How to manage medications in the setting of liver disease with the application of six questions.

OBJECTIVE: Reviewing the current literature to guide clinicians managing medications in the setting of liver disease. LITERATURE SOURCES: Using the terms liver disease, medication management, and therapeutic monitoring, a literature review was conducted to identify peer-reviewed articles in MEDLINE (1966-April 2009). Reference citations were reviewed as an additional resource. Published English-language literatures, articles and trials were reviewed. Emphasis was placed on prospective, randomised, double-blind, placebo-controlled clinical trials. QUESTION SYNTHESIS: An informed decision on how to manage medications in the setting of liver disease should account for changes that transpire in a medication's first-pass metabolism, protein binding, volume of distribution, clearance and pharmacodynamic interactions. To incorporate these issues within one's thought process, clinicians can utilise the following six questions to evaluate a medication use: (i) Is the patient experiencing acute or chronic liver failure? (ii) Does the drug have high hepatic first-pass metabolism? (iii) Is the medication highly protein-bound? (iv) Is there a change in the volume of distribution for the medication? (v) Is the clearance of the medication significantly altered? and (vi) Is there a pharmacodynamic interaction with the medication? CONCLUSIONS: The introduction and use of six clinically relevant questions in the setting of liver disease can serve as a guide to clinicians who manage patients with liver disease.

Evaluating the appropriateness of thromboprophylaxis in an acute care setting using a computerised reminder, through order-entry system.

AIMS: Evidence suggests that thromboprophylaxis is still significantly underutilised across the United States despite its relationship with morbidity, mortality and resource expenditure. Previous randomised trials that have incorporated computerised reminders, through order-entry systems, have resulted in increased rates of thromboprophylaxis and lower incidences of clinically diagnosed deep-vein thrombosis or pulmonary embolism. The primary purpose of this prospective, observational study is to evaluate the use and appropriateness of preset computerized thromboprophylaxis regimens for patients in a major county metropolitan hospital over a 1-month period by evaluating the proportion of patients actually receiving recommended thromboprophylaxis according to established hospital guidelines. METHODS: This prospective, observational study was conducted in a large county hospital that recently established an evidence-based routine computerised policy to decrease risk of venous thromboembolism. Physicians, residents, medical interns, medical students, pharmacy students, and nurses were the targets of the investigation. Data were randomly collected between 10 internal medicine teams from 10 October 2006 to 10 November 2006. Investigators completed one DVT/PE risk assessment form for each patient reviewed and compared this to actual prescribed therapy to determine appropriateness of therapy. RESULTS: Pharmacological or non-pharmacological thromboprophylaxis was administered to 100% of patients evaluated. Eighty-six patients received recommended DVT/PE prophylaxis based on established hospital guidelines. DISCUSSION: Reported values seem to indicate that computerized reminders are capable of providing venous thromboprophylaxis for medically ill (non-surgical) patients relative to published norms. CONCLUSION: Results of this observational study reinforces the evidence that computerized, reminders, through order-entry systems might increase the delivery of thromboprophylaxis for hospitalized patients.

Ranolazine: a novel agent that improves dysfunctional sodium channels.

Treatment for coronary heart disease is usually directed at either increasing myocardial oxygen supply or decreasing myocardial oxygen demand. Although combination therapy with beta-blockers, calcium-channel blockers and nitrates are effective, many patients suffer from adverse effects of hypotension and bradycardia. Ranolazine is a novel medication that reduces ischaemia by preventing sodium induced calcium overload in myocardial cells without adversely affecting haemodynamic parameters. This agent is the first in the USA to be approved to treat angina in over 10 years. The purpose of this review is to evaluate the pharmacology, pharmacokinetics, clinical trials for safety and efficacy, precautions, adverse effects, drug interactions, and dosage and administration of ranolazine in the treatment of chronic stable angina and acute coronary syndrome.

Regulation of the ferritin heavy-chain homologue gene in the yellow fever mosquito, Aedes aegypti.

In the yellow fever mosquito Aedes aegypti, the ferritin heavy-chain homologue (HCH) gene is induced by blood feeding. This suggests that ferritin may serve as a cytotoxic protector against the oxidative challenge of the blood meal and may be essential for the survival of the insect. In this study, various cis-acting elements for the gene were identified and mapped. Transfection assays showed that the strength and activity of a subset of these elements are orientation-dependent. The shift observed for the ferritin HCH cis-acting elements is unique among known ferritin genes. DNase I footprinting data together with Transfac analyses identified a number of putative sites known for their involvement in developmental and cell proliferation processes.

The ferritin light-chain homologue promoter in Aedes aegypti.

Promoters that direct the expression of antipathogenic molecules to primary sites of pathogenic invasions provide a means to interfere with these invasions. Thus, they have the potential to be used in mosquito control. However, exogenous elements are known to lower the fitness of most insects, and given the ability of insects to evolve rapidly, all currently known promoters could be rendered useless. As transgenic mosquitoes may be a major component in the fight against mosquito-borne diseases, the identification of new mosquito promoters is needed. The promoter of the Aedes aegypti ferritin light-chain homologue (LCH) gene, a gene whose expression is induced in gut tissues during blood feeding has been identified and mapped. Transfection data indicate that the ferritin LCH promoter is a strong promoter. DNase I footprinting data and Transfac analyses suggest that the ferritin LCH promoter contains putative GATA, E2F, NIT2, TATA and DPE sites. These data together provide the first detailed map of a known ferritin LCH gene.

Identification and mapping of the promoter for the gene encoding the ferritin heavy-chain homologue of the yellow fever mosquito Aedes aegypti.

Mosquitoes are responsible for the transmission of numerous human diseases. The recent development of transgenic mosquitoes provides a new tool to examine molecular interactions between insect vectors and the pathogens they transmit. One focus in generating transgenic mosquito lies on expressing anti-pathogenic proteins at primary sites of pathogenic invasions, specifically the mosquito gut. Promoters that direct the expression of anti-pathogenic proteins in the mosquito gut are thus sought after because they may provide ways to hinder pathogenic development in the mosquito. Here, we report the identification and mapping of a strong promoter from the Aedes aegypti ferritin heavy-chain homologue (HCH) gene. All known insect ferritin HCH genes are expressed in the gut and inducible by an iron overload. Our transfection assays and DNase I footprinting analyses show that the mosquito ferritin HCH-gene contains regulatory elements both upstream and downstream of the transcriptional start site. The promoter of this gene contains a CF2 site, two GATA-binding sites, an E2F site, a TATA-box, an AP-1 site and a C/EBP binding site.

Ribonucleotide reductase subunits from the yellow fever mosquito, Aedes aegypti: cloning and expression.

Ribonucleotide reductase catalyses the de novo synthesis of deoxyribonucleotides. Class I reductases use an iron center to generate a tyrosyl free radical that can initiate formation of the deoxyribonucleotide. These reductases are alpha 2 beta 2 holoenzymes, and the subunits are denoted as R1 and R2. R1 contains the allosteric binding site and the active site, whereas R2 contains a binuclear iron center that initiates formation of the tyrosyl radical. We have cloned and sequenced the cDNAs encoding the R1 and R2 subunit in the yellow fever mosquito, Aedes aegypti. The messages for these proteins are increased in response to blood-feeding.

Repression of Manduca sexta ferritin synthesis by IRP1/IRE interaction.

Mammalian ferritin subunit synthesis is controlled at the translational level by the iron regulatory protein 1 (IRP1)/iron responsive element (IRE) interaction. Insect haemolymph ferritin subunit messages have an IRE in the 5'-untranslated region (UTR). We have shown that recombinant M. sexta IRP1 represses the in vitro translation of both the heavy and light chain ferritin subunits from this species without altering transcription. Deletion of either the 5'-UTR or the IRE from the mRNA abolishes IRP1 repression. Our studies indicated that the translational control of ferritin synthesis by IRP/IRE interaction could occur in insects in a manner similar to that of mammals. To our knowledge, this is the first report of the control of insect ferritin synthesis by IRP1/IRE interaction. Furthermore, this is the first indication that the synthesis of a secreted ferritin subunit can also be controlled in this manner.

Structure and location of a ferritin gene of the yellow fever mosquito Aedes aegypti.

We have isolated and sequenced a genomic clone encoding the 24- and 26-kDa ferritin subunits in the mosquito Aedes aegypti (Rockefeller strain). The A. aegypti gene differs from other known ferritin genes in that it possesses an additional intron and an unusually large second intron. The additional intron is located within the 5' untranslated region, between the CAP site and the start codon. The second intron contains numerous putative transposable elements. In addition, unlike the human and rat ferritin genes, the A. aegypti ferritin gene is a single copy gene, located at 88.3% FLpter on the q-arm of chromosome 1. Primer extension analysis indicates that the A. aegypti ferritin gene has multiple transcriptional start sites. A differential usage of these sites is observed with varied cellular iron concentrations.

Predictive intervals for age-specific fertility.

A multivariate ARIMA model is combined with a Gamma curve to predict confidence intervals for age-specific birth rates by 1-year age groups. The method is applied to observed age-specific births in Norway between 1900 and 1995, and predictive intervals are computed for each year up to 2050. The predicted two-thirds confidence intervals for Total Fertility (TF) around 2010 agree well with TF errors in old population forecasts made by Statistics Norway. The method gives useful predictions for age-specific fertility up to the years 2020-30. For later years, the intervals become too wide. Methods that do not take into account estimation errors in the ARIMA model coefficients underestimate the uncertainty for future TF values. The findings suggest that the margin between high and low fertility variants in official population forecasts for many Western countries are too narrow.

Transcriptional control is relevant in the modulation of mosquito ferritin synthesis by iron.

In yellow fever mosquito cells (Aag2 clone), iron treatment induces a threefold increase in ferritin message (fer mRNA) and protein (ferritin) by 16 h. These data contrast with work in mammalian hepatocytes and fibroblasts in which fer mRNA levels do not change with iron stimulation, but ferritin levels increase 50-fold. Pretreatment of the Aag2 cells with actinomycin D blocks induction of fer mRNA and reduces the ferritin subunit synthesis, suggesting that iron induction of ferritin subunit synthesis is subjected to transcriptional control. A putative iron-regulatory protein has also been identified in cytoplasmic extracts from Aag2 cells.

Purification of an expressed insect transferrin from cell culture media using high-capacity Ni(2+)-dipicolylamine gel.

Vertebrate transferrin is a well characterized iron transport protein. In contrast, little is known concerning the role of transferrin in insects. Yet, study of iron metabolism in insects could give insights into strategies for insect control, particularly for insects that transmit disease.

Manduca sexta hemolymph ferritin: cDNA sequence and mRNA expression.

A cDNA clone encoding a subunit of the tobacco hornworm Manduca sexta (Ms) hemolymph (serum) ferritin (Fer) has been identified and sequenced. The deduced amino acid (aa) sequence shows approx. 50% similarity to vertebrate Fer subunit sequences, and the nucleotide sequence contains a stem-loop structure in the 5' untranslated region that could serve as an iron-responsive element (IRE). The stem-loop of this putative IRE exhibits high identity to vertebrate IRE that play an essential role in the control of Fer synthesis. The Ms Fer subunit lacks one of the three Tyr residues required for the rapid biomineralization of iron shown in vertebrate heavy-chain Fer. In addition, aa residues that comprise the putative ferroxidase centers generally are not conserved, suggesting that the Ms Fer subunit more closely resembles the vertebrate light-chain subunit. Northern blot analyses indicate that the fer mRNA is expressed in the midgut, fat body and hemocytes, with the greatest expression in the midgut.

Purification of recombinant insect transferrin from large volumes of cell culture medium using high capacity Ni(2+)-dipicolylamine gel.

We report the purification of secreted recombinant Manduca sexta transferrin from Spodoptera frugiperda (Sf9) cell culture medium in a single step using high capacity Ni(2+)-dipicolylamine (DPA)-Novarose gel. Although the original sample was highly diluted (approximately 10 micrograms transferrin/ml medium) and the cell culture medium contained 10% surfactant (Pluronic F68) and a lipid emulsion, we were able to recover the recombinant transferrin (1 mg protein/100 ml) under gentle elution conditions with 70% yield at > 90% homogeneity. This work demonstrates the versatility of immobilized metal ion affinity chromatography using a high metal ion capacity gel to purify a recombinant protein and illustrates the potential of this affinity technique for protein separations from large volumes of cell culture media that contain surfactants.

The 1629-bp open reading frame of the Autographa californica multinucleocapsid nuclear polyhedrosis virus encodes a virion structural protein.

A 1629-bp open reading frame (ORF) of Autographa californica multinucleocapsid nuclear polyhedrosis virus (AcMNPV) is shown to encode a 78-kDa virion structural protein. To determine this, polyclonal antibody was made to a fusion protein synthesized in Escherichia coli from a chimeric gene that contained 1415 bp of the 1629-bp gene. In Western blot analyses, this antibody cross-reacted with a protein of about 78 kDa in both extracellular virions (ECV) and virions isolated from polyhedra (PDV), and with a 78-kDa protein in PDV envelope preparations, but not with PDV nucleocapsids. This suggests that the protein encoded by the 1629-bp ORF is a virion envelope protein or a protein that occurs in the virion intermediate layer between the envelope and nucleocapsid.

Sequence and in vitro translational analysis of a 1629-nucleotide ORF in Autographa californica nuclear polyhedrosis virus strain E2.

The complete nucleotide (nt) sequence of an open reading frame (ORF) (map unit 5.1 to 3.8) from Autographa californica nuclear polyhedrosis virus strain E2 (AcMNPV-E2) has been determined. This 1629-nt ORF has a coding potential for a 61-kDa Pro-rich protein. However, in vitro translation of the 1629-nt ORF and sodium dodecyl sulfate-polyacrylamide-gel electrophoresis (SDS-PAGE) revealed a 78-kDa protein product. The discrepancy between the M(r) predicted by the nt sequence and that obtained from the in vitro translational analysis is due to the high Pro content of this protein. The high Pro content causes anomalous migration of this protein during SDS-PAGE.

In vivo transcriptional analysis of three baculovirus genes: evidence of homology between viral and host transcripts.

Transcripts for the gp64 and polyhedrin genes as well as a 1629 open reading frame (1629 ORF) of the Autographa californica nuclear polyhedrosis virus were examined in the midgut tissues and hemocytes of uninfected and infected host Trichoplusia ni larvae and Sf21 cells. Polyhedrin-specific transcripts of 1.2, 3.4, and 4.9 kb were expressed in both infected larval tissues and infected Sf21 cells. The highest level of expression for polyhedrin-specific transcripts was observed in hemocytes, whereas the lowest level occurred in midgut. The expression of the 2.0-kb transcript for the gp64 gene increased continuously through 72 hr postinfection in the infected midgut tissues. This transcript was also observed in infected hemocytes, though its expression declined at 72 hr postinfection, as the expression for polyhedrin-specific transcripts peaked. The 1629 ORF transcripts of 2.0 and 3.2 kb were expressed in both types of infected tissues. More significantly, a 1629-ORF-specific probe detected host transcripts of 0.7 and 2.5 kb in uninfected midgut tissues as well as transcripts of 2.5, 8.8, and 11.0 kb in uninfected hemocytes under high stringency conditions. The latter results indicate that these host transcripts share homology with the 1629 ORF gene.