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Biomedical subjects

E Rubio

Publications and source records attributed to E Rubio.

At least 109 records · Page 6Linked to original sources
PubMed1983

Unusual penetrating craniocerebral injury.

We report a 29-year-old patient who was operated on for a penetrating craniocerebral injury caused by an underwater fishing harpoon. It had penetrated through the roof of the left orbit, upward toward the calvaria. The patient was immediately operated upon and the foreign body was easily removed through a small left parietal craniectomy. In spite of the spectacular appearance of the injury on admission to the hospital, neurological impairment before and after the operation was minimal.

Adult↗
PubMed1980

A model for non-linear processing in cat's retina.

The model is based on the concept that non-linear lateral interaction at the inner plexiform layer accounts for most of the specialization and marked non-linearities in cat's retinal ganglion cell responses. The inputs to the lateral interaction processes are a spatio-temporal signal and its retarded, as suggested by the behaviour of simple ganglion cells. Lateral interaction in the model consists of lateral linear inhibition followed by local half wave rectification. The resulting signals are weighted and summated by the ganglion cell thereafter. A transparent and general expression is obtained for the response of the cell model which, albeit its simplicity, leads to most of known types of non-linear responses, including the rarely encountered specialized cells in cat's, retina, except colour coding units. For negligible lateral interaction, the model reduces to spatio-temporal linear models under the two paths hypothesis. A discussion of the possible role of anatomical units in these retinal processes in presented, where a general interpretation for visual processing in cat's retina evolves from.

Animals↗
PubMed1980

A layered model for visual processing in avian retina.

Visual processing in avian retina is interpreted by means of a layered model in which: a) outer layers provide with spatio temporal fast and retarded versions of the stimuli incident on the retina; a possibility is that horizontal cells are involved in isotropically generating the retarded version which is transversally translated; b) prominent specialization of ganglion cells is the result of local non-linear lateral interaction at the inner plexiform layer, mediated by amacrines which return, also isotropically, the translated retarded signals. Small though systematic deviations in the sites of the lateral interaction result in anisotropic but uniform receptive fields for some ganglion cells. A simple though general expression for the model is derived which includes the various types of recorded avian ganglion retinal cells responses, which also permits a unified interpretation of visual processing in avian and cat's retinae.

Animals↗
PubMed1980

A theoretical proposal to account for visual computation in a frog's retina.

Our theoretical account for visual computation in a frog's retina is based on the concepts that: (a) outer retinal layers provide three spatial channels of information pertaining to local spatio-temporal properties of retinal stimuli; (b) prominent specialisation in a frog's retina is the result of a non-linear lateral interaction at the inner plexiform layer; (c) ganglion cell firing frequency is determined by a local computation wherein signals from processes above are either excitatory, facilitatory or defacilitatory. General though concrete expressions for the processing at different layers are developed from these concepts. They result in a unified model for ganglion retinal cells in frog, from which the various extreme groups of ganglia can be deduced. The model leaves a natural margin to fit intermediate types, both found and likely to be found.

Animals↗
PubMed1979

A theoretical model for layered visual processing.

A theoretical general model of layered computation in the retina is presented. Each layer is functional in the sense that it may correspond or not to an anatomical layer. It is formed by computing elements which can perform in principle any non-linear arbitrary function on a three-dimensional input space. This space consists of 2 spatial dimensions, plus time. The function performed by each computing element of a layer is simplified for the cases of invariance, space or time linearity and for time independence. Two illustrations are also presented. The first is a model of the simple ganglion cells in cat's retina. The second, a model of the group 2 ganglion cell of the frog's retina.

Animals↗
PubMed1977

Recuperative potential of cardiac muscle following relief of pressure overload hypertrophy and right ventricular failure in the cat.

This study examined the recuperative potential of cat hearts subjected to experimental right ventricular pressure overload (for a 10- to 14-day period) which provoked hypertrophy with and without congestive heart failure. Five groups of cats were studied: normal controls; one group with 70% pulmonary artery constriction which produced right ventricular hypertrophy (RVH); one group with an 87% constriction which also produced right ventricular hypertrophy but with congestive heart failure (CHF); and two groups which had been similarly subjected to pressure overload but which had been allowed a recovery period of 30 days after relief of the pressure overload. Both the 70% and 87% pulmonic constrictions were associated with extensive right ventricular hypertrophy, depression of myocardial contractile function, and severe redlction of cardiac norepinephrine stores (normal, 1.42 mug/g: RVH, 0.11 mug/g; CHF, 0.01 mug/g). After a 30-day period of relief from the pulmonic constriction normal hemodynamic function returned. In cats in which RVH had been relieved, right ventricular weight and contractile function were normal but catecholamine depletion persisted. Cats with relieved CHF showed depressed contractile function and depleted myocardial norepinephrine, and the right ventricular weight did not return to normal. Cardiac muscle of all pressure-overloaded nonrelieved hearts showed depressed velocity of shortening and depressed ability to sustain load. Cats with RVH alone regained normal muscle shortening velocity and load-bearing ability after relief. However, cardiac muscle from the CHF-relieved group recovered only unloaded shortening velocity while the ability to sustain load remained depressed. We conclude that the recuperative potential of myocardium damaged by pressure overload is adequate provided congestive heart failure has not occurred. Heart failure produces a persistent reduction in force-generating ability of the myocardium. Hypertrophy due to pressure overload, with or without CHF, leads to cardiac catecholamine depletion which is not readily reversed by relief of the overload.

Animals↗
PubMedDate not supplied

Weight gain associated with cinnarizine.

OBJECTIVE: To report four cases of cinnarizine-induced weight gain. DATA SOURCES: Case reports from a local obesity center and review articles. DATA EXTRACTION: Data were abstracted from spontaneous comments made by patients to one of the authors, who was a doctor at the clinic, and reviewed by the remaining authors. DATA SYNTHESIS: We reviewed the cases of four women, aged 50-57 years without endocrine or metabolic pathologies, that showed weight gain associated with the intake of cinnarizine for one to two years. No other drugs usually were administered during the period in which the women gained weight, although in two cases cinnarizine was associated with dihydroergocristine in the same medicine (Clinadil). The mean weight increase was 6.25 kg (range 4-10). The increases do not appear to be related to whether the patients' initial weight was ideal or excessive. The weight gain was always associated with increased appetite and food intake. One patient discontinued cinnarizine treatment and her weight returned to its previous level. CONCLUSIONS: Cinnarizine is a piperazine derivative used in the treatment of vertigo and in the prophylaxis of migraine. In contrast to related drugs, data about cinnarizine are scarce because randomized trials of cinnarizine have been inconclusive. Our observations indicate that cinnarizine may cause weight gain, as observed with other drugs in the same class.

Appetite↗
PubMedDate not supplied

[Subarachnoid hemorrhage, cerebral ischemia and endothelin-1].

INTRODUCTION: Cerebral vasospasm is involved in the development of delayed ischemic lesions in patients with subarachnoid hemorrhage. We developed an integral theoretical model to explain the pathophysiology of cerebral vasospasm, in which endothelin-1 has a pivotal role in the development of both cerebral vasospasm and delayed ischemic neurological deficits (DIND). OBJECTIVE: The objective of this study is to analyze the relationship between temporal profile of plasma endothelin-1 levels and the development of cerebral vasospasm and DIND. PATIENTS AND METHODS: We analyzed sequentially plasma endothelin-1 levels in 17 patients with aneurysmatic subarachnoid hemorrhage. All the patients had complete clinical and neuroradiological studies. Patients were classified according to Fisher's score. RESULTS: Patients (4 males and 13 females, aged 48.1 +/- 20.3 years) had a good clinical condition (Hunt-Hess < 4, GCS > 10). Two weeks after bleeding, patients had higher plasma endothelin-1 levels than healthy volunteers (p = 0.024). Patients who developed DIND had higher plasma endothelin-1 levels (p = 0.034) and a different evolution (p = 0.0146) than patients without DIND. There is a significant correlation (p = 0.02) between basal plasma endothelin-1 levels and GOS score. Multiple regression analysis shows a significant dependence between plasma endothelin-1 levels and Fisher's score (p = 0.0195), development of DIND (p = 0.0095), and GOS score (p = 0.0319). Logistic regression analysis finds a predictive relation between Fisher's score and plasma endothelin-1 levels for the development of DIND (overall predicted = 74.24%; p = 0.0148). CONCLUSIONS: Plasma endothelin-1 levels are increased in patients after subarachnoid hemorrhage and are associated with the development of cerebral vasospasm and DIND.

Aged↗
PubMedDate not supplied

[Hypertrophic pachymeningitis. A review of the histories of two cases and pathological relationship with the Tolosa-Hunt syndrome and the orbital pseudotumor].

INTRODUCTION: Hypertrophic pachymeningitis is an infrequent condition which starts with a thickening of the dura mater and whose pathogenesis is unknown. We present two new cases of unknown aetiology. CLINICAL CASE: Case 1. A 53 year old man complained of occipital headache, tinnitus and deafness since February 1981. In October 1981 he was admitted to hospital with a worse headache, perio-orbital pain, dysgeusia and ipsilateral peripheral facial palsy. In December he had generalized tonic-clonic seizures and paralysis of the VII and XI right cranial nerves and IX, X and XII left cranial nerves. In February 1982 he developed right trigeminal neuralgia. He was readmitted in November 1983 with continuous headache, vomiting and a behavior disorder. On CT there was marked attenuation of the posterior dura mater, which the neurosurgical department considered unsuitable for biopsy. He died in March 1985. On necropsy there was hypertrophic pachymeningitis. Case 2. A 62 year old patient consulted in November 1995 complaining of right hypoacusia for the past six months, progressively accompanied by ipsilateral paralysis of the II, IV, VI, VII and VIII cranial nerves but with no other alterations on physical examination. Analytical and serological investigations were normal. Cranial MR showed an extraparenchymatous infiltrating lesion in the middle cranial fossa. Biopsy was decided on when no clinical improvement was seen with corticosteroid treatment. The pathologist reported hypertrophic pachymeningitis. Treatment was started with cyclophosphamide in monthly doses and the condition has remained stable to date. CONCLUSION: With these two cases we wish to establish a pathogenic relation between the Tolosa-Hunt syndrome and orbital pseudotumor and show the role played by immunosuppressive treatment in the control of hypertrophic pachymeningitis.

Brain↗
PubMedDate not supplied

[Distal aneurysms of the vertebrobasilar system. A report of five cases].

INTRODUCTION: Aneurysms distal to the circle of Willis are uncommon. Among the rarest of such aneurysms are those found in the territory of the vertebrobasilar artery. OBJECTIVE: To describe clinico-radiological aspects and the clinico-surgical evolution of five patients with distal aneurysms of the cerebellar arteries. PATIENTS AND METHODS: Five patients (2.5%), with aneurysms of the cerebellar arteries, of a total of 194 patients with cerebral aneurysms admitted to our hospital between 1995 and 1998. RESULTS: All patients presented with subarachnoid hemorrhage. One patient also had an arteriovenous malformation (AVM). One patient refused surgical treatment, three were treated surgically and one using the endovascular approach. The patient who was successfully treated using the endovascular approach to an aneurysm of the antero-inferior cerebellar artery, and who also had an AVM had a further episode of bleeding following partial embolization of his AVM. The patients who were treated surgically and the one who refused surgical treatment made good progress. CONCLUSIONS: A multidisciplinary approach to the treatment of cerebral aneurysms is essential. Microsurgical techniques are very useful, especially in peripheral aneurysms.

Aged↗