High-Density, Conformable Conducting Polymer-Based Implantable Neural Probes for the Developing Brain

Neurologic and neuropsychiatric disorders substantially impact the pediatric population, but there is a lack of dedicated devices for monitoring the developing brain in animal models, leading to gaps in mechanistic understanding of how brain functions emerge and their disruption in disease states. Due to the small size, fragility, and high water content of immature neural tissue, as well as the absence of a hardened skull to mechanically support rigid devices, conventional neural interface devices are poorly suited to acquire brain signals without inducing damage. Here, the authors design conformable, implantable, conducting polymer-based probes (NeuroShanks) for precise targeting in the developing mouse brain without the need for skull-attached, rigid mechanical support structures. These probes enable the acquisition of high spatiotemporal resolution neurophysiologic activity from superficial and deep brain regions across unanesthetized behavioral states without causing tissue disruption or device failure. Once implanted, probes are mechanically stable and permit precise, stable signal monitoring at the level of the local field potential and individual action potentials. These results support the translational potential of such devices for clinically indicated neurophysiologic recording in pediatric patients. Additionally, the role of organic bioelectronics as an enabling technology to address questions in developmental neuroscience is revealed.

Ancestry-specific high-risk gene variant profiling unmasks diabetes-associated genes

How ancestry-associated genetic variance affects disparities in the risk of polygenic diseases and influences the identification of disease-associated genes warrants a deeper understanding. We hypothesized that the discovery of genes associated with polygenic diseases may be limited by the overreliance on single-nucleotide polymorphism (SNP)-based genomic investigation, as most significant variants identified in genome-wide SNP association studies map to introns and intergenic regions of the genome. To overcome such potential limitations, we developed a gene-constrained, function-based analytical method centered on high-risk variants (hrV) that encode frameshifts, stopgains or splice site disruption. We analyzed the total number of hrV per gene in populations of different ancestry, representing a total of 185 934 subjects. Using this analysis, we developed a quantitative index of hrV (hrVI) across 20 428 genes within each population. We then applied hrVI analysis to the discovery of genes associated with type 2 diabetes mellitus (T2DM), a polygenic disease with ancestry-related disparity. HrVI profiling and gene-to-gene comparisons of ancestry-specific hrV between the case (20 781 subjects) and control (24 440 subjects) populations in the T2DM national repository identified 57 genes associated with T2DM, 40 of which were discoverable only by ancestry-specific analysis. These results illustrate how a function-based, ancestry-specific analysis of genetic variations can accelerate the identification of genes associated with polygenic diseases. Besides T2DM, such analysis may facilitate our understanding of the genetic basis for other polygenic diseases that are also greatly influenced by environmental and behavioral factors, such as obesity, hypertension and Alzheimer's disease.

Muscle-building supplement β-hydroxy β-methylbutyrate stimulates the maturation of oligodendroglial progenitor cells to oligodendrocytes

Oligodendrocytes are the myelinating cells in the CNS and multiple sclerosis (MS) is a demyelinating disorder that is characterized by progressive loss of myelin. Although oligodendroglial progenitor cells (OPCs) should be differentiated into oligodendrocytes, for multiple reasons, OPCs fail to differentiate into oligodendrocytes in MS. Therefore, increasing the maturation of OPCs to oligodendrocytes may be of therapeutic benefit for MS. The β-hydroxy β-methylbutyrate (HMB) is a muscle-building supplement in humans and this study underlines the importance of HMB in stimulating the maturation of OPCs to oligodendrocytes. HMB treatment upregulated the expression of different maturation markers including PLP, MBP, and MOG in cultured OPCs. Double-label immunofluorescence followed by immunoblot analyses confirmed the upregulation of OPC maturation by HMB. While investigating mechanisms, we found that HMB increased the maturation of OPCs isolated from peroxisome proliferator-activated receptor β-/- (PPARβ-/- ) mice, but not PPARα-/- mice. Similarly, GW6471 (an antagonist of PPARα), but not GSK0660 (an antagonist of PPARβ), inhibited HMB-induced maturation of OPCs. GW9662, a specific inhibitor of PPARγ, also could not inhibit HMB-mediated stimulation of OPC maturation. Furthermore, PPARα agonist GW7647, but neither PPARβ agonist GW0742 nor PPARγ agonist GW1929, alone increased the maturation of OPCs. Finally, HMB treatment of OPCs led to the recruitment of PPARα, but neither PPARβ nor PPARγ, to the PLP gene promoter. These results suggest that HMB stimulates the maturation of OPCs via PPARα and that HMB may have therapeutic prospects in remyelination.

Expansion of HLA-DR Positive Peripheral Helper T and Naive B cells in Anticitrullinated Protein Antibody-Positive Individuals At Risk for Rheumatoid Arthritis

OBJECTIVE

To investigate immune dysregulation in the peripheral blood that contributes to the pre-rheumatoid arthritis (RA) stage of RA development in anticitrullinated protein antibody (ACPA)+ individuals.

METHODS

Using 37 markers by mass cytometry, we investigated peripheral blood mononuclear cells (PBMCs) from ACPA+ at-risk individuals, ACPA+ early untreated patients with RA, and ACPA- controls in the Tokyo Women's Medical University cohort (n = 17 in each group). Computational algorithms, FlowSOM and Optimized t-Distributed Stochastic Neighbor Embedding, were employed to explore specific immunologic differences between study groups. These findings were further evaluated, and longitudinal changes were explored, using flow cytometry and PBMCs from the US-based Targeting Immune Responses for Prevention of RA cohort that included 11 ACPA+ individuals who later developed RA (pre-RA), of which 9 had post-RA diagnosis PBMCs (post-RA), and 11 ACPA- controls.

RESULTS

HLA-DR+ peripheral helper T (Tph) cells, activated regulatory T cells, PD-1hi CD8+ T cells, and CXCR5-CD11c-CD38+ naive B cells were significantly expanded in PBMCs from at-risk individuals and patients with early RA from the Tokyo Women's Medical University cohort. Expansion of HLA-DR+ Tph cells and CXCR5-CD11c-CD38+ naive B cells was likewise found in both pre-RA and post-RA time points in the Targeting Immune Responses for Prevention of RA cohort.

CONCLUSION

The expansion of HLA-DR+ Tph cells and CXCR5-CD11c-CD38+ naive B cells in ACPA+ individuals, including those who developed inflammatory arthritis and classified RA, supports a key role of these cells in transition from pre-RA to classified RA. These findings may identify a new mechanistic target for treatment and prevention in RA.

Clinical application of ultrashort echo time (UTE) and zero echo time (ZTE) magnetic resonance (MR) imaging in the evaluation of osteoarthritis

Novel compositional magnetic resonance (MR) imaging techniques have allowed for both the qualitative and quantitative assessments of tissue changes in osteoarthritis, many of which are difficult to characterize on conventional MR imaging. Ultrashort echo time (UTE) and zero echo time (ZTE) MR imaging have not been broadly implemented clinically but have several applications that leverage contrast mechanisms for morphologic evaluation of bone and soft tissue, as well as biochemical assessment in various stages of osteoarthritis progression. Many of the musculoskeletal tissues implicated in the initiation and progression of osteoarthritis are short T2 in nature, appearing dark as signal has already decayed to its minimum when image sampling starts. UTE and ZTE MR imaging allow for the qualitative and quantitative assessments of these short T2 tissues (bone, tendon, calcified cartilage, meniscus, and ligament) with both structural and functional reference standards described in the literature [1-3]. This review will describe applications of UTE and ZTE MR imaging in musculoskeletal tissues focusing on its role in knee osteoarthritis. While the review will address tissue-specific applications of these sequences, it is understood that osteoarthritis is a whole joint process with involvement and interdependence of all tissues. KEY POINTS: • UTE MR imaging allows for the qualitative and quantitative evaluation of short T2 tissues (bone, calcified cartilage, and meniscus), enabling identification of both early degenerative changes and subclinical injuries that may predispose to osteoarthritis. • ZTE MR imaging allows for the detection of signal from bone, which has some of the shortest T2 values, and generates tissue contrast similar to CT, potentially obviating the need for CT in the assessment of osseous features of osteoarthritis.

A guide to membrane atg8ylation and autophagy with reflections on immunity

The process of membrane atg8ylation, defined herein as the conjugation of the ATG8 family of ubiquitin-like proteins to membrane lipids, is beginning to be appreciated in its broader manifestations, mechanisms, and functions. Classically, membrane atg8ylation with LC3B, one of six mammalian ATG8 family proteins, has been viewed as the hallmark of canonical autophagy, entailing the formation of characteristic double membranes in the cytoplasm. However, ATG8s are now well described as being conjugated to single membranes and, most recently, proteins. Here we propose that the atg8ylation is coopted by multiple downstream processes, one of which is canonical autophagy. We elaborate on these biological outputs, which impact metabolism, quality control, and immunity, emphasizing the context of inflammation and immunological effects. In conclusion, we propose that atg8ylation is a modification akin to ubiquitylation, and that it is utilized by different systems participating in membrane stress responses and membrane remodeling activities encompassing autophagy and beyond.

An Investigation of (Diacetoxyiodo)arenes as Precursors for Preparing No-Carrier-Added [(18)F]Fluoroarenes from Cyclotron-Produced [(18)F]Fluoride Ion

Treatment of (diacetoxyiodo)arenes (1a-1u) with cyclotron-produced [(18)F]fluoride ion rapidly affords no-carrier-added [(18)F]fluoroarenes (2a-2u) in useful yields and constitutes a new method for converting substituted iodoarenes into substituted [(18)F]fluoroarenes in just two steps.

The design and methods of genetic studies on acute and chronic postoperative pain in patients after total knee replacement

OBJECTIVE

Total knee replacement (TKR) is the treatment option of choice for the millions of individuals whose osteoarthritis pain can no longer be managed through non-invasive methods. Over 500,000 TKRs are performed annually in the United States. Although most patients report improvement in pain and functioning following TKR, up to 30% report persistent pain that interferes with daily function. However, the reasons for poor outcomes are not clear. To best determine which patients are at risk for pain post TKR, a detailed and comprehensive approach is needed. In this article, we present the methodology of a study designed to identify a set of genetic, proteomic, clinical, demographic, psychosocial, and psychophysical risk factors for severe acute and chronic pain post TKR.

DESIGN

Prospective longitudinal observational study.

SETTING

University Hospital System.

SUBJECTS

Patients scheduled for unilateral TKR with a target number of 150.

METHODS

Prior to surgery, we collect demographic, psychosocial, and pain data. Biological data, including blood samples for genetic analyses, and serum, urine, and joint fluid for cytokine assessment are collected intraoperatively. Pain assessments as well as medication use are collected during each of the three days postsurgery. Additionally, pain and psychosocial information is collected 6 and 12 months following surgery.

CONCLUSIONS

This study, for the first time, captures the information on both genetic and "environmental" risk factors for acute and chronic pain post-TKR and has the potential to lead to the next step-multicenter large-scale studies on predictors and biomarkers of poor TKR outcomes as well as on tailored interventions and personalized medicine approaches for those at risk.

Usability testing, initial implementation, and formative evaluation of an evidence-based intervention: lessons from a demonstration project to reduce long-term foster care

The field of child welfare faces an undersupply of evidence-based interventions to address long-term foster care. The Permanency Innovations Initiative is a five-year federal demonstration project intended to generate evidence to reduce long stays in foster care for those youth who encounter the most substantial barriers to permanency. This article describes a systematic and staged approach to implementation and evaluation of a PII project that included usability testing as one of its key activities. Usability testing is an industry-derived practice which analyzes early implementation processes and evaluation procedures before they are finalized. This article describes the iterative selection, testing, and analysis of nine usability metrics that were designed to assess three important constructs of the project's initial implementation and evaluation: intervening early, obtaining consent, and engaging parents. Results showed that seven of nine metrics met a predetermined target. This study demonstrates how findings from usability testing influenced the initial implementation and formative evaluation of an evidence-supported intervention. Implications are discussed for usability testing as a quality improvement cycle that may contribute to better operationalized interventions and more reliable, valid, and replicable evidence.

Normal mutation rate variants arise in a Mutator (Mut S) Escherichia coli population

The rate at which mutations are generated is central to the pace of evolution. Although this rate is remarkably similar amongst all cellular organisms, bacterial strains with mutation rates 100 fold greater than the modal rates of their species are commonly isolated from natural sources and emerge in experimental populations. Theoretical studies postulate and empirical studies teort the hypotheses that these “mutator” strains evolved in response to selection for elevated rates of generation of inherited variation that enable bacteria to adapt to novel and/or rapidly changing environments. Less clear are the conditions under which selection will favor reductions in mutation rates. Declines in rates of mutation for established populations of mutator bacteria are not anticipated if such changes are attributed to the costs of augmented rates of generation of deleterious mutations. Here we report experimental evidence of evolution towards reduced mutation rates in a clinical isolate of Escherichia coli with an hyper-mutable phenotype due a deletion in a mismatch repair gene, (ΔmutS). The emergence in a ΔmutS background of variants with mutation rates approaching those of the normal rates of strains carrying wild-type MutS was associated with increase in fitness with respect to ancestral strain. We postulate that such an increase in fitness could be attributed to the emergence of mechanisms driving a permanent “aerobic style of life”, the negative consequence of this behavior being regulated by the evolution of mechanisms protecting the cell against increased endogenous oxidative radicals involved in DNA damage, and thus reducing mutation rate. Gene expression assays and full sequencing of evolved mutator and normo-mutable variants supports the hypothesis. In conclusion, we postulate that the observed reductions in mutation rate are coincidental to, rather than, the selective force responsible for this evolution.

Gymnemic acids inhibit hyphal growth and virulence in Candida albicans

Candida albicans is an opportunistic and polymorphic fungal pathogen that causes mucosal, disseminated and invasive infections in humans. Transition from the yeast form to the hyphal form is one of the key virulence factors in C. albicans contributing to macrophage evasion, tissue invasion and biofilm formation. Nontoxic small molecules that inhibit C. albicans yeast-to-hypha conversion and hyphal growth could represent a valuable source for understanding pathogenic fungal morphogenesis, identifying drug targets and serving as templates for the development of novel antifungal agents. Here, we have identified the triterpenoid saponin family of gymnemic acids (GAs) as inhibitor of C. albicans morphogenesis. GAs were isolated and purified from Gymnema sylvestre leaves, the Ayurvedic traditional medicinal plant used to treat diabetes. Purified GAs had no effect on the growth and viability of C. albicans yeast cells but inhibited its yeast-to-hypha conversion under several hypha-inducing conditions, including the presence of serum. Moreover, GAs promoted the conversion of C. albicans hyphae into yeast cells under hypha inducing conditions. They also inhibited conidial germination and hyphal growth of Aspergillus sp. Finally, GAs inhibited the formation of invasive hyphae from C. albicans-infected Caenorhabditis elegans worms and rescued them from killing by C. albicans. Hence, GAs could be useful for various antifungal applications due to their traditional use in herbal medicine.

Evaluating reported candidate gene associations with polycystic ovary syndrome

OBJECTIVE

To replicate variants in candidate genes associated with polycystic ovary syndrome (PCOS) in a population of European women with PCOS and control subjects.

DESIGN

Case-control association analysis and meta-analysis.

SETTING

Major academic hospital.

PATIENT(S)

Women of European ancestry with PCOS (n = 525) and controls (n = 472), aged 18-45 years.

INTERVENTION(S)

Variants previously associated with PCOS in candidate gene studies were genotyped (n = 39). Metabolic, reproductive, and anthropomorphic parameters were examined as a function of the candidate variants. All genetic association analyses were adjusted for age, body mass index, and ancestry and were reported after correction for multiple testing.

MAIN OUTCOME MEASURE(S)

Association of candidate gene variants with PCOS.

RESULT(S)

Three variants, rs3797179 (SRD5A1), rs12473543 (POMC), and rs1501299 (ADIPOQ), were nominally associated with PCOS. However, they did not remain significant after correction for multiple testing, and none of the variants replicated in a sufficiently powered meta-analysis. Variants in the FBN3 gene (rs17202517 and rs73503752) were associated with smaller waist circumferences, and variant rs727428 in the SHBG gene was associated with lower sex hormone-binding globulin levels.

CONCLUSION(S)

Previously identified variants in candidate genes do not seem to be associated with PCOS risk.

CLINICAL TRIAL REGISTRATION NUMBER

NCT00166569.

Most reported genetic associations with general intelligence are probably false positives

General intelligence (g) and virtually all other behavioral traits are heritable. Associations between g and specific single-nucleotide polymorphisms (SNPs) in several candidate genes involved in brain function have been reported. We sought to replicate published associations between g and 12 specific genetic variants (in the genes DTNBP1, CTSD, DRD2, ANKK1, CHRM2, SSADH, COMT, BDNF, CHRNA4, DISC1, APOE, and SNAP25) using data sets from three independent, well-characterized longitudinal studies with samples of 5,571, 1,759, and 2,441 individuals. Of 32 independent tests across all three data sets, only 1 was nominally significant. By contrast, power analyses showed that we should have expected 10 to 15 significant associations, given reasonable assumptions for genotype effect sizes. For positive controls, we confirmed accepted genetic associations for Alzheimer's disease and body mass index, and we used SNP-based calculations of genetic relatedness to replicate previous estimates that about half of the variance in g is accounted for by common genetic variation among individuals. We conclude that the molecular genetics of psychology and social science requires approaches that go beyond the examination of candidate genes.

Training child welfare workers from an intersectional cultural humility perspective: a paradigm shift

The increasing diversity of the populations encountered and served by child welfare workers challenges cultural competence models. Current concerns focus on the unintentional over-emphasis on shared group characteristics, undervaluing unique differences of individuals served, and privileging worker expertise about the client's culture, thereby exacerbating the power imbalance between them. This article promotes cultural humility in child welfare service delivery as a compliment to cultural competence, to liberate workers from expectations of cultural expertise about others, and to actively engage the clients, inclusive of their cultural differences, in the service delivery process. Skills and practice principles are discussed.

Changes in serum TSH and free T4 during human sleep restriction

STUDY OBJECTIVES

To examine whether recurrent sleep restriction is accompanied by changes in measures of thyroid function.

DESIGN

Two-period crossover intervention study.

SETTING

University clinical research center and sleep laboratory.

PARTICIPANTS

11 healthy volunteers (5F/6M) with a mean (+/- SD) age of 39 +/- 5 y and BMI 26.5 +/- 1.5 kg/m2.

INTERVENTION

Randomized exposure to 14 days of sedentary living with ad libitum food intake and 5.5- vs. 8.5-h overnight sleep opportunity.

MEASUREMENTS AND RESULTS

Serum thyroid-stimulating hormone (TSH) and free thyroxine (T4) were measured at the end of each intervention. Partial sleep restriction was accompanied by a modest but statistically significant reduction in TSH and free T4, seen mainly in the female participants of the study.

CONCLUSIONS

Compared to the well-known rise in TSH and thyroid hormone concentrations during acute sleep loss, tests obtained after 14 days of partial sleep restriction did not show a similar activation of the human thyroid axis.

Bioinformatics: Tools to accelerate population science and disease control research

Population science and disease control researchers can benefit from a more proactive approach to applying bioinformatics tools for clinical and public health research. Bioinformatics utilizes principles of information sciences and technologies to transform vast, diverse, and complex life sciences data into a more coherent format for wider application. Bioinformatics provides the means to collect and process data, enhance data standardization and harmonization for scientific discovery, and merge disparate data sources. Achieving interoperability (i.e. the development of an informatics system that provides access to and use of data from different systems) will facilitate scientific explorations and careers and opportunities for interventions in population health. The National Cancer Institute's (NCI's) interoperable Cancer Biomedical Informatics Grid (caBIG) is one of a number of illustrative tools in this report that are being mined by population scientists. Tools are not all that is needed for progress. Challenges persist, including a lack of common data standards, proprietary barriers to data access, and difficulties pooling data from studies. Population scientists and informaticists are developing promising and innovative solutions to these barriers. The purpose of this paper is to describe how the application of bioinformatics systems can accelerate population health research across the continuum from prevention to detection, diagnosis, treatment, and outcome.

Prevalence of cardiometabolic risk factors in Hispanics living with HIV

OBJECTIVE

Human immunodeficiency virus (HIV) infection and antiretroviral treatment are associated with metabolic and cardiovascular complications that resemble metabolic syndrome (MetS) and potentially increase the risk of diabetes and cardiovascular disease in this population. The purpose of this study was to determine the prevalence of MetS and its individual components among Hispanics living with HIV in Puerto Rico.

METHODS

Data from 909 clinical records were extracted and the prevalence of MetS determined using the NCEP-ATPIII criteria. Fisher's exact test was used to detect sex differences, and logistic regression to examine the effect of age, sex, smoking, years of HIV infection, antiretroviral therapy, and Hepatitis C coinfection.

RESULTS

The prevalence of MetS in our study group (35.4%) was higher than previously reported in the United States, but not higher than in the general population in Puerto Rico. Females had a higher prevalence of MetS (44.2%) than males (30.5%); mostly explained by high body mass index and waist circumference. Age and sex were associated with the presence of MetS.

CONCLUSION

Understanding ethnic and sex differences in the prevalence of metabolic risk factors is essential for the implementation of specific targeted interventions to prevent subsequent vascular morbidity and mortality in this population.

The Universal Protein Resource (UniProt) 2009

The mission of UniProt is to provide the scientific community with a comprehensive, high-quality and freely accessible resource of protein sequence and functional information that is essential for modern biological research. UniProt is produced by the UniProt Consortium which consists of groups from the European Bioinformatics Institute, the Protein Information Resource and the Swiss Institute of Bioinformatics. The core activities include manual curation of protein sequences assisted by computational analysis, sequence archiving, a user-friendly UniProt website and the provision of additional value-added information through cross-references to other databases. UniProt is comprised of four major components, each optimized for different uses: the UniProt Archive, the UniProt Knowledgebase, the UniProt Reference Clusters and the UniProt Metagenomic and Environmental Sequence Database. One of the key achievements of the UniProt consortium in 2008 is the completion of the first draft of the complete human proteome in UniProtKB/Swiss-Prot. This manually annotated representation of all currently known human protein-coding genes was made available in UniProt release 14.0 with 20 325 entries. UniProt is updated and distributed every three weeks and can be accessed online for searches or downloaded at www.uniprot.org.

White blood cell counts in healthy Jamaican adults

The investigation of presumed neutropenia places a burden on the health services, especially those of developing countries, including Jamaica. This may be because the normal ranges used in the laboratory are based on the values generated from the Caucasian population. Previous studies looking at African and Afro-Caribbean groups have found lower counts for these populations compared with Caucasians. To address this issue, 195 healthy adults donating blood at the National Public Health Laboratory and the University Hospital of the West Indies blood banks in Kingston, Jamaica, were screened for complete blood count (CBC) differentials between June 2001 and June 2006. The geometric means for the neutrophil counts were found to be 2.4 x 10(9)/L for men and 2.7 x 10(9)/L for women, with 95% confidence intervals of 2.2-2.8 x 10(9)/L and 2.5-3.1 x 10(9)/L respectively. Values for the Jamaican population were similar to those of other Afro-Caribbean groups. Based on this distribution, 14% of healthy Jamaicans would fall below the normal ranges derived from Caucasians and therefore presumed to have neutropenia. We recommend that the lower reference ranges obtained for Afro-Caribbean adults be adopted for that population.

The role of particulate matter-associated zinc in cardiac injury in rats

BACKGROUND

Exposure to particulate matter (PM) has been associated with increased cardiovascular morbidity; however, causative components are unknown. Zinc is a major element detected at high levels in urban air.

OBJECTIVE

We investigated the role of PM-associated zinc in cardiac injury.

METHODS

We repeatedly exposed 12- to 14-week-old male Wistar Kyoto rats intratracheally (1x/week for 8 or 16 weeks) to a) saline (control); b) PM having no soluble zinc (Mount St. Helens ash, MSH); or c) whole-combustion PM suspension containing 14.5 microg/mg of water-soluble zinc at high dose (PM-HD) and d ) low dose (PM-LD), e) the aqueous fraction of this suspension (14.5 microg/mg of soluble zinc) (PM-L), or f ) zinc sulfate (rats exposed for 8 weeks received double the concentration of all PM components of rats exposed for 16 weeks).

RESULTS

Pulmonary inflammation was apparent in all exposure groups when compared with saline (8 weeks > 16 weeks). PM with or without zinc, or with zinc alone caused small increases in focal subepicardial inflammation, degeneration, and fibrosis. Lesions were not detected in controls at 8 weeks but were noted at 16 weeks. We analyzed mitochondrial DNA damage using quantitative polymerase chain reaction and found that all groups except MSH caused varying degrees of damage relative to control. Total cardiac aconitase activity was inhibited in rats receiving soluble zinc. Expression array analysis of heart tissue revealed modest changes in mRNA for genes involved in signaling, ion channels function, oxidative stress, mitochondrial fatty acid metabolism, and cell cycle regulation in zinc but not in MSH-exposed rats.

CONCLUSION

These results suggest that water-soluble PM-associated zinc may be one of the causal components involved in PM cardiac effects.

Amino acid side chain interactions in the presence of salts

The effects of salt on the intermolecular interactions between polar/charged amino acids are investigated through molecular dynamics simulations. The mean forces and associated potentials are calculated for NaCl salt in the 0-2 M concentration range at 298 K. It is found that the addition of salt may stabilize or destabilize the interactions, depending on the nature of the interacting molecules. The degree of (de)stabilization is quantified, and the origin of the salt-dependent modulation is discussed based upon an analysis of solvent density profiles. To gain insight into the molecular origin of the salt modulation, spatial distribution functions (sdf's) are calculated, revealing a high degree of solvent structuredness in all cases. The peaks in the sdf's are consistent with long-range hydrogen-bonding networks connecting the solute hydrophilic groups, and that contribute to their intermolecular solvent-induced forces. The restructuring of water around the solutes as they dissociate from close contact is analyzed. This analysis offers clues on how the solvent structure modulates the effective intermolecular interactions in complex solutes. This modulation results from a critical balance between bulk electrostatic forces and those exerted by (i) the water molecules in the structured region between the monomers, which is disrupted by ions that transiently enter the hydration shells, and (ii) the ions in the hydration shells in direct interactions with the solutes. The implications of these findings in protein/ligand (noncovalent) association/dissociation mechanisms are briefly discussed.

Mean time-of-flight of photons in transillumination measurements of optically anisotropic tissue with an inclusion

We study the effect of optical anisotropy on the mean time-of-flight of photons in a slab of turbid medium containing an inclusion whose optical properties differ from those of the bulk. For this analysis the difference in the mean time for a photon introduced into the slab to reach a specified target point with and without the inclusion is calculated. This difference is defined to be a measure of the contrast. The theoretical model is based on a continuous-time random walk on a lattice, which can be solved exactly and furnishes an exact expression for the contrast. Qualitative and quantitative characteristics of the contrast are analysed as functions of the geometric configuration of the system components (locations of the source, the inclusion and the detector), parameters that specify the optical anisotropy of the medium, and either the scattering properties of the inclusion or the lifetime of the small fluorophore in the case of the time-resolved fluorescence experimental configuration.

Interspecific transfer of bacterial endosymbionts between tsetse fly species: infection establishment and effect on host fitness

Tsetse flies (Glossina spp.) can harbor up to three distinct species of endosymbiotic bacteria that exhibit unique modes of transmission and evolutionary histories with their host. Two mutualist enterics, Wigglesworthia and Sodalis, are transmitted maternally to tsetse flies' intrauterine larvae. The third symbiont, from the genus Wolbachia, parasitizes developing oocytes. In this study, we determined that Sodalis isolates from several tsetse fly species are virtually identical based on a phylogenetic analysis of their ftsZ gene sequences. Furthermore, restriction fragment-length polymorphism analysis revealed little variation in the genomes of Sodalis isolates from tsetse fly species within different subgenera (Glossina fuscipes fuscipes and Glossina morsitans morsitans). We also examined the impact on host fitness of transinfecting G. fuscipes fuscipes and G. morsitans morsitans flies with reciprocal Sodalis strains. Tsetse flies cleared of their native Sodalis symbionts were successfully repopulated with the Sodalis species isolated from a different tsetse fly species. These transinfected flies effectively transmitted the novel symbionts to their offspring and experienced no detrimental fitness effects compared to their wild-type counterparts, as measured by longevity and fecundity. Quantitative PCR analysis revealed that transinfected flies maintained their Sodalis populations at densities comparable to those in flies harboring native symbionts. Our ability to transinfect tsetse flies is indicative of Sodalis ' recent evolutionary history with its tsetse fly host and demonstrates that this procedure may be used as a means of streamlining future paratransgenesis experiments.

Advances in homology protein structure modeling

Homology modeling plays a central role in determining protein structure in the structural genomics project. The importance of homology modeling has been steadily increasing because of the large gap that exists between the overwhelming number of available protein sequences and experimentally solved protein structures, and also, more importantly, because of the increasing reliability and accuracy of the method. In fact, a protein sequence with over 30% identity to a known structure can often be predicted with an accuracy equivalent to a low-resolution X-ray structure. The recent advances in homology modeling, especially in detecting distant homologues, aligning sequences with template structures, modeling of loops and side chains, as well as detecting errors in a model, have contributed to reliable prediction of protein structure, which was not possible even several years ago. The ongoing efforts in solving protein structures, which can be time-consuming and often difficult, will continue to spur the development of a host of new computational methods that can fill in the gap and further contribute to understanding the relationship between protein structure and function.

Effects of electric fields on proton transport through water chains

Molecular dynamics simulations on quantum energy surfaces are carried out to study the effects of perturbing electric fields on proton transport (PT) in protonated water chains. As an idealized model of a hydrophobic cavity in the interior of a protein the water molecules are confined into a carbon nanotube (CNT). The water chain connects a hydrated hydronium ion (H3O+) at one end of the CNT and an imidazole molecule at the other end. Without perturbing electric fields PT from the hydronium proton donor to the imidazole acceptor occurs on a picosecond time scale. External perturbations to PT are created by electric fields of varying intensities, normal to the CNT axis, generated by a neutral pair of charges on the nanotube wall. For fields above approximately 0.5 VA, the hydronium ion is effectively trapped at the CNT center, and PT blocked. Fields of comparable strength are generated inside proteins by nearby polar/charged amino acids. At lower fields the system displays a rich dynamic behavior, where the excess charge shuttles back and forth along the water chain before reaching the acceptor group on the picosecond time scale. The effects of the perturbing field on the proton movement are analyzed in terms of structural and dynamic properties of the water chain. The implications of these observations on PT in biomolecular systems and its control by external perturbing fields are discussed.

Duration of peginterferon therapy in acute hepatitis C: a randomized trial

Spontaneous resolution of acute hepatitis C virus infection cannot be predicted, and chronic evolution of the disease occurs in a majority of cases. To assess the efficacy and safety of peginterferon alpha-2b administered for 8, 12, or 24 weeks in patients with acute hepatitis C virus infection a total of 161 patients were identified with acute hepatitis C virus infection. Of these, 30 patients refused treatment but were retained in the study as a nonrandomized comparison group. Of the 131 patients who consented to treatment, 29 patients spontaneously resolved, leaving 102 patients randomly assigned to peginterferon alpha-2b (1.5 microg/kg) for 8 weeks (group A; n=34), 12 weeks (group B; n=34), and 24 weeks (group C; n=34). The primary end point was sustained virologic response. An intent-to-treat analysis was used for efficacy and safety end points. Sustained virologic response was achieved in 23/34 (67.6%), 28/34 (82.4%), and 31/34 (91.2%) of patients in groups A, B, and C, respectively; all had undetectable hepatitis C virus RNA 48 weeks after the end of therapy. Treatment for 8 or 12 weeks was effective in genotypes 2, 3, and 4, whereas genotype 1 required 24 weeks of therapy. The 8- and 12-week regimens were associated with fewer adverse events compared with the 24-week regimen. In conclusion, peginterferon alpha-2b effectively induces high sustained virologic response rates in patients with acute hepatitis C virus infection, thus preventing development of chronic hepatitis C. Duration of treatment should be further optimized based on genotype and rapid virologic response at week 4.

Integration of digital signal processing technologies with pulsed electron paramagnetic resonance imaging

The integration of modern data acquisition and digital signal processing (DSP) technologies with Fourier transform electron paramagnetic resonance (FT-EPR) imaging at radiofrequencies (RF) is described. The FT-EPR system operates at a Larmor frequency (L(f)) of 300MHz to facilitate in vivo studies. This relatively low frequency L(f), in conjunction with our approximately 10MHz signal bandwidth, enables the use of direct free induction decay time-locked subsampling (TLSS). This particular technique provides advantages by eliminating the traditional analog intermediate frequency downconversion stage along with the corresponding noise sources. TLSS also results in manageable sample rates that facilitate the design of DSP-based data acquisition and image processing platforms. More specifically, we utilize a high-speed field programmable gate array (FPGA) and a DSP processor to perform advanced real-time signal and image processing. The migration to a DSP-based configuration offers the benefits of improved EPR system performance, as well as increased adaptability to various EPR system configurations (i.e., software configurable systems instead of hardware reconfigurations). The required modifications to the FT-EPR system design are described, with focus on the addition of DSP technologies including the application-specific hardware, software, and firmware developed for the FPGA and DSP processor. The first results of using real-time DSP technologies in conjunction with direct detection bandpass sampling to implement EPR imaging at RF frequencies are presented.

A proposed curvilinearity index for quantifying airflow obstruction

BACKGROUND

Though forced expiratory volume in the first second (FEV(1)) is the primary indicator of airway obstruction, curvilinearity in the expiratory flow-volume curve is used to support the quantitative assessment of obstruction via FEV(1). Currently there is no available index to quantify a pathological contour of curvilinearity.

STUDY PURPOSE

We propose a "curvature" index (k(max)) and compare FEV(1) values to the index with a sequential sample of spirometry data.

METHODS

The hyperbolic function b(0)Q + b(1)Q V + b(2)V = 1 (in which Q = flow rate, V = volume, and b(0), b(1), and b(2) are estimated from the patient's flow-volume data) is fit to a fixed segment of the descending phase of the expiratory flow-volume curve. A previously developed biomechanical interpretation of this relationship associates the coefficient b(1) with the rate of airway-resistance-increase as exhaled volume increases. A global curvature index k(max)=b(1)/2(b(0)b(2)+b(1)) is defined to quantify the curvilinearity phenomenon. We used statistics software to determine the k(max) of spirometry data from 67 sequential patients, and to determine the relationship of k(max) to FEV(1).

RESULTS

Individual k(max) estimates appeared to correspond well with the degree of curvilinearity observed and were related in an exponential manner to FEV(1).

CONCLUSIONS

We defined a curvature index to quantify the curvilinearity phenomenon observed in the expiratory limb of flow-volume loops from patients with obstructive lung disease. This index uses data from a major segment of the flow-volume curve, and our preliminary data indicate an exponential relationship with FEV(1). This new index allows the putative association between curvilinearity and obstructive lung disease to be examined quantitatively in clinical practice and future studies.

Spectral signal-to-noise ratio and resolution assessment of 3D reconstructions

Measuring the quality of three-dimensional (3D) reconstructed biological macromolecules by transmission electron microscopy is still an open problem. In this article, we extend the applicability of the spectral signal-to-noise ratio (SSNR) to the evaluation of 3D volumes reconstructed with any reconstruction algorithm. The basis of the method is to measure the consistency between the data and a corresponding set of reprojections computed for the reconstructed 3D map. The idiosyncrasies of the reconstruction algorithm are taken explicitly into account by performing a noise-only reconstruction. This results in the definition of a 3D SSNR which provides an objective indicator of the quality of the 3D reconstruction. Furthermore, the information to build the SSNR can be used to produce a volumetric SSNR (VSSNR). Our method overcomes the need to divide the data set in two. It also provides a direct measure of the performance of the reconstruction algorithm itself; this latter information is typically not available with the standard resolution methods which are primarily focused on reproducibility alone.

Virus maturation: dynamics and mechanism of a stabilizing structural transition that leads to infectivity

For many viruses, the final stage of assembly involves structural transitions that convert an innocuous precursor particle into an infectious agent. This process -- maturation -- is controlled by proteases that trigger large-scale conformational changes. In this context, protease inhibitor antiviral drugs act by blocking maturation. Recent work has succeeded in determining the folds of representative examples of the five major proteins -- major capsid protein, scaffolding protein, portal, protease and accessory protein -- that are typically involved in capsid assembly. These data provide a framework for detailed mechanistic investigations and elucidation of mutations that affect assembly in various ways. The nature of the conformational change has been elucidated: it entails rigid-body rotations and translations of the arrayed subunits that transfer the interactions between them to different molecular surfaces, accompanied by refolding and redeployment of local motifs. Moreover, it has been possible to visualize maturation at the submolecular level in movies based on time-resolved cryo-electron microscopy.

High-performance liquid chromatography method for determination of N-glucuronidation of 4-aminobiphenyl by mouse, rat, and human liver microsomes

A simple and sensitive method for determination of the N-glucuronidation activity of mouse, rat, and human liver microsomes toward the carcinogenic arylamine 4-aminobiphenyl (4-ABP) using high-performance liquid chromatography with ultraviolet detection has been developed. The method uses chemically synthesized 4-ABP-N-glucuronide (4-ABP-G) as a standard for method validation. Validation was done with respect to specificity, linearity, precision, accuracy, and lower limits of detection. The method was specific since there were no interference peaks from the reaction matrix. The calibration curve for 4-ABP-G was linear from 50 to 5000 pmol/200 microl with R2=0.999. The newly developed method has good precision and accuracy. The intra- and interday precisions were less than 5 and 10%, respectively, and the highest values for intra- and interday accuracies were -4.6 and -12%, respectively. The lower limit of detection was 10 pmol/200 microl. The developed method was used to determine the glucuronidation activity of mouse, rat, and human liver microsomes. Human liver microsomes were the most active in 4-ABP glucuronidation (344.1 pmol/min/mg) followed by rats (30.6 pmol/min/mg) and then mice (12.3 pmol/min/mg). Human UGT1A4 supersomes were much more active than UGT1A9 (184.4 mol/min/mg versus 25.2 mol/min/mg). These results are consistent with those of earlier studies that used the radioactive [C14]UDPGA.

Dilated cardiomyopathy in Erb-b4-deficient ventricular muscle

The neuregulin receptor tyrosine kinase Erb-b4, initially linked to early cardiac development, is shown here to play a critical role in adult cardiac function. In wild-type mice, Erb-b4 protein localized to Z lines and to intercalated disks, suggesting a role in subcellular and intercellular communications of cardiomyocytes. Conditional inactivation of erb-b4 in ventricular muscle cells led to a severe dilated cardiomyopathy, characterized by thinned ventricular walls with eccentric hypertrophy, reduced contractility, and delayed conduction. This cardiac dysfunction may account for premature death in adult erb-b4-knockout mice. This study establishes a critical role for Erb-b4 in the maintenance of normal postnatal cardiac structure and function.

Association Between Functional Status and Use and Effectiveness of Beta-Blocker Prophylaxis in Elderly Survivors of Acute Myocardial Infarction

OBJECTIVES

To examine whether physical and cognitive impairments explain low use of beta-blockers in elderly patients and whether functionally impaired older adults have improved survival if a beta-blocker is prescribed at hospital discharge.

DESIGN

Cross-sectional and retrospective cohort study.

SETTING

Acute care hospitals in the United States.

PARTICIPANTS

National cohort of 45,370 elderly acute myocardial infarction survivors, with no chart-documented contraindications to beta-blocker treatment.

MEASUREMENTS

The main outcome measures were beta-blocker prescription at hospital discharge and 1-year survival.

RESULTS

Fifty percent (n=22,683) of eligible patients were prescribed a beta-blocker at discharge. Older age and functional impairments (incontinence, mobility impairment, and cognitive impairment) were independently associated with decreased use of beta-blockers. The odds ratios for prescribing a beta-blocker at hospital discharge were 0.82 (95% confidence interval (CI)=0.77-0.86), 0.63 (95% CI=0.56-0.71), and 0.40 (95% CI=0.32-0.51) for persons with one, two, and three impairments, respectively, compared with those with no impairments. In survival analysis, patients prescribed a beta-blocker were 21% less likely than nonrecipients to die within 1 year of follow-up (relative risk=0.79, P=.0001). Similar survival benefit was observed in patients with and without functional impairments.

CONCLUSION

This study shows a strong association between functional impairment and the use of beta-blockers after acute myocardial infarction in elderly patients. The results suggest that increasing use of beta-blockers in this group provides an opportunity to improve outcomes.

Effects of Cytochalasin D on Electrical Restitution and the Dynamics of Ventricular Fibrillation in Isolated Rabbit Heart

Cytochalasin D in Rabbit Ventricle.

INTRODUCTION

Cytochalasin D (cyto-D) has been used as an excitation-contraction uncoupler during optical mapping studies. However, its effects on action potential duration restitution (APDR) and dynamics during ventricular fibrillation (VF) are unclear.

METHODS AND RESULTS

Langendorff-perfused rabbit hearts (N = 6) were immersed in a tissue chamber. Transmembrane potential was recorded using glass microelectrodes. APD measured to 90% repolarization (APD90) was used to construct the APDR curve. During regular pacing at 300-msec cycle length, increasing concentrations of cyto-D resulted in progressively prolonged APD90 (131 +/- 26 msec, 171 +/- 14 msec, and 177 +/- 14 msec) and steepened maximum slope of the APDR curve (1.1 +/- 0.2, 1.3 +/- 0.2, and 1.6 +/- 0.4 for control, 5 micromoles, and 10 micromoles, respectively; P < 0.01). Resting membrane potential, AP amplitude, and maximum dV/dt did not change. Cyto-D lengthened VF cycle length and APD90, and steepened the maximum slope of the APDR curve. However, cyto-D did not significantly change the diastolic interval. The dominant frequency of pseudoelectrocardiogram progressively decreased with increasing concentrations of cyto-D (15.2 +/- 0.6 Hz, 11.1 +/- 2.4 Hz, and 9.8 +/- 3.2 Hz for control, 5 micromoles, and 10 micromoles, respectively; P < 0.01). Sustained (>1 min) VF was repeatedly inducible at baseline and with 5 or 10 micromoles of cyto-D.

CONCLUSION

Continuous perfusion of cyto-D at 5 or 10 micromoles prolonged APD90, steepened APDR slope, and reduced dominant frequency in rabbit ventricles. Cyto-D at these concentrations allowed induction of sustained VF.

Influence of a 3-day regimen of azithromycin on the disposition kinetics of cyclosporine A in stable renal transplant patients

Some macrolide antibiotics have been shown to produce significant drug-drug interactions through the inhibition of cytochrome P450 (CYP) enzymes. In renal transplant patients these interactions pose potentially serious problems for the safe administration of cyclosporine A (CSA), a substrate of CYP3A4. The effects of azithromycin on CSA disposition kinetics were evaluated in eight stable renal transplant patients. Patients had been stabilized on individualized doses of CSA which remained unchanged throughout the study. Azithromycin was administered for 3 days. Baseline measurements of CSA disposition kinetics were taken prior to azithromycin treatment (study day 2) and after 3 days (study day 5) of azithromycin treatment (500mg/day, orally). The key parameters of interest were the area under the CSA blood concentration versus time curve (AUC) measured for 24h after the morning dose of CSA on both days 2 and 5, and the C(max) values of CSA. The geometric mean ratios (GMRs) of those parameters (day 5/day 2) and their 90% confidence intervals (90% CI) were 107 (98,116) and 119 (104,136), respectively. The 7% increase in exposure level and 19% increase in peak plasma concentration are not likely to be clinically significant. It is concluded that azithromycin (500mg/dayx3 days) does not alter the disposition kinetics of CSA in a clinically significant way, and that CSA dosage adjustments are not warranted in renal transplant patients taking these two drugs together.

Simultaneous analysis of nicotine, nicotine metabolites, and tobacco alkaloids in serum or urine by tandem mass spectrometry, with clinically relevant metabolic profiles

BACKGROUND

Assessment of nicotine metabolism and disposition has become an integral part of nicotine dependency treatment programs. Serum nicotine concentrations or urine cotinine concentrations can be used to guide nicotine patch dose to achieve biological concentrations adequate to provide the patient with immediate relief from nicotine withdrawal symptoms, an important factor in nicotine withdrawal success. Absence of nicotine metabolites and anabasine can be used to document abstinence from tobacco products, an indicator of treatment success.

METHODS

The procedure was designed to quantify nicotine, cotinine, trans-3'-hydroxycotinine, anabasine, and nornicotine in human serum or urine. The technique required simple extraction of the sample with quantification by HPLC-tandem mass spectrometry.

RESULTS

The procedure for simultaneous analysis of nicotine, its metabolites, and tobacco alkaloids simultaneously quantified five different analytes. Test limit of quantification, linearity, imprecision, and accuracy were adequate for clinical evaluation of patients undergoing treatment for tobacco dependency. The test readily distinguished individuals who had no exposure to tobacco products from individuals who were either passively exposed or were abstinent past-tobacco users from those who were actively using a tobacco or nicotine product.

CONCLUSIONS

Nicotine, cotinine, trans-3'-hydroxycotinine, nornicotine, and anabasine can be simultaneously and accurately quantified in either serum or urine by HPLC-tandem mass spectrometry with imprecision <10% at physiologic concentrations and limits of quantification ranging from 0.5 to 5 micro g/L. Knowledge of serum or urine concentrations of these analytes can be used to guide nicotine replacement therapy or to assess tobacco abstinence in nicotine dependency treatment. These measurements are now an integral part of the clinical treatment and management of patients who wish to overcome tobacco dependence.

Genetic heterogeneity of small ruminant lentiviruses involves immunodominant epitope of capsid antigen and affects sensitivity of single-strain-based immunoassay

The pol and gag gene fragments of small ruminant lentivirus field isolates collected in the last decade in Italy were amplified, sequenced, and analyzed. Phylogenetic analysis revealed that the majority of ovine isolates form a distinct cluster more similar to caprine lentivirus prototypes than to the visna virus prototype. These findings confirm and extend those reported by Leroux et al. (Arch. Virol., 142:1125-1137, 1997). Moreover, we observed that a variable region of Gag, included in the fragment analyzed, corresponded to one of the three major capsid antigen epitopes, which suggests that the antibody response to this epitope may be type specific. To test this hypothesis, two recombinant peptides, derived from the Icelandic prototype K1514 and this novel genotype, were expressed and used in an enzyme-linked immunosorbent assay to screen a panel of ovine and caprine sera collected from different geographical locations in Italy. Several sera reacted in a type-specific manner, indicating that in a diagnostic setting the combination of at least these two type-specific peptides is necessary to cover a wide range of infections. Additionally, these results support the hypothesis of cross-species transmission based on the phylogenetic analysis described above. This has implications for the control and eradication of small ruminant lentivirus infections.

Functional conservation of subfamilies of putative UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases in Drosophila, Caenorhabditis elegans, and mammals. One subfamily composed of l(2)35Aa is essential in Drosophila

The completed fruit fly genome was found to contain up to 15 putative UDP-N-acetyl-alpha-d-galactosamine:polypeptide N-acetylgalactosaminyltransferase (GalNAc-transferase) genes. Phylogenetic analysis of the putative catalytic domains of the large GalNAc-transferase enzyme families of Drosophila melanogaster (13 available), Caenorhabditis elegans (9 genes), and mammals (12 genes) indicated that distinct subfamilies of orthologous genes are conserved in each species. In support of this hypothesis, we provide evidence that distinctive functional properties of Drosophila and human GalNAc-transferase isoforms were exhibited by evolutionarily conserved members of two subfamilies (dGalNAc-T1 (l(2)35Aa) and GalNAc-T11; dGalNAc-T2 (CG6394) and GalNAc-T7). dGalNAc-T1 and novel human GalNAc-T11 were shown to encode functional GalNAc-transferases with the same polypeptide acceptor substrate specificity, and dGalNAc-T2 was shown to encode a GalNAc-transferase with similar GalNAc glycopeptide substrate specificity as GalNAc-T7. Previous data suggested that the putative GalNAc-transferase encoded by l(2)35Aa had a lethal phenotype (Flores, C., and Engels, W. (1999) Proc. Natl. Acad. Sci. U. S. A. 96, 2964-2969), and this was substantiated by sequencing of three lethal alleles l(2)35Aa(HG8), l(2)35Aa(SF12), and l(2)35Aa(SF32). The finding that subfamilies of GalNAc-transferases with distinct catalytic functions are evolutionarily conserved stresses that GalNAc-transferase isoforms may serve unique biological functions rather than providing functional redundancy, and this is further supported by the lethal phenotype of l(2)35Aa.

Cytochrome P450 isozymes involved in the metabolism of phenol, a benzene metabolite

Benzene is an occupational and environmental toxicant. The major health concern for humans is acute myelogenous leukemia. To exert its toxic effects, benzene must be metabolized by cytochrome P450 to phenol and subsequently to catechol and hydroquinone. Previous research has implicated CYP2E1 in the metabolism of phenol. In this study the cytochrome P450 isozymes involved in the metabolism of phenol were examined in hepatic and pulmonary microsomes utilizing chemical inhibitors of CYP2E1, CYP2B, and CYP2F2 and using CYP2E1 knockout mice. CYP2E1 was found to be responsible for only approximately 50% of 20 microM phenol metabolism in the liver. This suggests another isozyme(s) is involved in hepatic phenol metabolism. In pulmonary microsomes both CYP2E1 and CYP2F2 were significantly involved.

Sex differences in cardiac catheterization: the role of physician gender

CONTEXT

Many studies indicate that women are less likely than men to undergo cardiac procedures after an acute myocardial infarction (AMI), raising concerns of sexual bias in clinical care. However, no data exist regarding the relationship between patient sex, physician sex, and use of cardiac procedures.

OBJECTIVE

To determine whether sex differences in cardiac catheterization after AMI were greater when patients were treated by male attending physicians compared with female attending physicians.

DESIGN, SETTING, AND PATIENTS

Analysis of data from the Cooperative Cardiovascular Project, a retrospective medical record review. A total of 104 >231 Medicare fee-for-service beneficiaries who were hospitalized in US acute care hospitals for an AMI between January 1994 and February 1995.

MAIN OUTCOME MEASURE

Use of cardiac catheterization within 60 days of admission, compared between the 4 groups of patient sex-physician sex combinations.

RESULTS

Women underwent fewer cardiac catheterizations than men when treated by either male physicians (38.6% vs 50.8%; P =.001) or female physicians (34.8% vs 45.8%; P =.001). Sex differences in procedure use were not greater when a patient and physician were of different sexes (P for interaction =.85). After potential confounders in multivariable analysis were accounted for, women were less likely to undergo cardiac catheterization (risk ratio, 0.90 [95% confidence interval (CI), 0.88-0.92]), regardless of the treating physician's sex. Patients treated by male physicians were more likely to undergo cardiac catheterization (risk ratio, 1.06 [95%CI, 1.02-1.10]) than those treated by female physicians, regardless of patient sex.

CONCLUSIONS

Women who have had an AMI undergo a cardiac catheterization less often than men, whether treated by a male or female physician. These results suggest that factors other than sexual bias by male physicians toward women account for sex differences in cardiac procedure use.

Bioterrorism. Implications for the occupational and environmental health nurse

1. Bioterrorism is the intentional release of a biological agent--bacterial, viral, or genetically altered--to instill fear or create chaos, massive casualities, illness, and death in humans, animals, or plants. 2. The threat of bioterrorism is real. Although every community is vulnerable, terrorists seek densely populated, highly visible targets. 3. Occupational and environmental health nurses must to be able to recognize and report signs and symptoms of an early bioweapons outbreak in their workplaces and communities. Only thorough preparedness and planning will result in effective mitigation and treatment. 4. The Bioterrorism Readiness Plan (at http://www.apic.org and http://www.CDC.gov/ncidod/hip) is a template for health care professionals to help plan a realistic response to bioterrorism. It serves as a tool for successful collaboration and communication among all disciplines and public health agencies for the best possible outcomes.

Genetic variability in the development of pulmonary tolerance to inhaled pollutants in inbred mice

After repeated exposures, many individuals develop tolerance to the adverse health effects of inhaled pollutants. Pulmonary tolerance can be characterized as the ability of the lung to withstand the adverse actions of a toxic compound after repeated exposures. To determine whether genetic background is important to the development of pulmonary tolerance to inhaled pollutants, 11 inbred strains of mice were exposed once (1x) or for 5 consecutive days (5x) to 1.0 mg/m(3) of zinc oxide (ZnO). Development of pulmonary tolerance was assessed by measuring polymorphonuclear leukocyte and protein levels in bronchoalveolar lavage fluid and comparing the responses of the 1x and 5x groups. Significant interstrain variation in polymorphonuclear leukocyte and protein responses was observed between the groups with 1x and 5x exposures, which indicates that genetic background has an important role in the development of pulmonary tolerance. The BALB/cByJ strain and the DBA/2J strain were the most tolerant and nontolerant, respectively. The CByD2F1/J offspring were uniformly nontolerant. The development of tolerance was also investigated in BALB/cByJ and DBA/2J mice after 1x and 5x exposure to ozone and aerosolized endotoxin. Discordance in the phenotypic pattern of pulmonary tolerance among strains after exposure to ZnO, ozone, and endotoxin suggested that different mechanisms may be responsible for the development of pulmonary tolerance to these agents.

Electrochromatographic separation of proteins

We have developed a modified electrochromatography system which minimizes Joule heating at electric field strengths up to 125 V/cm. A non-linear equilibrium model is described which incorporates electrophoretic mobility, hydrodynamic flow velocity, and an electrically induced concentration polarization at the surface of the stationary phase. This model is able to provide useful estimates of protein retention time and velocity in a column packed with Sephadex gel and subjected to an electric field. A correlation of electrophoretic mobility of peptide and proteins with respect to their charge, molecular mass, and asymmetry enables the selection of solute target molecules for electrochromatographic separations. Good separation of protein mixtures have been obtained.

Acute myocardial infarction in the elderly: differences by age

OBJECTIVES

We evaluated the clinical characteristics and outcomes of elderly patients hospitalized with acute myocardial infarction (AMI) to describe differences by age.

BACKGROUND

Elderly patients with AMI are perceived as a homogeneous population, though the extent by which clinical characteristics vary among elderly patients has not been well described.

METHODS

Data from 163,140 hospital admissions of Medicare beneficiaries age > or =65 years between 1994 and 1996 with AMI at U.S. hospitals were evaluated for differences in clinical characteristics and mortality across five age-based strata (in years): 65 to 69, 70 to 74, 75 to 79, 80 to 84 and > or =85.

RESULTS

Older age was associated with a greater proportion of patients with functional limitations, heart failure, prior coronary disease and renal insufficiency and a lower proportion of male and diabetic patients. Of note, the proportion of patients presenting with chest pain within 6 h of symptom onset, and with ST-segment elevation, was lower in each successive age group. Thirty-day mortality rates were higher in older age groups (65 to 69: 10.9%, 70 to 74: 14.1%, 75 to 79: 18.5%, 80 to 84: 23.2%, > or =85: 31.2%, p = 0.001 for trend). The effect of age persisted but was attenuated after adjustment for differences in patient characteristics; similar trends were observed for one-year mortality.

CONCLUSIONS

Our data indicate significant age-associated differences in clinical characteristics in elderly patients with AMI, which account for some of the age-associated differences in mortality. The practice of grouping older patients together as a single age group may obscure important age-associated differences.

Antibody responses to HIV-1 antigens are higher in HIV-1(+) intravenous drug users than in HIV-1(+) homosexuals

Immune responses to HIV-1 infection of 42 HIV-1-positive asymptomatic intravenous drug users (IVDUs) were compared with those of 135 HIV-1-infected asymptomatic homosexual men in the present study. Twenty-five HIV-1(-) individuals served as normal controls. The comparison included antibody responses to five computer-predicted epitopes of HIV-1 p17, and viral proteins gp120 and p24 as well as p17. Major immunophenotypes were also investigated. Results showed that antibody responses to the five epitopes were significantly higher in the IVDUs. A larger proportion of the IVDUs, with respect to that of homosexuals, showed positive antibody responses to p24 and p17, respectively. However, the antibody response to gp120 was similar between the two cohorts. Immunophenotyping showed that HIV-1(+) homosexuals had higher profiles in most of the major subsets than did the IVDUs, especially in the total count of lymphocytes, absolute numbers of CD3+ cells and CD8+ cells. It appeared that the HIV-1(+) IVDU cohort had higher antibody responses to most of the viral antigens, but had lower levels of lymphocyte subsets in comparison with HIV(+) homosexuals.

Recent risk rates of occupational fatalities, injuries, and illnesses in U.S. industries and their use in planning environmental controls

Cost/benefit justifications are now required for new environmental regulations. The benefit is related to the difference between the currently existing health risk rate and the rate corresponding to the proposed permissible exposure limit. The adoption of many permissible exposure limits has been delayed by the lack of supporting human data and the use of animal data instead. This has resulted in difficulties and controversies not likely to be resolved soon. Meanwhile, a review of currently existing occupational risk rates can provide a perspective for best use of available funds. Tables and text are presented summarizing published occupational risk data for 1996. Transportation incidents cause 42 percent of occupational fatalities. Proper selection and training of workers and proper work rules should be cost-effective, also especially in other listed dangerous industries. Annual risk rates per hundred workers for occupational nonfatal injuries and illness were surprisingly high: for manufacturing 10.6, and for the entire private sector, 7.4. Seven worst industries ranged from 25.8 to 30.3. The benefit from controlling such high rates is almost the same whether the final rate is 10(-3) or 10(-6). Thus, specifying a good low-cost procedure that reduces most of the initial risk can provide the lowest cost/benefit ratio, eligible for priority use of available funds.

Organ-specific differences in 8-oxoguanosine glycosylase (OGG1) repair following acute treatment with benzo[a]pyrene

The lung has been shown to be a target organ for the deleterious effects of Benzo[a]pyrene (B[a]P), regardless of the route of exposure. 8-hydroxy-2'-deoxyguanosine (oxo8dG) is a mutagenic lesion formed in DNA following exposure to B[a]P. The objective of this study was to determine the capacity of different organs to repair oxo8dG following intraperitoneal (i.p.) treatment with B[a]P. Male Spraque-Dawley rats were administered 20 mg/kg B[a]P i.p., 2 times/day for 5 days. A 26% decrease in the capacity to remove oxo8dG was observed in lung tissue at 72 hours and recovered 20% above control values at 120 hours. The capacity of the liver and kidney remained at baseline for all time points analyzed. A 7-fold increase in oxo8dG was observed in the lung at 72 hours. This study demonstrates that organ-specific differences exist in the capacity to remove oxo8dG and further demonstrates the susceptibility of lung tissue to the effects of B[a]P.

Lognormal model for determining dose-response curves from epidemiological data and for health risk assessment

A practical method is proposed for determining human dose-response curves based on reasonable assumptions and simplifications. The epidemiological data needed are the fractions of the population suffering an adverse response from exposures to two or more patterns of fluctuating concentrations of a pollutant, and the statistical parameters of each pattern. The method calculates the two parameters of the threshold type dose-response curve of the pollutant, represented by a cumulative lognormal distribution. This distribution was derived from a reasonable statistical model. The calculation does not require any arbitrary safety factors and yields central values. The dose-response parameters then may be used to calculate the health risk rate of exposure to any other fluctuating concentration pattern. Another method is proposed to select appropriate threshold limit values (TLVs) using calculations involving these parameters. Examples are given to illustrate the calculations. Results with hypothetical data gave apparently reasonable results. They showed the importance not only of the geometric mean concentration but also of the geometric standard deviations of both the concentrations and of the dose-response curve, that greatly influence the results. It is believed that results of useful accuracy should be obtained. Health risk rates are readily understood. They are useful for cost-benefit calculations. Relative rates can be used to compare the hazards of different operations and different plants. The method may make possible the development of standards specifying maximum allowable risk rates.

Cytochromes P450 involved with benzene metabolism in hepatic and pulmonary microsomes

Benzene is an occupational hazard and environmental toxicant found in cigarette smoke, gasoline, and the chemical industry. The major health concern associated with benzene exposure is leukemia. The toxic effects of benzene are dependent on its metabolism by the cytochrome P450 enzyme system. Previous research has identified CYP2E1 as the primary P450 isozyme responsible for benzene metabolism at low concentrations, whereas CYP2B1 is involved at higher concentrations. Our studies using microsomal preparations from human, mouse, and rat indicate that CYP2E1 is the P450 isozyme primarily responsible for benzene metabolism in lung and in liver. CYP2B isozymes have little involvement in benzene metabolism by either lung or liver. Our results also indicate that isozymes of the CYP2F subfamily may play a role in benzene metabolism by lung.

Preparing for expected bioterrorism attacks

The threat of bioterrorism in the United States is increasing. Health professionals, especially "front-line" practitioners, must be able to recognize the potential for major impacts from a bioterrorism event. Although an effective attack could produce numbers of casualties equivalent to those resulting from a nuclear weapon, an unannounced attack would be unlikely to be recognized immediately. Health workers may be the first to recognize an attack. However, only limited assistance is available to aid local community medical organizations in planning for bioterrorism. Military medical personnel have had more experience in planning for terrorist activities than many of their civilian colleagues. Their experience may be invaluable to local civilian treatment facilities in developing practical plans to meet the unique aspects of bioterrorism. In addition to considering agent-specific medical problems and requirements, it is particularly important for plans to address command and control, communication, and coordination if the resultant response is to be effective.