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Biomedical subjects

O Romero

Publications and source records attributed to O Romero.

11 recordsLinked to original sources
PubMed2003

Molecular mechanisms of glutamate release by bovine chromaffin cells in primary culture.

Previous work indicated that glutamate could be involved in the regulation of catecholamine secretion in bovine chromaffin cells. Thus, the question arises on the source of this putative regulatory glutamate. In this work we have examined the possibility that glutamate could be released from chromaffin cells. Data from this study indicate that chromaffin cells are able to release glutamate when they are stimulated by different depolarising agents such as 60 mM KCl, 1 mM 4-aminopyridine or 50 microM veratridine. The amount of glutamate released by these compounds was 0.32 nmol/10(6) cells (9.24% of cellular glutamate content), 0.275 (7.86%) and 0.158 (4.52%) for KCl, 4-AP and veratridine stimulation, respectively. All these catecholamine-secretagogues induced glutamate secretion by two mechanisms: 1) a Ca(2+)-dependent, probably exocytotic, mechanism and 2) a Ca(2+)-independent mechanism mediated by reversion of the electrogenic glutamate transporter. Analysis of Ca(2+)-dependent and independent releases for different compounds carried out by several experimental approaches, indicate that Ca(2+)-dependent release was the predominant mechanism for release induced by 4-aminopyridine (84% of total release) and high KCl (63%) whilst Ca(2+)-independent release was predominant for veratridine (67%). The Ca(2+)-dependent glutamate release evoked by depolarisation of chromaffin cells with high KCl and 4-AP could be split into both a fast and a slow kinetic component, which might correspond to the release of docked and mobilised chromaffin granules, respectively. On the other hand, depolarisation of cells with veratridine result in glutamate release with only the fast kinetic component. In the case of 60 mM KCl-evoked glutamate release, the fast component exhibited a decay time of <1 s and accounted for 0.63 nmol glu/6x10(6) cells (70% of total exocytotic release), whereas the slow component, which exhibited a decay time of 231 s, accounted for the release of 0.27 nmol glu/6x10(6) cells (30% of total exocytotic release). By contrast in the case of 4-aminopyridine the fast component of exocytosis only represents a 19% of total secretion and the slow a 81% with a decay time of 94 s. These data are very similar to those found in neurones and support the possible intracellular origin of glutamate having a role in the regulation of catecholamine secretion from chromaffin cells. In support of this, we have found that glutamate secretion could be evoked by stimulation of the nicotinic cholinergic receptors.

Adrenal Glands↗
PubMed1995

Prevention of asthma with ketotifen in preasthmatic children: a three-year follow-up study.

Growing morbidity and mortality rates call for research towards more effective methods of preventing asthma. During the last decade several groups have reported the results of natural history and asthma prevention studies. However, the attempt to prevent development of asthma in genetically predisposed children, has not resulted in a generally accepted management scheme. The aim of this study was to evaluate the effectiveness of ketotifen in preventing the onset of asthma in infants considered to be at high risk of developing the disease, but who had no history of respiratory obstruction. These children have been described as preasthmatic. In this double-blind, placebo-controlled, parallel study, 100 infants with a family history of major allergy and elevated serum IgE levels, but with no history of bronchial obstruction, were treated with either ketotifen (n = 50) or placebo (n = 50) over a 3-year period. There were no statistically significant differences between the two groups with regard to age, sex, degree of hereditary allergy, levels of serum IgE upon joining the study, and family smoking habits. At the end of 3 years, only four of the 45 infants who had received ketotifen had developed asthma (9%). Of the 40 children given placebo, 14 had developed asthma (35%) (P = 0.003). These results suggest that ketotifen is effective in preventing the onset of asthma in preasthmatic children.

Asthma↗
PubMed1995

Phase advancement of slow-wave sleep in a patient with periodic hypersomnia.

Twenty-four-hour polysomnographic recordings were obtained during asymptomatic (ASP) and symptomatic (SP) periods in a patient with periodic hypersomnia. During both periods, an abnormal sleep architecture was detected, with a greater sleep fragmentation during the SP. An unexpected finding was a shortening of the latency of slow-wave sleep, with a difference of more than 5 hours between the ASP and the SP. The greater fragmentation of rapid eye movement sleep during the SP may suggest a disorganization of the ultradian rhythm of rapid eye movement sleep.

Adult↗
PubMed1992

Differential reactivity of Agaricus bisporus lectin with human IgA subclasses in gel precipitation.

The interaction between purified Agaricus bisporus lectin and several human proteins was studied using the Ouchterlony double diffusion and immunoelectrophoresis techniques. Only one precipitation line was observed with normal human serum, normal human colostrum, IgA1 myeloma serum, both serum monoclonal and secretory IgA1 and monoclonal IgD. No reaction was observed with monoclonal and secretory IgA2, IgG, IgM, alpha 2 macroglobulin or pregnancy-associated alpha 2 glycoprotein. These results were confirmed by hemagglutination inhibition assays when IgA1, IgA2 and IgD were tested. On the basis of this reactivity, ABL could be a useful tool for distinguishing and isolating human IgA subclasses.

Humans↗
PubMed1992

Plants used by Mexican traditional medicine with presumable sedative properties: an ethnobotanical approach.

An ethnobotanical study of plants used in Mexican traditional medicine was made. The source was the national inquiry done by the IMSS-COPLAMAR health program (1983-1985) in which the plants used to treat mental disorders were selected and analyzed, in order to select the most frequent botanical species used in traditional medicine as sedatives, anticonvulsants and hypnotics.

Anticonvulsants↗
PubMed1980

IgM in saliva from allergic children.

In this study the authors investigated the relationship between secretory IgA levels and the appearance of a compensatory mechanism, through IgM action in allergic children.

Child↗
PubMed1978

A simple method for quantifying IgM of low molecular weight.

A new and simple method for quantitation of IgM of low molecular weight in sera by radial immunodiffusion in 7% agar gel is described. The test is easy to perform and permits exact determination of low molecular weight IgM concentration down to very small quantities (1 mg%). Results obtained with the method described agree with previously used assay procedures and offer the advantage of convenience and rapidity.

Animals↗
PubMed1977

Induction of organ-specific antigens of the rabbit male accessory glands by injection of testosterone or gonadotrophin.

Highly specific antiserums for two antigens of rabbit male accessory glands, called FII and FV, were used to study the effect of hormonal treatment on their appearance during postnatal development. Single or double serial injection of testosterone, or human chorionic gonadotrophin, produces an increase in accessory gland and testis weight, and at the same time induces the synthesis of a detectable amount of specific antigens. This was proved by using groups of animals 4 and 6 1/2 weeks old. The antigens were consistently absent in accessory glands from normal and control animals of the same age. The histologic characteristics of maturation were also observed. Ultrastructural studies revealed an increase in number of microvilli supranuclear vaculoes with secretory content and well developed rough endoplasmic reticulum. These changes were more easily detected in young animals treated with chorionic gonadotrophin. The significance of these findings is discussed in relation to the presence of specific carriers (cytosols).

Animals↗
PubMedDate not supplied

[Insomnia in the elderly: cognitive involvement and therapeutic attitudes].

INTRODUCTION: Sleep is an important biological function, which greatly affects the quality of life at all ages. Sleep influences the alertness and stress levels, psychosomatic diseases and health in general. DEVELOPMENT: The predisposition to insomnia increases with age, illnesses such as heart disease, breathing disorders, cancer, strokes, pain and polyuria often disturb sleep patterns. In addition, the aging process, which directly alters sleep-wake cycles and other cerebral functions, affects the elderly. All the above points can lead to an increase in sleep latency, less total sleep time, increases in early awakening and a greater frequency of daytime naps. In an attempt to improve sleep in the elderly, and thus their quality of life, we can try to prevent stress and psychiatric symptoms by altering life-styles and improve the patients' awareness of the problem. Hypnotic drugs are useful for short periods but for longer ones we prefer techniques which attempt to modify behavior. In chronic patients who need treatment with hypnotic drugs for a long time, therapy must be individualized.

Aged↗