venoms from Vespula species currently used for in vivo and in vitro studies including immunotherapy. Pure VG venom was used as the reference material. Protein content and enzymatic and allergenic properties of all venoms studied were determined by dye stain reagent, hyaluronidase and phospholipase A1B enzyme activities, and radioallergosorbent test inhibition studies, respectively. Radioallergosorbent test discs sensitized with commercial and pure VG venom were compared using specific IgE antibodies from subjects allergic to VG venom. The data obtained indicate that there were important differences in the allergenic potency between the Vespula species venoms employed for in vivo and/or in vitro assays, VG venom obtained by sac dissection, and pure VG venom. These results indicate that venoms from Vespula species used for in vitro and in vivo tests have a lower concentration of allergens and contain nonvenom proteins. These data should be taken into account when these vespid venoms are used for diagnostic purposes and also when evaluating immunotherapy studies.
Following administration of met-enkephalin into the third ventricle of rats of both sexes, an ultrastructural-morphometric study was carried out of the neural lobe of the hypophysis, comparing the results with those obtained in untreated animals, controls (injected intraventricularly with distilled water) and animals previously receiving naloxone intraperitoneally. In the untreated and control animals, both males and females, there was a high percentage (about 70%) of neurosecretory axons considered to have a normal morphology; after met-enkephalin administration, this percentage decreased and was accompanied by a rise (slightly more pronounced in the females) in the percentage of degranulated axons and a slight rise in axons with a morphology indicative of regenerative and degenerative phases. Previous administration of the opiate antagonist naloxone led to a rise in the number of axons in the degenerative phase with respect to the other groups of animals; this occurred in both sexes.
Using a combined scanning and electron microscope technique, the repercussion on the rostral wall of the III ventricle in a patient affected with a retrochiasmatic craniopharyngioma with growth in the ventricular direction were analysed. The apical surface of the ependymocytes was found to be free of cilia, although there were numerous microvilli. The most striking finding appreciated with the scanning electron microscope was the presence of bulbous protrusions towards the lumen of the ventricle; these were formed of cells with shapes, sizes and surface characteristics different from the rest of the ependyma, which appeared flattened. The ultrastructural study revealed the presence of large numbers of filaments and junction complexes both in the ependymal and subependymal cells. Additionally, the protruded zones corresponded to areas showing different degrees of cellular disorganization.
Carney's triad is extremely rare. The authors report on a 12-year-old patient who had gastric epithelioid leiomyosarcoma, multiple pulmonary chondroma, and mediastinal paraganglioma. Thirty-five other cases are reviewed and analyzed.
The distribution of calretinin-immunoreactivity in the magnocellular neurosecretory nuclei of the rat hypothalamus was studied using a polyclonal antibody and the avidin-biotin immunoperoxidase technique. Calretinin-immunoreactive neurons were observed in the supraoptic and paraventricular nuclei. Additionally, we detected for the first time, immunoreactive neurons located in the circularis and fornicals nuclei, and isolated positive neurons situated in the hypothalamic area located between the supraoptic and paracentricular nuclei. When these results were compared to those obtained in previous studies for another two calcium-binding proteins: calbindin D-28k and parvalbumin, two major differences may be concluded: a) a different distribution of calretinin, especially in the paraventricular nucleus, and b) an expression of calretinin lower than calbindin D-28k and higher than parvalbumin in the magnocellular hypothalamic nuclei. Of special interest is the fact that calretinin is one of the few markers which demonstrates predominantly parvicellular neurons in the paraventricular nucleus. Although the exact biochemical function of these three calcium-binding proteins remains unknown, their uneven and characteristic distributions strongly suggest that specific neuronal populations in the hypothalamus may use alternatively different calcium-sequestering molecules.
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Sera from a group of 12 patients with anaphylactic reactions to vespids were studied. Field observations and RAST values suggested that the offending insect was Polistes dominulus (PD). Specific IgE antibodies to PD appeared in all cases and to Vespula germanica (VG) in nine. Absorption studies in these basal sera showed that IgE antibodies to VG were due to cross-reactivity with PD. The RAST value to both venoms was higher after immunotherapy (IT) in six cases. IgE antibodies increased to determinants common to both vespids, and in 41% of the cases to specific epitopes of VG venom allergens not initially detected in the basal sera. In one case antibodies increased only to VG without a corresponding rise to PD. These results indicate that if the correct venom to which the individuals are sensitized is not administered IgE antibodies may appear which were not initially detected in the patients' sera. The levels of these antibodies declined during the course of IT.
A morphometric-ultrastructural study was made of the supraoptic nucleus of rats of both sexes following central administration of met-enkephalin. Ten minutes after met-enkephalin treatment the number of axo-somatic synapses was significantly increased. This effect was more pronounced in female rats than in males and could be prevented by preceding administration of naloxone. Animals that received naloxone followed by met-enkephalin showed a dilation of the rough endoplasmic reticulum into a vesicular shape. Our results provide preliminary evidence for a fast remodeling of synaptic input to magnocellular hypothalamic neurons. It is likely that the known inhibitory action of opioids on the hypothalamo-neurohypophysial system is partly mediated by this plasticity.
The effects of testosterone on the volume and cytoarchitecture of the sexually dimorphic nucleus of the preoptic area (POM) were investigated in male and female Japanese quail. It was confirmed that castration decreases the POM volume in males and that, in gonadectomized birds of both sexes, testosterone increases this volume to values similar to those observed in intact sexually mature males. This suggests that the sex difference in POM volume results from a differential activation by T so that this brain morphological characteristic is not truly differentiated in the organizational sense. This conclusion was extended here by demonstrating that males exposed to a photoperiod simulating long days and that are known to have high plasma levels of testosterone have a larger POM than short-day males that have inactive testes. Detailed morphometric studies of POM neurons revealed a structural heterogeneity within the nucleus. A population of large neurons (cross-sectional area larger than 70-80 microns2) was well represented in the dorsolateral but was almost absent in the medial part of POM. This lateral population of neurons was sensitive to variations of testosterone levels in males but not in females. The cross-sectional area, diameter, and perimeter of the dorsolateral neurons were significantly increased in males exposed to high testosterone levels (intact birds exposed to long days or castrated birds treated with the steroid). These changes were not observed in the medial part of the nucleus. Interestingly, the size of the dorsolateral neurons was not affected by testosterone treatments in females. These results suggest that the swelling of neurons in the lateral POM of males might be responsible for the increase in total volume of the nucleus, which is observed in physiological situations associated with a high testosteronemia. In addition, the sensitivity to testosterone of the dorsolateral neurons in the POM appears to be sexually differentiated. This differential response to testosterone might represent a truly dimorphic feature in the organizational sense and additional studies manipulating the early steroid environment should be performed to test this possibility.
To evaluate the safe use of aztreonam (AZT) in patients allergic to penicillins and other beta-lactam antibiotics we studied 29 patients from a group of subjects allergic to beta-lactams, diagnosed by presenting systemic reactions after skin tests or challenge tests. Skin tests with benzylpenicilloyl (BPO), benzylpenicilloate, benzylpenicillin, ampicillin, amoxicillin, cephamandole and AZT, radioallergosorbent test (RAST) to BPO and AZT, RAST inhibition and challenge tests were performed. One patient was skin test-positive to AZT, another patient was RAST AZT-positive. IgE antibodies were specific to AZT as demonstrated by RAST inhibition studies with AZT coupled to epsilon-amino caproic acid. Nevertheless, AZT was unable to inhibit either a pool of sera or individual sera positive to BPO. Although all our 29 patients tolerated the administration of AZT (including those with skin test or RAST positive) and AZT appears to be safe in these subjects, this does not indicate that all beta-lactam-allergic patients tolerate AZT administration.