Using a chat-based informed consent tool in large-scale genomic research

OBJECTIVE

We implemented a chatbot consent tool to shift the time burden from study staff in support of a national genomics research study.

MATERIALS AND METHODS

We created an Institutional Review Board-approved script for automated chat-based consent. We compared data from prospective participants who used the tool or had traditional consent conversations with study staff.

RESULTS

Chat-based consent, completed on a user's schedule, was shorter than the traditional conversation. This did not lead to a significant change in affirmative consents. Within affirmative consents and declines, more prospective participants completed the chat-based process. A quiz to assess chat-based consent user understanding had a high pass rate with no reported negative experiences.

CONCLUSION

Our report shows that a structured script can convey important information while realizing the benefits of automation and burden shifting. Analysis suggests that it may be advantageous to use chatbots to scale this rate-limiting step in large research projects.

"Development and Implementation of Novel Chatbot-based Genomic Research Consent"

Objective

To conduct a retrospective analysis comparing traditional human-based consenting to an automated chat-based consenting process.

Materials and Methods

We developed a new chat-based consent using our IRB-approved consent forms. We leveraged a previously developed platform (GiaⓇ, or "Genetic Information Assistant") to deliver the chat content to candidate participants. The content included information about the study, educational information, and a quiz to assess understanding. We analyzed 144 families referred to our study during a 6-month time period. A total of 37 families completed consent using the traditional process, while 35 families completed consent using Gia.

Results

Engagement rates were similar between both consenting methods. The median length of the consent conversation was shorter for Gia users compared to traditional (44 vs. 76 minutes). Additionally, the total time from referral to consent completion was faster with Gia (5 vs. 16 days). Within Gia, understanding was assessed with a 10-question quiz that most participants (96%) passed. Feedback about the chat consent indicated that 86% of participants had a positive experience.

Discussion

Using Gia resulted in time savings for both the participant and study staff. The chatbot enables studies to reach more potential candidates. We identified five key features related to human-centered design for developing a consent chat.

Conclusion

This analysis suggests that it is feasible to use an automated chatbot to scale obtaining informed consent for a genomics research study. We further identify a number of advantages when using a chatbot.

A second cohort of CHD3 patients expands the molecular mechanisms known to cause Snijders Blok-Campeau syndrome

There has been one previous report of a cohort of patients with variants in Chromodomain Helicase DNA-binding 3 (CHD3), now recognized as Snijders Blok-Campeau syndrome. However, with only three previously-reported patients with variants outside the ATPase/helicase domain, it was unclear if variants outside of this domain caused a clinically similar phenotype. We have analyzed 24 new patients with CHD3 variants, including nine outside the ATPase/helicase domain. All patients were detected with unbiased molecular genetic methods. There is not a significant difference in the clinical or facial features of patients with variants in or outside this domain. These additional patients further expand the clinical and molecular data associated with CHD3 variants. Importantly we conclude that there is not a significant difference in the phenotypic features of patients with various molecular disruptions, including whole gene deletions and duplications, and missense variants outside the ATPase/helicase domain. This data will aid both clinical geneticists and molecular geneticists in the diagnosis of this emerging syndrome.

Varying levels of X chromosome coalescence in female somatic cells alters the balance of X-linked dosage compensation and is implicated in female-dominant systemic lupus erythematosus

The three-dimensional organization of the genome in mammalian interphase nuclei is intrinsically linked to the regulation of gene expression. Whole chromosome territories and their encoded gene loci occupy preferential positions within the nucleus that changes according to the expression profile of a given cell lineage or stage. To further illuminate the relationship between chromosome organization, epigenetic environment, and gene expression, here we examine the functional organization of chromosome X and corresponding X-linked genes in a variety of healthy human and disease state X diploid (XX) cells. We observe high frequencies of homologous chromosome X colocalization (or coalescence), typically associated with initiation of X-chromosome inactivation, occurring in XX cells outside of early embryogenesis. Moreover, during chromosome X coalescence significant changes in Xist, H3K27me3, and X-linked gene expression occur, suggesting the potential exchange of gene regulatory information between the active and inactive X chromosomes. We also observe significant differences in chromosome X coalescence in disease-implicated lymphocytes isolated from systemic lupus erythematosus (SLE) patients compared to healthy controls. These results demonstrate that X chromosomes can functionally interact outside of embryogenesis when X inactivation is initiated and suggest a potential gene regulatory mechanism aberration underlying the increased frequency of autoimmunity in XX individuals.

Clinical validity assessment of genes for inclusion in multi-gene panel testing: A systematic approach

BACKGROUND

Advances in sequencing technology have led to expanded use of multi-gene panel tests (MGPTs) for clinical diagnostics. Well-designed MGPTs must balance increased detection of clinically significant findings while mitigating the increase in variants of uncertain significance (VUS). To maximize clinical utililty, design of such panels should include comprehensive gene vetting using a standardized clinical validity (CV) scoring system.

METHODS

To assess the impact of CV-based gene vetting on MGPT results, data from MGPTs for cardiovascular indications were retrospectively analyzed. Using our CV scoring system, genes were categorized as having definitive, strong, moderate, or limited evidence. The rates of reported pathogenic or likely pathogenic variants and VUS were then determined for each CV category.

RESULTS

Of 106 total genes, 42% had definitive, 17% had strong, 29% had moderate, and 12% had limited CV. The detection rate of variants classified as pathogenic or likely pathogenic was higher for genes with greater CV, while the VUS rate showed an inverse relationship with CV score. No pathogenic or likely pathogenic findings were observed in genes with a limited CV.

CONCLUSION

These results demonstrate the importance of a standardized, evidence-based vetting process to establish CV for genes on MGPTs. Using our proposed system may help to increase the detection rate while mitigating higher VUS rates.

A retrospective review of multiple findings in diagnostic exome sequencing: half are distinct and half are overlapping diagnoses

PURPOSE

We evaluated clinical and genetic features enriched in patients with multiple Mendelian conditions to determine which patients are more likely to have multiple potentially relevant genetic findings (MPRF).

METHODS

Results of the first 7698 patients who underwent exome sequencing at Ambry Genetics were reviewed. Clinical and genetic features were examined and degree of phenotypic overlap between the genetic diagnoses was evaluated.

RESULTS

Among patients referred for exome sequencing, 2% had MPRF. MPRF were more common in patients from consanguineous families and patients with greater clinical complexity. The difference in average number of organ systems affected is small: 4.3 (multiple findings) vs. 3.9 (single finding) and may not be distinguished in clinic.

CONCLUSION

Patients with multiple genetic diagnoses had a slightly higher number of organ systems affected than patients with single genetic diagnoses, largely because the comorbid conditions affected overlapping organ systems. Exome testing may be beneficial for all cases with multiple organ systems affected. The identification of multiple relevant genetic findings in 2% of exome patients highlights the utility of a comprehensive molecular workup and updated interpretation of existing genomic data; a single definitive molecular diagnosis from analysis of a limited number of genes may not be the end of a diagnostic odyssey.

Inhibition of LTP-Induced Translation by IL-1β Reduces the Level of Newly Synthesized Proteins in Hippocampal Dendrites

In rodent hippocampus, the inflammatory cytokine interleukin-1β (IL-1β) impairs memory and long-term potentiation (LTP), a major form of plasticity that depends on protein synthesis. A better understanding of the mechanisms by which IL-1β impairs LTP may help identify targets for preventing cognitive deterioration. We tested whether IL-1β inhibits protein synthesis in hippocampal neuron cultures following chemically induced LTP (cLTP). Fluorescent-tagging using click-chemistry showed that IL-1β reduces the level of newly synthesized proteins in proximal dendrites of cLTP stimulated neurons. Relative to controls, in cLTP stimulated neurons, IL-1β inhibited Akt/mTOR signaling, as well as the upregulation of GluA1, an AMPA receptor subunit, and LIMK1, a kinase that promotes actin polymerization. Notably, a novel TIR domain peptidomimetic (EM163) blocked both the activation of p38 and the suppression of cLTP-dependent protein synthesis by IL-1β. Our data support a model where IL-1β suppresses LTP directly in neurons by inhibiting mTOR-dependent translation.

In vitro skin penetration of petrolatum and soybean oil and effects of glyceryl monooleate

OBJECTIVES

Petrolatum and soybean oil are common ingredients incorporated in topical skin formulations for skin protection and moisturization. However, the stratum corneum (SC) penetration kinetics of these two cosmetic ingredients has not been systematically studied. Glyceryl monooleate (GlyMOle) has been shown to enhance skin penetration of various compounds. It was hypothesized that GlyMOle could enhance skin penetration of petrolatum and soybean oil. This study aimed to examine the in vitro skin penetration of petrolatum and soybean oil in the presence or absence of GlyMOle.

METHODS

Skin permeation experiments were conducted using the in vitro Franz diffusion cell model with split-thickness human skin and human epidermal membrane (HEM). The effect of permeant dose and the kinetics of permeant penetration were examined with and without GlyMOle in vitro.

RESULTS

Petrolatum and soybean oil were found to permeate across HEM, and no effect of GlyMOle on skin permeation into the receptor chamber was observed. GlyMOle enhanced the penetration of petrolatum into the split-thickness skin at 50 μg dose (petrolatum:GlyMOle, 49 : 1, w/w). However, no effect of GlyMOle on petrolatum penetration was observed at 200 μg dose (of the same petrolatum:GlyMOle ratio), indicating a dose-dependent effect. GlyMOle at the level used in the study did not enhance the penetration of soybean oil with 50 and 200 μg doses at any timepoints.

CONCLUSION

GlyMOle was a skin penetration enhancer for petrolatum under the in vitro conditions identified in this study.

Clinical Epigenetic Therapies Disrupt Sex Chromosome Dosage Compensation in Human Female Cells

Sex chromosome gene dosage compensation is required to ensure equivalent levels of X-linked gene expression between males (46, XY) and females (46, XX). To achieve similar expression, X-chromosome inactivation (XCI) is initiated in female cells during early stages of embryogenesis. Within each cell, either the maternal or paternal X chromosome is selected for whole chromosome transcriptional silencing, which is initiated and maintained by epigenetic and chromatin conformation mechanisms. With the emergence of small-molecule epigenetic inhibitors for the treatment of disease, such as cancer, the epigenetic mechanism underlying XCI may be inadvertently targeted. Here, we test 2 small-molecule epigenetic inhibitors being used clinically, GSK126 (a histone H3 lysine 27 methyltransferase inhibitor) and suberoylanilide hydroxamic acid (a histone deacetylase inhibitor), on their effects of the inactive X (Xi) in healthy human female fibroblasts. The combination of these modifiers, at subcancer therapeutic levels, leads to the inability to detect the repressive H3K27me3 modification characteristic of XCI in the majority of the cells. Importantly, genes positioned near the X-inactivation center (Xic), where inactivation is initiated, exhibit robust expression with treatment of the inhibitors, while genes located near the distal ends of the X chromosome intriguingly exhibit significant downregulation. These results demonstrate that small-molecule epigenetic inhibitors can have profound consequences on XCI in human cells, and they underscore the importance of considering gender when developing and clinically testing small-molecule epigenetic inhibitors, in particular those that target the well-characterized mechanisms of X inactivation.

Interstitial telomeric loops and implications of the interaction between TRF2 and lamin A/C

The protein-DNA complexes that compose the end of mammalian chromosomes-telomeres-serve to stabilize linear genomic DNA and are involved in cellular and organismal aging. One mechanism that protects telomeres from premature degradation is the formation of structures called t-loops, in which the single-stranded 3' overhang present at the terminal end of telomeres loops back and invades medial double-stranded telomeric DNA. We identified looped structures formed between terminal chromosome ends and interstitial telomeric sequences (ITSs), which are found throughout the human genome, that we have termed interstitial telomeric loops (ITLs). While they form in a TRF2-dependent manner similar to t-loops, ITLs further require the physical interaction of TRF2 with the nuclear intermediate filament protein lamin A/C. Our findings suggest that interactions between telomeres and the nucleoskeleton broadly impact genomic integrity, including telomere stability, chromosome structure, and chromosome fragility. Here, we review the roles of TRF2 and lamin A/C in telomere biology and consider how their interaction may relate telomere homeostasis to cellular and organismal aging.

TNFα and IL-1β but not IL-18 Suppresses Hippocampal Long-Term Potentiation Directly at the Synapse

CNS inflammatory responses are linked to cognitive impairment in humans. Research in animal models supports this connection by showing that inflammatory cytokines suppress long-term potentiation (LTP), the best-known cellular correlate of memory. Cytokine-induced modulation of LTP has been previously studied in vivo or in brain slices, two experimental approaches containing multiple cell populations responsive to cytokines. In their target cells, cytokines commonly increase the expression of multiple cytokines, thus increasing the complexity of brain cytokine networks even after single-cytokine challenges. Whether cytokines suppress LTP by direct effects on neurons or by indirect mechanisms is still an open question. Here, we evaluated the effect of a major set of inflammatory cytokines including tumor necrosis factor-α (TNFα), interleukin-1β (IL-1β) and interleukin-18 (IL-18) on chemically-induced LTP (cLTP) in isolated hippocampal synaptosomes of mice, using fluorescence analysis of single-synapse long-term potentiation (FASS-LTP). We found that TNFα and IL-1β suppress synaptosomal cLTP. In contrast, cLTP was not affected by IL-18, at a concentration previously shown to block LTP in hippocampal slices. We also found that IL-18 does not impair cLTP or brain-derived neurotrophic factor (BDNF) signaling in primary hippocampal neuronal cultures. Thus, using both synaptosomes and neuron cultures, our data suggest that IL-18 impairs LTP by indirect mechanisms, which may depend on non-neuronal cells, such as glia. Notably, our results demonstrate that TNFα and IL-1β directly suppress hippocampal plasticity via neuron-specific mechanisms. A better understanding of the brain's cytokine networks and their final molecular effectors is crucial to identify specific targets for intervention.

Classification of Genes: Standardized Clinical Validity Assessment of Gene-Disease Associations Aids Diagnostic Exome Analysis and Reclassifications

Ascertaining a diagnosis through exome sequencing can provide potential benefits to patients, insurance companies, and the healthcare system. Yet, as diagnostic sequencing is increasingly employed, vast amounts of human genetic data are produced that need careful curation. We discuss methods for accurately assessing the clinical validity of gene-disease relationships to interpret new research findings in a clinical context and increase the diagnostic rate. The specifics of a gene-disease scoring system adapted for use in a clinical laboratory are described. In turn, clinical validity scoring of gene-disease relationships can inform exome reporting for the identification of new or the upgrade of previous, clinically relevant gene findings. Our retrospective analysis of all reclassification reports from the first 4 years of diagnostic exome sequencing showed that 78% were due to new gene-disease discoveries published in the literature. Among all exome positive/likely positive findings in characterized genes, 32% were in genetic etiologies that were discovered after 2010. Our data underscore the importance and benefits of active and up-to-date curation of a gene-disease database combined with critical clinical validity scoring and proactive reanalysis in the clinical genomics era.

Group A Streptococcus intranasal infection promotes CNS infiltration by streptococcal-specific Th17 cells

Group A streptococcal (GAS) infection induces the production of Abs that cross-react with host neuronal proteins, and these anti-GAS mimetic Abs are associated with autoimmune diseases of the CNS. However, the mechanisms that allow these Abs to cross the blood-brain barrier (BBB) and induce neuropathology remain unresolved. We have previously shown that GAS infection in mouse models induces a robust Th17 response in nasal-associated lymphoid tissue (NALT). Here, we identified GAS-specific Th17 cells in tonsils of humans naturally exposed to GAS, prompting us to explore whether GAS-specific CD4+ T cells home to mouse brains following i.n. infection. Intranasal challenge of repeatedly GAS-inoculated mice promoted migration of GAS-specific Th17 cells from NALT into the brain, BBB breakdown, serum IgG deposition, microglial activation, and loss of excitatory synaptic proteins under conditions in which no viable bacteria were detected in CNS tissue. CD4+ T cells were predominantly located in the olfactory bulb (OB) and in other brain regions that receive direct input from the OB. Together, these findings provide insight into the immunopathology of neuropsychiatric complications that are associated with GAS infections and suggest that crosstalk between the CNS and cellular immunity may be a general mechanism by which infectious agents exacerbate symptoms associated with other CNS autoimmune disorders.

A Comprehensive Analysis of Replicative Lifespan in 4,698 Single-Gene Deletion Strains Uncovers Conserved Mechanisms of Aging

Many genes that affect replicative lifespan (RLS) in the budding yeast Saccharomyces cerevisiae also affect aging in other organisms such as C. elegans and M. musculus. We performed a systematic analysis of yeast RLS in a set of 4,698 viable single-gene deletion strains. Multiple functional gene clusters were identified, and full genome-to-genome comparison demonstrated a significant conservation in longevity pathways between yeast and C. elegans. Among the mechanisms of aging identified, deletion of tRNA exporter LOS1 robustly extended lifespan. Dietary restriction (DR) and inhibition of mechanistic Target of Rapamycin (mTOR) exclude Los1 from the nucleus in a Rad53-dependent manner. Moreover, lifespan extension from deletion of LOS1 is nonadditive with DR or mTOR inhibition, and results in Gcn4 transcription factor activation. Thus, the DNA damage response and mTOR converge on Los1-mediated nuclear tRNA export to regulate Gcn4 activity and aging.

Sorbitol treatment extends lifespan and induces the osmotic stress response in Caenorhabditis elegans

The response to osmotic stress is a highly conserved process for adapting to changing environmental conditions. Prior studies have shown that hyperosmolarity by addition of sorbitol to the growth medium is sufficient to increase both chronological and replicative lifespan in the budding yeast, Saccharomyces cerevisiae. Here we report a similar phenomenon in the nematode Caenorhabditis elegans. Addition of sorbitol to the nematode growth medium induces an adaptive osmotic response and increases C. elegans lifespan by about 35%. Lifespan extension from 5% sorbitol behaves similarly to dietary restriction in a variety of genetic backgrounds, increasing lifespan additively with mutation of daf-2(e1370) and independently of daf-16(mu86), sir-2.1(ok434), aak-2(ok524), and hif-1(ia04). Dietary restriction by bacterial deprivation or mutation of eat-2(ad1113) fails to further extend lifespan in the presence of 5% sorbitol. Two mutants with constitutive activation of the osmotic response, osm-5(p813) and osm-7(n1515), were found to be long-lived, and lifespan extension from sorbitol required the glycerol biosynthetic enzymes GPDH-1 and GPDH-2. Taken together, these observations demonstrate that exposure to sorbitol at levels sufficient to induce an adaptive osmotic response extends lifespan in worms and define the osmotic stress response pathway as a longevity pathway conserved between yeast and nematodes.

TRF2 and lamin A/C interact to facilitate the functional organization of chromosome ends

Telomeres protect the ends of linear genomes, and the gradual loss of telomeres is associated with cellular ageing. Telomere protection involves the insertion of the 3' overhang facilitated by telomere repeat-binding factor 2 (TRF2) into telomeric DNA, forming t-loops. We present evidence suggesting that t-loops can also form at interstitial telomeric sequences in a TRF2-dependent manner, forming an interstitial t-loop (ITL). We demonstrate that TRF2 association with interstitial telomeric sequences is stabilized by co-localization with A-type lamins (lamin A/C). We also find that lamin A/C interacts with TRF2 and that reduction in levels of lamin A/C or mutations in LMNA that cause an autosomal dominant premature ageing disorder--Hutchinson Gilford Progeria Syndrome (HGPS)-lead to reduced ITL formation and telomere loss. We propose that cellular and organismal ageing are intertwined through the effects of the interaction between TRF2 and lamin A/C on chromosome structure.

Rapamycin and interleukin-1β impair brain-derived neurotrophic factor-dependent neuron survival by modulating autophagy

The mammalian target of rapamycin (mTOR) pathway has multiple important physiological functions, including regulation of protein synthesis, cell growth, autophagy, and synaptic plasticity. Activation of mTOR is necessary for the many beneficial effects of brain-derived neurotrophic factor (BDNF), including dendritic translation and memory formation in the hippocampus. At present, however, the role of mTOR in BDNF's support of survival is not clear. We report that mTOR activation is necessary for BDNF-dependent survival of primary rat hippocampal neurons, as either mTOR inhibition by rapamycin or genetic manipulation of the downstream molecule p70S6K specifically blocked BDNF rescue. Surprisingly, however, BDNF did not promote neuron survival by up-regulating mTOR-dependent protein synthesis or through mTOR-dependent suppression of caspase-3 activation. Instead, activated mTOR was responsible for BDNF's suppression of autophagic flux. shRNA against the autophagic machinery Atg7 or Atg5 prolonged the survival of neurons co-treated with BDNF and rapamycin, suggesting that suppression of mTOR in BDNF-treated cells resulted in excessive autophagy. Finally, acting as a physiological analog of rapamycin, IL-1β impaired BDNF signaling by way of inhibiting mTOR activation as follows: the cytokine induced caspase-independent neuronal death and accelerated autophagic flux in BDNF-treated cells. These findings reveal a novel mechanism of BDNF neuroprotection; BDNF not only prevents apoptosis through inhibiting caspase activation but also promotes neuron survival through modulation of autophagy. This protection mechanism is vulnerable under chronic inflammation, which deregulates autophagy through impairing mTOR signaling. These results may be relevant to age-related changes observed in neurodegenerative diseases.

A-type nuclear lamins act as transcriptional repressors when targeted to promoters

Regions of heterochromatin are often found at the periphery of the mammalian nucleus, juxtaposed to the nuclear lamina. Genes in these regions are likely maintained in a transcriptionally silent state, although other locations at the nuclear periphery associated with nuclear pores are sites of active transcription. As primary components of the nuclear lamina, A- and B-type nuclear lamins are intermediate filament proteins that interact with DNA, histones and known transcriptional repressors, leading to speculation that they may promote establishment of repressive domains. However, no direct evidence of a role for nuclear lamins in transcriptional repression has been reported. Here we find that human lamin A, when expressed in yeast and cultured human cells as a fusion protein to the Gal4 DNA-binding domain (DBD), can mediate robust transcriptional repression of promoters with Gal4 binding sites. Full repression by lamin A requires both the coiled-coil rod domain and the C-terminal tail domain. In human cells, other intermediate filament proteins such as lamin B and vimentin are unable to confer robust repression as Gal4-DBD fusions, indicating that this property is specific to A-type nuclear lamins. These findings indicate that A-type lamins can promote transcriptional repression when in proximity of a promoter.

Dietary restriction suppresses proteotoxicity and enhances longevity by an hsf-1-dependent mechanism in Caenorhabditis elegans

Dietary restriction increases lifespan and slows the onset of age-associated disease in organisms from yeast to mammals. In humans, several age-related diseases are associated with aberrant protein folding or aggregation, including neurodegenerative disorders such as Alzheimer's, Parkinson's, and Huntington's diseases. We report here that dietary restriction dramatically suppresses age-associated paralysis in three nematode models of proteotoxicity. Similar to its longevity-enhancing properties, dietary restriction protects against proteotoxicity by a mechanism distinct from reduced insulin/IGF-1-like signaling. Instead, the heat shock transcription factor, hsf-1, is required for enhanced thermotolerance, suppression of proteotoxicity, and lifespan extension by dietary restriction. These findings demonstrate that dietary restriction confers a general protective effect against proteotoxicity and promotes longevity by a mechanism involving hsf-1.

Genome-wide identification of conserved longevity genes in yeast and worms

Technological advancements in invertebrate model organisms have recently made it possible to survey many or all of the genes in the genome for phenotypes of interest. In both C. elegans and S. cerevisiae, genome-wide searches for hypomorphic mutations that extend life span have been performed. The results from these screens are starting to provide a more complete view of the range of life span determinants in eukaryotes. In addition, it is becoming possible to test the premise that conserved aging genes and pathways regulate aging in disparate eukaryotic species. Here we compare and contrast the results from genome-wide aging screens and assess the likelihood that there are "public" aging mechanisms.

Lifespan extension in Caenorhabditis elegans by complete removal of food

A partial reduction in food intake has been found to increase lifespan in many different organisms. We report here a new dietary restriction regimen in the nematode Caenorhabditis elegans, based on the standard agar plate lifespan assay, in which adult worms are maintained in the absence of a bacterial food source. These findings represent the first report in any organism of lifespan extension in response to prolonged starvation. Removal of bacterial food increases lifespan to a greater extent than partial reduction of food through a mechanism that is distinct from insulin/IGF-like signaling and the Sir2-family deacetylase, SIR-2.1. Removal of bacterial food also increases lifespan when initiated in postreproductive adults, suggesting that dietary restriction started during middle age can result in a substantial longevity benefit that is independent of reproduction.

The enigmatic role of Sir2 in aging

In this issue of Cell, Longo and colleagues (Fabrizio et al., 2005) examine the role of Sir2, a histone deacetylase, in chronological aging in yeast by measuring the long-term survival of nondividing cells. In contrast to measurements of aging for mitotic cells, cell survival in the nonmitotic state is decreased by Sir2 activity under conditions that mimic calorie restriction.

A-type nuclear lamins, progerias and other degenerative disorders

Nuclear lamins were identified as core nuclear matrix constituents over 20 years ago. They have been ascribed structural roles such as maintaining nuclear integrity and assisting in nuclear envelope formation after mitosis, and have also been linked to nuclear activities including DNA replication and transcription. Recently, A-type lamin mutations have been linked to a variety of rare human diseases including muscular dystrophy, lipodystrophy, cardiomyopathy, neuropathy and progeroid syndromes (collectively termed laminopathies). Most diseases arise from dominant, missense mutations, leading to speculation as to how different mutations in the same gene can give rise to such a diverse set of diseases, some of which share little phenotypic overlap. Understanding the cellular dysfunctions that lead to laminopathies will almost certainly provide insight into specific roles of A-type lamins in nuclear organization. Here, we compare and contrast the LMNA mutations leading to laminopathies with emphasis on progerias, and discuss possible functional roles for A-type lamins in the maintenance of healthy tissues.

More than blood, a novel gene required for mammalian postimplantation development

More than blood (Mtb) is a novel gene that is widely expressed in mouse embryos prior to gastrulation but is subsequently restricted to specific tissues, including the developing central nervous system and hematopoietic organs. Since MTB is highly expressed in the fetal liver and developing thymus, we predicted that MTB would be required for hematopoiesis and that embryos deficient in MTB would die of anemia. Surprisingly, embryos with a targeted disruption of Mtb died prior to the initiation of blood cell development, immediately following implantation. This lethality is due to a defect in expansion of the inner cell mass (ICM), as Mtb(-/-) blastocysts failed to exhibit outgrowth of the ICM, both in vitro and in vivo. Furthermore, Mtb(-/-) blastocysts exhibited a higher frequency of apoptotic cells than wild-type or heterozygous blastocysts. These findings demonstrate that Mtb is a novel gene that is essential for early embryonic development.

Cooperative and antagonistic interplay between PU.1 and GATA-2 in the specification of myeloid cell fates

PU.1 and GATA transcription factors appear to antagonize each other's function in the development of distinct lineages of the hematopoietic system. In contrast, we demonstrate that PU.1, like GATA-2, is essential for the generation of mast cells. PU.1-/- hematopoietic progenitors can be propagated in IL-3 and differentiate into mast cells or macrophages upon restoration of PU.1 activity. Using these progenitors and a conditionally activatable PU.1 protein, we show that PU.1 can negatively regulate expression of the GATA-2 gene. In the absence of GATA-2, PU.1 promotes macrophage but not mast cell differentiation. Reexpression of GATA-2 in such progenitors enables the generation of mast cells. We propose a developmental model in which cooperative function or antagonistic crossregulation by PU.1 of GATA-2 promotes distinct myeloid cell fates.

Interferon regulatory factor 4 (IRF4) interacts with NFATc2 to modulate interleukin 4 gene expression

Proteins of the nuclear factor of activated T cells (NFAT) family of transcription factors are critical for lymphocyte activation in the immune system. In particular, NFATs are important regulators of inducible IL-4 gene expression. Interferon regulatory factor 4 (IRF4) is an immune system-restricted interferon regulatory factor that is required for lymphocyte activation, but its molecular functions in the T lineage remain to be elucidated. We demonstrate that IRF4 potently synergizes with NFATc2 to specifically enhance NFATc2-driven transcriptional activation of the IL-4 promoter. This function is dependent on the physical interaction of IRF4 with NFATc2. IRF4 synergizes with NFATc2 and the IL-4-inducing transcription factor, c-maf, to augment IL-4 promoter activity as well as to elicit significant levels of endogenous IL-4 production. Furthermore, naïve T helper cells from mice lacking IRF4 are compromised severely for the production of IL-4 and other Th2 cytokines. The identification of IRF4 as a partner for NFATc2 in IL-4 gene regulation provides an important molecular function for IRF4 in T helper cell differentiation.

Cost of nonmelanoma skin cancer treatment in the United States

BACKGROUND

Despite being the most prevalent form of cancer, the economic impact of nonmelanoma skin cancer (NMSC) in the United States has not been assessed.

OBJECTIVE

To determine the overall cost and to estimate the cost per episode of NMSC care in the United States in physicians' offices, outpatient surgery centers, and inpatient settings.

METHODS

Data from the Medicare Current Beneficiary Study 1992-1995 were analyzed to obtain the total cost of NMSC and the cost in different settings. To normalize these data on a per episode basis, the cost in each setting was divided by the number of procedures performed in each setting obtained from the National Hospital Discharge Survey (NHDS, 1992-1997), the National Survey of Ambulatory Surgery (NSAS, 1994-1996), and the National Ambulatory Medical Care Survey (NAMCS, 1995).

RESULTS

The total cost of NMSC care in the United States in the Medicare population is $426 million/year. Physician office-based procedures for NMSC accounted for the greatest percentage of money spent to treat NMSC and the greatest percentage of procedures. The average cost per episode of NMSC when performed in a physician's office setting was found to be $492. The cost per episode of care in inpatient and outpatient settings were $5537 and $1043, respectively.

CONCLUSION

Compared to other cancers, the relative magnitude of NMSC treatment costs is currently small because NMSC is managed efficiently and effectively, primarily in office-based settings. Legislative or regulatory measures that discourage office treatment of NMSC will lead to increased cost.

Waiting times to see a dermatologist are perceived as too long by dermatologists: implications for the dermatology workforce

BACKGROUND

The issue of workforce requirements in dermatology has come to attention in recent years because it affects the delivery of dermatologic care in the United States.

OBJECTIVE

To determine the waiting times for appointments with dermatologists in order to assess the adequacy of the current level of dermatology workforce.

METHODS

Waiting times were determined for new and return patient appointments by telephone survey of a random sample of American Academy of Dermatology members. Physicians' perception of the adequacy of the number of dermatologists in their area was used as a criterion standard to validate waiting times as a measure of workforce adequacy. Benchmark waiting times of 3 weeks for a new patient appointment and 2 weeks for a return appointment were established.

RESULTS

Physicians' estimates of the waiting time for a new patient appointment and their perceptions of the adequacy of the number of practicing dermatologists in their area were closely correlated (r = -0.65; P<.001), validating the use of waiting times as a measure of workforce adequacy. More than 60% of the dermatologists surveyed exceeded the criterion cutoff waiting times, and more than 42% of the US population lives in areas underserved by dermatologists. Dermatologists practicing in areas of higher population density were more likely to have shorter waiting times for new patient appointments and were more likely to include cosmetic dermatology in their practices.

CONCLUSION

The long waiting times for appointments suggests that the current supply of dermatologists is not adequate to meet the demand for dermatologists' services.

Screening and early detection among racial and ethnic minority women

OBJECTIVES

To highlight sociocultural factors reported to influence and strategies to promote breast and cervical cancer screening and early detection behaviors of racial and ethnic minority women.

DATA SOURCES

Published articles, book chapters, and reports.

CONCLUSIONS

The most successful strategies for promoting screening and early detection among racial and ethnic minority women are collaborative and include approaches that are culturally sensitive and appropriate.

NURSING IMPLICATIONS

Intercultural and intracultural differences in racial and ethnic minority women challenge nurses to explore strategies that focus on the health care provider, the health care delivery system, and the individual woman within the context of the woman's culture.

Utilization of day stay general anaesthesia for the provision of dental treatment to children in New South Wales, Australia

OBJECTIVES

To assess the demand for paediatric dental general anaesthetic services at a specialist paediatric dental unit in Australia and to evaluate the changing pattern of general anaesthetic use in children at this unit over the past decade.

METHODS

A retrospective review of hospital records of a random sample of children receiving dental treatment under general anaesthesia during the years 1984 and 1996. Demographic and clinical data was collated and analysed using SPSS for Windows.

RESULTS

The number of children managed under general anaesthesia increased from 189 in 1984 to 777 in 1996. This was accompanied by an increase in the time the patients waited for treatment. There was little difference in the mean age of the patients with over two-thirds of the children being under the age of 6 years. Whilst children of Anglo-Saxon origin accounted for the majority of patients across the 13-year period there was a significant increase in the number of children from Asian or Middle Eastern backgrounds. A disproportionate number of these children accessed the services as self-referrals. Caries remained the most common reason for referral, with trauma and dental anomalies accounting for less than 10%.

CONCLUSIONS

Despite the general decline in dental caries there remain an important group of young children who have high treatment needs and for whom general anaesthesia provides a useful treatment option. Preventive strategies should be targeted towards these groups of children.

The needs and supportive networks of the dying: an assessment instrument and mapping procedure for hospice patients

If institutional systems that provide end-of-life care are to survive the demands of managed care, they will need to tie together methods of assessing the needs of the dying, leading to a new understanding of the functioning of a patient's existing helping networks. This paper presents the preliminary findings of a research project conducted at a Midwest hospice. The study utilized a cross sectional correlational survey of patients' needs via the Early Risk and Resiliency Inventory (ERRI), while mapping their helping networks with a Circles of Care Ecomap. It addressed the question, "What is the relationship between the needs of the dying and the formal and informal support provided?" Study findings supported the contention that higher need patients utilized the more expensive institutional services rather than relying on available natural networks; and statistical analysis of the study instrument suggested the creation of a new conceptual domain of psychospiritual need.

Sequential CD4-coreceptor interactions in human immunodeficiency virus type 1 Env function: soluble CD4 activates Env for coreceptor-dependent fusion and reveals blocking activities of antibodies against cryptic conserved epitopes on gp120

We devised an experimental system to examine sequential events by which the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) interacts with CD4 and coreceptor to induce membrane fusion. Recombinant soluble CD4 (sCD4) activated fusion between effector cells expressing Env and target cells expressing coreceptor (CCR5 or CXCR4) but lacking CD4. sCD4-activated fusion was dose dependent, occurred comparably with two- and four-domain proteins, and demonstrated Env-coreceptor specificities parallel to those reported in conventional fusion and infectivity systems. Fusion activation occurred upon sCD4 preincubation and washing of the Env-expressing effector cells but not the coreceptor-bearing target cells, thereby demonstrating that sCD4 exerts its effects by acting on Env. These findings provide direct functional evidence for a sequential two-step model of Env-receptor interactions, whereby gp120 binds first to CD4 and becomes activated for subsequent functional interaction with coreceptor, leading to membrane fusion. We used the sCD4-activated system to explore neutralization by the anti-gp120 human monoclonal antibodies 17b and 48d. These antibodies reportedly bind conserved CD4-induced epitopes involved in coreceptor interactions but neutralize HIV-1 infection only weakly. We found that 17b and 48d had minimal effects in the standard cell fusion system using target cells expressing both CD4 and coreceptor but potently blocked sCD4-activated fusion with target cells expressing coreceptor alone. Both antibodies strongly inhibited sCD4-activated fusion by Envs from genetically diverse HIV-1 isolates. Thus, the sCD4-activated system reveals conserved Env-blocking epitopes that are masked in native Env and hence not readily detected by conventional systems.

Screening to predict complicated grief in spouses of cancer patients

OBJECTIVES

Grief is the expected reaction to the death of a family member or close friend and is accompanied by substantial distress for almost everyone who experiences it. For some the grief response becomes complicated. This pilot study sought to identify individuals at high risk for complicated grief, by 1) examining the relationships that exist between family functioning before the death, psychological distress, and the grief reaction of a family after the death, and 2) presenting the use of screening with standardized measures to identify those at risk.

MATERIALS AND METHODS

This pilot study examined the relationships between family functioning, psychological distress, and grief reaction. A cross-sectional design was used and the instrument included the Family Adaptability and Cohesion Evaluation Scale (FACES III), the Brief Symptom Inventory (BSI), and the Texas Revised Inventory of Grief (TRIG). Significant relationships were identified between the level of family functioning, psychological distress and grief reaction. Depression, anxiety, and general distress were significantly correlated with the two subscales of the TRIG.

CONCLUSIONS

The findings clearly illustrate the merit of psychosocial screening of spouses and suggest the possible benefits of screening before the patient's death, using FACES III and the BSI to identify which spouses are at risk for complicated grief reactions.

Identification of CX3CR1. A chemotactic receptor for the human CX3C chemokine fractalkine and a fusion coreceptor for HIV-1

Fractalkine is a multimodular human leukocyte chemoattractant protein and a member of the chemokine superfamily. Unlike other human chemokines, the chemokine domain of fractalkine has three amino acids between two conserved cysteines, referred to as the CX3C motif. Both plasma membrane-associated and shed forms of fractalkine have been identified. Here, we show that the recombinant 76-amino acid chemokine domain of fractalkine is a potent and highly specific chemotactic agonist at a human orphan receptor previously named V28 or alternatively CMKBRL1 (chemokine beta receptor-like 1), which was shown previously to be expressed in neutrophils, monocytes, T lymphocytes, and several solid organs, including brain. CMKBRL1/V28 also functioned with CD4 as a coreceptor for the envelope protein from a primary isolate of HIV-1 in a cell-cell fusion assay, and fusion was potently and specifically inhibited by fractalkine. Thus CMKBRL1/V28 is a specific receptor for fractalkine, and we propose to rename it CX3CR1 (CX3C chemokine receptor 1), according to an accepted nomenclature system.

Church-based education: an outreach program for African Americans with hypertension

The goals of this education outreach demonstration study were to prepare a cadre of registered nurses (RN) as Church Health Educators (CHE), and to test the efficacy of a hypertension (HBP) education and support program in African American (AA) churches for persons with HBP in managing blood pressure (BP). In this two-phase study, RNs were prepared as CHEs in phase 1 and a convenience sample of 97 subjects with HBP was taught by the CHEs in phase 2. The intervention's content included the bases of HBP and HBP management strategies, and was taught in eight 1-hour sessions. Using a pre-test-post-test design, data on knowledge, social support and BP were collected at baseline (pre), post-intervention (post1) and 3 months post-intervention (post2). Major findings include: (1) there was a significant increase in knowledge scores from pre to post1 and post2 (P < or = 0.0001; F = 95.08; df = 1.79); (2) education, age and number of years with HBP explained 49% of the variance associated with HBP knowledge; (3) systolic BP (SBP) and mean arterial BP (MAP) significantly decreased from pre to post1 and post2 (SBP-p < or = 0.0001, F = 18.35, df = 1.91; MAP-p < or = 0.0001, F = 17.80, df = 1.86); (4) DBP significantly decreased from pre to post1 only (p < or = 0.008, F = 17.48, df = 1.91); and (5) relationships were found between social support and DBP, and social support and MAP. Issues that emerged from this study with implications for outreach programming include recruitment and retention, randomization, selective sampling, intervention design and use of volunteers.

The history of hypospadias

The dictum, "There is nothing new in surgery not previously described", is particularly true of hypospadias. The major significance of chordee was fully appreciated by Galen in the second century A. D. and then almost forgotten until Mettauer in 1842, all previous surgeons overstressing the position of the orifice. Mettauer recognised skin shortening as a cause of chordee, a fact not re-discovered until 1967. Urethroplasty from penile skin in situ was well described by Thiersch in 1869 and Duplay in 1874; additional covering skin flaps were developed in 1892 by Lauenstein. The modern enthusiasm for pedicle tubes from prepuce was first employed by Van Hook in 1896, Rochet in 1899, Hamilton Russell in 1900, and Mayo in 1901; the "buried skin" technique of Denis Browne was described by Duplay in 1880, although attributed by Browne to Hamilton Russell in 1915. Even scrotal tissues were incorporated in repairs in 1860 (Bouisson). Beck, in 1898, practised a repair for balanitic hypospadias very similar to the modern MAGPI repair, and free grafts, so popularised in the last 20 years, were performed by Nové-Josserand in 1897. We have certainly advanced from the era of the first millenium A. D., in which the treatment was amputation beyond the orifice, but almost all present-day techniques are well-founded in ideas developed by enterprising surgeons of the last century.

Laboratory Scale Thermal Plasma Arc Vitrification Studies of Heavy Metal-Laden Waste

Plasma processing has been identified as a useful tool for immobilizing heavy metal-contaminated wastes into safe, leach-resistant slag. Although much effort has gone into developing this technology on a pilot scale, not much information has been published on basic research topics. A laboratory-scale plasma arc furnace located at the University of Illinois was operated in cooperation with the U.S. Army Construction Engineering Research Laboratories in an effort to establish an understanding of the chemical and physical processes (such as metal volatilization and resultant gas evolution) that occur during thermal plasma treatment of metal-spiked samples. Experiments were conducted on nickel and chromium using a highly instrumented furnace equipped with a 75 kW transferred arc plasma torch. The volatility of nickel and chromium was examined as a function of varying oxygen partial pressures. Oxidizing conditions reduced the total dust gathered for both the nickel and chromium samples, although each dust sample was found to be metal-enriched. Plasma treating increased the leach-resistance of the slags by at least one order of magnitude when compared to unprocessed specimens. The leach- resistance of the nickel-containing slags increased in the presence of oxygen, whereas chromium samples remained relatively constant.

Characterization of intraembryonic freezing in Anopheles gambiae embryos

Intraembryonic freezing (IEF) in Anopheles mosquito embryos has been evaluated by differential scanning calorimetry with respect to embryo age, temperature, rate and duration of cooling, and absence or presence of extraembryonic ice. The initial temperatures for intraembryonic ice nucleation were -30.1 +/- 0.3, -28.4 +/- 0.4, and -29.1 +/- 0.2 degree C for embryos incubated for 15 h at 17 degrees C, 15 h at 26 degrees C, and 24 h at 26 degrees C, respectively, after oviposition. The first value is slightly but significantly lower than the latter two. These values were obtained on embryos in which the surface water was removed by brief drying; however, the values were nearly identical when external water and ice were present. Not only were the embryos of all three ages able to supercool at least transiently to -26 degrees C, but they could remain supercooled for up to 4 h at -20 degrees C after being cooled to -20 degrees C at 10 degrees C/min or (in the case of embryos incubated for 15 h at 26 degrees C) at 100 degrees C/min. The amount of freezable water in single embryos has been calculated from the differential scanning calorimetry measurements to be 3.45 +/- 0.08, and 3.53 +/- 0.06 microgram for embryos incubated for 15 h at 17 degrees C, 15 h at 26 degrees C, and 24 h at 26 degrees C, respectively. The differences are not significant. The corresponding values for the total water contents for embryos of the three ages were 4.04 +/- 0.20, 3.72 +/- 0.16, and 3.98 +/- 0.10 microgram, values that also did not differ significantly. Water thus makes up approximately 74% of the total weight of the embryo (approximately 5.3 micrograms) and about 91% of that water is freezable. Total water contents were determined gravimetrically after extensive air and vacuum drying. The kinetics of dehydration were determined during the air drying. They differed substantially among the three ages. The embryos incubated for 15 h at 17 degrees C lost water at about four times the rate of those incubated for 15 h at 26 degrees C and 10 times the rate of the embryos incubated for 24 h at 26 degrees C.

Addressing the psychospiritual distress of death as reality: a transpersonal approach

Many traditional Western psychologists fail to recognize spirituality and transcendental needs as intrinsic aspects of human nature and therefore may not be meeting the needs of terminally ill people or those in the process of confronting their own mortality. This article presents a model of transpersonal intervention appropriate for use by social work clinicians with anyone who is in the process of confronting his or her own mortality. It is based on the underlying assumptions that an individual has a level of transpersonal development with its related dimensions of spiritual awareness and personal death perspective and that the degree of interrelatedness of these two dimensions has a direct impact on the psychosocial distress he or she experiences when confronted with death.

Molecular Origins of Friction: The Force on Adsorbed Layers

Simulations and perturbation theory are used to study the molecular origins of friction in an ideal model system, a layer of adsorbed molecules sliding over a substrate. These calculations reproduce several surprising features of experimental results. In most cases, the frictional force on a solid monolayer has a different form from that observed between macroscopic solids. No threshold force or static friction is needed to initiate sliding; instead, the velocity is proportional to the force. As in experiments, incommensurate solid layers actually slide more readily than fluid layers. A comparison of experiment, simulation, and analytic results shows that dissipation arises from anharmonic coupling between phonon modes and substrate-induced deformations in the adsorbate.

Psoralen damage-induced plasmid recombination in Saccharomyces cerevisiae: dependence on RAD1 and RAD52

Photoreaction with psoralen, a DNA-crosslinking reagent, induces mitotic recombination in the yeast Saccharomyces cerevisiae. Psoralen damage-induced recombination was studied with non-replicating plasmids, which transform yeast cells by undergoing recombination events with chromosomal DNA. When plasmid DNA was photoreacted with psoralen in vitro and transformed into yeast cells, transformation was stimulated by psoralen modification in a dose-dependent manner. The stimulation by psoralen damage requires RAD52 gene function and is partially dependent on RAD1. Analysis of transformants indicates that plasmid integration occurs at the homologous chromosomal loci. Multiple tandem integrations are common in repair-proficient cells, with more than 20 copies of integrated plasmid seen in some transformants. Multiple integration depends on RAD1 function; only 9% of rad1 transformants, compared to 80% of RAD transformants, contained multiple plasmid copies, while 52% of the rad1 transformants were produced by gene conversion.

Red blood cell changes during the evolution of the sickle cell painful crisis

A longitudinal study of the red blood cell (RBC) deformability, percent of dense erythrocytes, and hematologic parameters has been conducted during 117 painful crises affecting 36 patients with sickle cell anemia between January, 1985 and December, 1990. RBC deformability was determined by osmotic gradient ektacytometry and the percentage of dense cells was quantitated by centrifugation on a discontinuous Stractan density gradient. The data indicate that the painful crisis is a process that follows a bimodal form of evolution. The first phase of the painful crisis is characterized by increase in the severity of pain, increase in the number of dense cells, and a decrease in RBC deformability. In some patients the changes in dense cells and RBC deformability are evident 1 to 3 days before the onset of pain. In addition, the hemoglobin level decreases and the reticulocyte count increases during this initial phase. The second phase of the crisis is characterized by reduction in pain intensity, decrease in the number of dense cells, and increase in RBC deformability to values higher than those seen in the steady state. Moreover, the improvement in RBC deformability and the decrease in the number of dense cells at the end of a crisis seem to constitute new risk factors that may incite a recurrence of the crisis within 1 month in about 50% of painful episodes. The pathophysiologic events responsible for this bimodal behavior of RBCs during painful episodes may represent the appearance of factors that induce (1) preferential trapping of deformable cells in the microcirculation during the first phase of the crisis, followed by a decrease of dense cells and the appearance of new deformable RBCs released from the bone marrow during the second phase of the crisis; or (2) variable sickling of all circulating RBCs during the first phase followed by disappearance of dense RBCs and their replenishment by deformable cells during the second phase.

Microleakage of glass ionomer/composite resin restorations: a laboratory study. 1. The influence of glass ionomer cement

Acid-etching of enamel margins, often combined with bevelling and use of a low viscosity resin, has resulted in improved sealing of composite restorations. When enamel is absent and margins involve dentine or cementum, microleakage is more often observed. The use of glass ionomer cement, as both a restorative material and as a base combined with a veneer of composite resin, has been advocated as a means of minimizing microleakage where margins are placed in dentine or cementum. Four restorative techniques incorporating glass ionomer cement were used, in vitro, to restore cervical cavities. After thermal cycling, dye penetration was scored along occlusal and gingival margins. In all instances the gingival margin exhibited a less reliable seal than the occlusal margin. The sandwich restorations produced a superior seal at both occlusal and gingival margins when compared with glass ionomer restorative cement.