Acute Adenoviral Infection Elicits an Arrhythmogenic Substrate Prior to Myocarditis

BACKGROUND

Viral cardiac infection represents a significant clinical challenge encompassing several etiological agents, disease stages, complex presentation, and a resulting lack of mechanistic understanding. Myocarditis is a major cause of sudden cardiac death in young adults, where current knowledge in the field is dominated by later disease phases and pathological immune responses. However, little is known regarding how infection can acutely induce an arrhythmogenic substrate before significant immune responses. Adenovirus is a leading cause of myocarditis, but due to species specificity, models of infection are lacking, and it is not understood how adenoviral infection may underlie sudden cardiac arrest. Mouse adenovirus type-3 was previously reported as cardiotropic, yet it has not been utilized to understand the mechanisms of cardiac infection and pathology.

METHODS

We have developed mouse adenovirus type-3 infection as a model to investigate acute cardiac infection and molecular alterations to the infected heart before an appreciable immune response or gross cardiomyopathy.

RESULTS

Optical mapping of infected hearts exposes decreases in conduction velocity concomitant with increased Cx43Ser368 phosphorylation, a residue known to regulate gap junction function. Hearts from animals harboring a phospho-null mutation at Cx43Ser368 are protected against mouse adenovirus type-3-induced conduction velocity slowing. Additional to gap junction alterations, patch clamping of mouse adenovirus type-3-infected adult mouse ventricular cardiomyocytes reveals prolonged action potential duration as a result of decreased IK1 and IKs current density. Turning to human systems, we find human adenovirus type-5 increases phosphorylation of Cx43Ser368 and disrupts synchrony in human induced pluripotent stem cell-derived cardiomyocytes, indicating common mechanisms with our mouse whole heart and adult cardiomyocyte data.

CONCLUSIONS

Together, these findings demonstrate that adenoviral infection creates an arrhythmogenic substrate through direct targeting of gap junction and ion channel function in the heart. Such alterations are known to precipitate arrhythmias and likely contribute to sudden cardiac death in acutely infected patients.

20 kDa isoform of connexin-43 augments spatial reorganization of the brain endothelial junctional complex and lesion leakage in cerebral cavernous malformation type-3

Cerebral cavernous malformation type-3 (CCM3) is a type of brain vascular malformation caused by mutations in programmed cell death protein-10 (PDCD10). It is characterized by early life occurrence of hemorrhagic stroke and profound blood-brain barrier defects. The pathogenic mechanisms responsible for microvascular hyperpermeability and lesion progression in CCM3 are still largely unknown. The current study examined brain endothelial barrier structural defects formed in the absence of CCM3 in vivo and in vitro that may lead to CCM3 lesion leakage. We found significant upregulation of a 20 kDa isoform of connexin 43 (GJA1-20 k) in brain endothelial cells (BEC) in both non-leaky and leaky lesions, as well as in an in vitro CCM3 knockdown model (CCM3KD-BEC). Morphological, biochemical, FRET, and FRAP analyses of CCM3KD-BEC found GJA1-20 k regulates full-length GJA1 biogenesis, prompting uncontrolled gap junction growth. Furthermore, by binding to a tight junction scaffolding protein, ZO-1, GJA1-20 k interferes with Cx43/ZO-1 interactions and gap junction/tight junction crosstalk, promoting ZO-1 dissociation from tight junction complexes and diminishing claudin-5/ZO-1 interaction. As a consequence, the tight junction complex is destabilized, allowing "replacement" of tight junctions with gap junctions leading to increased brain endothelial barrier permeability. Modifying cellular levels of GJA1-20 k rescued brain endothelial barrier integrity re-establishing the spatial organization of gap and tight junctional complexes. This study highlights generation of potential defects at the CCM3-affected brain endothelial barrier which may underlie prolonged vascular leakiness.

Epigenetics and stroke: role of DNA methylation and effect of aging on blood-brain barrier recovery

Incomplete recovery of blood-brain barrier (BBB) function contributes to stroke outcomes. How the BBB recovers after stroke remains largely unknown. Emerging evidence suggests that epigenetic factors play a significant role in regulating post-stroke BBB recovery. This study aimed to evaluate the epigenetic and transcriptional profile of cerebral microvessels after thromboembolic (TE) stroke to define potential causes of limited BBB recovery. RNA-sequencing and reduced representation bisulfite sequencing (RRBS) analyses were performed using microvessels isolated from young (6 months) and old (18 months) mice seven days poststroke compared to age-matched sham controls. DNA methylation profiling of poststroke brain microvessels revealed 11,287 differentially methylated regions (DMR) in old and 9818 DMR in young mice, corresponding to annotated genes. These DMR were enriched in genes encoding cell structural proteins (e.g., cell junction, and cell polarity, actin cytoskeleton, extracellular matrix), transporters and channels (e.g., potassium transmembrane transporter, organic anion and inorganic cation transporters, calcium ion transport), and proteins involved in endothelial cell processes (e.g., angiogenesis/vasculogenesis, cell signaling and transcription regulation). Integrated analysis of methylation and RNA sequencing identified changes in cell junctions (occludin), actin remodeling (ezrin) as well as signaling pathways like Rho GTPase (RhoA and Cdc42ep4). Aging as a hub of aberrant methylation affected BBB recovery processes by profound alterations (hypermethylation and repression) in structural protein expression (e.g., claudin-5) as well as activation of a set of genes involved in endothelial to mesenchymal transformation (e.g., Sox9, Snai1), repression of angiogenesis and epigenetic regulation. These findings revealed that DNA methylation plays an important role in regulating BBB repair after stroke, through regulating processes associated with BBB restoration and prevalently with processes enhancing BBB injury.

Cerebral Cavernous Malformation Pathogenesis: Investigating Lesion Formation and Progression with Animal Models

Cerebral cavernous malformation (CCM) is a cerebromicrovascular disease that affects up to 0.5% of the population. Vessel dilation, decreased endothelial cell-cell contact, and loss of junctional complexes lead to loss of brain endothelial barrier integrity and hemorrhagic lesion formation. Leakage of hemorrhagic lesions results in patient symptoms and complications, including seizures, epilepsy, focal headaches, and hemorrhagic stroke. CCMs are classified as sporadic (sCCM) or familial (fCCM), associated with loss-of-function mutations in KRIT1/CCM1, CCM2, and PDCD10/CCM3. Identifying the CCM proteins has thrust the field forward by (1) revealing cellular processes and signaling pathways underlying fCCM pathogenesis, and (2) facilitating the development of animal models to study CCM protein function. CCM animal models range from various murine models to zebrafish models, with each model providing unique insights into CCM lesion development and progression. Additionally, these animal models serve as preclinical models to study therapeutic options for CCM treatment. This review briefly summarizes CCM disease pathology and the molecular functions of the CCM proteins, followed by an in-depth discussion of animal models used to study CCM pathogenesis and developing therapeutics.

An In Vivo Mouse Model to Study Blood-Brain Barrier Destabilization in the Chronic Phase of Stroke

Cerebral ischemic injury evokes a complex cascade of pathophysiological events at the blood-vascular-parenchymal interface. These evolve over time and space and result in progressive neurological damage. Emerging evidence suggests that blood-brain barrier (BBB) recovery and reestablishment of BBB impermeability are incomplete and that these could influence stroke injury recovery, increase the risk of new stroke occurrence, and be a solid substrate for developing vascular dementia. Recent work from the author's laboratory has established the existence of incomplete BBB recovery in chronic stroke conditions that was induced by structural alterations to brain endothelial junctional complexes and persistent BBB leakage. The experimental methodology presented here is focused on modelling chronic stroke injury using an in vivo thromboembolic mouse stroke model and how to evaluate the kinetics and magnitude of BBB hyperpermeability in chronic stroke conditions using a combination of magnetic resonance imaging, tracer studies, and immunohistochemistry.

Maternal and paternal dietary quality, dietary inflammation status, and offspring DNA methylation

Background

Altered nutritional conditions at early life stages may increase the risk of future disease in offspring. Recent evidence suggests that developmental programming may involve epigenetic mechanisms. However, few studies have evaluated the effect of parental dietary quality on offspring DNA methylation. We investigated the relationships between dietary quality and inflammatory potential of future parents and DNA methylation of their children at nine years.

Methods

We used data from the Lifeways Cross-Generation cohort, established between 2001 and 2003 in the Republic of Ireland. Maternal dietary intake during the first trimester and paternal diet of the 12 previous months were assessed with a food-frequency questionnaire. Dietary quality and inflammation were determined by the healthy eating index (HEI) 2015 score and the energy-adjusted dietary inflammation index (E-DII), respectively. The Illumina Infinium HumanMethylationEPIC (EPIC array) assessed methylation levels in saliva samples from 264 children. Dietary associations with DNA methylation at individual CpG sites were examined.

Results

After adjusting for multiple tests, maternal HEI-2015 scores were inversely associated with DNA methylation at 1 CpG site (cg21840035, p-value=5.5 × 10-8) located near the PLEKHM1 gene, whose functions involve regulation of bone development. An increase in paternal HEI score was related to lower methylation at one CpG site (cg22431767, p-value=4.1× 10-8) located near cell signaling gene LUZP1. No significant associations between maternal or paternal E-DII and DNA methylation at individual CpG sites were observed.

Conclusions

Parental dietary quality in the prenatal period may influence offspring childhood DNA methylation. A better understanding of the nutritional programming effects on epigenetic markers is essential to design public health strategies that could help women to achieve a healthier diet and optimize the health capital of children and future generations.

Key messages

Our findings suggest that both maternal and paternal dietary quality may have a long-term influence on the offspring epigenome, expand the current understanding of parental nutritional programming. Replication in other populations with contrasted dietary intake is warranted, with a view to informing public health recommendations to benefit the health of future generations.

The Influence of Different Physical Activity Behaviours on the Gut Microbiota of Older Irish Adults

OBJECTIVE

A 24-hour day is made up of time spent in a range of physical activity (PA) behaviours, including sleep, sedentary time, standing, light-intensity PA (LIPA) and moderate-to-vigorous PA (MVPA), all of which may have the potential to alter an individual's health through various different pathways and mechanisms. This study aimed to explore the relationship between PA behaviours and the gut microbiome in older adults.

DESIGN

Cross-sectional study.

SETTINGS AND PARTICIPANTS

Participants (n=100; age 69.0 [3.0] years; 44% female) from the Mitchelstown Cohort Rescreen (MCR) Study (2015-2017).

METHODS

Participants provided measures of gut microbiome composition (profiled by sequencing 16S rRNA gene amplicons), and objective measures of PA behaviours (by a 7-day wear protocol using an activPAL3 Micro).

RESULTS

Standing time was positively correlated with the abundance of butyrate-producing and anti-inflammatory bacteria, including Ruminococcaceae, Lachnospiraceae and Bifidobacterium, MVPA was positively associated with the abundance of Lachnospiraceae bacteria, while sedentary time was associated with lower abundance of Ruminococcaceae and higher abundance of Streptococcus spp.

CONCLUSION

Physical activity behaviours appear to influence gut microbiota composition in older adults, with different PA behaviours having diverging effects on gut microbiota composition.

Modeling blood-brain barrier pathology in cerebrovascular disease in vitro: current and future paradigms

The complexity of the blood–brain barrier (BBB) and neurovascular unit (NVU) was and still is a challenge to bridge. A highly selective, restrictive and dynamic barrier, formed at the interface of blood and brain, the BBB is a “gatekeeper” and guardian of brain homeostasis and it also acts as a “sensor” of pathological events in blood and brain. The majority of brain and cerebrovascular pathologies are associated with BBB dysfunction, where changes at the BBB can lead to or support disease development. Thus, an ultimate goal of BBB research is to develop competent and highly translational models to understand mechanisms of BBB/NVU pathology and enable discovery and development of therapeutic strategies to improve vascular health and for the efficient delivery of drugs. This review article focuses on the progress being made to model BBB injury in cerebrovascular diseases in vitro.

Involvement of Epigenetic Mechanisms and Non-coding RNAs in Blood-Brain Barrier and Neurovascular Unit Injury and Recovery After Stroke

Cessation of blood flow leads to a complex cascade of pathophysiological events at the blood-vascular-parenchymal interface which evolves over time and space, and results in damage to neural cells and edema formation. Cerebral ischemic injury evokes a profound and deleterious upregulation in inflammation and triggers multiple cell death pathways, but it also induces a series of the events associated with regenerative responses, including vascular remodeling, angiogenesis, and neurogenesis. Emerging evidence suggests that epigenetic reprograming could play a pivotal role in ongoing post-stroke neurovascular unit (NVU) changes and recovery. This review summarizes current knowledge about post-stroke recovery processes at the NVU, as well as epigenetic mechanisms and modifiers (e.g., DNA methylation, histone modifying enzymes and microRNAs) associated with stroke injury, and NVU repair. It also discusses novel drug targets and therapeutic strategies for enhancing post-stroke recovery.

Clustering high-dimensional mixed data to uncover sub-phenotypes: joint analysis of phenotypic and genotypic data

The LIPGENE-SU.VI.MAX study, like many others, recorded high-dimensional continuous phenotypic data and categorical genotypic data. LIPGENE-SU.VI.MAX focuses on the need to account for both phenotypic and genetic factors when studying the metabolic syndrome (MetS), a complex disorder that can lead to higher risk of type 2 diabetes and cardiovascular disease. Interest lies in clustering the LIPGENE-SU.VI.MAX participants into homogeneous groups or sub-phenotypes, by jointly considering their phenotypic and genotypic data, and in determining which variables are discriminatory. A novel latent variable model that elegantly accommodates high dimensional, mixed data is developed to cluster LIPGENE-SU.VI.MAX participants using a Bayesian finite mixture model. A computationally efficient variable selection algorithm is incorporated, estimation is via a Gibbs sampling algorithm and an approximate BIC-MCMC criterion is developed to select the optimal model. Two clusters or sub-phenotypes ('healthy' and 'at risk') are uncovered. A small subset of variables is deemed discriminatory, which notably includes phenotypic and genotypic variables, highlighting the need to jointly consider both factors. Further, 7 years after the LIPGENE-SU.VI.MAX data were collected, participants underwent further analysis to diagnose presence or absence of the MetS. The two uncovered sub-phenotypes strongly correspond to the 7-year follow-up disease classification, highlighting the role of phenotypic and genotypic factors in the MetS and emphasising the potential utility of the clustering approach in early screening. Additionally, the ability of the proposed approach to define the uncertainty in sub-phenotype membership at the participant level is synonymous with the concepts of precision medicine and nutrition. Copyright © 2017 John Wiley & Sons, Ltd.

A gene variation (rs12691) in the CCAT/enhancer binding protein α modulates glucose metabolism in metabolic syndrome

BACKGROUND AND AIMS

CCAAT/enhancer-binding protein alpha (CEBPA) is a transcription factor involved in adipogenesis and energy homeostasis. Caloric restriction reduces CEBPA protein expression in patients with metabolic syndrome (MetS). A previous report linked rs12691 SNP in CEBPA to altered concentration of fasting triglycerides. Our objective was to assess the effects of rs12691 in glucose metabolism in Metabolic Syndrome (MetS) patients.

METHODS AND RESULTS

Glucose metabolism was assessed by static (glucose, insulin, adiponectin, leptin and resistin plasma concentrations) and dynamic (disposition index, insulin sensitivity index, HOMA-IR and acute insulin response to glucose) indices, performed at baseline and after 12 weeks of 4 dietary interventions (high saturated fatty acid (SFA), high monounsaturated fatty acid (MUFA), low-fat and low-fat-high-n3 polyunsaturated fatty acid (PUFA)) in 486 subjects with MetS. Carriers of the minor A allele of rs12691 had altered disposition index (p = 0.0003), lower acute insulin response (p = 0.005) and a lower insulin sensitivity index (p = 0.025) indicating a lower insulin sensitivity and a lower insulin secretion, at baseline and at the end of the diets. Furthermore, A allele carriers displayed lower HDL concentration.

CONCLUSION

The presence of the A allele of rs12691 influences glucose metabolism of MetS patients.

The organization of the brainstem nuclei associated with the vagus nerve in the Agouti (Dasyprocta leporina). A neurohistological study

A total of six adult animals were used for the study. Following anaesthesia via intraperitoneal injection of a mixture of ketamin and bombazine in ratio 2:1, thoracotomy was performed to exteriorize the heart for intracardial perfusion. The perfusion canular was inserted into the left ventricle and animal perfused sequentially with normal saline and 10% formal saline. Following perfusion, craniotomy was performed to remove the entire brain along with the upper segments of the spinal cord. The brain specimen was then dehydrated, cleared and infiltrated with paraffin wax. The specimen was then cut in 15 micron thick serial sections. The sections were then processed for neurohistological analyses using a Nikon microscope to which was attached Nikon camera. Analyses of the sections revealed bilateral representation of the dorsal motor nucleus of the vagus nerve in the medulla oblongata. The nucleus ambiguus, nucleus of the tractus solitarius, hypoglossal nucleus and the area postrema were also identified in the medulla oblongata. The implications of our findings are discussed in the text of the article.

Pleiotropic effects of TCF7L2 gene variants and its modulation in the metabolic syndrome: from the LIPGENE study

AIMS/HYPOTHESIS

Variants of the TCF7L2 gene predict the development of type 2 diabetes mellitus (T2DM). We investigated the associations between gene variants of TCF7L2 and clinical features of the metabolic syndrome (MetS) (an entity often preceding T2DM), and their interaction with non-genetic factors, including plasma saturated fatty acids (SFA) concentration and insulin resistance (IR).

METHODS

Fasting lipid profiles, insulin sensitivity, insulin secretion, anthropometrics, blood pressure and 10 gene variations of the TCF7L2 gene were determined in 450 subjects with MetS.

RESULTS

Several single nucleotide polymorphisms (SNP) showed phenotypic associations independent of SFA or IR. Carriers of the rare T allele of rs7903146, and of three other SNPs in linkage disequilibrium with rs7903146, had lower blood pressure and insulin secretion. High IR and the presence of the T-allele of rs7903146 acted synergistically to define those with reduced insulin secretion. Carriers of the minor allele of rs290481 exhibited an altered lipid profile, with increased plasma levels of apolipoprotein B, non-esterified fatty acids, cholesterol and apolipoprotein B in triglyceride rich lipoproteins, and LDL cholesterol. Carriers of the minor allele of rs11196224 that had higher plasma SFA levels showed elevated procoagulant/proinflammatory biomarkers, impaired insulin secretion and increased IR, whereas carriers of the minor allele of rs17685538 with high plasma SFA levels exhibited higher blood pressure.

CONCLUSIONS/INTERPRETATION

SNP in the TCF7L2 gene are associated with differences in insulin secretion, blood pressure, blood lipids and coagulation in MetS patients, and may be modulated by SFA in plasma or IR.

Differential activation of dendritic cells by Toll-like receptor agonists isolated from the Gram-positive vaccine vector Streptococcus gordonii

The oral commensal bacterium Streptococcus gordonii has been gathering interest as a candidate live mucosal vaccine delivery vector. S. gordonii has been shown to be capable of activating antigen presenting immune cells in a manner which leads to their activation and maturation, yet the mechanism used by S. gordonii to do so is poorly understood. The aim of this work was to investigate the immunostimulatory components of S. gordonii in inducing murine dendritic cell (DC) activation and maturation. Lipoteichoic acid (LTA), lipoprotein (LP), peptidoglycan (PGN), and DNA were isolated from S. gordonii, and used to stimulate murine DC. Cytokine production and DC surface marker upregulation in response to the bacterial components was quantified by enzyme-linked immunosorbent assay and flow cytometry respectively. The results were contrasted against data obtained from DC derived from MyD88, TRIF [TIR(Toll/Interleukin-1 Receptor)-domain-containing adapter-inducing interferon-beta] or toll-like receptor-2 (TLR-2) knockout mice. The four S. gordonii bacterial components were found to differentially induce cytokine production and surface marker upregulation by murine DC. Activation of DC by both whole S. gordonii cells and the four bacterial components was abrogated in the absence of MyD88, but not in the absence of TRIF. LTA, LP and PGN, but not DNA and whole S. gordonii, required TLR-2 to induce a DC response. The results collectively indicate that S. gordonii activates DC predominantly through a MyD88-dependent and TRIF-independent pathway. This activation can be attributed to multiple immunostimulatory components present within S. gordonii bacterial cells.

The role of religion in predicting adolescent alcohol use and problem drinking

OBJECTIVE

There are racial differences in adolescents' propensity to consume alcohol--with white adolescents tending to consume more alcohol than black adolescents--but there is no clear explanation for why such differences exist. The purpose of this study was to examine the relationship between religiosity, a cultural factor that is not well understood currently, and racial differences in adolescent alcohol use.

METHOD

Participants were white and black ninth-grade adolescents (N = 899; 54% female, 57.5% white) involved in a 3-year longitudinal study of ways to reduce alcohol use and sexual risk-taking behavior among adolescents in Ohio and Kentucky.

RESULTS

Findings indicate that religiosity is differentially associated with alcohol use and problem drinking for white and black adolescents. Religious service attendance was the most significant predictor of alcohol use for black adolescents, whereas religious fundamentalism was most important for white adolescents. In contrast, frequency of prayer was the significant predictor of problem drinking for black adolescents, whereas the level of importance placed on religion was the significant predictor for white adolescents. Important gender differences also emerged in both prediction models and are discussed.

CONCLUSIONS

Since there is great heterogeneity among adolescents (in terms of race and gender) in their alcohol use and misuse, the "one-size-fits-all" approach to alcohol treatment and prevention is likely inappropriate. Moreover, conceptualizations of alcohol use and misuse, and its prevention and treatment, should include the consideration of such key cultural factors as religiosity.

Do people aggress to improve their mood? Catharsis beliefs, affect regulation opportunity, and aggressive responding

Do people aggress to make themselves feel better? We adapted a procedure used by G. K. Manucia, D. J. Baumann, and R. B. Cialdini (1984), in which some participants are given a bogus mood-freezing pill that makes affect regulation efforts ineffective. In Study 1, people who had been induced to believe in the value of catharsis and venting anger responded more aggressively than did control participants to insulting criticism, but this aggression was eliminated by the mood-freezing pill. Study 2 showed similar results among people with high anger-out (i.e., expressing and venting anger) tendencies. Studies 3 and 4 provided questionnaire data consistent with these interpretations, and Study 5 replicated the findings of Studies 1 and 2 using measures more directly concerned with affect regulation. Taken together, these results suggest that many people may engage in aggression to regulate (improve) their own affective states.

Dermatology teleconsultations to Central Prison: experience at East Carolina University

OBJECTIVE

To review our experience with dermatology teleconsultations between East Carolina University School of Medicine in Greenville and Central Prison in Raleigh, NC.

MATERIALS AND METHODS

Consultation forms kept on file in the Department of Internal Medicine served as the source of data. One physician reviewed the forms from the initial 22 months of our dermatology teleconsultation service to Central Prison. Patient demographics and the diagnoses made by the consulting physician were recorded. Recommendations were tabulated as either diagnostic or therapeutic. Diagnoses and recommendations for known HIV-positive individuals were separately recorded.

RESULTS

One hundred thirty-eight dermatology teleconsultations were performed over the 22-month period. Seventy two per cent of the patients seen were African-American. The average age was 32 years. One hundred fifty-nine diagnoses were made. The most common problems were eczema and acneiform eruptions. Fifty-nine diagnostic and 252 therapeutic recommendations were made.

CONCLUSION

Consultants generally were confident of their diagnoses and management decisions. Dermatologists can assist primary care physicians through telemedicine consultation.

Reliability of telemedicine in evaluating skin tumors

OBJECTIVES

To determine the reliability of videoconferencing technology in evaluating skin tumors, the impact of the technology on the clinicians' degree of suspicion that a skin tumor is malignant, and the recommendation to do a biopsy.

MATERIALS AND METHODS

Four skin cancer screenings were conducted at rural health care facilities in eastern North Carolina that were connected to East Carolina University School of Medicine. A dermatologist saw the patients in person at the local facility, and the same patient was seen by a dermatologist via a T-1 connection to Greenville, North Carolina.

RESULTS

The two physicians were in absolute agreement on 59% of the 107 skin tumors evaluated. There were five lesions identified by the on-site dermatologist as a probable or definite malignancy. The degree of concern about a lesion being malignant and the decision whether to do a biopsy were not significantly different, as shown by kappa analysis.

CONCLUSION

The concern about the malignancy of a particular skin lesion and the recommendation whether to do a biopsy were not significantly affected by telemedicine technology.

Reliability of dermatology teleconsultations with the use of teleconferencing technology

BACKGROUND

Recent advances in telecommunications technology allow physicians to consult on patients at a distance via an interactive video format. Few data exist as to the reliability of this form of consultation.

OBJECTIVE

Our purpose was to measure the degree of concordance between a dermatologist seeing a patient in a clinic and another dermatologist seeing the same patient over a commercially available videoconferencing system.

METHODS

Patients referred to a general dermatology clinic were seen by both a "live" dermatologist and a "teledermatologist" via a T1 connection. Diagnosis and recommendations were recorded by both physicians and compared. The physicians were also asked to rate the degree of confidence they had in their diagnosis.

RESULTS

Seventy-nine diagnoses were made on 60 patients. The two physicians were in absolute agreement on 61 of the diagnoses (77.2%). Race or sex of the patient, nature of the skin problems, or which of the two physicians was the teledermatologist did not statistically correlate with the concordance of the two physicians.

CONCLUSION

There was a reasonable degree of agreement between the two examining physicians. Despite the relatively high degree of concordance the teledermatologist had a significantly lower degree of confidence in his diagnoses.

Teledermatology and underserved populations

BACKGROUND

The dermatologic needs of many communities in the United States and worldwide are underserved. Telemedicine enables physicians and non-physician primary care providers to use modern telecommunications devices to gain access to specialist consultations promptly and with much less travel. The independently developed telemedicine programs described herein support 3 traditionally underserved populations: Pacific Islanders, migrant farmworkers, and prison inmates.

OBSERVATIONS

In 3 independently designed telemedicine programs, dermatology emerged as the specialty most used by remote practitioners. Patients were presented for both diagnosis and treatment and in the setting of initial evaluation and as part of follow-up care.

CONCLUSION

Teledermatology is a useful way to provide dermatologic support to remote or underserved communities.

Psoriasis and pregnancy: hormone and immune system interaction

BACKGROUND

Various hormonal states are known to be associated with the waxing and waning of psoriasis. Patients with psoriasis commonly experience changes in their cutaneous disease during pregnancy or post partum.

OBJECTIVE

We evaluated 100 women with psoriasis by questionnaire and interview. The women had been seen at the Baylor Psoriasis Center, Dallas, and had experienced a pregnancy while having psoriasis. The answers were sorted and tabulated. In addition, we reviewed the literature to ascertain possible causes of clinical changes in psoriasis during pregnancy.

RESULTS

Ninety questionnaires were completed. Sixty-nine women (76.7%) described a change in their psoriasis during pregnancy with 57 (63.3%) noting improvement. Seventy-nine patients (87.7%) had a postpartum flare, most within 4 months of delivery.

CONCLUSIONS

The majority of women with psoriasis, who become pregnant, experience a change, usually an improvement, in their cutaneous disease. Pregnancy is associated with hormonal changes in estrogens and progesterone resulting in a state of altered immune surveillance.

Ultrafast thermally induced unfolding of RNase A

A temperature jump (T-jump) method capable of initiating thermally induced processes on the picosecond time scale in aqueous solutions is introduced. Protein solutions are heated by energy from a laser pulse that is absorbed by homogeneously dispersed molecules of the dye crystal violet. These act as transducers by releasing the energy as heat to cause a T-jump of up to 10 K with a time resolution of 70 ps. The method was applied to the unfolding of RNase A. At pH 5.7 and 59 degrees C, a T-jump of 3-6 K induced unfolding which was detected by picosecond transient infrared spectroscopy of the amide I region between 1600 and 1700 cm-1. The difference spectral profile at 3.5 ns closely resembled that found for the equilibrium (native-unfolded) states. The signal at 1633 cm-1, corresponding to the beta-sheet structure, achieved 15 +/- 2% of the decrease found at equilibrium, within 5.5 ns. However, no decrease in absorbance was detected until 1 ns after the T-ump. The disruption of beta-sheet therefore appears to be subject to a delay of approximately 1 ns. Prior to 1 ns after the T-jump, water might be accessing the intact hydrophobic regions.

Dynamics of parvalbumin studied by fluorescence emission and triplet absorption spectroscopy of tryptophan

Fluorescence emission and triplet-triplet absorbance spectroscopy of the single tryptophan in cod parvalbumin were used to study the stability and dynamics of the protein as influenced by Ca2+ binding and interaction with a chaotropic agent. The concentrations for half-saturation for Ca binding were 3.6 x 10(-9), 3.3 x 10(-4), 7.1 x 10(-3), and 0.14 M in the presence of 0, 2, 3, and 4 M guanidine hydrochloride, respectively. As predicted for thermodynamic reversibility, the guanidine hydrochloride unfolding reaction depends upon Ca2+, and the delta G are as follows: 22.9, 29.3, 35.2, and 44.2 kJ/mol for no added Ca2+, 1, 2, and 5 mM Ca2+, respectively. The stability toward denaturation imparted by the binding of two Ca2+ is about -60 kJ/mol. For Ca(2+)-bound parvalbumin in the presence of excess Ca2+, the decay of the triplet state tryptophan is approximately exponential, and the lifetime decreases from 6.5 to 3.8 ms as the temperature increases from 10 to 40 degrees C. In contrast, the triplet decay of the calcium-free protein is nonexponential over the time range of microseconds to milliseconds, a result that may indicate that the Ca-free protein is molten-globule-like. At Ca2+ concentrations where the protein is partially saturated with Ca2+, the lifetime of the longest decay component is less than that for the Ca-saturated protein; this finding suggests an exchange of Ca2+ and a conformational change during the triplet lifetime. From these data, a rate constant for the process that includes calcium-related protein conformational change can be surmised to range between 200 and 500 s-1.

How residents spend their time in clinic and the effects of clerical support

The authors conducted a time study of residents in clinic to determine the effects of providing clerical assistance. The residents recorded their activities at 5-minute intervals at baseline and six months after hiring three clerical assistants. Before and after introduction of the clerical assistants, approximately 40% of the time was devoted to direct interaction with patients. Statistically significant improvements were observed in the availability of medical records (89% vs 100%) and the time spent looking up test results (5% vs 3% of the clinic time). The residents felt the clerical assistants greatly improved their clinic experience and the quality of patient care.

Excited states of tryptophan in cod parvalbumin. Identification of a short-lived emitting triplet state at room temperature

The fluorescence and phosphorescence spectra of model indole compounds and of cod parvalbumin III, a protein containing a single tryptophan and no tyrosine, were examined in the time scale ranging from subnanoseconds to milliseconds at 25 degrees C in aqueous buffer. For both Ca- bound and Ca-free parvalbumin and for model indole compounds that contained a proton donor, a phosphorescent species emitting at 450 nm with a lifetime of approximately 20-40 ns could be identified. A longer-lived phosphorescence is also apparent; it has approximately the same absorption and emission spectrum as the short-lived triplet molecule. For Ca parvalbumin, the decay of the long-lived triplet tryptophan is roughly exponential with a lifetime of 4.7 ms at 25 degrees C whereas for N-acetyltryptophanamide in aqueous buffer the decay lifetime was 30 microseconds. In contrast, the lifetime of the long-lived tryptophan species is much shorter in the Ca-free protein compared with Ca parvalbumin, and the decay shows complex nonexponential kinetics over the entire time range from 100 ns to 1 ms. It is concluded that the photochemistry of tryptophan must take into account the existence of two excited triplet species and that there are quenching moieties within the protein matrix that decrease the phosphorescence yield in a dynamic manner for the Ca-depleted parvalbumin. In contrast, for Ca parvalbumin, the tryptophan site is rigid on the time scale of milliseconds.

The annual cost of psoriasis

BACKGROUND

The need for comparative cost figures for psoriasis therapy has become increasingly important.

OBJECTIVE

Our purpose was to compare the yearly costs of various psoriasis treatments.

METHODS

Ten patients were selected for each treatment modality and the average total cost per year, per patient was evaluated.

RESULTS

All treatments evaluated were cheaper than inpatient therapy, with Goeckerman treatment in the day-care setting the most expensive and hydroxyurea the cheapest. Cyclosporine, which was used for comparison, was at least twice as expensive as all the other treatments except for Goeckerman treatment in the day-care setting, compared with which it was about 70% more expensive.

CONCLUSION

No single treatment appears to be universally superior to others. In considering specific treatment for psoriasis, cost analyses, including appropriate laboratory and other specialized evaluations, must be taken into account. With use of these data, practitioners and health care organizations may be better able to select appropriate therapy.

Ecology of the rufous hare-wallaby, Lagorchestes hirsutus Gould (Marsupialia : Macropodidae) in the Tanami Desert, Northern Territory. III Interactions with introduced mammal species

This paper reports a study of the interactions between a remnant population of the rufous hare-wallaby, Lagorchestes hirsutus, and populations of several introduced mammal species in a region of the Tanami Desert. Transect counts of faecal pellets and tracks were used to determine the local distributions of all species and analysis of faeces from both predators and competitors of hare-wallabies was undertaken. Six species of introduced mammals were recorded within the study area: dingoes, rabbits, camels, foxes, feral cats and cattle. The local distributions for a number of these species were found to be significantly correlated with that of L. hirsutus during some seasons. Analysis of dingo scats collected from fire trails within the study area identified a total of 12 different food classes including harewallabies which occurred in 6.9% of the scats. Foxes and feral cats appear to be more important predators as demonstrated by their impacts on natural and reintroduced populations of hare-wallabies. Comparison of the diets of the rabbit and L. hirsutus identified significant overlap in utilised plant species, particularly during drier times. Competition between rabbits and L. hirsutus seems probable, given the overlap of their diets and their similar body sizes and metabolic requirements. Cattle and camels are potentially as important at densities above present levels. The complex web of interactions between L. hirsutus and these introduced species have important implications for management of remnant and reintroduced hare-wallaby populations.

Ecology of the rufous hare-wallaby, Lagorchestes hirsutus Gould (Marsupialia : Macropodidae) in the Tanami Desert, Northern Territory.II Diet and feeding strategy

The diet preferences and selectivity of the rufous hare-wallaby in the Tanami Desert were examined at a number of sites and over a number of seasons by microscopic analysis of faecal pellets and direct observations. Perennial grasses were the most consistent plant items in the diet. Grass seeds were seasonally important as were the seeds and bulbs of sedges. Species of dicots were also used but most represented only minor components in the diet. Several species of plant common to the area were noticeably absent from the diet. Differences in the diets between four sites of varying floristic composition and fire history were consistent with differences in vegetation cover at each site. Overall, the absolute proportions and ratios of monocots and dicots and of leaf and seed portions were strongly similar for all sites, as were seasonal changes in the proportions of the four main plant categories (monocots, dicots, seeds and fruits). These changes correlated with local rainfall. Comparisons of plants eaten and plants available indicate the hare-wallabies' preference for monocots, particularly seed and fruit components. In contrast consumption of dicots was influericed by the declining quality of other preferred plants. Insects were seasonally important in the diet and appear to be a potentially important nitrogen supplement during drier times. The feeding strategy of the rufous hare-wallaby is flexible and enables it to exploit fully food resources whose availability is often limited in both time and space. During droughts it seems likely that the species is food stressed and this could lead to localised declines.

Oral lesions in patients with psoriasis: a controlled study

Stomatitis areata migrans was found in 5.4 percent of patients with psoriasis compared to 1 percent of control patients, while benign migratory glossitis was identified in 10.3 percent of patients with psoriasis and 2.5 percent of control patients. The association of these disorders with psoriasis indicates that they may be manifestations of psoriasis of the oral mucosa.

Diets of Black-stripped wallabies in New South Wales

In both the wet and dry extremes of its remnant range in northern New South Wales, the black-striped wallaby, Macropus dorsalis, eats predominantly monocotyledonous plants, selecting leaves and, in some seasons, seedheads. The wallabies eat a wide range of monocot species, taking these from the habitat in which they shelter in the daytime as well as from that in which they forage at night. This study suggests that reserves for the conservation of the species need to include nocturnal foraging as well as diurnal sheltering habitats.

A new method for monitoring the kinetics of calcium binding to the sarcoplasmic reticulum Ca(2+)-ATPase employing the flash-photolysis of caged-calcium

The kinetics of Ca2+ binding to the high-affinity sites of the sarcoplasmic reticulum (SR) Ca2(+)-ATPase were directly investigated by continuously monitoring the extravesicular calcium concentration via the metallochromic indicator Arsenazo III following the release of Ca2+ from a photolabile caged-calcium molecule, 1-(2-nitro-4,5-dimethoxyphenyl)-N,N,N',N'-tetrakis [(oxycarbony)methyl]-1,2-ethanediamine (DM-nitrophen), utilizing a pulsed Nd:YAG laser for photolysis. The nature of the binding kinetics is at least biphasic over the first 400 ms for vesicular dispersions of SR. The stoichiometry for calcium binding expressed as Ca:E1 approximately P has been calculated to be approximately 1.4:1 for the pure SR preparation under the reaction conditions employed.

Reactions of excited triplet states of metal substituted myoglobin with dioxygen and quinone

The triplet state absorption and phosphorescence of Zn and Pd derivatives of myoglobin were compared. Both metal derivatives exhibit long triplet state lifetimes at room temperature, but whereas the Pd derivative showed exponential decay and an isosbestic point in the transient absorption spectra, the decay of the Zn derivative was nonsingle exponential and the transient absorption spectra showed evidence of more than one excited state species. No difference was seen in triplet quenching by oxygen for either derivative, indicating that differences in the polypeptide chain between the two derivatives are not large enough to affect oxygen penetrability. Quenching was also observed by anthraquinone sulfonate. In this case, the possibility of long-range transfer by an exchange mechanism is considered.

Breast reconstruction after classic radical mastectomy: use of omental pedicled grafts and fascia lata

The omental pedicle graft is a technic developed to replace tissues removed by classic radical mastectomies in preparation for constructing a new breast. The graft and the reconstruction may be done in one stage. The advantages of the technic are (1) the tissue is readily available, (2) it can be done in one or two stages, and (3) it provides improved esthetic results. During the past eight years, I have used this technic for breast reconstruction in 24 cases.

Efficient optical waveguide coupler

A new method for high-efficiency interconnection of two planar optical waveguides is described. This technique is based on mode-matched coupling and is particularly useful when the difference between the refractive indices of the individual guides is large. The method consists of etching a deep vertical step in the highindex waveguide followed by the deposition of low-index waveguide on the etched section so that the two guides remain connected end to end. A theoretical treatment for the design of the coupler and for determination of fabricational tolerences is given. Couplers were fabricted using high-index waveguides like GaAs and LiNbO(3) and low-index waveguides made up of glass or solution-deposited (polyurethane or photoresist) films on SiO(2) substrate. It is shown that by controlling the junction profile, efficiencies close to theoretical values can be obtained. Some applications of such a coupler are given.