Systematic analysis of enhancer and critical cis-acting RNA elements in the protein-encoding region of the hepatitis C virus genome.

Hepatitis C virus (HCV) causes chronic hepatitis, cirrhosis, and liver cancer. cis-acting RNA elements of the HCV genome are critical for translation initiation and replication of the viral genome. We hypothesized that the coding regions of nonstructural proteins harbor enhancer and essential cis-acting replication elements (CRE). In order to experimentally identify new cis RNA elements, we utilized an unbiased approach to introduce synonymous substitutions. The HCV genome coding for nonstructural proteins (nucleotide positions 3872 to 9097) was divided into 17 contiguous segments. The wobble nucleotide positions of each codon were replaced, resulting in 33% to 41% nucleotide changes. The HCV genome containing one of each of 17 mutant segments (S1 to S17) was tested for genome replication and infectivity. We observed that silent mutations in segment 13 (S13) (nucleotides [nt] 7457 to 7786), S14 (nt 7787 to 8113), S15 (nt 8114 to 8440), S16 (nt 8441 to 8767), and S17 (nt 8768 to 9097) resulted in impaired genome replication, suggesting CRE structures are enriched in the NS5B region. Subsequent high-resolution mutational analysis of NS5B (nt 7787 to 9289) using approximately 51-nucleotide contiguous subsegment mutant viruses having synonymous mutations revealed that subsegments SS8195-8245, SS8654-8704, and SS9011-9061 were required for efficient viral growth, suggesting that these regions act as enhancer elements. Covariant nucleotide substitution analysis of a stem-loop, JFH-SL9098, revealed the formation of an extended stem structure, which we designated JFH-SL9074. We have identified new enhancer RNA elements and an extended stem-loop in the NS5B coding region. Genetic modification of enhancer RNA elements can be utilized for designing attenuated HCV vaccine candidates.

Antiviral drugs and the treatment of hepatitis C.

With effective treatment of HIV-1, hepatitis C virus (HCV) has become increasingly recognized as a major cause of morbidity and mortality in this population. Rapid progression of liver disease and cirrhosis has been documented in HIV/HCV co-infected individuals, particularly with lower CD4-counts (< 200/µL). Therefore, HCV treatment has become a priority for many clinicians, despite the presence of many. An important issue among HIV/HCV co-infected patients is the selection of antiretroviral therapy (ART) during treatment with pegylated interferon, ribavirin (RBV), plus new HCV protease inhibitors. Extensive drug-drug interactions (DDI) and overlapping drug-associated adverse events can impact the outcome of HCV therapy. In this review, we focus on the important data and studies regarding optimizing antiretroviral regimens before starting HCV treatment in HIV/HCV co-infected patients to increase the chance of sustained virologic response (SVR).

Perioperative management of patients on adenosine diphosphate inhibitors in the era of drug-eluting stents: review of the literature and clinical implications.

The current adenosine diphosphate inhibitors, ticlopidine and clopidogrel, are thienopyridine compounds that inhibit adenosine diphosphate mediated platelet aggregation. They interfere with platelet activation by selectively and irreversibly blocking P2Y12 sub-unit of the adenosine diphosphate receptor on the surface of platelets. This provides an antiplatelet effect that is additive to the inhibition of the thromboxane A2 pathway by aspirin. Dual antiplatelet therapy is extensively used in cardiovascular medicine. Randomized controlled trials have substantiated the fact that thrombotic complications after percutaneous coronary intervention procedures can be decreased by using dual antiplatelet therapy. However, there is a concern of bleeding due to enhanced and irreversible platelet inhibition in patients who will require any operation including coronary artery bypass grafting while on adenosine diphosphate inhibitors. This applies to a large population of patients requiring either coronary artery bypass grafting after angiographic definition of their coronary anatomy, or patients requiring semi-elective or urgent operation while under dual antiplatelet therapy. This concern is more present in era of drug-eluting stents, where long-term use of dual antiplatelet therapy is encouraged, and the incidence of late thrombosis after late cessation of adenosine diphosphate inhibitors is increasingly surfacing in the literature. The goal this review is to provide the medical chemistry of most commonly used adenosine diphosphate inhibitors, examine the literature on the effect of adenosine diphosphate inhibitors in hemorrhagic-related complications after surgical intervention, and provide the ramifications and alternatives in modern clinical practice.

The role of intravenous dihydropyridine calcium channel blockers in the perioperative management of patients undergoing coronary artery bypass surgery.

The pharmacology characteristics of dihydropyridine calcium channel blockers (CCB) make them an attractive antihypertensive medication for use in the perioperative setting of coronary artery bypass graft (CABG) surgery. They lack the negative inotropic, negative chronotropic, and negative bathmotropic effects of phenylalkylamine and benzothiazepine CCB that limit the use in patients with heart failure or patients with bradyarrythmias. With the aging population and significant rise in the prevalence of heart failure, the use of dihydropyridine CCB as antihypertensive medication after CABG surgery has become more common. Furthermore, intravenous dihydropyridine CCB are being used in the perioperative setting as vasodilatory agents after radial artery harvesting for total arterial coronary revascularization. We review the pharmacological effects of intravenous dihydropyridine CCB, analyze the literature, and comment on the consequences in modern clinical practice.

Daptomycin non-susceptible meticillin-resistant Staphylococcus aureus USA 300 isolate.

Daptomycin is a novel bactericidal agent active against Gram-positive pathogens including meticillin-resistant Staphylococcus aureus (MRSA). Our case is unique in the description of an MRSA USA 300 isolate that developed decreased susceptibility to daptomycin during daptomycin and vancomycin therapy. Directed sequencing detected a previously reported mutation in mprF, resulting in a T345A substitution, associated with non-susceptibility to daptomycin.

A synopsis of research in cardiac apoptosis and its application to congestive heart failure.

Cardiac apoptosis diminishes the contractile mass, which leads to heart failure. Apoptosis of cardiac non-myocytes also contributes to maladaptive remodeling and the transition to decompensated congestive heart failure. New antiapoptotic interventions and medications will be available within the next decade. The aim of this study is to provide a critical synopsis of research projects on cardiocyte apoptosis that have implications for current and future practice and to identify methods to prevent or attenuate apoptosis in patients who have poor ventricular function. A retrospective literature review reveals a great many important publications. However, very few investigators discuss the clinical ramifications of cardiocyte apoptosis, nor do they address the clinician who sees poor ventricular contractility daily. Most studies are still investigational and involve antiapoptotic agents such as broad-spectrum caspase inhibitors, antioxidants, calcium channel blockers, insulin-like growth-factor 1, and poly(adenosine diphosphate ribose) synthetase inhibitors. some options have already been incorporated into the clinical practices of cardiologists and cardiac surgeons: repairing or replacing diseased or damaged valves before ventricular function deteriorates; reducing afterload with medication or intra-aortic balloon pulsation in patients who display acute increases in afterload; decreasing catecholamine-induced cardiotoxicity in hemodynamically compromised patients, by using beta-blockers and phosphodiesterase inhibitors; and inserting intra-aortic balloon pumps or ventricular assist devices early in cases of failing myocardium. Coronary revascularization early in myocardial infarction is effective antiapoptotic therapy. Other therapeutic targets are cardiopulmonary bypass and aortic cross-clamping, both of which require reductions in associated myocardial apoptosis.

Current status of thoracic endografting and its adjunctive pharmacology.

BACKGROUND: Thoracic endovascular aortic repair is a promising treatment modality. The advantages in the short term include shorter hospital stay, avoidance of lengthy invasive procedures, and decreased anesthesia time. It has made possible the treatment of elderly patients with coexisting comorbidities who otherwise would be difficult candidates for open surgery. OBJECTIVE: Although the technical aspects of thoracic endovascular procedures have been described in the literature, the adjunct pharmacology has not been discussed. The aim of this study is therefore to review the clinical pharmacology necessary for procedural details in repair of patients with aortic aneurysms and aortic dissection. METHODS: A literature search was performed using PUBMED by combining relevant Medical Subject Heading key words. The query was subsequently limited to English language, and involving "human". The articles were assessed for their validity, importance, and applicability. The publications were analyzed and clinically important data were collected and incorporated. RESULTS/CONCLUSION: Thoracic endovascular aortic repair is a complex procedure on a morbid cohort of patients with aortic pathologies. The pharmacotherapy is a crucial component of the procedure: It is aimed at facilitating the endovascular procedure and improving outcomes.

Clinical utility of interferon gamma assay in the diagnosis of tuberculosis.

Newly developed assays that measure the production of cellular interferon gamma are useful diagnostic tools for the diagnosis of tuberculosis and may potentially replace or complement the tuberculin skin test in some circumstances. Importantly, interferon gamma release assays are more specific than tuberculin skin tests. Unfortunately the tests do not differentiate between active or latent infection. In addition, immunocompromised patients are more likely to have indeterminate results. The current interferon gamma release assays test approved in the United States is costly and requires drawing blood and processing within 12 hours of collection. This study discusses the potential benefits and drawbacks in patients, including those who are immunocompromised.

Antibody response to Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan in patients after solid-organ transplantation.

Cryptococcosis is an important complication of solid-organ transplantation, but the risk factors for disease are poorly understood. The goal of this study was to investigate whether specific or nonspecific serum immunoglobulin levels determined in samples obtained before and after solid-organ transplantation differed in patients who did or did not develop cryptococcosis after transplantation. We analyzed pretransplantation sera from 25 subjects, 15 who subsequently developed cryptococcosis and 10 who did not, and posttransplantation sera from 24 subjects, 13 who developed cryptococcosis and 11 who did not. All subjects received a tacrolimus-based immunosuppressive regimen. Total immunoglobulin levels were measured by immunodiffusion, and Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan (GXM)-specific serum antibody levels were determined by enzyme-linked immunosorbent assays. The results showed that solid-organ transplantation had a significant effect on total immunoglobulin and GXM-reactive antibody levels. GXM-reactive antibody levels differed in subjects who did and did not develop cryptococcosis. In pretransplant serum samples, the levels of GXM-reactive immunoglobulin M (IgM) were significantly lower in subjects who developed cryptococcosis after transplantation than in those who did not. For posttransplant serum samples, the levels of GXM-reactive IgM and IgG were significantly higher among the subjects who developed cryptococcosis than among those who did not. These findings suggest that perturbations in the preexisting antibody or B-cell repertoire and/or related to treatment of rejection, transplantation, or immunosuppressive therapy could translate into an increased risk for transplant-associated cryptococcosis.

Apoptosis: pathophysiology and therapeutic implications for the cardiac surgeon.

Cardiomyocyte apoptosis has been associated with the pathogenesis of heart failure as well as ischemic and inflammatory myocardial conditions. The aim of this study is to give a critical synopsis of cardiomyocyte apoptosis and identify methods to prevent or attenuate apoptosis in patients undergoing cardiac surgery. Clinical conditions and agents associated with decreased apoptotic index are early repair or replacement of valvular pathology before deterioration of ventricular function, afterload reduction with medication or intraaortic balloon pulsation in patients with acute increase in afterload or in hemodynamically compromised patients, decreasing catecholamine-induced cardiotoxicity by using beta-blockers, phosphodiesterase inhibitors, or early insertion of intraaortic balloon pulsation or ventricular assist device. Prompt coronary revascularization, which reduces myocardial ischemia time, is the most effective antiapoptotic therapy. Reduction of myocardial apoptosis associated with cardiopulmonary bypass and aortic cross-clamping are other therapeutic targets. Some investigational therapies include ischemic preconditioning and use of antiapoptotic medication such as the caspase inhibitors, antioxidants, calcium-channel blockers, the insulin-like growth factor-1, and the poly-adenosine diphosphate-ribose-synthetase inhibitors. Most of the therapeutic implications in reducing cardiomyocyte apoptosis are still in the experimental phase. Some options are already incorporated in the clinical practice of the cardiovascular surgeon. New therapeutic considerations include avoiding sustained and long-term use of catecholamines and reducing or avoiding cardiopulmonary bypass-when clinically feasible. Noncatecholamine inotropes should be preferred for patients undergoing heart failure surgery and for patients with low output syndrome after open-heart surgery. The lessons learned from apoptosis research reinforce more liberal and early insertion of intraaortic balloon pulsation or ventricular assist device in clinical low output states.

Modulation of nuclear factor kappa b (NF-kB) activity in human herpes virus-6 (HHV-6) infection and its sequellae for cell function: Effects of antisense DNA treatment

Varias poblaciones celulares, susceptibles y no susceptibles, fueron infectadas con el virus herpes humano-6 (HHV-6) y tratadas posteriormente con ácido desoxirribonucleico (ADN) -NF-kB antisentido. Algunos cambios celulares secundarios a la integración del genoma viral pudieron ser corregidos con este tratamiento, mientras que aquellos inducidos por efecto de membrana celular del virus no respondieron de manera uniforme. Es así como el tratamiento con NF-kB puede servir para investigaciones posterioes específicas de los efectos virales en la célula. También puede servir para estudiar las actividades competitivas de las proteínas de NF-kB en los sitios genómicos homólogos