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Biomedical subjects

C Vidal

Publications and source records attributed to C Vidal.

At least 145 records · Page 8Linked to original sources
PubMed1979

Coordinated rhythmic bursting in respiratory and locomotor muscle nerves in the spinal rabbit.

In unanaesthetized, curarized spinal rabbits (C2 level) treated with Niamide and DOPA, rhythmic activities were recorded from the phrenic nerves; close coordination was observed between the phrenic bursts and the locomotor bursts which developed in hindlimb muscle nerves. The frequency of phrenic bursts was reduced after a second spinal transection at the Th12 level, while rhythms in the hindlimb remained unchanged. It thus appears that in the spinal preparation and under certain pharmacological conditions, phrenic bursts generated by the cervico-thoracic spinal cord can be driven by the lumbar generators of locomotion; spinal links thus exist between these hindlimb locomotion generators and spinal interneuronal networks involved in phrenic motoneuronal activation, may be via hindlimb forelimb driving.

Animals↗
PubMed1978

Acetylcholinesterase from Wistar rat brain.

Acetylcholinesterase (E.C.3.1.1.7) was partially purified from rat brains stored in toluene. Extraction was performed using buffers containing non-ionic tensoactive detergents. Some properties of the enzyme were affected by the use of different activity measurement methods, such as the short-time radiometric or the long-time colorimetric method. There were two zones of maximum activity in the range pH 7.5-8.0 and 8.0-8.6, respectively. There seems to be a histidine residue in the enzyme that participates in the catalytic process. Thermal denuration presented first order kinetics and different thermodynamic parameters were obtained on using different incubation periods. On using the short-time activity measurement method there was activation at high substrate concentration, but with the long time method there was a marked inhibition produced by excess of substrate. However, if the enzyme was extracted from fresh rat brain, toluene untreated, these differences dissapeared. Gel filtration and disc electrophoresis showed the presence of multiple and interconvertible forms of the enzyme.

Acetylcholinesterase↗
PubMed1977

[Integrated teaching of morphological sciences in medical training].

To provide more information to participants in the Second Meeting of the Textbook Committee of PAHO/WHO for the teaching of the Morphological Sciences in the Medical Schools of Latin American, a survey was held of the departments of those sciences, in 150 Latin American schools to acquire updated information on the academic organization, the work schedule of the teachers, the levels of integration of the instruction, use of textbooks by students, and the degree of familiarity with the PAHO/WHO Testbook Program and its coverage. The results of the survey, presented in detail in this document, demonstrate the persistence of most of the problems discussed in the First Meeting of the Committee (1969), which makes it necessary to reconsider the integrated teaching of the morphological sciences and the strategies for attaining it. The document also analyzes the development of the morphological sciences and of integration in them.

Education, Medical↗
PubMedDate not supplied

Nicotinic receptors in the brain. Molecular biology, function, and therapeutics.

Although the psychological and physiological effects of nicotine have long suggested that nicotine exerts specific actions in the brain, the identification of neuronal nicotinic receptors (nAChRs) only began in the past few years with the development of molecular genetics. It is now clear that neuronal nAChRs form a family of highly heterogenous receptor subtypes, as evidenced by the number of genes encoding nAChR subunits, the diversity of immunopurified receptor proteins, and the multiple functional types of ligand-gated ion channels. Neuronal nAChRs have discrete localizations within the brain, and are involved in modulating neuronal firing and transmitter release. Cumulative evidence from animal and human studies indicates that nicotinic systems play a major role in higher cognitive functions and dysfunctions. In particular, the loss of cortical nAChRs is a neuro-chemical hallmark of Alzheimer (AD) and Parkinson (PD) diseases. In addition, nicotine improves memory and attention in Ad and PD. Our recent studies using electrophysiological biochemical and behavioral approaches suggest that the prefrontal cortex is a major target site for the cognitive actions of nicotine.

Animals↗
PubMedDate not supplied

Stress hyperalgesia in rats: an experimental animal model of anxiogenic hyperalgesia in human.

Emotional, non-noxious stress consisting of inescapable holding or exposure to novelty were found to produce clearcut and reproducible hyperalgesia in the rat. The mechanisms of the two stress hyperalgesia appeared to be different: 1) hypophysectomy enhanced holding hyperalgesia but reduced novelty hyperalgesia, indicating that pituitary factors respectively compensate (through opioids ?) and participate (through ACTH ?) in stress hyperalgesia; 2) diazepam did not alter holding hyperalgesia but abolished novelty hyperalgesia. The two types of stress hyperalgesia might represent animal models of anxiogenic hyperalgesia observed in human: as for clinical anxieties, they are alleviated or not by diazepam.

Animals↗
PubMedDate not supplied

Relationship of clinical and aerobiological pollen data in the north-west of Spain.

BACKGROUND: few studies report clinical and aerobiological pollen data in the north-west of Spain, a region similar to northern and central Europe. Moreover, it is difficult to obtain patients' collaboration in filling out symptom cards. The aim of this study was to establish a relationship between pollen types and clinical data obtained through questionnaire and telephone calls. PATIENTS AND METHODS: from January to December 2000, 24 patients aged 28 10.6 years and allergic to pollens were studied. The seasonal and hourly rhythm of symptoms and their intensity were obtained monthly by telephone calls. Atmospheric pollen was collected over the same period using a Hirst-type volumetric pollen sampler. RESULTS: the most important pollen types recorded were Poaceae, Betula, Parietaria and Plantago. Most patients (83 %) showed symptoms during March and in the period between May and July (99 %), which coincided with the greatest quantity of atmospheric pollen. Fifty-six percent of the patients complained of symptoms during the first hours of the morning, 63 % during the central hours of the day and 22 % at nightfall. In specific sensitizations, symptoms were more evident during the hours of maximum atmospheric levels of their taxa. CONCLUSIONS: the method employed in the present study to obtain information on patients' symptomatology (telephoning their homes once a month) proved useful and revealed a clear relationship between the presence of certain pollens in the atmosphere and the development of symptoms.

Adolescent↗
PubMedDate not supplied

[Bioelectric impedance in the nutritional evaluation of mentally deficient quadriplegic adults].

Severely mentally retarded persons with cerebral palsy show a high rate of acute and chronic malnutrition. Without discarging other factors which might be at play, caloric intake deficiency stemming from the difficulties involved in being fed appear to play a crucial role in its etiology. In the assessment of these disorders, anthropometry is limited by the lack of adequate reference values and by the difficulty or impossibility of measuring height using the conventional method. The purpose of this study is to see how changes in body composition brought about by an increase in dietary caloric intake are perceived by both anthropometry and biolectrical impedance analysis. To do so, 13 subjects were selected from a group of 203 severely mentally retarded persons made up of 25% cerebral palsy patients and 13% quadriplegics. The 13 subjects were fed orally without tubes and all had tricipital skinfolds of less than P25. All 13 were given a 25% caloric increase over the regular diets for a period of two months. This increase was provided by means of a polymeric, normoproteic, hypercaloric preparation. Weight and brachial perimeter showed significant increases coinciding with the administration of the supplement. Theses increases were not noticeable two months after discontinuing the supplement. There were no significant changes in tricipital and subescapular skinfolds, muscular circumference of de mid-arm, resistance, reactance, or the total body an extracellular water calculated from the latter two values. From these results we deduce that biolectrical impedance analisys offers no advantages over anthropometry in monitoring the nutritional status of quadriplegics.

Adult↗
PubMedDate not supplied

Telangiectasia macularis eruptiva perstans presented as a pseudoallergic food reaction.

Telangiectasia macularis eruptiva perstans (TMEP) is a rare form of cutaneous mastocytosis observed in less than 1% of cases of mastocytosis. Clinically, anaphylaxis may appear as a result of increased mast cell degranulation in different circumstances. A case of TMEP presented as pseudoallergic reactions to foods is reported in which the appearance of typical lesions on the trunk and their histological analysis together with a negative food allergy study confirmed the diagnosis.

Adult↗