Mutant versions of von Hippel-Lindau (VHL) can protect HIF1α from SART1-mediated degradation in clear-cell renal cell carcinoma.

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor drives the development of clear-cell renal cell carcinoma (ccRCC) through hypoxia-inducible factors (HIFs). Although ccRCC cells exhibit constitutive normoxic HIF signaling, the potential role of hypoxia in this setting is not fully understood. We show here that the ccRCC cell lines RCC4 and RCC10, which express mutant versions of VHL, have reduced HIF1α expression in hypoxia, whereas HIF2α expression is increased or not affected. Similar findings were observed in normoxia after abrogation of prolyl hydroxylase activity by siRNA or pharmacological inhibition, and by siRNA inhibition of mutant VHL. This reduction of HIF1α protein is due to proteasome-dependent degradation and is mediated by the E3 ubiquitin ligase SART1. HIF1α degradation favors ccRCC proliferation, in line with the previously recognized tumor suppressor capability of HIF1α. Our data indicate that mutant VHL can protect HIF1α from SART1-dependent degradation in normoxic conditions, but this protection is lost in hypoxic settings, favoring hypoxia-dependent ccRCC proliferation. This mechanism of HIF1α degradation might operate in some VHL-related clear-cell renal carcinomas in which the deletion of HIF1α locus does not occur.

The mitochondrial transporter ABC-me (ABCB10), a downstream target of GATA-1, is essential for erythropoiesis in vivo.

The mitochondrial transporter ATP binding cassette mitochondrial erythroid (ABC-me/ABCB10) is highly induced during erythroid differentiation by GATA-1 and its overexpression increases hemoglobin production rates in vitro. However, the role of ABC-me in erythropoiesis in vivo is unknown. Here we report for the first time that erythrocyte development in mice requires ABC-me. ABC-me-/- mice die at day 12.5 of gestation, showing nearly complete eradication of primitive erythropoiesis and lack of hemoglobinized cells at day 10.5. ABC-me-/- erythroid cells fail to differentiate because they exhibit a marked increase in apoptosis, both in vivo and ex vivo. Erythroid precursors are particularly sensitive to oxidative stress and ABC-me in the heart and its yeast ortholog multidrug resistance-like 1 have been shown to protect against oxidative stress. Thus, we hypothesized that increased apoptosis in ABC-me-/- erythroid precursors was caused by oxidative stress. Within this context, ABC-me deletion causes an increase in mitochondrial superoxide production and protein carbonylation in erythroid precursors. Furthermore, treatment of ABC-me-/- erythroid progenitors with the mitochondrial antioxidant MnTBAP (superoxide dismutase 2 mimetic) supports survival, ex vivo differentiation and increased hemoglobin production. Altogether, our findings demonstrate that ABC-me is essential for erythropoiesis in vivo.

[Gossypiboma in neurosurgery. Case report and literature review]. / Gossypiboma en Neurocirugía. Descripción de un caso y revisión de la literatura.

The terms gossypiboma, textiloma or retained foreign objects are medical terms used to describe textile elements that are left intentionally or accidentally in the operative site and generate a reaction to foreign objects. It can be avoided when preventive measures are taken during surgery. Gossypibomas are rare in surgery of the central nervous system. They are more frequent in thoracic and abdominal surgeries. Depending on their location they can present with complications and symptoms or they may remain undetected for many years. In this article we want to present a case of a spinal asymptomatic gossypiboma in a patient who was operated on 15 years ago for a lumbar disectomy. We will review the literature on the implications of these lesions on the neurosurgical field.

Gossypiboma en Neurocirugía. Descripción de un caso y revisión de la literatura / Gossypiboma in Neurosurgery. Case report and literature review

Los términos gossypiboma, textiloma o cuerpo extrañotextil retenido son términos médicos usados paradescribir elementos quirúrgicos textiles que intencionalo accidentalmente son dejados sobre el lecho quirúrgico,generando una reacción a cuerpo extraño. Es unapatología prevenible siempre y cuando se tomen algunasmedidas durante la cirugía. Los gossypiboma sonpoco frecuentes a nivel del sistema nervioso central. Sonmás frecuentes en las cirugías torácicas o abdominales.Dependiendo de su localización y su comportamiento,éstos pueden presentar complicaciones y sintomatologíao pueden permanecer silentes por muchos años.En este trabajo se presenta un caso de un gossypibomaparaespinal asintomático en una pacienteoperada 15 años antes para una discectomía lumbar.Se hace además una revisión de la literatura y secomenta acerca de la implicación de estas lesiones enneurocirugía (AU)

The terms gossypiboma, textiloma or retainedforeign objects are medical terms used to describe textileelements that are left intentionally or accidentallyin the operative site and generate a reaction to foreignobjects. It can be avoided when preventive measuresare taken during surgery. Gossypibomas are rare insurgery of the central nervous system. They are morefrequent in thoracic and abdominal surgeries. Dependingon their location they can present with complications and symptoms or they may remain undetected formany years.In this article we want to present a case of a spinalasymptomatic gossypiboma in a patient who was operatedon 15 years ago for a lumbar disectomy. We willreview the literature on the implications of these lesionson the neurosurgical field (AU)

Chromatographic characterisation, under highly aqueous conditions, of a molecularly imprinted polymer binding the herbicide 2,4-dichlorophenoxyacetic acid.

The affinity of a 2,4-dichlorophenoxyacetic acid (2,4-D) molecularly imprinted polymer (MIP), which was synthesised directly in an aqueous organic solvent, for its template (2,4-D) was studied and compared with the affinity exhibited by two other reference (control) polymers, NIPA and NIPB, for the same analyte. Zonal chromatography was performed to establish the optimal selectivity, expressed as imprinting factor (IF), under chromatographic conditions more aqueous than those described so far in the literature. Frontal analysis (FA) was performed on columns packed with these polymers, using an optimized mobile phase composed of methanol/phosphate buffer (50/50, v/v), to extract adsorption isotherm data and retrieve binding parameters from the best isotherm model. Surprisingly, the template had comparable and strong affinity for both MIP (K = 3.8x10(4) M(-1)) and NIPA (K = 1.9x10(4) M(-1)), although there was a marked difference in the saturation capacities of selective and non-selective sites, as one would expect for an imprinted polymer. NIPB acts as a true control polymer in the sense that it has relatively low affinity for the template (K = 8.0x10(2) M(-1)). This work provides the first frontal chromatographic characterization of such a polymer in a water-rich environment over a wide concentration range. The significance of this work stems from the fact that the chromatographic approach used is generic and can be applied readily to other analytes, but also because there is an increasing demand for well-characterised imprinted materials that function effectively in aqueous media and are thus well-suited for analytical science applications involving, for example, biofluids and environmental water samples.

Resección endometrial en el tratamiento de la hemorragia uterina disfuncional / Endometrial resection in the treatment of dysfunctional uterine bleeding

Objetivos: Analizar la efectividad de la resección endometrial como tratamiento de la hemorragia uterina disfuncional. Pacientes y método: Se incluyen 100 pacientes con hemorragia uterina disfuncional en quienes se realiza resección endometrial. Se mide el éxito terapéutico (desaparición o mejoría de la sintomatología) y el grado de satisfacción de las pacientes (encuesta). Resultados: Se obtuvo un porcentaje de éxito del 82 per cent con un grado de satisfacción del 76 per cent. Conclusión: La resección endometrial es una alternativa a la histerectomía que puede ofrecerse a pacientes pre-perimenopáusicas en quienes ha fallado el tratamiento médico. (AU)

Beta-arrestin- and c-Src-dependent degradation of G-protein-coupled receptor kinase 2.

G-protein-coupled receptor kinase 2 (GRK2) plays a key role in the regulation of G-protein-coupled receptors (GPCRs). GRK2 expression is altered in several pathological conditions, but the molecular mechanisms that modulate GRK2 cellular levels are largely unknown. We recently have described that GRK2 is degraded rapidly by the proteasome pathway. This process is enhanced by GPCR stimulation and is severely impaired in a GRK2 mutant that lacks kinase activity (GRK2-K220R). In this report, we find that beta-arrestin function and Src-mediated phosphorylation of GRK2 are critically involved in GRK2 proteolysis. Overexpression of beta-arrestin triggers GRK2-K220R degradation based on its ability to recruit c-Src, since this effect is not observed with beta-arrestin mutants that display an impaired c-Src interaction. The presence of an inactive c-Src mutant or of tyrosine kinase inhibitors strongly inhibits co-transfected or endogenous GRK2 turnover, respectively, and a GRK2 mutant with impaired phosphorylation by c-Src shows a markedly retarded degradation. This pathway for the modulation of GRK2 protein stability puts forward a new feedback mechanism for regulating GRK2 levels and GPCR signaling.

Three different genes encode the iron-sulfur subunit of succinate dehydrogenase in Arabidopsis thaliana.

The iron-sulfur protein is an essential component of mitochondrial complex II (succinate dehydrogenase, SDH), which is a functional enzyme of both the citric acid cycle and the respiratory electron transport chain. This protein is encoded by a single-copy nuclear gene in mammals and fungi and by a mitochondrial gene in Rhodophyta and the protist Reclinomonas americana. In Arabidopsis thaliana, the homologous protein is now found to be encoded by three nuclear genes. Two genes (sdh2-1 and sdh2-2) likely arose from a relatively recent duplication event since they have similar structures, encode nearly identical proteins and show similar expression patterns. Both genes are interrupted by a single intron located at a conserved position. Expression was detected in all tissues analysed, with the highest steady-state mRNA levels found in flowers and inflorescences. In contrast, the third gene (sdh2-3) is interrupted by 4 introns, is expressed at a low level, and encodes a SDH2-3 protein which is only 67% similar to SDH2-1 and SDH2-2 and has a different N-terminal presequence. Interestingly, the proteins encoded by these three genes are probably functional because they are highly conserved compared with their homologues in other organisms. These proteins contain the cysteine motifs involved in binding the three iron-sulfur clusters essential for electron transport. Furthermore, the three polypeptides are found to be imported into isolated plant mitochondria.

[Cholesterol crystals pericarditis]. / Pericarditis con cristales de colesterol.

Cholesterol pericarditis is an uncommon, specific form of pericardial disease that is characterized by the presence of cholesterol crystals in pericardial fluid. The etiology may be either idiopathic or in association with systemic disorders such as tuberculosis, rheumatoid arthritis, myxedema or hypercholesterolemia. We report a case of cholesterol pericarditis in a 51-year-old male who was diagnosed with chronic renal failure due to polycystic kidney disease. To our knowledge no similar cases have been reported to date in the literature.

Resección de pólipos por histeroscopia en mujeres premenopáusicas con hemorragia uterina anormal / Hysteroscopic resection of polyps in premenopausal women with abnormal uterine bleeding

Los pólipos endometriales se encuentran en aproximadamente el 25 por ciento de las mujeres que consultan por hemorragia uterina anormal. Hemos querido analizar en qué medida la resección de los pólipos por histeroscopia logra corregir la sintomatología. Se realizó una encuesta telefónica a 74 mujeres premenopáusicas que consultaron por hemorragia uterina anormal y a las que se les realizó una polipectomía durante el período de enero de 1996 a agosto de 1999. Encontramos que un 68,5 por ciento de las pacientes habían mejorado claramente, lo que ha confirmado, por una parte, la relación del pólipo con la hemorragia uterina anormal y, por otro, el papel de la histeroscopia como método de tratamiento. Un 17,1 por ciento de las pacientes no mejoraron, lo que podría explicarse por el trastorno funcional del endometrio que suele acompañar al pólipo y que mantendría el proceso (AU)

Citología peritoneal positiva tras histeroscopia en cáncer de endometrio / Positive peritoneal cytology afte hysteroscopy for endometrial cáncer

Objetivo: Analizar la frecuencia de citologías peritoneales positivas en una serie de 121 pacientes con carcinoma de endometrio diagnosticados por histeroscopia.Sujetos y métodos: Se incluyen 121 pacientes en las que se diagnosticó un cáncer de endometrio utilizando la histeroscopia, realizándose posteriormente laparotomía y lavado peritoneal previo al tratamiento quirúrgico.Resultados: Se obtuvieron en total cinco citologías peritoneales positivas, cuatro de ellas eran casos de carcinoma endometrial en estadios III y IV y uno de ellos estadio 1. La frecuencia de citologías positivas en estadio I fue de 1,07 por 100, que es inferior a lo esperado según las diferentes publicaciones.Conclusión: En nuestra experiencia, el uso de la histeroscopia no aumenta la frecuencia de citologías peritoneales positivas en estadio 1 de carcinoma endometrial (AU)

Agonist-dependent modulation of G protein-coupled receptor kinase 2 by mitogen-activated protein kinases.

A variety of G protein-coupled receptors (GPCRs) are phosphorylated by G protein-coupled receptor kinase 2 (GRK2). This event promotes the binding of regulatory proteins termed beta-arrestins to GPCRs, leading to uncoupling from G proteins and receptor internalization. Recent data indicate that GRK2 and beta-arrestins also play an important role in the stimulation of the extracellular signal-regulated kinases (ERK)/mitogen-activated protein kinase (MAPK) cascade by GPCRs. In this report, we have investigated the existence of functional interactions between GRK2 and MAPK. We show that activation of beta(2)-adrenergic receptors (beta(2)-AR) promotes the rapid association of GRK2 and MAPK in living cells, as assessed by coimmunoprecipitation experiments in COS-7 cells transfected with beta(2)-AR, GRK2, and an epitope-tagged MAPK. Coimmunoprecipitation of MAPK and GRK2 is blocked by inhibition of the MAPK cascade and is not observed upon activation of MAPK in the absence of beta(2)-AR stimulation, thus indicating that both an active MAPK and agonist occupancy of GPCR are required for the association to occur. Interestingly, we have found that purified ERK1/MAPK can directly phosphorylate the C-terminal domain of GRK2, and that the phosphorylation process is favored by the presence of Gbetagamma-subunits or an activated receptor. Furthermore, GRK2 phosphorylation by MAPK leads to a decreased activity of GRK2 toward GPCR. Taken together, our results suggest that stimulation of GPCRs promotes the rapid association of GRK2 and MAPK leading to modulation of GRK2 functionality, thus putting forward a new feedback mechanism for the regulation of GPCR signaling.

Agonist-dependent phosphorylation of the G protein-coupled receptor kinase 2 (GRK2) by Src tyrosine kinase.

GRK2 is a member of the G protein-coupled receptor kinase (GRK) family, which phosphorylates the activated form of a variety of G protein-coupled receptors (GPCR) and plays an important role in GPCR modulation. It has been recently reported that stimulation of the mitogen-activated protein kinase cascade by GPCRs involves tyrosine phosphorylation of docking proteins mediated by members of the Src tyrosine kinase family. In this report, we have investigated the possible role of c-Src in modulating GRK2 function. We demonstrate that c-Src can directly phosphorylate GRK2 on tyrosine residues, as shown by in vitro experiments with purified proteins. The phosphorylation reaction exhibits an apparent K(m) for GRK2 of 12 nM, thus suggesting a physiological relevance in living cells. Consistently, overexpression of the constitutively active c-Src Y527F mutant in COS-7 cells leads to tyrosine phosphorylation of co-expressed GRK2. In addition, GRK2 can be detected in phosphotyrosine immunoprecipitates from HEK-293 cells transiently transfected with this Src mutant. Interestingly, phosphotyrosine immunoblots reveal a rapid and transient increase in GRK2 phosphorylation upon agonist stimulation of beta(2)-adrenergic receptors co-transfected with GRK2 and wild type c-Src in COS-7 cells. This tyrosine phosphorylation is maximal within 5 min of isoproterenol stimulation and reaches values of approximately 5-fold over basal conditions. Furthermore, GRK2 phosphorylation on tyrosine residues promotes an increased kinase activity toward its substrates. Our results suggest that GRK2 phosphorylation by c-Src is inherent to GPCR activation and put forward a new mechanism for the regulation of GPCR signaling.

G protein-coupled receptor kinase 2 (GRK2): mechanisms of regulation and physiological functions.

G protein-coupled receptor kinase 2 (GRK2) plays a key role in determining the rate and extent of G protein-coupled receptor (GPCR) desensitization and resensitization. Recent data indicate that GRK2 activity, subcellular distribution and expression are tightly regulated. The important physiological function of GRK2 as a modulator of the efficacy of GPCR signal transduction systems is exemplified by its relevance in cardiovascular physiopathology as well as by its emerging role in the regulation of chemokine receptors.