Simulation Training to Improve Informed Consent and Pharmacokinetic/Pharmacodynamic Sampling in Pediatric Trials

Background: Pediatric trials to add missing data for evidence-based pharmacotherapy are still scarce. A tailored training concept appears to be a promising tool to cope with critical and complex situations before enrolling the very first patient and subsequently to ensure high-quality study conduct. The aim was to facilitate study success by optimizing the preparedness of the study staff shift. Method: An interdisciplinary faculty developed a simulation training focusing on the communication within the informed consent procedure and the conduct of the complex pharmacokinetic/pharmacodynamic (PK/PD) sampling within a simulation facility. Scenarios were video-debriefed by an audio-video system and manikins with artificial blood simulating patients were used. The training was evaluated by participants' self-assessment before and during trial recruitment. Results: The simulation training identified different optimization potentials for improved informed consent process and study conduct. It facilitated the reduction of avoidable errors, especially in the early phase of a clinical study. The knowledge gained through the intervention was used to train the study teams, improve the team composition and optimize the on-ward setting for the FP-7 funded "LENA" project (grant agreement no. 602295). Self-perceived ability to communicate core elements of the trial as well as its correct performance of sample preparation increased significantly (mean, 95% CI, p ≤ 0.0001) from 3 (2.5-3.5) to four points (4.0-4.5), and from 2 (1.5-2.5) to five points (4.0-5.0). Conclusion: An innovative training concept to optimize the informed consent process and study conduct was successfully developed and enabled high-quality conduct of the pediatric trials as of the very first patient visit.

Orodispersible minitablets of enalapril for use in children with heart failure (LENA): Rationale and protocol for a multicentre pharmacokinetic bridging study and follow-up safety study

Introduction

Treatment of paediatric heart failure is based on paradigms extensively tested in the adult population assuming similar underlying pathophysiological mechanisms. Angiotensin converting enzyme inhibitors (ACEI) like enalapril are one of the cornerstones of treatment and commonly used off-label in children. Dose recommendations have been extrapolated from adult experience, but the relationship between dose and pharmacokinetics (PK) in (young) children is insufficiently studied. Furthermore, appropriate paediatric formulations are lacking. Within the European collaborative project LENA, a novel formulation of enalapril orodispersible minitablets (ODMT), suitable for paediatric administration, will be tested in (young) children with heart failure due to either dilated cardiomyopathy or congenital heart disease in two pharmacokinetic bridging studies. Paediatric PK data of enalapril and its active metabolite enalaprilat will be obtained. In a follow-up study, the safety of enalapril ODMTs will be demonstrated in patients on long-term treatment of up to 10 months. Furthermore, additional information about pharmacodynamics (PD) and ODMT acceptability will be collected in all three studies.

Methods and Analysis

Phase II/III, open-label, multicentre study. Children with dilated cardiomyopathy (DCM) (n = 25; 1 month to less than 12 years) or congenital heart disease (CHD) (n = 60; 0 to less than 6 years) requiring or already on ACEI will be included. Exclusion criteria include severe heart failure precluding ACEI use, hypotension, renal impairment, hypersensitivity to ACEI. For those naïve to ACEI up-titration to an optimal dose will be performed, those already on ACEI will be switched to an expected equivalent dose of enalapril ODMT and optimised. In the first 8 weeks of treatment, a PK profile will be obtained at the first dose (ACEI naïve patients) or when an optimal dose is reached. Furthermore, population PK will be done with concentrations detected over the whole treatment period. PD and safety data will be obtained at least at 2-weeks intervals. Subsequently, an intended number of 85 patients will be followed-up up to 10 months to demonstrate long-term safety, based on the occurrence of (severe) adverse events and monitoring of vital signs and renal function.

Ethics and dissemination

Clinical Trial Authorisation and a favourable ethics committee opinion were obtained in all five participating countries. Results of the studies will be submitted for publication in a peer-reviewed journal.

Trial registration numbers

EudraCT 2015-002335-17, EudraCT 2015-002396-18, EudraCT 2015-002397-21.

Genomic organization of the human CYP3A locus: identification of a new, inducible CYP3A gene

Proteins encoded by the human CYP3A genes metabolize every second drug currently in use. The activity of CYP3A gene products in the general population is highly variable and may affect the efficacy and safety of drugs metabolized by these enzymes. The mechanisms underlying this variability are poorly understood, but they include gene induction, protein inhibition and unknown genetic polymorphisms. To better understand the regulation of CYP3A expression and to provide a basis for a screen of genetic polymorphisms, we determined and analysed the sequence of the human CYP3A locus. The 231 kb locus sequence contains the three CYP3A genes described previously (CYP3A4, CYP3A5 and CYP3A7), three pseudogenes as well as a novel CYP3A gene termed CYP3A43. The gene encodes a putative protein with between 71.5% and 75.8% identity to the other CYP3A proteins. The highest expression level of CYP3A43 mRNA is observed in the prostate, an organ with extensive steroid metabolism. CYP3A43 is also expressed in several other tissues including liver, where it can be induced by rifampicin. CYP3A43 transcripts undergo extensive splicing. The identification of a new member of the CYP3A family and the characterization of the full CYP3A locus will aid efforts to identify the genetic variants underlying its variable expression. This, in turn, will lead to a better optimization of therapies involving the numerous substrates of CYP3A proteins.

The nucleotide sequence of Saccharomyces cerevisiae chromosome XV

Chromosome XV was one of the last two chromosomes of Saccharomyces cerevisiae to be discovered. It is the third-largest yeast chromosome after chromosomes XII and IV, and is very similar in size to chromosome VII. It alone represents 9% of the yeast genome (8% if ribosomal DNA is included). When systematic sequencing of chromosome XV was started, 93 genes or markers were identified, and most of them were mapped. However, very little else was known about chromosome XV which, in contrast to shorter chromosomes, had not been the object of comprehensive genetic or molecular analysis. It was therefore decided to start sequencing chromosome XV only in the third phase of the European Yeast Genome Sequencing Programme, after experience was gained on chromosomes III, XI and II. The sequence of chromosome XV has been determined from a set of partly overlapping cosmid clones derived from a unique yeast strain, and physically mapped at 3.3-kilobase resolution before sequencing. As well as numerous new open reading frames (ORFs) and genes encoding tRNA or small RNA molecules, the sequence of 1,091,283 base pairs confirms the high proportion of orphan genes and reveals a number of ancestral and successive duplications with other yeast chromosomes.

Overview of the yeast genome

The collaboration of more than 600 scientists from over 100 laboratories to sequence the Saccharomyces cerevisiae genome was the largest decentralised experiment in modern molecular biology and resulted in a unique data resource representing the first complete set of genes from a eukaryotic organism. 12 million bases were sequenced in a truly international effort involving European, US, Canadian and Japanese laboratories. While the yeast genome represents only a small fraction of the information in today's public sequence databases, the complete, ordered and non-redundant sequence provides an invaluable resource for the detailed analysis of cellular gene function and genome architecture. In terms of throughput, completeness and information content, yeast has always been the lead eukaryotic organism in genomics; it is still the largest genome to be completely sequenced.

The nucleotide sequence of Saccharomyces cerevisiae chromosome XII

The yeast Saccharomyces cerevisiae is the pre-eminent organism for the study of basic functions of eukaryotic cells. All of the genes of this simple eukaryotic cell have recently been revealed by an international collaborative effort to determine the complete DNA sequence of its nuclear genome. Here we describe some of the features of chromosome XII.

The nucleotide sequence of Saccharomyces cerevisiae chromosome XIV and its evolutionary implications

In 1992 we started assembling an ordered library of cosmid clones from chromosome XIV of the yeast Saccharomyces cerevisiae. At that time, only 49 genes were known to be located on this chromosome and we estimated that 80% to 90% of its genes were yet to be discovered. In 1993, a team of 20 European laboratories began the systematic sequence analysis of chromosome XIV. The completed and intensively checked final sequence of 784,328 base pairs was released in April, 1996. Substantial parts had been published before or had previously been made available on request. The sequence contained 419 known or presumptive protein-coding genes, including two pseudogenes and three retrotransposons, 14 tRNA genes, and three small nuclear RNA genes. For 116 (30%) protein-coding sequences, one or more structural homologues were identified elsewhere in the yeast genome. Half of them belong to duplicated groups of 6-14 loosely linked genes, in most cases with conserved gene order and orientation (relaxed interchromosomal synteny). We have considered the possible evolutionary origins of this unexpected feature of yeast genome organization.

The nucleotide sequence of Saccharomyces cerevisiae chromosome VII

The complete nucleotide sequence of Saccharomyces cerevisiae chromosome VII has 572 predicted open reading frames (ORFs), of which 341 are new. No correlation was found between G+C content and gene density along the chromosome, and their variations are random. Of the ORFs, 17% show high similarity to human proteins. Almost half of the ORFs could be classified in functional categories, and there is a slight increase in the number of transcription (7.0%) and translation (5.2%) factors when compared with the complete S. cerevisiae genome. Accurate verification procedures demonstrate that there are less than two errors per 10,000 base pairs in the published sequence.

Sequence analysis of the 43 kb CRM1-YLM9-PET54-DIE2-SMI1-PHO81-YHB4-PFK1 region from the right arm of Saccharomyces cerevisiae chromosome VII

The nucleotide sequence of a 43 118 bp fragment from chromosome VII of Saccharomyces cerevisiae has been determined and analysed. The fragment originates from the right arm of chromosome VII. It starts approximately 11 kb centromere-proximal to the per54 marker and ends in the middle of the PFK1 gene. The sequence contains a small nuclear RNA gene (SNR7) and 29 open reading frames (ORFs) larger than 100 amino acids. Six of these were completely internal to or partially overlapped other ORFs. Six previously described genes, YLM9/MRPL9, CRM1, DIE2, SMI1, PHO81 and YHB4, were mapped to this region in addition to pet54 and PFK1. Of the remaining 17 ORFs, four showed homology with other S. cerevisiae genes and four, including one of the partially overlapping ORFs, with genes from other organisms. Eight ORFs had no homology with any sequence in the databases.

Sequence analysis of the 43 kb CRM1-YLM9-PET54-DIE2-SMI1-PHO81-YHB4-PFK1 region from the right arm of Saccharomyces cerevisiae chromosome VII

The nucleotide sequence of a 43 118 bp fragment from chromosome VII of Saccharomyces cerevisiae has been determined and analysed. The fragment originates from the right arm of chromosome VII. It starts approximately 11 kb centromere-proximal to the per54 marker and ends in the middle of the PFK1 gene. The sequence contains a small nuclear RNA gene (SNR7) and 29 open reading frames (ORFs) larger than 100 amino acids. Six of these were completely internal to or partially overlapped other ORFs. Six previously described genes, YLM9/MRPL9, CRM1, DIE2, SMI1, PHO81 and YHB4, were mapped to this region in addition to pet54 and PFK1. Of the remaining 17 ORFs, four showed homology with other S. cerevisiae genes and four, including one of the partially overlapping ORFs, with genes from other organisms. Eight ORFs had no homology with any sequence in the databases.

The effect of the JE (MCP-1) gene, which encodes monocyte chemoattractant protein-1, on the growth of HeLa cells and derived somatic-cell hybrids in nude mice

To investigate the effect of tumor-associated macrophages on the in vivo growth properties of cervical carcinoma cells, tumorigenic human papilloma virus (HPV) 18-positive HeLa cells were transfected with an expression vector harboring the cDNA for the macrophage chemoattractant protein-1 JE (MCP-1). Although the endogenous gene is present and not structurally rearranged, its expression seems to be negatively affected by a still unknown mechanism. Inoculation of JE (MCP-1)-negative HeLa cells into nude mice led to rapidly growing tumors, where macrophage infiltration into the inner tumor mass was not detectable immunohistochemically. The activity that attracted mononuclear cells under both in vitro and in vivo condition was reconstituted in HeLa cells after transfection with the JE (MCP-1) expression vector. Heterotransplantation of those cells into immunocompromised animals resulted in significant growth retardation that was accompanied by a strong infiltration of macrophages. On the other hand, in vivo selection of nonmalignant hybrids made between wild-type HeLa cells and normal human fibroblasts in nude mice resulted in tumorigenic segregants 4 mo after inoculation into the animals. Monitoring JE (MCP-1) expression directly within those nodules, we found that transcription was either absent or only weakly detectable. Recultivation of JE (MCP-1)-positive tissue grafts under in vitro conditions revealed that the gene was only marginally inducible by tumor necrosis factor-alpha, a cytokine that normally induces a very strong activation of transcription in nontumorigenic cells. These findings suggest that functional JE (MCP-1) expression and in turn activated macrophages may play a pivotal role in controlling the proliferation rate of HPV-positive cells in vivo.

The primary structure of sensory rhodopsin II: a member of an additional retinal protein subgroup is coexpressed with its transducer, the halobacterial transducer of rhodopsin II

The blue-light receptor genes (sopII) of sensory rhodopsin (SR) II were cloned from two species, the halophilic bacteria Haloarcula vallismortis (vSR-II) and Natronobacterium pharaonis (pSR-II). Upstream of both sopII gene loci, sequences corresponding to the halobacterial transducer of rhodopsin (Htr) II were recognized. In N. pharaonis, psopII and phtrII are transcribed as a single transcript. Comparison of the amino acid sequences of vHtr-II and pHtr-II with Htr-I and the chemotactic methyl-accepting proteins from Escherichia coli revealed considerable identities in the signal domain and methyl-accepting sites. Similarities with Htr-I in Halobacterium salinarium suggest a common principle in the phototaxis of extreme halophiles. Alignment of all known retinal protein sequences from Archaea identifies both SR-IIs as an additional subgroup of the family. Positions defining the retinal binding site are usually identical with the exception of Met-118 (numbering is according to the bacteriorhodopsin sequence), which might explain the typical blue color shift of SR-II to approximately 490 nm. In archaeal retinal proteins, the function can be deduced from amino acids in positions 85 and 96. Proton pumps are characterized by Asp-85 and Asp-96; chloride pumps by Thr-85 and Ala-96; and sensors by Asp-85 and Tyr-96 or Phe-96.

Complete DNA sequence of yeast chromosome II

In the framework of the EU genome-sequencing programmes, the complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome II (807 188 bp) has been determined. At present, this is the largest eukaryotic chromosome entirely sequenced. A total of 410 open reading frames (ORFs) were identified, covering 72% of the sequence. Similarity searches revealed that 124 ORFs (30%) correspond to genes of known function, 51 ORFs (12.5%) appear to be homologues of genes whose functions are known, 52 others (12.5%) have homologues the functions of which are not well defined and another 33 of the novel putative genes (8%) exhibit a degree of similarity which is insufficient to confidently assign function. Of the genes on chromosome II, 37-45% are thus of unpredicted function. Among the novel putative genes, we found several that are related to genes that perform differentiated functions in multicellular organisms of are involved in malignancy. In addition to a compact arrangement of potential protein coding sequences, the analysis of this chromosome confirmed general chromosome patterns but also revealed particular novel features of chromosomal organization. Alternating regional variations in average base composition correlate with variations in local gene density along chromosome II, as observed in chromosomes XI and III. We propose that functional ARS elements are preferably located in the AT-rich regions that have a spacing of approximately 110 kb. Similarly, the 13 tRNA genes and the three Ty elements of chromosome II are found in AT-rich regions. In chromosome II, the distribution of coding sequences between the two strands is biased, with a ratio of 1.3:1. An interesting aspect regarding the evolution of the eukaryotic genome is the finding that chromosome II has a high degree of internal genetic redundancy, amounting to 16% of the coding capacity.

Analysis of a 17.4 kb DNA segment of yeast chromosome II encompassing the ribosomal protein L19 as well as proteins with homologies to components of the hnRNP and snRNP complexes and to the human proliferation-associated p120 antigen

We report the nucleotide sequence of a 17.4 kb DNA segment from the left arm of Saccharomyces cerevisiae chromosome II. This sequence contains 12 open reading frames (ORFs) longer than 300 bp and a putative autonomously replicating sequence (ARS). The ORF YBL0418 contains the KH motif present in several nucleic acid-binding proteins and shares homologies with the mouse X protein of the heterogeneous nuclear ribonucleoprotein (hnRNP) complexes involved in pre-mRNA processing. YBL0424 is the yeast member of the ribosomal protein L19 (YL14) family. YBL0425 is related to the D1 core polypeptide of the small nuclear ribonucleoprotein (snRNP) particles involved in the splicing of introns. YBL0437 is a putative homologue of the human protein p120, one of the major antigens associated with malignant tumours. Mcm2, a protein important for ARS activity, as well as Aac2, one of the three isoforms of the mitochondrial ATP/ADP carrier, were previously described (Yan et al., 1991; Lawson and Douglas, 1988). Four ORFs show no homology or particular features that could help to assess their functions. The last ORFs are not likely to be expressed for they are localized on the complementary strand of longer ORFs.

Complete DNA sequence of yeast chromosome XI

The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map demonstrate the need for using independent physical mapping criteria.

Differential regulation of the JE gene encoding the monocyte chemoattractant protein (MCP-1) in cervical carcinoma cells and derived hybrids

Malignant human papillomavirus type 18 (HPV18)-positive cervical carcinoma cells can be reverted to a nonmalignant phenotype by generation of somatic cell hybrids with normal human fibroblasts. Although nontumorigenic hybrids, their tumorigenic segregants, and the parental HeLa cells have similar in vitro properties, inoculation only of nontumorigenic cells into nude mice results in a selective suppression of HPV18 transcription which precedes cessation of cellular growth. Our present study, aimed at understanding the differential regulation in vitro and in vivo, shows that the JE gene, encoding the monocyte chemoattractant protein (MCP-1), is expressed only in nontumorigenic hybrids. Although the gene, including its regulatory region, is intact, no JE (MCP-1) mRNA is detected in the tumorigenic segregants and in other malignant HPV-positive cervical carcinoma cell lines. Tests of several monocyte-derived cytokines showed that only tumor necrosis factor alpha strongly induces the JE (MCP-1) gene in nontumorigenic cells and that this is accompanied by a dose-dependent reduction of HPV transcription. The JE (MCP-1) up-regulation occurs within 2 h and does not require de novo protein synthesis. The response to tumor necrosis factor alpha seems to be mediated by an NF-kappa B-related mechanism, since the induction can be completely abrogated by pretreating the cells with an antioxidant such as pyrrolidine dithiocarbamate. Interestingly, cocultivation of nonmalignant hybrids with monocyte-enriched fractions from human peripheral blood also results in an induction of the JE (MCP-1) gene and a concomitant suppression of HPV18 transcription. Neither effect is observed in malignant cells. These data suggest that JE (MCP-1) may play a pivotal role in the intercellular communication by triggering an intracellular pathway which negatively interferes with viral transcription in HPV-positive nontumorigenic cells.