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Biomedical subjects

C Suárez

Publications and source records attributed to C Suárez.

At least 91 records · Page 5Linked to original sources
PubMed1995

Loss of heterozygosity and mutation analysis of the p16 (9p21) and p53 (17p13) genes in squamous cell carcinoma of the head and neck.

We analyzed allelic loss at the p53 gene (17p13) and at chromosome region 9p21 in 35 primary head and neck squamous cell carcinomas. Loss of heterozygosity (LOH) at p53 and 9p21 was found in 50 and 75% of informative cases, respectively. LOH at the p53 gene did not increase significantly with tumor stage, but was more frequent in moderately and poorly differentiated tumors than in well-differentiated tumors. LOH plus mutation or homozygous deletion of p53 was limited to advanced stage and poorly differentiated tumors. Allelic loss at 9p21 is frequent in early stage head and neck squamous cell carcinoma and is not significantly associated with LOH at p53. The second exon of the p16/MTS1/CDKN2 gene was found to be homozygously deleted in 1 of 19 cases showing LOH at 9p21, but direct sequencing did not show mutations in the remaining 18 cases. This suggests that p16 plays a limited role in the development of head and neck squamous cell carcinoma.

Carcinoma, Squamous Cell↗
PubMed1994

[Essential and symptomatic trigeminal neuralgia].

We present the principal differential characteristics of neuralgia of symptomatic and idiopathic trigeminus. Out of 39 consecutive patients with neuralgia of trigeminus evaluated clinically and with neuroimage study, we find recognizable pathology in 10 (3 arterio-venous malformations, 1 dolichoestasia of basilar artery, 3 tumors, 3 multiple sclerosis). Symptomatic neuralgia occurs in patients with lower average age and is accompanied by atypical symptoms or abnormal neurological signs and is no different from idiopathy as a response to pain from medical treatment. Painful affectation of the trigeminus requires the realization of complementary explorations aiming to dismiss associated neurological pathology.

Adult↗
PubMed1993

Computer assisted CT-guided stereotactic transplantation of foetal ventral mesencephalon to the caudate nucleus and putamen in Parkinson's disease.

We report our preliminary results related to CT-guided stereotactic transplantation of foetal ventral mesencephalic cell suspension into the striatum of five patients with idiopathic Parkinson's disease. The mean age was 51 years, the evolution time of the disease ranged from 7 to 14 years, and all of them had motor complications associated with chronic L-dopa therapy. The patients were evaluated according to the Core Assessment Program for Intracerebral Transplantations (CAPIT) for one year before and three months after surgery. The postoperative clinical assessment demonstrated significant improvement of neurological symptoms and reduction of daily L-dopa dosage.

Caudate Nucleus↗
PubMed1993

Neck dissection with or without postoperative radiotherapy in supraglottic carcinomas.

A retrospective review of 302 previously untreated patients with primary supraglottic carcinoma was undertaken to ascertain the efficacy of postoperative radiotherapy. The 302 patients underwent a total of 383 functional neck dissections and 45 classic radical neck dissections. Pathological examination revealed nodal involvement in 117 patients (39%). In the histologically N0 group, the incidence of contralateral neck recurrence when a unilateral neck dissection and postoperative radiotherapy were carried out was 8%, rising 21% when no postoperative radiation was given. There was no difference in the ipsilateral recurrence rate in the N0 group, radiated patients (3%) and nonradiated patients (2%). Similar figures were found in the N1 group. Bilateral functional neck dissection in histologically N0, N1, and N2 necks had similar recurrence rates with or without radiotherapy. Distant metastasis appeared in 10% of N0 patients and in 35% of N3 patients. Patients who received postoperative radiotherapy showed a significantly higher rate of distant metastasis (21%) than patients who did not (8%). The number of involved lymph nodes had no relevance both in neck recurrence and distant metastasis.

Carcinoma↗
PubMed1993

Morphometric analysis of the vestibular complex in the rat.

The characteristics of the four major vestibular nuclei and accessory cell groups in the rat have been studied in serially cut horizontal sections. Camera lucida drawings of the vestibular nuclei and their neurons were made in these sections and subjected to a computerized image analysis. The dimensions (volume and length) and the number of cells of each vestibular nucleus were obtained, as well as morphometric parameters of their neurons (cross-sectional area, maximum and minimum diameter, and shape). These parameters were statistically analyzed by comparing the cell population from different nuclei and different parts of each nucleus. Of the major nuclei, the medial, which is the largest, has the greatest number of cells, its neurons being the smallest of all the nuclei, with the size of cells decreasing in a rostrocaudal direction. In contrast, the lateral nucleus contains the fewest cells but also the largest ones. Neurons of the superior and descending nuclei are of an intermediate size and number, with a rostrocaudal decrease in the size of the descending nucleus cells. In addition, minor nuclei are identified and described in their relationship to the other structures in the brain stem. The relevant aspects of the anatomical information in regard to functional roles are reviewed.

Animals↗
PubMed1993

Morphologic and quantitative study of the efferent vestibular system in the chinchilla: 3-D reconstruction.

An HRP study of the EVN has been performed. Three groups of somas have been identified: Those located in the proximity of the vestibular nuclei, those sandwiched between the facial genu and the IVth ventricle, and those in the RF, surrounding the abducens nucleus. The number of somas is greater in the contralateral brain-stem side. Axons could be followed through the midline, but could not be traced to a labelled soma. A 3-D reconstruction of the EVN within the brain stem is presented.

Animals↗
PubMed1992

Afferent innervation of the vestibular nuclei in the chinchilla. II. Description of the vestibular nerve and nuclei.

The morphological characteristics of the vestibular nuclei of the chinchilla were studied in horizontally cut serial sections of the brain stem. Horseradish peroxidase labeling allowed unambiguous delineation of the vestibular nuclei and areas of innervation by the vestibular afferent fibers. The cytoarchitecture of the vestibular nuclei was documented with the aid of camera lucida drawings and quantitatively evaluated with computerized methodology. The cellular groups identified in other species were found in the chinchilla. The superior vestibular nucleus (SN) originated ventromedial to the mesencephalic tract and nuclei of the trigeminal nerve. This nucleus contained medium-sized cells with a central group of larger cells (20-34 microns in diameter). It received its maximum vestibular innervation caudally in the ventrolateral and dorsal aspects of the nucleus. Fibers projected to the SN in bundles with thick fibers surrounded by thin ones. The lateral vestibular nucleus (LN) originated 0.9-1.2 mm below the rostral aspect of the vestibular area. It was ventrocaudal to the SN and contained many large cells with diameters of 45-60 microns. The LN was innervated mainly in the ventrocaudal aspect by oblique and transverse fibers that formed a dense mesh. The medial vestibular nucleus (MN) originated 0.3-0.6 mm caudal to the beginning of the SN, adjacent to the floor of the IVth ventricle. It extended for 3-4 mm along the SN, LN and descending vestibular nucleus (DN). The MN contained the densest and most homogeneous cells, which had diameters of 10-20 microns. This nucleus received its greatest innervation at the level of the vestibular root. Thin fibers traveled to the MN through the SN and LN. The caudal pole of the nucleus did not receive fibers. The DN originated 1.8-2.5 mm caudal to the origination of the SN, between the caudal LN and the MN. Caudally it replaced the LN. Most of the cells of the DVN were medium-sized, with diameters of 10-20 microns. The main vestibular innervation of the DN was in the lateral aspect of the nucleus. Tertiary fibers projected in small, separate bundles of uniform-sized thick fibers. The interstitial nucleus originated 1.1-1.4 mm from the beginning of the SN. It occupied the center of the vestibular root, 0.8-0.9 mm medial to the root entry zone. It contained a few large cells (greater than 20 microns in diameter), many medium-sized cells, and some small cells.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1990

Morphological aspects of the human vestibular nerve.

A quantitative study was made of the number of fibers, their diameters, and distribution in the nerves innervating individual vestibular receptor organs of three human temporal bones. The specimens were obtained from autopsies conducted within 4 hours postmortem. The temporal bones containing the nerves were fixed in 3% glutaraldehyde and decalcified with EDTA until they were soft enough to allow dissection of the nerve branches to the individual receptors. The nerve branches were processed for osmium staining, embedded in plastic, and cut serially in 1-micron-thick sections for light-microscopic histologic evaluation of their fiber composition. Quantitative evaluation of nerve-fiber characteristics was made with the aid of a laboratory computer and programs for graphic representation and statistical analysis. In the nerves to the individual cristae the number of fibers ranged between 1416 and 2335. Fibers with diameters between 2.5 microns and 3 microns were the most numerous. The number of fibers decreased exponentially with increased size. The thickest fibers had diameters up to 11.5 microns. The distribution of fibers in the nerve of each crista was different for the central and intermediate areas of the crista than it was for the ends. Thin fibers with diameters less than 2.5 microns, which represented 36% of the population, projected to the ends of the receptor area. Thick fibers with diameters greater than 4.5 microns, which represented 8% of the fibers, were distributed relatively uniformly except for the extreme ends of the crista, where they were nearly absent. Fibers with intermediate diameters were distributed throughout the crista, although they were more concentrated at the ends. In the nerves to three maculae, the number of fibers ranged from 3744 to 5538. The percentage of fibers of each size, however, was similar to that in the cristae. The greater portion of fibers had diameters between 3.0 microns and 3.5 microns. Because of the anatomical configuration of the maculae, it was not possible to compare fiber diameters from one area to another. The composition and differential projection of fibers to the crista in the human labyrinth were similar to those found earlier in squirrel monkeys and bullfrogs. On the basis of these similarities in the pattern of innervation, it is suggested that the physiological properties in humans must be similar to those in animals.

Aged↗
PubMed1989

Primary vestibular projections in the chinchilla.

The central projections of fibers from the vestibular nerve were studied in 19 chinchillas after horseradish peroxidase labelling. In addition, the limits of the vestibular nuclei and the anatomical characteristics of their neurons were also studied. All five vestibular nuclei received primary afferents, but there were extensive areas of them that received very little or no projections at all, such as the rostral part of the superior vestibular nucleus, the dorsocaudal part of the lateral vestibular nucleus, the caudal half of the medial vestibular nucleus and the caudalmost aspect of the dorsal vestibular nucleus.

Afferent Pathways↗
PubMed1985

Preparation and evaluation of a soluble derivative of the antiallergic compound trans-2, 3b, 4, 5, 7, 8b, 9, 10-octahydronaphtho [1, 2-c:5, 6-c'] dipyrazole (LC-6).

In the present report we describe the preparation of LC-6.2HCl, a soluble derivative of the synthetic bispyrazole LC-6. Because the latter was practically insoluble in aqueous and organic media, experiments which indicated that it had antiallergic activity were confined to in vivo studies following its oral administration. The availability of soluble LC-6.2HCl made it possible to administer the drug i.v. or i.p. Through these routes it exhibited greater antiallergic activity than by the oral route, as judged by lower ID50's and by the achievement of 100% PCA inhibition. The latter result had not previously been attained orally with the base. Furthermore, when injected i.v. or i.p. LC-6.2HCl showed prolonged inhibitory activity, a valuable attribute of the parent compound. The in vivo activity of the soluble salt, which we describe, further establishes the potential therapeutic value of the drug.

Administration, Oral↗
PubMed1985

Defective radioresistant suppressor cell activity in hemodialysis patients.

The immunologic alterations in patients on hemodialysis are only partially understood. We studied the Concanavalin A (Con A) induced suppressor cell activity of irradiated and nonirradiated cells in a mixed lymphocyte culture. Peripheral blood lymphocytes from 18 normal individuals and 14 patients on regular hemodialysis were incubated with two different concentrations of Con A (10 micrograms and 40 micrograms of Con A/million cells). Irradiated and nonirradiated cells were then tested for their capacity to suppress a standard MLC. The proliferative response to phytohemagglutinin, pokeweed mitogen and Con A was also determined. Suppressor cell activity of nonirradiated cells in hemodialysis patients was similar to that of controls, at both concentrations of Con A, while irradiated cells of hemodialysis patients showed a suppressor cell activity significantly lower than that of the controls, at a Con A concentration of 40 micrograms/10(6) cells (25.78 +/- 18.86% vs. 46.05 +/- 9.79%, p less than 0.001). The proliferative response of lymphocytes from hemodialysis patients to the three mitogens, did not show any difference when compared with normal controls. The normal proliferative response of lymphocytes from hemodialysis patients to mitogens and the normal suppressor cell activity of nonirradiated cells, suggest a normal T cell function. The abnormal suppressor cell activity in irradiated cells indicate that the radioresistant population has a functional defect. The cell responsible for this suppressor defect probably belongs to the monocyte/macrophage population because of its relative radioresistance.

Adult↗