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Pivot/Remote: a distributed database for remote data entry in multi-center clinical trials.

1. INTRODUCTION. Data collection is a critical component of multi-center clinical trials. Clinical trials conducted in intensive care units (ICU) are even more difficult because the acute nature of illnesses in ICU settings requires that masses of data be collected in a short time. More than a thousand data points are routinely collected for each study patient. The majority of clinical trials are still "paper-based," even if a remote data entry (RDE) system is utilized. The typical RDE system consists of a computer housed in the CC office and connected by modem to a centralized data coordinating center (DCC). Study data must first be recorded on a paper case report form (CRF), transcribed into the RDE system, and transmitted to the DCC. This approach requires additional monitoring since both the paper CRF and study database must be verified. The paper-based RDE system cannot take full advantage of automatic data checking routines. Much of the effort (and expense) of a clinical trial is ensuring that study data matches the original patient data. 2. METHODS. We have developed an RDE system, Pivot/Remote, that eliminates the need for paper-based CRFs. It creates an innovative, distributed database. The database resides partially at the study clinical centers (CC) and at the DCC. Pivot/Remote is descended from technology introduced with Pivot [1]. Study data is collected at the bedside with laptop computers. A graphical user interface (GUI) allows the display of electronic CRFs that closely mimic the normal paper-based forms. Data entry time is the same as for paper CRFs. Pull-down menus, displaying the possible responses, simplify the process of entering data. Edit checks are performed on most data items. For example, entered dates must conform to some temporal logic imposed by the study. Data must conform to some acceptable range of values. Calculations, such as computing the subject's age or the APACHE II score, are automatically made as the data is entered. Data that is collected serially (BP, HR, etc.) can be displayed graphically in a trend form along with other related variables. An audit trail is created that automatically tracks all changes to the original data, making it possible to reconstruct the CRF to any point in time. On-line help provides information on the study protocol as well as assistance with the use of the system. Electronic security makes it possible to lock certain parts of the CRF once it has been monitored. Completed CRFs are transmitted to the DCC via electronic mail where it is reviewed and merged into the study database. Questions about subject data are transmitted back to the CC via electronic mail. This approach to maintaining the study database is unique in that the study data files are distributed among the CC and DCC. Until a subject's CRF is monitored (verified against the original patient data residing in the hospital record), it logically resides at the CC where it was collected. Copies are transmitted to the DCC and are only read there. Any pre-monitoring changes must be made to the data at the CC. Once the subject's CRF is monitored, it logically moves to the DCC, and any subsequent changes are made at the DCC with copies of the CRF flowing back to the CC. 3. DISCUSSION. Pivot/Remote eliminates the need for paper forms by utilizing portable computers that can be used at the patient bedside. A GUI makes it possible to quickly enter data. Because the user gets instant feedback on possible error conditions, time is saved because the original data is close at hand. The ability to display trended data or variables in the context of other data allows detection of erroneous conditions beyond simple range checks. The logical construction of the database minimizes the problem of managing dual databases (at the CC and DCC) and keeps CC personnel in the loop until all changes are made.

Computer Communication Networks↗

Regulation of implant surface cell adhesion: characterization and quantification of S-phase primary osteoblast adhesions on biomimetic nanoscale substrates.

Integration of an orthopedic prosthesis for bone repair must be associated with osseointegration and implant fixation, an ideal that can be approached via topographical modification of the implant/bone interface. It is thought that osteoblasts use cellular extensions to gather spatial information of the topographical surroundings prior to adhesion formation and cellular flattening. Focal adhesions (FAs) are dynamic structures associated with the actin cytoskeleton that form adhesion plaques of clustered integrin receptors that function in coupling the cell cytoskeleton to the extracellular matrix (ECM). FAs contain structural and signalling molecules crucial to cell adhesion and survival. To investigate the effects of ordered nanotopographies on osteoblast adhesion formation, primary human osteoblasts (HOBs) were cultured on experimental substrates possessing a defined array of nanoscale pits. Nickel shims of controlled nanopit dimension and configuration were fabricated by electron beam lithography and transferred to polycarbonate (PC) discs via injection molding. Nanopits measuring 120 nm diameter and 100 nm in depth with 300 nm center-center spacing were fabricated in three unique geometric conformations: square, hexagonal, and near-square (300 nm spaced pits in square pattern, but with +/-50 nm disorder). Immunofluorescent labeling of vinculin allowed HOB adhesion complexes to be visualized and quantified by image software. Perhipheral adhesions as well as those within the perinuclear region were observed, and adhesion length and number were seen to vary on nanopit substrates relative to smooth PC. S-phase cells on experimental substrates were identified with bromodeoxyuridine (BrdU) immunofluorescent detection, allowing adhesion quantification to be conducted on a uniform flattened population of cells within the S-phase of the cell cycle. Findings of this study demonstrate the disruptive effects of ordered nanopits on adhesion formation and the role the conformation of nanofeatures plays in modulating these effects. Highly ordered arrays of nanopits resulted in decreased adhesion formation and a reduction in adhesion length, while introducing a degree of controlled disorder present in near-square arrays, was shown to increase focal adhesion formation and size. HOBs were also shown to be affected morphologicaly by the presence and conformation of nanopits. Ordered arrays affected cellular spreading, and induced an elongated cellular phenotype, indicative of increased motility, while near-square nanopit symmetries induced HOB spreading. It is postulated that nanopits affect osteoblast-substrate adhesion by directly or indirectly affecting adhesion complex formation, a phenomenon dependent on nanopit dimension and conformation.

Biomimetic Materials↗

Using networks to identify fine structural differences between functionally distinct protein states.

The vast increase in available data from the "-omics" revolution has enabled the fields of structural proteomics and structure prediction to make great progress in assigning realistic three-dimensional structures to each protein molecule. The challenge now lies in determining the fine structural details that endow unique functions to sequences that assume a common fold. Similar problems are encountered in understanding how distinct conformations contribute to different phases of a single protein's dynamic function. However, efforts are hampered by the complexity of these large, three-dimensional molecules. To overcome this limitation, structural data have been recast as two-dimensional networks. This analysis greatly reduces visual complexity but retains information about individual residues. Such diagrams are very useful for comparing multiple structures, including (1) homologous proteins, (2) time points throughout a dynamics simulation, and (3) functionally different conformations of a given protein. Enhanced structural examination results in new functional hypotheses to test experimentally. Here, network representations were key to discerning a difference between unliganded and inducer-bound lactose repressor protein (LacI), which were previously presumed to be identical structures. Further, the interface of unliganded LacI was surprisingly similar to that of the K84L variant and various structures generated by molecular dynamics simulations. Apo-LacI appears to be poised to adopt the conformation of either the DNA- or inducer-bound structures, and the K84L mutation appears to freeze the structure partway through the conformational transition. Additional examination of the effector binding pocket results in specific hypotheses about how inducer, anti-inducer, and neutral sugars exert their effects on repressor function.

Bacterial Proteins↗

Functional characterization of recombinant chloroplast signal recognition particle.

The signal recognition particle (SRP) is a ubiquitous system for the targeting of membrane and secreted proteins. The chloroplast SRP (cpSRP) is unique among SRPs in that it possesses no RNA and is functional in post-translational as well as co-translational targeting. We have expressed and purified the two components of the Arabidopsis thaliana chloroplast signal recognition particle (cpSRP) involved in post-translational transport: cpSRP54 and the chloroplast-specific protein, cpSRP43. Recombinant cpSRP supports the efficient in vitro insertion of pea preLhcb1 into isolated thylakoid membranes. Recombinant cpSRP is a stable heterodimer with a molecular mass of approximately 100 kDa as determined by analytical ultracentrifugation, gel filtration analysis, and dynamic light scattering. The interactions of the components of the recombinant heterodimer and pea preLhcb1 were probed using an immobilized peptide library (pepscan) approach. These data confirm two previously reported interactions with the L18 region and the third transmembrane helix of Lhcb1 and suggest that the interface of the cpSRP43 and cpSRP54 proteins is involved in substrate binding. Additionally, cpSRP components are shown to recognize peptides from the cleavable, N-terminal chloroplast transit peptide of preLhcb1. The interaction of cpSRP43 with cpSRP54 was probed in a similar experiment with a peptide library representing cpSPR54. The C terminus of cpSRP54 is essential for the formation of the stable cpSRP complex and cpSPR43 interacts with distinct regions of the M domain of cpSRP54.

Amino Acid Sequence↗

A structural basis for selection and cross-species reactivity of the semi-invariant NKT cell receptor in CD1d/glycolipid recognition.

Little is known regarding the basis for selection of the semi-invariant alphabeta T cell receptor (TCR) expressed by natural killer T (NKT) cells or how this mediates recognition of CD1d-glycolipid complexes. We have determined the structures of two human NKT TCRs that differ in their CDR3beta composition and length. Both TCRs contain a conserved, positively charged pocket at the ligand interface that is lined by residues from the invariant TCR alpha- and semi-invariant beta-chains. The cavity is centrally located and ideally suited to interact with the exposed glycosyl head group of glycolipid antigens. Sequences common to mouse and human invariant NKT TCRs reveal a contiguous conserved "hot spot" that provides a basis for the reactivity of NKT cells across species. Structural and functional data suggest that the CDR3beta loop provides a plasticity mechanism that accommodates recognition of a variety of glycolipid antigens presented by CD1d. We propose a model of NKT TCR-CD1d-glycolipid interaction in which the invariant CDR3alpha loop is predicted to play a major role in determining the inherent bias toward CD1d. The findings define a structural basis for the selection of the semi-invariant alphabeta TCR and the unique antigen specificity of NKT cells.

Animals↗

PUMA2--grid-based high-throughput analysis of genomes and metabolic pathways.

The PUMA2 system (available at http://compbio.mcs.anl.gov/puma2) is an interactive, integrated bioinformatics environment for high-throughput genetic sequence analysis and metabolic reconstructions from sequence data. PUMA2 provides a framework for comparative and evolutionary analysis of genomic data and metabolic networks in the context of taxonomic and phenotypic information. Grid infrastructure is used to perform computationally intensive tasks. PUMA2 currently contains precomputed analysis of 213 prokaryotic, 22 eukaryotic, 650 mitochondrial and 1493 viral genomes and automated metabolic reconstructions for >200 organisms. Genomic data is annotated with information integrated from >20 sequence, structural and metabolic databases and ontologies. PUMA2 supports both automated and interactive expert-driven annotation of genomes, using a variety of publicly available bioinformatics tools. It also contains a suite of unique PUMA2 tools for automated assignment of gene function, evolutionary analysis of protein families and comparative analysis of metabolic pathways. PUMA2 allows users to submit batch sequence data for automated functional analysis and construction of metabolic models. The results of these analyses are made available to the users in the PUMA2 environment for further interactive sequence analysis and annotation.

Computational Biology↗

Mediator modulates Gli3-dependent Sonic hedgehog signaling.

The physiological and pathological manifestations of Sonic hedgehog (Shh) signaling arise from the specification of unique transcriptional programs dependent upon key nuclear effectors of the Ci/Gli family of transcription factors. However, the underlying mechanism by which Gli proteins regulate target gene transcription in the nucleus remains poorly understood. Here, we identify and characterize a physical and functional interaction between Gli3 and the MED12 subunit within the RNA polymerase II transcriptional Mediator. We show that Gli3 binds to MED12 and intact Mediator both in vitro and in vivo through a Gli3 transactivation domain (MBD; MED12/Mediator-binding domain) whose activity derives from concerted functional interactions with both Mediator and the histone acetyltransferase CBP. Analysis of MBD truncation mutants revealed an excellent correlation between the in vivo activation strength of an MBD derivative and its ability to bind MED12 and intact Mediator in vitro, indicative of a critical functional interaction between the Gli3 MBD and the MED12 interface in Mediator. Disruption of the Gli3-MED12 interaction through dominant-negative interference inhibited, while RNA interference-mediated MED12 depletion enhanced, both MBD transactivation function and Gli3 target gene induction in response to Shh signaling. We propose that activated Gli3 physically targets the MED12 interface within Mediator in order to functionally reverse Mediator-dependent suppression of Shh target gene transcription. These findings thus link MED12 to the modulation of Gli3-dependent Shh signaling and further implicate Mediator in a broad range of developmental and pathological processes driven by Shh signal transduction.

Adaptor Proteins, Signal Transducing↗

Intestinal microflora and the interaction with immunocompetent cells.

The intestinal mucosal surface is colonised by the comensal microflora that attains very high numbers of bacterial cells in the distal intestine, more specifically in the colon. At the same time these extensive areas are the interface with the external environment, through which most pathogens initiate infectious processes in mammals. Intestinal mechanisms of defense need to discriminate accurately between comensal, symbiotic microflora, and exogenous pathogens. Today we do not fully understand the essence of the mechanism of discrimination but, probably, innate as well as adaptive immune responses participate in this process. We have explored, in in vitro models, the capacity of mucosal immunocompetent cells to discriminate amongst signals delivered by different types of bacteria. We have found at least two different patterns of innate response to gram-negative and gram-positive bacteria, and within this last group big differences are observed between species. We have only worked with non-pathogenic bacteria in what may represent the modulation of the physiological host status. The understanding of these modulatory functions could render a unique possibility for the use of food-borne bacteria to prevent or correct intestinal problems associated with food allergy, inflammatory bowel disease, and autoimmunity.

Animals↗

Crystal structure of three consecutive laminin-type epidermal growth factor-like (LE) modules of laminin gamma1 chain harboring the nidogen binding site.

The structure of three consecutive laminin-type EGF-like (LE) modules of mouse laminin gammma1 chain, gamma1III3-5 (positions 738 to 899), has been determined by multiple isomorphous replacement in a crystal of space group p6(4)22 (a=b=74.57 angstroms, c = 185.11 angstroms and gamma = 120 degrees). The crystal structure was refined using restrained crystallographic refinement to an R-factor of 19.72% for 14,983 independent reflections with intensities F(obs)> 0 at 2.1 angstroms resolution, with root mean square deviation of 0.012 angstroms and 1.690 degrees from ideal bond lengths and bond angles, respectively. The final model consisted of 1179 (non-hydrogen) protein atoms within 162 residues and 119 water molecules. The molecule showed a rod-like structure of about 76 angstroms length with individual modules twisted relative to each other by about 70 degrees. Each module has the same disulfide bond connections Cys1-Cys3 (loop a), Cys2-Cys4 (loop b), Cys5-Cys6 (loop c) and Cys7-Cys8 (loop d), the first three being identical to epidermal growth factor (EGF). All three LE modules showed little secondary structure which was mainly restricted to loop d, but they differed in several other details of their structure. The interface contacts between the LE modules are based on hydrogen bonds and hydrophobic interactions between the hydrophobic core of loop d of the preceding module and the first cysteine and an exposed residue in loop b of the following module. Module 4 was previously shown to contribute the major nidogen binding site of laminis and site-directed mutagenesis demonstrated a specific binding role for Asp800, Asn802, Val804 and Tyr819 in loops a and c. The side-chain of these four residues are all located on the surface in a linear array and separated by a distance of 17 angstroms between Tyr819 and Val804. The entire nidogen binding site is stabilized via main-chain hydrogen bonds which are in part derived from the link between loops b and c (residues Leu815 and Lys816). The data demonstrate the unique nature of the LE modules and only a remote similarity to EGF. They also indicate that the crucial residues in the binding loops provide direct contacts with nidogen and explain the synergism between loops a and c which is essential for binding.

Amino Acid Sequence↗

Accessibility and environment probing using cysteine residues introduced along the putative transmembrane domain of the major coat protein of bacteriophage M13.

The major coat protein of the filamentous bacteriophage M13 is located in the inner membrane of host cell Escherichia coli prior to assembly into virions. To identify the transmembrane domain of the coat protein, we have introduced unique cysteine residues along the putative transmembrane domain at position 25, 31, 33, 36, 38, 46, 47, 49, or 50. The mutant major coat protein was solubilized by membrane-mimicking detergents or reconstituted into mixed bilayers of phospholipids. Information about the environmental polarity was deduced from the wavelength of maximum emission, using N-[[(iodoacetyl)-amino)ethyl]-1-sulfonaphthylamine (IAEDANS) attached to the SH groups of the cysteines as a fluorescent probe. Additional information was obtained by determining the accessibility of AEDANS for the fluorescence quencher molecules acrylamide and 5-doxylstearic acid, and the reactivity of the cysteine's sulfhydryl group toward 5,5'-dithiobis(2-nitrobenzoic acid) (DTNB). Our data suggest transmembrane boundaries close to residue 25 and 46, with residue 25 inside the hydrophobic part of the membrane in very close proximity to the membrane-water interface and residue 46 located at the membrane-water interface. Domains of the mutant coat protein which are packed or coated by cholate molecules and various other detergents [except for sodium dodecyl sulfate (SDS)] are at least similarly packed by phospholipid molecules in bilayers. SDS is a good solubilizing detergent but badly mimics the typical nature of a membrane structure. The overall results are interpreted with respect to the established conformation of the coat protein and its membrane anchoring mechanism.

Acrylamide↗

Surface properties of membrane systems: apoprotein of the Folch-Lees proteolipid from beef-brain myelin.

Structural proteins in biological membranes are bimodal and ideally possess a unique surface activity that should be amenable to study by monolayer techniques. Proteins so studied, however, display, of necessity, a surface activity that reflects the laboratory history of the protein. The Folch-Lees proteolipid apoprotein was isolated from calf-brain myelin in both an organic solvent (CHCl(3)-CH(3)OH-CH(3)COOH; 50:50:1) and water. The apoprotein did not spread as a film from water, but did spread readily from the organic solvent into films that had high saturation pressures. The partitioning of the apoprotein from organic solvent to water was found to be reversible, as was the gain and loss of surface activity. Infrared spectroscopy demonstrated that the preponderant structure in films of the apoprotein was not that of extended polypeptide chains. The results suggested that the preferred structures at the interface are bimodal coils of alpha helix. This structure can sustain the high film pressures observed, whereas beta keratin structures would build films with high surface viscosity and very low surface pressure.

Animals↗

GenomeBlast: a web tool for small genome comparison.

BACKGROUND: Comparative genomics has become an essential approach for identifying homologous gene candidates and their functions, and for studying genome evolution. There are many tools available for genome comparisons. Unfortunately, most of them are not applicable for the identification of unique genes and the inference of phylogenetic relationships in a given set of genomes. RESULTS: GenomeBlast is a Web tool developed for comparative analysis of multiple small genomes. A new parameter called "coverage" was introduced and used along with sequence identity to evaluate global similarity between genes. With GenomeBlast, the following results can be obtained: (1) unique genes in each genome; (2) homologous gene candidates among compared genomes; (3) 2D plots of homologous gene candidates along the all pairwise genome comparisons; and (4) a table of gene presence/absence information and a genome phylogeny. We demonstrated the functions in GenomeBlast with an example of multiple herpesviral genome analysis and illustrated how GenomeBlast is useful for small genome comparison. CONCLUSION: We developed a Web tool for comparative analysis of small genomes, which allows the user not only to identify unique genes and homologous gene candidates among multiple genomes, but also to view their graphical distributions on genomes, and to reconstruct genome phylogeny. GenomeBlast runs on a Linux server with 4 CPUs and 4 GB memory. The online version of GenomeBlast is available to public by using a Web browser with the URL http://bioinfo-srv1.awh.unomaha.edu/genomeblast/.

Algorithms↗

Computer-aided instruction in radiology: opportunities for more effective learning.

Little doubt remains that computers will play an important part in the future of education. What should be of special concern to radiologists, however, is the unique way that computer-aided instruction differs from printed text and its potential for facilitating education in medical imaging. Adapting to this media will require a mental shift on the part of educators as well as students. As the sophistication of the student increases, attention will shift from the novel presentational power of the computer to the opportunities that computers offer to expedite learning and to evaluate the extent to which knowledge is mastered.

Computer-Assisted Instruction↗

Crystal structures of a unique thermal-stable thymidylate synthase from Bacillus subtilis.

Unlike all other organisms studied to date, Bacillus subtilis expresses two different thymidylate synthases: bsTS-A and bsTS-B. bsTS-A displays enhanced enzymatic and structural thermal stability uncharacteristic of most TSs. Despite the high level of TS conservation across most species, bsTS-A shares low sequence identity (<40%) with the majority of TSs from other organisms. This TS and the TSs from Lactococcus lactis and phage Phi3T-to which it is most similar-have been of interest for some time since, by structure-based sequence alignment, they appear to lack several key residues shown by mutagenesis to be essential to enzymatic function [Greene, P. J., Yu, P. L., Zhao, J., Schiffer, C. A., and Santi, D. (1994) Protein Sci. 3, 1114-6]. In addition, bsTS-A demonstrates specific activity 2-3-fold higher than TS from Lactobacillus casei or Escherichia coli. We have solved the crystal structure of this unusual TS in four crystal forms to a maximum resolution of 1.7 A. Each of these crystal forms contains either one or two noncrystallographically related dimers. Stabilization of the beta-sheet dimer interface through a dramatic architecture of buttressed internal salt bridges maintains the structural integrity of bsTS-A at elevated temperatures. Melting curves of TSs from L. casei and E. coli are compared to that of TS-A from B. subtilis and correlated with numbers of hydrogen bonds, salt bridges, and the numbers of interactions localized to the dimer interface. Analysis of this structure will shed light on the conservation of function across diversity of sequence, as well as provide insights into the thermal stabilization of a highly conserved enzyme.

Amino Acid Sequence↗

Freeze-fracture analysis of phloem structure in plant tissue cultures. I. The sieve element reticulum.

During the differentiation of phloem sieve elements, the endoplasmic reticulum undergoes unique modifications to form the sieve element reticulum (SER) which persists in mature, functioning sieve tubes. Cisternae of the SER lack ribosomes and are restricted to the periphery of the sieve element at late stages of development. Some of the SER is seen as single cisternae that are in close contact with the sieve element plasma membrane. Thin sections and freeze-fracture images of sieve elements formed in tissue cultures demonstrate that the SER consists of both single cisternae and regions of stacked cisternae at some stages of maturity. The unstacked regions of the SER are continuous with the cisternae of the stacked regions. In freeze-fracture images the single cisternae adjacent to the plasma membrane are seen to be fenestrated and the openings allow continuity between the plasma membrane and the cell lumen. It is concluded that the interface between the SER and the plasma membrane of the sieve element serves to allow membrane functions such as proton efflux, proton-sucrose cotransport and compensating movements of ions to occur in a microenvironment that is separated from the moving translocation stream in the sieve element lumen. Passage of water and translocated solutes from the plasma membrane or the SER/PM interface to the interior of the cell is enhanced by the openings in the fenestrated regions of the SER. It is suggested tha the SER may also play a role in channeling ATP from mitochondria associated with the SER to the proton-pumping ATPase in the plasma membrane and that the SER may function in the uptake and release of potassium ions in the sieve element.

Brassica↗

Role of the C-terminal helix 9 in the stability and ligandin function of class alpha glutathione transferase A1-1.

Helix 9 at the C-terminus of class alpha glutathione transferase (GST) polypeptides is a unique structural feature in the GST superfamily. It plays an important structural role in the catalytic cycle. Its contribution toward protein stability/folding as well as the binding of nonsubstrate ligands was investigated by protein engineering, conformational stability, enzyme activity, and ligand-binding methods. The helix9 sequence displays an unfavorable propensity toward helix formation, but tertiary interactions between the amphipathic helix and the GST seem to contribute sufficient stability to populate the helix on the surface of the protein. The helix's stability is enhanced further by the binding of ligands at the active site. The order of ligand-induced stabilization increases from H-site occupation, to G-site occupation, to the simultaneous occupation of H- and G-sites. Ligand-induced stabilization of helix9 reduces solvent accessible hydrophobic surface by facilitating firmer packing at the hydrophobic interface between helix and GST. This stabilized form exhibits enhanced affinity for the binding of nonsubstrate ligands to ligandin sites (i.e., noncatalytic binding sites). Although helix9 contributes very little toward the global stability of hGSTA1-1, its conformational dynamics have significant implications for the protein's equilibrium unfolding/refolding pathway and unfolding kinetics. Considering the high concentration of reduced glutathione in human cells (about 10 mM), the physiological form of hGSTA1-1 is most likely the thiol-complexed protein with a stabilized helix9. The C-terminus region (including helix9) of the class alpha polypeptide appears not to have been optimized for stability but rather for catalytic and ligandin function.

Acrylamide↗

Entrez Gene: gene-centered information at NCBI.

Entrez Gene (www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene) is NCBI's database for gene-specific information. It does not include all known or predicted genes; instead Entrez Gene focuses on the genomes that have been completely sequenced, that have an active research community to contribute gene-specific information, or that are scheduled for intense sequence analysis. The content of Entrez Gene represents the result of curation and automated integration of data from NCBI's Reference Sequence project (RefSeq), from collaborating model organism databases, and from many other databases available from NCBI. Records are assigned unique, stable and tracked integers as identifiers. The content (nomenclature, map location, gene products and their attributes, markers, phenotypes, and links to citations, sequences, variation details, maps, expression, homologs, protein domains and external databases) is updated as new information becomes available. Entrez Gene is a step forward from NCBI's LocusLink, with both a major increase in taxonomic scope and improved access through the many tools associated with NCBI Entrez.

Databases, Genetic↗

Solutions to challenges facing a university digital library and press.

During the creation of a university digital library and press intended to serve as a medical reference and education tool for health care providers and their patients, six distinct and complex digital publishing challenges were encountered. Over nine years, through a multidisciplinary approach, solutions were devised to the challenges of digital content ownership, management, mirroring, translation, interactions with users, and archiving. The result is a unique, author-owned, internationally mirrored, university digital library and press that serves as an authoritative medical reference and education tool for users around the world. The purpose of this paper is to share the valuable digital publishing lessons learned and outline the challenges facing university digital libraries and presses.

Hospitals↗