An adenosine-to-inosine tRNA-editing enzyme that can perform C-to-U deamination of DNA

Adenosine-to-inosine editing in the anticodon of tRNAs is essential for viability. Enzymes mediating tRNA adenosine deamination in bacteria and yeast contain cytidine deaminase-conserved motifs, suggesting an evolutionary link between the two reactions. In trypanosomatids, tRNAs undergo both cytidine-to-uridine and adenosine-to-inosine editing, but the relationship between the two reactions is unclear. Here we show that down-regulation of the Trypanosoma brucei tRNA-editing enzyme by RNAi leads to a reduction in both C-to-U and A-to-I editing of tRNA in vivo. Surprisingly, in vitro, this enzyme can mediate A-to-I editing of tRNA and C-to-U deamination of ssDNA but not both in either substrate. The ability to use both DNA and RNA provides a model for a multispecificity editing enzyme. Notably, the ability of a single enzyme to perform two different deamination reactions also suggests that this enzyme still maintains specificities that would have been found in the ancestor deaminase, providing a first line of evidence for the evolution of editing deaminases.     

The Irvine-Minnesota inventory to measure built environments: development

BACKGROUND: Researchers and policymakers increasingly identify active living-including walking and bicycling for travel and recreation-as a potential strategy to increase rates of physical activity in the United States. Understanding the impact of the built environment on physical activity levels requires reliable methods to measure potentially relevant built environment features. This paper presents an audit tool-the Irvine Minnesota Inventory-that was designed to measure a wide range of built environment features that are potentially linked to active living, especially walking. METHODS: The inventory was created through a literature review, focus group interviews, a panel of experts, and field testing in 27 settings. The inventory was developed in 2003-2004. RESULTS: The Irvine Minnesota Inventory includes 162 items, organized into four domains: accessibility (62 items), pleasurability (56 items), perceived safety from traffic (31 items), and perceived safety from crime (15 items). (Some items are in multiple domains.) The inventory includes both a paper version and a version in Microsoft Access, to allow data to be input directly into the computer. CONCLUSIONS: Limitations of methods used to develop the inventory are discussed. Strategies are offered for using the Irvine Minnesota Inventory to systematically and reliably measure characteristics of the built environment that are potentially linked to active living.     

Chronic kidney disease in Cuba: epidemiological studies, integral medical care, and strategies for prevention

The experience of the Republic of Cuba regarding epidemiological studies, integral medical care, and strategies for the prevention of chronic kidney disease is summarized in this report. Cuba has a National Program for Chronic Renal Disease, Dialysis, and Renal Transplantation. There is a national nephrology net, integrated by the Institute of Nephrology as the coordinator center, that has 47 nephrology services with a hemodialysis unit (24 of them with peritoneal dialysis unit), 9 transplantation centers, 33 organ procurement hospitals, and 5 histocompatibility laboratories.In 2004, the incidence rate in dialysis patients was 111 pmp, and the prevalence rate was 149 pmp, demonstrating an increasing mean of 17.0% and 10.0% per year, respectively. Renal transplantation rate was 16.6 pmp. The detection, registration, and follow-up of patients with chronic kidney disease (serum creatinine > or =1.5 mg/dL or glomerular filtration rate <60 mL/min) by family doctors was 9,761 patients, 0.87 patients per 1,000 inhabitants.In the 1980s, three population-based screening studies were performed to define the burden of chronic renal failure in different regions of Cuba. The prevalence rate was 1.1, 3.3, and 3.5 per 1,000 inhabitants, respectively. At present, another three population-based screening studies are ongoing in order to detect the chronic kidney disease in earliest stages.The continuing medical education activities have been very useful in raising the awareness of medical doctors and the basic health staff about the threats posed by and the strategies to prevent, diagnose, and treat chronic kidney disease.     

Acute renal cortical necrosis in a series of young men with severe acute pancreatitis

Diffuse renal cortical necrosis from any cause is rare in the Western World. Over the last 5 decades, there have been isolated case reports of acute cortical necrosis as a consequence of acute pancreatitis, but the long-term outcome of these patients has not previously been reported. Here, we report 3 young men, aged 16-21 years, who have presented over the past 19 years with severe acute pancreatitis associated with oliguric acute renal failure. They were all found to have diffuse renal cortical necrosis and consequently made no renal recovery. Despite the appreciable mortality associated with acute pancreatitis complicated by acute renal failure, they all survived the initial illness and all have successfully undergone renal transplantation. We present a detailed account of each patient including diagnostic strategies and discuss the possible factors contributing to a favorable outcome in these patients.     

In vitro leishmanicidal activity of Tityus discrepans scorpion venom

Leishmania parasites are sensitive to peptides with antimicrobial and ion-channel inhibitory activity. Because scorpion venoms are rich sources of such peptides, the leishmanicidal effect of Tityus discrepans venom was investigated. A negative correlation between cell growth and venom concentration was observed for venom-treated cultures of Leishmania (L.) mexicana mexicana promastigotes; 50% growth inhibition was obtained at 0.4 μg/ml. Light microscopy showed rounded, highly vacuolated L. (L.) m. mexicana cells with impaired flagellar motion after 15 min of incubation at 35 μg/ml. Ultrastructural studies confirmed an intense cytoplasm vacuolation and also enlargement of the flagellar pocket. Survival rates for New World Leishmania promastigotes (75% venom effective concentration, μg/ml) obtained after acute (1 h) venom toxicity tests were: L. (L.) m. mexicana (2.3), Leishmania (V.) braziliensis (11.3), and Leishmania (L.) chagasi (56.2). Heat (90°C) treatment of venom and fraction TdII abolished most of their leishmanicidal effect. Acute toxicity assays performed with Sephadex G-50 fractions indicated that leishmanicidal activity is associated with the venom lowest molecular mass components (2.8–7.4 kDa), as determined by MALDI-TOF mass spectrometry.     

Clinical Course of Patients With Worsening Heart Failure With Reduced Ejection Fraction

Background

Epidemiology of patients with worsening heart failure and reduced ejection fraction (HFrEF) in the real-world setting is not well described.

5-ethoxymethyl-7-fluoro-3-oxo-1,2,3,5-tetrahydrobenzo[4,5]imidazo[1,2a]pyridine-4-N-(2-fluorophenyl)carboxamide (RWJ-51204), a new nonbenzodiazepine anxiolytic

5-ethoxymethyl-7-fluoro-3-oxo-1,2,3,5-tetrahydrobenzo[4,5] imidazo[1,2a]pyridine-4-N-(2-fluorophenyl)carboxamide) (RWJ-51204) binds selectively and with high affinity (K(i) = 0.2-2 nM) to the benzodiazepine site on GABA(A) receptors. Considering the GABA shift, the intrinsic modulatory activity of RWJ-51204 is lower than that of full agonist anxiolytics (lorazepam, diazepam, alprazolam, and clonazepam) but similar to partial agonists (bretazenil, abecarnil, panadiplon, and imidazenil). RWJ-51204 was orally active in anxiolytic efficacy tests; pentylenetetrazole induced seizure inhibition in mice (ED(50) = 0.04 mg/kg), Vogel conflict in rats (ED(50) = 0.36 mg/kg), elevated plus-maze in rats (minimal effective dose = 0.1 mg/kg), and conflict in squirrel monkeys (ED(50) = 0.49 mg/kg). RWJ-51204 attenuated chlordiazepoxide-induced motor impairment in mice. Usually, RWJ-51204 was more potent than reference anxiolytics in rodent efficacy tests but less potent in monkey conflict. Usually, the slope of the dose-response lines for RWJ-51204 was more shallow than the full agonist anxiolytics but steeper than partial agonists in efficacy tests but typically shallow in tests for central nervous system side effects. In monkeys only mild or moderate sedation was observed at doses equivalent to 20 or 40 times the anxiolytic ED(50). RWJ-51204 fits into the partial agonist class of GABA(A) receptor modulators. In conclusion, RWJ-51204 exhibits a profile in in vitro experiments and in animal models, in mice and monkeys (but not in rats), suggesting that it has a profile of anxiolytic activity associated with less sedation, motor impairment, or muscle relaxation than currently available GABA(A) receptor modulators, i.e., the benzodiazepines.     

2-Amino-3,4-dihydroquinazolines as inhibitors of BACE-1 (beta-site APP cleaving enzyme): Use of structure based design to convert a micromolar hit into a nanomolar lead

A new aspartic protease inhibitory chemotype bearing a 2-amino-3,4-dihydroquinazoline ring was identified by high-throughput screening for the inhibition of BACE-1. X-ray crystallography revealed that the exocyclic amino group participated in a hydrogen bonding array with the two catalytic aspartic acids of BACE-1 (Asp(32), Asp(228)). BACE-1 inhibitory potency was increased (0.9 microM to 11 nM K(i)) by substitution into the unoccupied S(1)' pocket.