Ricardo J. Vazquez

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By means of the peroxidase-antiperoxidase technique a comparative immunocytochemical study of the distribution of the vasotocin- and vasopressin-reacting system in the chicken and rat hypothalamus was carried out. In both species it is possible to distinguish, on the basis of their topographical location, three different comparable populations: The first(More)
Decapitating phorid flies in the genus Pseudacteon are being studied as classical biological control agents of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Pseudacteon curvatus Borgmeier (Diptera: Phoridae) is a small decapitating fly that attacks small fire ant workers. We released a biotype of P. curvatus from Formosa,(More)
The distribution of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase activity was histochemically investigated in the Japanese quail brain. This enzyme is now considered responsible for the synthesis of nitric oxide, a novel neural messenger whose distribution has not been described in the avian brain until now. The histochemical(More)
On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass(More)
Using double labelling for proliferating cell nuclear antigen (PCNA) and vasoactive intestinal peptide (VIP), a study was conducted to elucidate the repercussions of the addition of estradiol to monolayer pituitary cultures on the morphology, size, number, mitotic index and PCNA labelling index of VIP-immunoreactive cells, comparing the results with those(More)
A histochemical study of the distribution of NADPH diaphorase activity in the hypothalamus of normal rats was carried out. Our study demonstrates the presence of NADPH-diaphorase activity in the circularis and anterior and posterior fornicals nuclei for the first time. Additionally, we confirm the presence of NADPH-diaphorase-stained neurons in the(More)
Regulatory control of the hypothalamic-pituitary-adrenocortical axis (HPA) originates principally from the paraventricular nucleus (PVN), which contains an important population of nitric oxide synthesizing (NOS) neurons. In the present study, the effect of swim stress upon these neurons was investigated by means of the NADPH-diaphorase (ND) histochemical(More)
Coexistence of the calcium binding protein calbindin D-28k and NADPH-diaphorase activity was studied in the magnocellular secretory nuclei of the rat hypothalamus using both immunocytochemical and histochemical techniques. Coexistence was found in all the nuclei considered (supraoptic, paraventricular, circularis and fornicals nuclei) with the exception of(More)
As in vitro study was carried out to determine whether testosterone directly inhibits the secretion of pituitary vasoactive intestinal peptide (VIP). A study was also conducted to elucidate the repercussions of treatment with 10(-6) M testosterone of monolayer cultures in the size and proliferation rate of pituitary VIP-immunoreactive cells, using double(More)
In order to establish the correlation between in vitro proliferation rate and morphometric variations of prolactin immunoreactive cells, a morphometric study was carried out in rat pituitary monolayer cultures by means of the double immunocytochemical staining methods employing mouse monoclonal antiproliferative cell nuclear antigen (PCNA) and rabbit(More)