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Biomedical subjects

L Ruiz

Publications and source records attributed to L Ruiz.

141 records · Page 8Linked to original sources
PubMedDate not supplied

Germination of Nosema algerae (Microspora) spores: conditional inhibition by D2O, ethanol and Hg2+ suggests dependence of water influxupon membrane hydration and specific transmembrane pathways.

The germination of microsporidian spores under conditions expected to affect water flow across the plasma membrane-wall complex was studied by assessing their responses to in vitro stimulation with Na+ or K+. Partial or full substitution of common water with D2O, which more effectively coats ions and electrostatically-charged cell surfaces with relatively stable hydration layers, delayed and inhibited spore germination in a concentration-dependent manner; yet, preincubation in 100% D2O did not change the normal response to standard stimulation. Water structure-breaking conditions, such as an increase in temperature (within the 15 degrees C to 40 degrees C range) or in ionic strength (1- to 10-fold normal), opposed the inhibition by D2O and allowed significant stimulation by Li+, the monovalent cation with the largest hydration diameter and a usually weak stimulant action on the spores. Ethanol, known to reduce water permeation across cell membranes and phospholipid bilayers, also caused a powerful and dose-dependent (1% to 4% v/v) inhibition of spore germination, but pretreatment with ethanol did not affect the normal response. HgCl2, an inhibitor of specific water channels, blocked spore germination at just 250 microM in the normal stimulation solution irrespective of the temperature, and permitted only a delayed response in high salt stimulation solutions. However,the inhibition by Hg2+ was abolished by the simultaneous presence of 2-mercaptoethanol in the medium. These results suggest (1) that spore germination is keenly dependent upon the hydration states of both the plasma membrane-wall complex and the stimulant ions, and (2) that osmotic water flows into the spores through specific transmembrane pathways with critical sulfhydryl groups, i.e., analogous to the water channels that facilitate water movements across the plasma membranes of highly permeable cells.

Animals↗
PubMedDate not supplied

Subcutaneous phaeohyphomycosis caused by Phoma cava. Report of a case and review of the literature.

We report a case of subcutaneous phaeohyphomycosis observed in a male patient presenting pulmonary sarcoidosis and submitted to corticosteroid treatment. He presented nodular erythematous-violaceous skin lesions in the dorsum of the right hand. Histopathological examination of the biopsied lesion revealed dematiaceous hyphae and yeast-like cells, with a granulomatous tissual reaction. The isolated fungus was identified as Phoma cava. A review of the literature on fungal infection caused by different Phoma species, is presented. The patient healed after therapy with amphotericin B. followed by itraconazole.

Amphotericin B↗
PubMedDate not supplied

[Characteristics of the tuberculin reaction in Cantabria].

For the purpose of establishing the maximum cutoff point defining a positive tuberculin reaction in Cantabria, a study was made of a total of 1,814 school-age children, 7 and 14 years of age, selected at random from the school-age children in that region. 2 U of PPD RT-23 were used. It was observed that 26.8% of these children had a scar from having been vaccinated with BCG. The graph of induration frequencies is bimodal for both age groups and for those vaccinated and those not having been vaccinated. In the 5-9 mm. range, 69 (71%) of those studied had a scar, and 25 (26%) did not (p less than 0.001). In our region, a different cutoff point must be used for the purpose of this test: 5 mm. for screening and 10 mm. for estimating the prevalence of infection.

Adolescent↗
PubMedDate not supplied

The trigeminal pupillary reflex as a model of vegetative-nociceptive interaction: physiological and clinical aspects.

The study of pupil response to stimuli applied at the corneal level is particularly interesting for the study of integrative sensory-vegetative functions in both physiological and clinical research. In the present study we tried to evaluate and describe pupil response to quantified corneal stimuli in 7 healthy subjects by means of a binocular TV pupillometric device. The pupil response to corneal stimuli was bilateral, direct and consensual. It was characterized by a biphasic progression with an initial response in mydriasis and a later miotic component which was smaller, slower and of longer duration. A direct correlation was observed between the intensity of the stimulus applied and the extent of the mydriasis and between the intensity of the stimulus at the corneal level and the length of the mydriatic response.

Adult↗
PubMedDate not supplied

[Psychosis and cannabis consumption: study of the psychopathologic differences and risk factors].

The consumption of Cannabis has been related with different psychiatric disorders. However the role of this drug in the etiology of disorders has not yet precisely been established. It has been discussed that the existence of an Induced Psychosis is brought about by the consumption of Cannabis. The objective of our study is to determine if there exists specific characteristics in the psychotic disorders manifested after the Cannabis consumption in comparison with a group of Psychotics non consumers. We also defined the risk factors that influence the appearance of the psychopathologic troubles.

Adolescent↗
PubMedDate not supplied

Age-related changes in excitability of nociceptive flexion reflex. An electrophysiological study in school-age children and young adults.

By stimulating the sural nerve at the retromalleolar level and recording EMG response from biceps femoris muscle two components can be evoked: RII (shorter latency, lower threshold, non-nociceptive) and RIII (longer latency, higher threshold, nociceptive). RIII reflex represents a useful tool for pain research in humans since a close correlation exists between the reflex threshold and that of pain. In our study, latency, amplitude, duration and threshold of RII and RIII reflexes were investigated in school-age children (aged 7-14 years) and young adults. RIII threshold was significantly lowered in children, while the other parameters were similar in both groups. Our data suggest the existence of a reduced inhibitory descending control in nociceptive spinal neurones in children.

Adolescent↗
PubMedDate not supplied

A record card for the study of Neuronal Hyperexcitability Syndrome.

Neuronal Hyperexcitability Syndrome (NHS) is a nosographic picture which is difficult to diagnose, due to the lack of specific standard diagnostic criteria. With slightly varying symptoms the syndrome has also been defined as Spasmophilia and Hyperventilation Syndrome. It is difficult to distinguish between NHS and panic attack disorder as there is considerable overlapping of symptomatology. We aimed to propose a standardized card which will be the first step toward a valid diagnosis of this complex neuropsychiatric problem. This card, which will be validated and of which the reliability will be evaluated, is proposed for clinical and research purposes. The card is made up of 6 parts (113 items) covering: personal data, pharmacological treatment, persistent diseases and related therapies, symptomatology trend, factors interfering with calcium-magnesium homeostasis and symptom assessment. The symptom assessment section is essential for the checking of diagnostic criteria and the earlier sections are important for the monitoring of other factors which can cause symptoms able to simulate NHS. There are also two special sections for recording laboratory tests and patients' psychic profiles.

Anti-Anxiety Agents↗