A Protein Nuclear Extract from D. melanogaster Larval Tissues

Preparation of protein nuclear extracts is often the first step to study in vitro biological processes occurring in the nucleus of the eukaryotic cell. Nuclear extracts have been extensively used in different model organisms to identify and study protein function in nuclei. Drosophila embryos can be collected in large quantities and have been the source of choice for the production of protein nuclear extracts. However, most of Drosophila in vivo studies on protein function are conducted in larval tissues. Here we report a new method to produce highly stable large-scale protein nuclear extracts from whole Drosophila larvae that are suited for a variety of biochemical analyses

Hypertonic Saline in Conjunction with High-Dose Furosemide Improves Dose–Response Curves in Worsening Refractory Congestive Heart Failure

Introduction: Diuretic responsiveness in patients with chronic heart failure (CHF) is better assessed by urine production per unit diuretic dose than by the absolute urine output or diuretic dose. Diuretic resistance arises over time when the plateau rate of sodium and water excretion is reached prior to optimal fluid elimination and may be overcome when hypertonic saline solution (HSS) is added to high doses of furosemide. Methods: Forty-two consecutively hospitalized patients with refractory CHF were randomized in a 1:1:1 ratio to furosemide doses (125 mg, 250 mg, 500 mg) so that all patients received intravenous furosemide diluted in 150 ml of normal saline (0.9%) in the first step (0–24 h) and the same furosemide dose diluted in 150 ml of HSS (1.4%) in the next step (24–48 h) as to obtain 3 groups as follows: Fourteen patients receiving 125 mg (group 1), fourteen patients receiving 250 mg (group 2), and fourteen patients receiving 500 mg (group 3) of furosemide. Urine samples of all patients were collected at 30, 60, and 90 min, and 3, 4, 5, 6, 8, and 24 h after infusion. Diuresis, sodium excretion, osmolality, and furosemide concentration were evaluated for each urine sample. Results: After randomization, 40 patients completed the study. Two patients, one in group 2 and one in group 3 dropped out. Patients in group 1 (125 mg furosemide) had a mean age of 77 ± 17 years, 43% were male, 6 (43%) had heart failure with a preserved ejection fraction (HFpEF), and 64% were in New York Heart Association (NYHA) class IV; the mean age of patients in group 2 (250 mg furosemide) was 80 ± 8.1 years, 15% were male, 5 (38%) had HFpEF, and 84% were in NYHA class IV; and the mean age of patients in group 3 (500 mg furosemide) was 73 ± 12 years, 54% were male, 6 (46%) had HFpEF, and 69% were in NYHA class IV. HSS added to furosemide increased total urine output, sodium excretion, urinary osmolality, and furosemide urine delivery in all patients and at all time points. The percentage increase was 18,14, and 14% for urine output; 29, 24, and 16% for total sodium excretion; 45, 34, and 20% for urinary osmolarity; and 27, 36, and 32% for total furosemide excretion in groups 1, 2, and 3, respectively. These findings were translated in an improvement in the furosemide dose–response curves in these patients. Conclusion: These results may serve as new pathophysiological basis for HSS use in the treatment of refractory CHF

The Nucleosome-Remodeling ATPase ISWI Is Regulated by Poly-ADP-Ribosylation

ATP-dependent nucleosome-remodeling enzymes and covalent modifiers of chromatin set the functional state of chromatin. However, how these enzymatic activities are coordinated in the nucleus is largely unknown. We found that the evolutionary conserved nucleosome-remodeling ATPase ISWI and the poly-ADP-ribose polymerase PARP genetically interact. We present evidence showing that ISWI is target of poly-ADP-ribosylation. Poly-ADP-ribosylation counteracts ISWI function in vitro and in vivo. Our work suggests that ISWI is a physiological target of PARP and that poly-ADP-ribosylation can be a new, important post-translational modification regulating the activity of ATP-dependent nucleosome remodelers

Genetic Identification of a Network of Factors that Functionally Interact with the Nucleosome Remodeling ATPase ISWI

Nucleosome remodeling and covalent modifications of histones play fundamental roles in chromatin structure and function. However, much remains to be learned about how the action of ATP-dependent chromatin remodeling factors and histone-modifying enzymes is coordinated to modulate chromatin organization and transcription. The evolutionarily conserved ATP-dependent chromatin-remodeling factor ISWI plays essential roles in chromosome organization, DNA replication, and transcription regulation. To gain insight into regulation and mechanism of action of ISWI, we conducted an unbiased genetic screen to identify factors with which it interacts in vivo. We found that ISWI interacts with a network of factors that escaped detection in previous biochemical analyses, including the Sin3A gene. The Sin3A protein and the histone deacetylase Rpd3 are part of a conserved histone deacetylase complex involved in transcriptional repression. ISWI and the Sin3A/Rpd3 complex co-localize at specific chromosome domains. Loss of ISWI activity causes a reduction in the binding of the Sin3A/Rpd3 complex to chromatin. Biochemical analysis showed that the ISWI physically interacts with the histone deacetylase activity of the Sin3A/Rpd3 complex. Consistent with these findings, the acetylation of histone H4 is altered when ISWI activity is perturbed in vivo. These findings suggest that ISWI associates with the Sin3A/Rpd3 complex to support its function in vivo

Roles of the Core Components of the Mammalian miRISC in Chromatin Biology

The Argonaute (AGO) and the Trinucleotide Repeat Containing 6 (TNRC6) family proteins are the core components of the mammalian microRNA-induced silencing complex (miRISC), the machinery that mediates microRNA function in the cytoplasm. The cytoplasmic miRISC-mediated post-transcriptional gene repression has been established as the canonical mechanism through which AGO and TNRC6 proteins operate. However, growing evidence points towards an additional mechanism through which AGO and TNRC6 regulate gene expression in the nucleus. While several mechanisms through which miRISC components function in the nucleus have been described, in this review we aim to summarize the major findings that have shed light on the role of AGO and TNRC6 in mammalian chromatin biology and on the implications these novel mechanisms may have in our understanding of regulating gene expression

A Protein Nuclear Extract from D. melanogaster

Preparation of protein nuclear extracts is often the first step to study in vitro biological processes occurring in the nucleus of the eukaryotic cell. Nuclear extracts have been extensively used in different model organisms to identify and study protein function in nuclei. Drosophila embryos can be collected in large quantities and have been the source of choice for the production of protein nuclear extracts. However, most of Drosophila in vivo studies on protein function are conducted in larval tissues. Here we report a new method to produce highly stable large-scale protein nuclear extracts from whole Drosophila larvae that are suited for a variety of biochemical analyses

The multiplicity of Argonaute complexes in mammalian cells

Argonautes (AGOs) are a highly conserved family of proteins found in most Eukaryotes, and involved in mechanisms of gene regulation, both at the transcriptional and post-transcriptional level. Among other functions, AGO proteins associate with microRNAs to mediate the post-transcriptional repression of protein-coding genes. In this process, AGOs associate with members of the trinucleotide repeat containing 6 protein (TNRC6) protein family to form the core of the RNA-induced silencing complex (RISC), the effector machinery that mediates microRNA function. However, the description of the exact composition of the RISC has been a challenging task due to the fact the AGO's interactome is dynamically regulated in a cell type- and condition-specific manner. Here, we summarize some of the most significant studies that have identified AGO complexes in mammalian cells, as well as the approaches used to characterize them. Finally, we discuss possible opportunities to exploit what we have learned on the properties of the RISC to develop novel anti-cancer therapies. Significance Statement The RNA-induced silencing complex (RISC) is the molecular machinery that mediates miRNA function in mammals. Studies over the past two decades have shed light on important biochemical and functional properties of this complex. However, still many aspects of this complex await further elucidation, mostly due to technical limitations that have hindered full characterization. Here, we summarize some of the most significant studies on the mammalian RISC, and discuss possible sources of biases in the approaches used to characterize it

Changes in estimating echocardiography pulmonary capillary wedge pressure after hypersaline plus furosemide versus furosemide alone in decompensated heart failure.

BACKGROUND: The aim of the study was to verify the effects of hypertonic saline solution (HSS) plus a high furosemide dose and light restriction of sodium intake compared with a high-dose infusion of furosemide alone on pulmonary capillary wedge pressure (PCWP), as determined by Doppler echocardiography and tissue Doppler imaging in patients suffering from decompensated heart failure. METHODS AND RESULTS: Consecutive patients in New York Heart Association functional class IV, unresponsive to oral high doses of furosemide up to 250-500 mg/d and/or combinations of diuretics, with ejection fraction <40%, serum creatinine <2 mg/dL, blood urea nitrogen ≤60 mg/dL, reduced urinary volume (<500 mL/24 h), and low natriuresis (<60 mEq/24 h) were randomized into 2 groups (double blind). The first group received a furosemide infusion (250 mg) plus HSS (150 mL 3.0% Na) bid and light Na restriction (120 mmol), and the second group received furosemide infusion (250 mg) twice daily, and low Na diet (80 mmol). The fluid intake of both groups was restricted (1 L/d). Body weight, whole-body bioelectrical impedance analysis (BIA), 24-hour urinary volume, and serum and urinary laboratory parameters were measured daily. Estimations of echocardiographic PCWP (Echo-PCWP) were detected on entry, 1 hour after concluding the initial treatment, and 6 days thereafter. A total of 133 patients (47 women and 86 men), aged 65-82 years, met the entry criteria.The HSS group revealed a significant increase in daily diuresis, natriuresis, and serum sodium compared with the furosemide group. Six days after treatment, renal function was significantly improved in the HSS group. Both groups showed a significant reduction in Echo-PCWP, but the HHS group revealed a faster reduction and significant lower values at 6 days compared with the group taking furosemide alone. We observed a positive correlation between values of Echo-PCWP and BNP and an inverse correlation between BIA parameters and Echo-PCWP. CONCLUSIONS: Our data show that the combination of high diuretic dose and HSS infusion plus light restriction in dietary sodium intake determine a more rapid and significant hemodynamic stabilization through the improvement of echo-PCWP, BNP levels, and BIA parameters than the group treated without HSS

One-year renal and cardiac effects of bisoprolol versus losartan in recently diagnosed hypertensive patients: a randomized, double-blind study.

BACKGROUND AND OBJECTIVES: Hypertension is a significant cause of chronic renal injury and its effective treatment is capable of reducing the rate of renal failure. beta-Adrenoceptor antagonists (beta-blockers) have been reported to induce a deterioration in renal function, while several data have indicated a renoprotective effect of treatment with the angiotensin II type 1 receptor antagonist losartan. Previous studies of the interaction between the selective beta(1)-blocker bisoprolol and kidney function were performed only for short- and medium-term periods. The aim of this study was to compare the antihypertensive efficacy and renal and cardiac haemodynamic effects of bisoprolol with those of losartan over a 1-year time period in patients with essential hypertension. METHODS: Seventy-two patients (40 males) with recently diagnosed uncomplicated (European Society of Hypertension [ESH] criteria stage 1-2) hypertension (mean +/- SD age 52 +/- 12 years) were enrolled in the study. After a run-in period of 14 days on placebo, the patients were randomized in a double-blind, prospective study to receive either bisoprolol 5 mg or losartan 50 mg, administered once daily for 1 year. At recruitment and 12 months after treatment, cardiac output and renal haemodynamics and function were evaluated by echocardiography and radionuclide studies, respectively. RESULTS: There were no significant differences in baseline clinical data, including glomerular filtration rate and blood pressure, between the two treatment groups. At 1 year, blood pressure had decreased significantly (p < 0.001) with both treatments, and heart rate was reduced only in the group taking bisoprolol. The long-term effects on renal haemodynamics and cardiac function were similar with both drugs, the only change being a significant reduction in the filtration fraction for each group. CONCLUSIONS: These data suggest that both bisoprolol and losartan are effective agents for the treatment of patients with recently diagnosed ESH stage 1-2 hypertension. Over a 1-year period, both agents maintained good renal and cardiac performance and haemodynamics

Is delayed facilitated percutaneous coronary intervention better than immediate in reperfused myocardial infarction? Six months follow up findings

Background: There are several new strategies proposed to improve the outcome of patients with ST-elevation myocardial infarction (STEMI). One approach is the resurgent use of facilitated percutaneous coronary interventions (PCI). Until recently, deciding whether immediate PCI after combined treatment (facilitated PCI) is more appropriate than delayed PCI (short time) has not been investigated. The aim of this study, therefore, was to investigate the outcomes in patients initially successfully treated pharmacologically and immediate PCI < 2 hr, and in patients initially successfully treated with pharmacological therapy and with delayed PCI (12–72 h). Methods: 451 reperfused STEMI patients, aged 18 to 75 years, class I–II Killip, with an acceptable echocardiographic window and admitted within 12 hs of the onset of symptoms were randomized into two groups. All patients had to have successful reperfusion, to receive the combination of a standard tirofiban infusion or abciximab plus half dose rtPA. Thereafter, patients were sub-grouped as follows:group 1 (immediate PCI) patients had PCI within 2 h; and group 2 (delayed PCI) patients in which PCI was performed after 12 hs and within 72 hs. Results: The 225 reperfused (immediate-PCI) and 226 reperfused (delayed-PCI) patients (time from randomization to PCI 165 ± 37 min in immediate PCI versus 45.1 ± 20.2 h in delayed PCI group) showed similar results in ejection fraction, CK release and patency of the IRA. In addition, the delayed PCI group showed a significant reduction in ischemic events, restenosis and bleedings (P = 0.005, 0.01, 0.01 respectively) and significant reduced angiographic evidence of thrombus formation in the infarction-related artery (IRA) (p = 0.001). Conclusion: Our data suggest the safety and possible use of delayed facilitated PCI in patients with STEMI, and that delayed PCI in patients treated with combined lytic and IIb/IIIa inhibitors appears to be as effective and possibly superior (reduced ischemic events and repeat PCI) as immediate PCI. The patients in this study were successfully reperfused, with TIMI-3 flow and our data may not apply to patients with TIMI 0–2 flow. This strategy could allow transferring the reperfused patients and performing PCI after hours < 72 hours and not immediately, thereby reducing the number of urgent PCI and costs, obtaining similar results, but mostly causing less discomfort to the patient. Our results had to be interpreted with caution, because current guidelines do not recommend the combined therapy, but suggest further studies