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Biomedical subjects

I Hurtado

Publications and source records attributed to I Hurtado.

At least 37 records · Page 2Linked to original sources
PubMed1987

House dust mites in Caracas, Venezuela.

An investigation of bedding dust fauna was carried out in Caracas, Venezuela. Mites were recovered from all samples. The average mite density of 15.6 mites/mg dust was among the highest reported worldwide. Pyroglyphid mites were the most frequent and abundant, and Dermatophagoides pteronyssinus was the largest contributor to the total mite counts. It was also found that the storage mite Blomia tropicalis occurred in 96% of the samples examined and contributed an average of 15% of the total mites. The genera Tyrophagus and Tarsonemus were infrequent but occasionally large contributors to the bedding dust fauna. In our area, therefore, sensitivity to those abundant nonpyroglyphid mites should be routinely investigated in house dust-sensitive patients.

Animals↗
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↗
PubMed1983

Effect of sulfhydryl-reactive ATPase inhibitors upon mast cell and basophil activation.

Ethacrynic acid is an inhibitor of Ca2+-Mg2+-activated ATPases which also inhibits histamine release. By testing analogs of ethacrynic acid, the molecular structural requirements for ATPase inhibition and for inhibition of histamine release were compared. The results indicated that effective inhibition involves several structural features of the molecule. Analogs void of chlorine atoms were ineffective as inhibitors of histamine release and ATPase activity. Inhibition of both ATPase and histamine release requires a sulfhydryl-reactive olefinic bond, but sulfhydryl reactivity alone is not sufficient, as certain analogs which have a high capacity to react with sulfhydryl moieties were not active. Replacement of carboxy by highly ionized moieties like sulfo, rendered the molecules ineffective as an inhibitor of histamine release. Compounds which did not inhibit ATPase activity did not inhibit histamine release. The data indicate that mast cells and basophils require an intact ATPase system for histamine release, and raises the question of whether both ecto and endo ATPases are essential.

Adenosine Triphosphatases↗
PubMed1983

Presence of basophils in PHA-reacted skin sites of mice. An electron microscopic study.

Subcutaneous injections of the lymphocyte mitogen PHA in mice induced a local reaction which was delayed in time course and characterized histologically by dermal infiltration with blood granulocytes. Basophils were identified in the skin sections by electron microscopy as their granules differ from those of other blood granulocytes and tissue mast cells.

Animals↗
PubMed1983

The orally active antiallergic compound, LC-6 (trans-2,3b,4,5,7,8b,9,10-octahydronaphtho[1,2-c:5,6-C] dipyrazole) inhibits the arachidonate lipoxygenase enzyme.

Trans-2,3,4,5,7,8b,9,10-octahydronaphtho[1,2-C:5,6-C]dipyrazole (LC-6), which is active in vivo when administered orally, inhibits histamine release from peritoneal rat mast cells and human basophils in vitro. LC-6.2Cl blocks both IgE-mediated and non-IgE-mediated histamine release. Histamine release induced by antigen, dextran, compound 48/80, or the Ca2+ ionophore A23187 was effectively inhibited. The in vitro data indicate that LC6.2HCl has the capacity to inhibit the mediator release phase of anaphylaxis. The drug has the ability to inhibit arachidonate lipoxygenase activity. The IC50 for IgE-mediated histamine release inhibition is in good agreement with the IC50 for inhibition of arachidonate lipoxygenase activity. The data indicate that LC-6 acts in vivo by blocking the release of mediators; its activity may be explained by its ability to stop the synthesis of lipoxygenase-derived arachidonic acid products.

Animals↗
PubMed1983

Ultrastructure of the mouse blood basophil.

This work establishes the presence of basophils in mouse peripheral blood and describes their ultrastructure. In this species, the cytoplasmic granules, which are membrane-bound and relatively scarce, differ both in size and electron-density. The intragranular particle size is often markedly heterogeneous. All cytoplasmic organelles are visible including a well-defined Golgi and centriole. The bi-lobed or multi-lobed nucleus has peripherally condensed heterochromatin, nuclear pores and often nucleoli. The surface membrane is characteristically abundant in projections and associated cavities. The electron microscope image of the mouse basophil shows similarities to that of the human basophil, but appears different from that of the guinea pig, chicken and rat.

Animals↗
PubMed1981

Synthesis and study of the potential antiallergic activity of some pyrazole derivatives.

The synthesis and study of the oral antiallergic activity of a series of monopyrazole derivatives (2-14) considered as analogues of active bispyrazole 1 are described. None of the compounds showed significant inhibition of the rat passive cutaneous anaphylaxis (PCA), with the exception of the already known 5-aminoindazole (2). The activity of this compound, is however, lower than that of compound 1.

Animals↗
PubMed1981

A new look at basophils in mice.

It is believed that mice do not express cutaneous basophil hypersensitivity because they have few or no basophils. We have looked for these cells in peripheral blood smears of C3H/He, DBA/2, C57BL/6, and Balb/c mice before and after a series of foreign protein injections, a treatment known to induce basophilia. We found 0.2 and 1.5% basophils in the untreated C3H/He and DBA/2 mice and no basophils in the untreated C57BL/6 and Balb/c mice. Basophilia of 2--10% was found in the treated mice of the four strains. We noticed that the microscopic appearance of the mouse basophils differs from that in other species. These results indicate that basophils may be as frequent in mice--believed not to express cutaneous basophil hypersensitivity--as they are both in man and guinea pigs--known to express this entity. Since the mouse basophils have a distinct morphology, different from that of other species, it is possible that they may not have been noticed in routine skin preparations.

Animals↗
PubMed1978

Inhibition of allergic reactions by a new antiallergic drug, LC-6 (trans-2,3b,4,5,7,8b,9,10-octahydronaphthol[1,2-c:5,6-c'] dipyrazole). I. Inhibition of the rat reaginic passive cutaneous anaphylaxis.

A new synthetic compound, LC-6, has been shown to inhibit the passive cutaneous anaphylaxis reactions induced in rats by mouse reaginic antibody. In this system, the ED50 was 35 mg/kg body weight of LC-6 administered per os. LC-6 prevented neither histamine skin reactions nor the reactions to histamine and other chemical mediators released by 48/80. Therefore, its inhibitory activity is comparable to that of the model anti-allergic compound, disodium cromoglycate (DSCG). In contrast to DSCG, the new drug exhibits the distinct advantage of being active per os and over prolonged periods of time. Its activity has been shown to persist for at least 6 h when doses 4 times higher than the ED50 were administered. The duration of the drug effect was clearly dose-dependent. Predoses of the compound increased its effectiveness. The long-lasting association of LC-6 with mast cells, as indicated by its prolonged inhibitory activity, makes it a valuable tool in the search for receptors involved in anaphylactic reactions.

Animals↗
PubMedDate not supplied

A one year survey of airborne pollen and spores in the neotropical city of Bogota (Colombia).

A one-year study of potentially allergenic airborne biological particles was carried out in Bogotá, the capital city of Colombia. Bogotá is a populous city of approximately 6 million inhabitants. Located at 4 degrees Lat N and 2,600 m on the sea level, it has a mild tropical climate. The mean annual temperature of the city is 14 degrees C, the annual rainfall 1,013 mm and the relative humidity 72%. During the year June '86-May '87 the pollen count was 7,626 contributed by 72 grain types. Among these, 24 taxa have been identified. The majority of the grains came from imported trees; Cupressus spp was the main contributor. Weed pollen counts, which include the Compositae (ragweed), were notoriously low (4% of the total). The spore count was 13,264, almost twice as large as that of pollen. Fourty-four spore taxa were identified out of 72 types recorded. More than two-thirds (72%) of the spore count was contributed by the deuteromycetes. Cladosporium was the more frequently recorded genus, Penicillium/Aspergillus second next. Miscellaneous particles recorded were 609 Algae and 142 fern spores. Because of its location in the tropics, Bogotá has neither true seasons nor the large variations in atmospheric particle counting which are typical of temperate zones. However, distinct periodical increments in the counts of various species (peaks) may be the cause of seasonal allergic symptoms.

Air Pollutants↗
PubMedDate not supplied

Soft contact lens damage: a one-year study in Caracas, Venezuela.

We reviewed 424 requests for soft contact lens cleaning that had been sent to a service laboratory in Caracas, Venezuela in the course of a year. We believe that this sample represents a cross-section of problem lenses in a tropical country (Venezuela). Among the cases for which data were available, there were more extended wear lenses than daily wear lenses sent for cleaning. A majority of the lens wearers were females and/or over age 20. The wearers were experienced handling their lenses. A relatively high percentage of them (52 of 184; 28%) used homemade solutions (unpreserved saline, distilled water, tap water, and/or baby shampoo) for the care and cleaning of their lenses. Although the reasons for referral were similar to those reported from temperate zones, we found a much higher incidence of combined deposits (protein-lipid-inorganic) than reported in studies carried out in other countries. Fungal invasion seemed more prevalent in our area than in temperate zones. From our results, the need for better education of wearers is obvious. In addition, special measures for the control of fungal growth may be required locally. The high incidence of this type of growth may be partly related to tropical conditions that favor the dispersal of fungal spores.

Adolescent↗