SummaryNitric oxide (NO) is a short-lived biologic mediator that is shown to be induced in various cell types and to cause many metabolic changes in target cells. Inhibition of tumor cell growth and antimicrobial activity has been attributed to the stimulation of the inducible type of the NO synthase (NOS). However, there is limited evidence for the existence of such inducible NOS in a human cell type. We show here the induction of NO biosynthesis in freshly isolated human hepatocytes (HC) after stimulation with interleukin 1, tumor necrosis factor (TNF), IFN-% and endotoxin. Increased levels of nitrite (NO2-) and nitrate (N03-) in culture supernatants were associated with NADPH-dependent NOS activity in the cell lysates. The production of NO2-and N03-was inhibited by N6-monomethyl I.-arginine and was associated with an increase in cyclic guanylate monophosphate release. The data presented here provide evidence for the existence of typical inducible NO biosynthesis in a human cell type.A variety of cell types have been shown to produce nitric oxide (NO) from t-arginine by either a constitutive and/or an inducible enzyme (1). Recent reports provide strong evidence that vasorelaxation, induced through the constitutive and inducible NO pathway, might play an important role in the regulation of vascular tone in humans (2, 3). Little evidence for the existence of inducible NO enzyme activity in specific human cell types has been documented, despite its clear potential role in the elimination of tumor cells (4) and intra-and extracellular pathogens (recently reviewed in reference 5), as well as in the induction of sustained hypotension (6), as shown in animal models.We have shown that rat hepatocytes (HC) cocultured with Kupffer ceils and stimulated with LPS can produce large amounts of nitrite (NO2-) and nitrate (N03-), the stable end products of NO (7). Furthermore, we have shown that HC alone are capable of biosynthesis of NO when exposed to various immunostimuli (8-10). The expression of the inducible nitric oxide synthase (NOS) alters various HC functions in vitro. These include a substantial decrease in total protein synthesis (7, 11), the inhibition of mitochondrial aconitase (12), and the stimulation of cyclic guanylate monophosphate (cGMP) synthesis and release (13). In vivo studies suggest that hepatic NO can protect the liver from damage in sepsis (14). In this communication, we report that nitrogen oxides are also produced in large amounts by human HC in a reproducible manner, demonstrating that a human call type can, indeed, express an inducible NOS. Materials and MethodsCulture Medium. HC cultures were performed in Williams medium E (Gibco Laboratories, Grand Island, NY) supplemented with 10 .6 M insulin, 15 mM Hepes, t-glutamine, penicillin, streptomycin, and 10% dialyzed calf serum. Additional culture reagents included t-arginine hydrochloride (Gibco Laboratories) and N ~-monomethyl-r-arginine acetate (NMA), prepared by a modification of the method previously described (15).Hepatocyte Isolation. In acc...

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The data presented in this article are related to the research paper entitled “Increased expression of mitochondrial sodium-coupled ascorbic acid transporter-2 (mitSVCT2) as a central feature in breast cancer”, available in Free Radical Biology and Medicine Journal [1]. In this article, we examined the SVCT2 transporter expression in various breast cancer cell lines using RT-PCR and Western blot assays. In addition, we analyzed the subcellular localization of SVCT2 by immunofluorescence colocalization assays and cellular fractionation experiments. Finally, an analysis of different cancer tissue microarrays immunostained for SVCT2 and imaged by The Human Protein Atlas (https://www.proteinatlas.org) is presented.

(Rev Méd Chile 2004; 132: 75-80La causa más frecuente de síndrome de Cushing en pacientes embarazadas es un adenoma suprarrenal 2,3 . La causa hipofisiaria es infrecuente, al contrario de lo que ocurre en no gestantes. En la literatura se han publicado alrededor de 10 pacientes con enfermedad de Cushing durante el embarazo.La paciente que se presenta corresponde al quinto caso tratado durante la gestación mediante adenomectomía transesfenoidal. CASO CLÍNICOPaciente de 26 años de edad, quien presentó progresivamente, en un lapso de 9 meses antes de la consulta, cuadro caracterizado por aumento de peso de 20 kilos, aumento de volumen facial e