Urocortin-2 induces vasorelaxation of coronary arteries isolated from patients with heart failure.

1. Urocortin-2 (Ucn2) is a vasoactive peptide belonging to the corticotrophin-releasing factor (CRF) family that has potent cardiovascular actions. It has been suggested that Ucn2 participates in the pathophysiology of heart failure. However, little is known about the mechanisms underlying the action of Ucn2 in human coronary arteries. The aim of the present study was to assess the effects of Ucn2 on the vascular tone of human coronary arteries dissected from heart failure patients. 2. Human coronary arteries were dissected from the hearts of patients subjected to orthotopic heart transplantation. Coronary arteries were obtained from 17 patients with heart failure due to dilated cardiomyopathy of ischaemic origin in Stage III-IV of the New York Heart Association classification. Changes in tone were measured in arterial rings using force transducers. 3. Application of increasing concentrations of Ucn2 (5-20 nmol/L) to arterial rings precontracted with agonists induced dose-dependent relaxation of the coronary artery, which was independent of endothelial cell activation. Furthermore, the inhibition of the adenylyl cyclase by MDL-12 (100 nmol/L) and protein kinase A (PKA) by H89 (1 µmol/L) prevented Ucn2-mediated relaxation of coronary artery rings. 4. The results of the present study suggest that, in heart failure patients, Ucn2 could be useful in modulating coronary artery circulation independent of endothelial integrity through mechanisms that involve adenylyl cyclase activation and PKA stimulation. The findings warrant further investigation of the role of Ucn2 in circulatory regulation and its potential therapeutic application in heart disease.

Assessment of the radiation absorbed dose produced by 177Lu-iPSMA, 225Ac-iPSMA and 223RaCl2 to prostate cancer cell nuclei in a bone microenvironment model.

This research aimed to assess the radiation absorbed dose produced by 177Lu-iPSMA (177Lu-prostate specific membrane antigen inhibitor), 225Ac-iPSMA and 223RaCl2 to prostate cancer cell nuclei in a simplified model of bone by using an experimental in-vitro prostate cancer LNCaP cell biokinetic study and Monte Carlo simulation with the MCNPX code. Results showed that 225Ac-iPSMA releases a nine hundred-fold radiation dose greater than 177Lu-iPSMA and 14 times more than 223RaCl2 per unit of activity retained in bone. 225Ac-iPSMA could be the best option for treatment of bone metastases in prostate cancer.

Decreased expression of maxi-K+ channel beta1-subunit and altered vasoregulation in hypoxia.

BACKGROUND: Hypertension, a major cause of cardiovascular morbidity and mortality, can result from chronic hypoxia; however, the pathogenesis of this disorder is unknown. We hypothesized that downregulation of the maxi-K+ channel beta1-subunit by hypoxia decreases the ability of these channels to hyperpolarize arterial smooth muscle cells, thus favoring vasoconstriction and hypertension. METHODS AND RESULTS: Lowering O2 tension produced a decrease of maxi-K+ beta1-subunit mRNA levels in rat (aortic and basilar) and human (mammary) arterial myocytes. This was paralleled by a reduction of the beta1-subunit protein level as determined by immunocytochemistry and flow cytometry. Exposure to hypoxia also produced a decrease of open probability, mean open time, and sensitivity to the xenoestrogen tamoxifen of single maxi-K+ channels recorded from patch-clamped dispersed myocytes. The number of channels per patch and the single-channel conductance were not altered. The vasorelaxing force of maxi-K+ channels was diminished in rat and human arterial rings exposed to low oxygen tension. CONCLUSIONS: These results indicate that a decrease of the maxi-K+ channel beta1-subunit expression in arterial myocytes is a key factor in the vasomotor alterations induced by hypoxia.

Prolapso rectal incarcerado secundario a adenoma velloso gigante / Incarcerated rectal prolapse due to a giant villous adenoma

Los adenomas vellosos pueden manifestarse con sangrado, diarrea, alteraciones hidroelectrolíticas (síndrome Mackittrick-Weelock), obstrucción intestinal, y, muy infrecuentemente, condicionar un prolapso rectal. El prolapso rectal es la protrusión de la pared completa del recto a través del canal anal, su presentación como prolapso rectal incarcerado es poco habitual. Cuando la reducción manual no es posible, la rectosigmoidectomía vía perineal o procedimiento de Altemeier es una buena opción quirúrgica; como alternativa puede realizarse una resección transanal del pólipo y la posterior reducción manual del prolapso rectal. Referiremos el caso de una mujer que acude al Servicio de urgencias presentando un prolapso rectal incarcerado con una masa ulcerada, friable, de 10 × 8 × 5 cm compatible con un pólipo velloso en la cara posterior del recto. Ante la imposibilidad de reducirlo se decide una resección transanal del pólipo con posterior reducción manual del prolapso rectal. Este caso es de interés por la infrecuente asociación entre un prolapso rectal incarcerado y un pólipo velloso gigante, con solo 4 casos comunicados en la literatura.

Villous adenomas may present with bleeding, diarrhea, electrolyte imbalance (Mackittrick-Weelock syndrome), obstruction, being a very rare cause of rectal prolapse. Rectal prolapse is a full thickness protrusion of the rectum through the anal canal and its presentation as an incarcerated rectal prolapse is very infrequent. If manual reduction is deemed impossible, perineal recto-sigmoidectomy, or Altemeier's procedure, is one of the best surgical options, as an alternative transanal excision of the polyp could be performed with subsequent manual reduction of the rectal prolapse. We report the case of a female patient, admitted to the emergency room presenting an incarcerated rectal prolapse with a friable ulcerated mass of 10 × 8 × 5 cm, compatible with a villous polyp in the back side of the rectum. Since manual reduction was considered not feasible, surgery was decided and a transanal excision of the polyp was performed, following a successful manual reduction of the rectal prolapse. This case is of particular interest for its unusual association of incarcerated rectal prolapse due to a giant villous adenoma, having only 4 cases been reported in the literature.

Rotura espontánea de bazo en paciente tratado con acenocumarol / Spontaneous rupture of spleen in a patient treated with acenocoumarol

Aunque la causa más frecuente de rotura esplénica es la traumática, podemos encontrar roturas sin relación a un traumatismo previo. Se está objetivando un aumento de roturas espontáneas en relación con tratamiento anticoagulante. Presentamos el caso de un hombre en tratamiento con acenocumarol que presentó una rotura espontánea esplénica que requirió esplenectomía urgente. La rotura de bazo es una entidad grave que debe considerarse ante todo paciente con un abdomen agudo. Aunque las causas más frecuentes de rotura esplénica atraumática son las complicaciones neoplásicas e infecciosas, se han objetivado varios casos asociados a terapias antiagregantes y anticoagulantes. Dado el aumento de población que precisa anticoagulación oral, la sobredosificación con acenocumarol debe considerarse como una posible causa de rotura esplénica. Debemos sospechar esta entidad ante todo paciente en tratamiento con anticoagulación oral con un abdomen agudo.

The splenic rupture is most commonly related to trauma, but spontaneus ruptures have also been described with increasing frequency. We present a case of a male patient with spontaneous splenic rupture due to oral anticoagulant overdose that required urgent splenectomy. The spontaneous splenic rupture is a life-threatening condition that must be considered in patients with acute abdomen. Although most ruptures are associated with to neoplastic and infectious complications , recent reports have related rupture with anticoagulant and antiaggregant therapies. Moreover, since the number of patients undergoing oral anticoagulant therapies is growing, overdose of anticoagulant drugs must be considered as a possible ethiology of spontaneous splenic rupture and suspect this association in patient with acute abdomen undergoing anticoagulant therapy.

Cardiotrophin-1 induces sarcoplasmic reticulum Ca(2+) leak and arrhythmogenesis in adult rat ventricular myocytes.

AIMS: Plasma levels of cardiotrophin-1 (CT-1) are elevated in several cardiovascular diseases and are correlated with the severity of the pathology. However, the mechanisms by which this inflammatory cytokine participates in the pathology of the heart are not completely understood. It is well established that alterations in intracellular calcium ([Ca(2+)](i)) handling are involved in cardiac dysfunction during heart failure, but it is unknown whether CT-1 modulates [Ca(2+)](i) handling in adult cardiomyocytes. Here we have analyzed for the first time the effects of CT-1 on [Ca(2+)](i) homeostasis in adult rat cardiomyocytes. METHODS AND RESULTS: L-type calcium current (I(CaL)) was recorded using patch-clamp techniques, and [Ca(2+)](i) transients and Ca(2+) sparks were viewed by confocal microscopy. Treatment of cardiomyocytes with 1 nM CT-1 for 20-60 min induced a significant increase in I(CaL) density, [Ca(2+)](i) transients, and cell shortening compared with control cells. Our study reveals that CT-1 increases I(CaL) by a protein kinase A-dependent mechanism, and Ca(2+) sparks by a Ca(2+)/calmodulin kinase II-dependent and protein kinase A-independent mechanism. Cardiomyocytes treated with CT-1 exhibited a higher occurrence of arrhythmogenic behaviour, manifested as spontaneous Ca(2+) waves and aftercontractions. CONCLUSION: Our findings provide evidence that cardiomyocytes treated with CT-1 present high spontaneous Ca(2+) release during diastole, a mechanism linked to arrhythmogenicity in the pathologic heart.

99mTc-N2S2-Tat (49-57)-bombesin internalized in nuclei of prostate and breast cancer cells: kinetics, dosimetry and effect on cellular proliferation.

BACKGROUND: The gastrin-releasing peptide receptor (GRP-r) is overexpressed in prostate and breast cancers. technetium-99m-bombesin (Tc-BN) has been reported as a radiopharmaceutical with specific cell GRP-r binding. The HIV Tat (49-57)-derived peptide has been used to deliver a large variety of molecules to cell nuclei. A new hybrid radiopharmaceutical of type Tc-N2S2-Tat(49-57)-Lys-BN (Tc-Tat-BN) internalized in cancer cell nuclei could act as an effective system of targeted radiotherapy using Auger and internal conversion electron emissions near DNA. AIM: The aim of this study was to assess the in-vitro nucleus internalization kinetics of Tc-Tat-BN in GRP r-positive cancer cells and to evaluate the subcellular-level radiation-absorbed dose associated with the observed effect on cancer cell DNA proliferation. METHODS: Tc-Tat-BN in-vitro internalization kinetics were evaluated in human prostate cancer PC-3 cells and breast carcinoma cell lines MCF7 and MDA-MB231. Nuclei from cells were isolated using a nuclear extraction kit. Total disintegration in each subcellular compartment was calculated by the integration of experimental time-activity kinetic curves. Nucleus internalization was corroborated by confocal microscopy images using immunofluorescently labelled Tat-BN. The PENELOPE code was used to simulate and calculate the absorbed dose by the contribution of Auger and internal conversion electrons in the cytoplasm and nucleus using geometric models built from immunofluorescent cell images. A cell proliferation kit was used to evaluate DNA concentration after cancer cell incubation with Tc-Tat-BN. RESULTS: The results showed that 59.7, 61.2 and 41.5% of total disintegration per unit of Tc-Tat-BN activity (1 Bq) bound to the cell occurred in the nucleus of PC-3, MCF7 and MDA-MB231, respectively. The Tc-Tat-BN absorbed doses delivered to nuclei were 0.142 mGy/decay (PC-3), 0.434 mGy/decay (MCF7) and 0.276 mGy/decay (MDA-MB231). Tc-Tat-BN produced a significant decrease in PC-3 (52.98%), MCF7 (45.71%) and MDA-MB231 (35.80%) cellular proliferation with respect to untreated cells. CONCLUSION: The hybrid radiopharmaceutical could be potentially useful as a therapeutic agent for prostate and breast cancers.

Lys3-bombesin conjugated to 99mTc-labelled gold nanoparticles for in vivo gastrin releasing peptide-receptor imaging.

UNLABELLED: The gastrin releasing peptide-receptor (GRP-r) is over-expressed in breast and prostate cancer and lymph node metastases. Lys3-bombesin is a peptide that binds with high affinity to GRP-r. The aim of this research was to prepare a multifunctional system of technetium-99m labelled gold nanoparticles conjugated to Lys3-bombesin/HYNIC-GGC and to evaluate its biological behaviour as a potential radiopharmaceutical for in vivo GRP-r imaging. METHODS: Lys3-bombesin and hydrazinonicotinamide-Gly-Gly-Cys-NH2 (HYNIC-GGC) peptides were conjugated to gold nanoparticles (AuNP, 20 nm) to prepare a multifunctional system of HYNIC-GGC-AuNP-Lys3-bombesin by means of spontaneous reaction of the thiol (Cys) present in HYNIC-GGC sequence and the amine of Lys3-bombesin. The nanoconjugate was characterized by transmission electron microscopy (TEM), IR, UV-Vis, Raman, and X-ray photoelectron spectroscopy (XPS). Technetium-99m labelling through the HYNIC-GGC ligand was carried out using EDDA/tricine as coligands and SnCl2 as reducing agent with further size exclusion chromatography purification. Radiochemical purity was determined by size exclusion HPLC and ITLC-SG analyses. In vitro binding studies were carried out in human prostate cancer PC-3 cells (GRP-r positive cells). Biodistribution studies were accomplished in athymic mice with PC-3 induced tumours and images obtained using a micro-SPECT/CT system. RESULTS: TEM and spectroscopy techniques demonstrated that AuNPs were functionalized with HYNIC-GGC-NH2 and Lys3-bombesin through interactions with thiol groups of Cysteine and the N-terminal and epsilon-amine of Lysine respectively. Radio-chromatograms showed radiochemical purity higher than 95%. 99mTc-EDDA/HYNIC-GGC-AuNP-Lys3-bombesin (99mTc-AuNP-Lys3-bombesin) showed specific recognition for GRP-r over-expressed in PC-3 cells. After administration of 99mTc-AuNP-Lys3-bombesin in mice the pancreas-to-blood ratio was 36 at 1 h demonstrating ability to target in vivo GRP receptor-bearing cells. In vivo micro-SPECT/CT images in mice showed an evident tumour uptake (6.39 +/- 0.83% IA/g at 1 h). CONCLUSIONS: This study demonstrated that the 99mTc-AuNP-Lys3-bombesin multifunctional system shows specific recognition for GRP-r and suitable properties to be used as a molecular imaging agent.

Metabotropic Ca(2+) channel-induced Ca(2+) release and ATP-dependent facilitation of arterial myocyte contraction.

Voltage-gated Ca(2+) channels in arterial myocytes can mediate Ca(2+) release from the sarcoplasmic reticulum and, thus, induce contraction without the need of extracellular Ca(2+) influx. This metabotropic action of Ca(2+) channels (denoted as calcium-channel-induced calcium release or CCICR) involves activation of G proteins and the phospholipase C-inositol 1,4,5-trisphosphate pathway. Here, we show a form of vascular tone regulation by extracellular ATP that depends on the modulation of CCICR. In isolated arterial myocytes, ATP produced facilitation of Ca(2+)-channel activation and, subsequently, a strong potentiation of CCICR. The facilitation of L-type channel still occurred after full blockade of purinergic receptors and inhibition of G proteins with GDPbetaS, thus suggesting that ATP directly interacts with Ca(2+) channels. The effects of ATP appear to be highly selective, because they were not mimicked by other nucleotides (ADP or UTP) or vasoactive agents, such as norepinephrine, acetylcholine, or endothelin-1. We have also shown that CCICR can trigger arterial cerebral vasoconstriction in the absence of extracellular calcium and that this phenomenon is greatly facilitated by extracellular ATP. Although, at low concentrations, ATP does not induce arterial contraction per se, this agent markedly potentiates contractility of partially depolarized or primed arteries. Hence, the metabotropic action of L-type Ca(2+) channels could have a high impact on vascular pathophysiology, because, even in the absence of Ca(2+) channel opening, it might mediate elevations of cytosolic Ca(2+) and contraction in partially depolarized vascular smooth muscle cells exposed to small concentrations of agonists.

Detection of West Nile virus in the Mexican blood supply.

BACKGROUND: West Nile virus (WNV) is the etiologic agent of an emerging disease in the Western Hemisphere that can be transmitted to humans by blood transfusion. WNV first appeared in the United States in 1999, in Canada in 2001, and in Mexico in 2002. The aim of this nationwide study was to determine the prevalence of WNV in blood donors in Mexico as a first step in preventing its transfusion-associated transmission. STUDY DESIGN AND METHODS: In July and August 2004, a total of 3856 fresh plasma specimens collected from each state's center for blood transfusion in 29 of 31 Mexican states were screened with an investigational WNV assay (Procleix,(R) Gen-Probe Inc. and Chiron Corp.), a nucleic acid test based on transcription-mediated amplification (TMA). Reactive specimens were confirmed with a second TMA-based test, the alternative WNV assay (Gen-Probe), and with WNV capture enzyme-linked immunosorbent assays (ELISAs) for detection of immunoglobulin M (IgM) and IgG antibodies. In addition, 3714 frozen plasma samples collected in 2002 and 2003 were similarly tested. RESULTS: One of 3856 fresh samples from an asymptomatic donor from Chihuahua was reactive by both TMA-based tests and IgM ELISA, suggesting a recently acquired infection. The observed percentage of viremic donors blood donors was 0.03 percent. Results from frozen samples were not included in the prevalence calculation and none were TMA-reactive for WNV. CONCLUSIONS: WNV is present in the Mexican blood supply and measures should be taken to reduce the risk of transfusion transmission.