Transient disruption of functional connectivity and depression of neural fluctuations in a mouse model of acute septic encephalopathy.

Septic encephalopathy leads to major and costly burdens for a large percentage of admitted hospital patients. Elderly patients are at an increased risk, especially those with dementia. Current treatments are aimed at sedation to combat mental status changes and are not aimed at the underlying cause of encephalopathy. Indeed, the underlying pathology linking together peripheral infection and altered neural function has not been established, largely because good, acutely accessible readouts of encephalopathy in animal models do not exist. Behavioral testing in animals lasts multiple days, outlasting the time frame of acute encephalopathy. Here, we propose optical fluorescent imaging of neural functional connectivity (FC) as a readout of encephalopathy in a mouse model of acute sepsis. Imaging and basic behavioral assessment were performed at baseline, Hr8, Hr24, and Hr72 following injection of either lipopolysaccharide or phosphate buffered saline. Neural FC strength decreased at Hr8 and returned to baseline by Hr72 in motor, somatosensory, parietal, and visual cortical regions. Additionally, neural fluctuations transiently declined at Hr8 and returned to baseline by Hr72. Both FC strength and fluctuation tone correlated with neuroscore indicating this imaging methodology is a sensitive and acute readout of encephalopathy.

Integration of genetically modified virus-like-particles with an optical resonator for selective bio-detection.

A novel virus-like particle (TMV-VLP) receptor layer has been integrated with an optical microdisk resonator transducer for biosensing applications. This bioreceptor layer is functionalized with selective peptides that encode unique recognition affinities. Integration of bioreceptors with sensor platforms is very challenging due their very different compatibility regimes. The TMV-VLP nanoreceptor exhibits integration robustness, including the ability for self-assembly along with traditional top-down microfabrication processes. An optical microdisk resonator has been functionalized for antibody binding with this receptor, demonstrating resonant wavelength shifts of (Δλo) of 0.79 nm and 5.95 nm after primary antibody binding and enzyme-linked immunosorbent assay (ELISA), respectively, illustrating label-free sensing of this bonding event. This demonstration of label-free sensing with genetically engineered TMV-VLP shows the flexibility and utility of this receptor coating when considering integration with other existing transducer platforms.

Variants of uncertain significance in BRCA testing: evaluation of surgical decisions, risk perception, and cancer distress.

Studies suggest that patients carrying a BRCA variant of uncertain significance (VUS) may have lingering confusion concerning results interpretation. Counseling for uninformative BRCA-negative (UN) results is thought to be more straightforward, despite the fact that both results lead to similar methods of empiric cancer risk counseling. This study compared surgical choices and perceptions between 71 patients with VUS results and 714 patients with UN results. All patients underwent genetic counseling because of a personal or family history of breast or ovarian cancer between 1997 and 2010, and completed a 2-year follow-up survey. Risk-reducing mastectomy rates in both groups were 7% (p = 1.00) and risk-reducing oophorectomy rates were 5% and 3%, respectively (p = 0.42). The VUS group reported less cancer distress reduction than the UN group (23.0% vs 35.8%, respectively, p = 0.043). Over 90% of both groups found the counseling process helpful. Overall, the study suggests that VUS results disclosed in genetic counseling did not cause excessive surgery or exaggerated cancer distress, though patients with a VUS found counseling somewhat less informative or reassuring. Future research on communication of VUS results, including pre-and post-test counseling, is essential for full realization of the potential for genomic medicine.

Fluorescence lifetime imaging microscopy using near-infrared contrast agents.

Although single-photon fluorescence lifetime imaging microscopy (FLIM) is widely used to image molecular processes using a wide range of excitation wavelengths, the captured emission of this technique is confined to the visible spectrum. Here, we explore the feasibility of utilizing near-infrared (NIR) fluorescent molecular probes with emission >700 nm for FLIM of live cells. The confocal microscope is equipped with a 785 nm laser diode, a red-enhanced photomultiplier tube, and a time-correlated single photon counting card. We demonstrate that our system reports the lifetime distributions of NIR fluorescent dyes, cypate and DTTCI, in cells. In cells labelled separately or jointly with these dyes, NIR FLIM successfully distinguishes their lifetimes, providing a method to sort different cell populations. In addition, lifetime distributions of cells co-incubated with these dyes allow estimate of the dyes' relative concentrations in complex cellular microenvironments. With the heightened interest in fluorescence lifetime-based small animal imaging using NIR fluorophores, this technique further serves as a bridge between in vitro spectroscopic characterization of new fluorophore lifetimes and in vivo tissue imaging.

Rumination, gender, and depressive symptoms associated with caregiving strain in bipolar disorder.

OBJECTIVE: To evaluate the associations between indices of caregiving strain, ruminative style, depressive symptoms, and gender among family members of patients with bipolar disorder. METHOD: One hundred and fifty primary caregivers of patients enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) participated in a cross-sectional study to evaluate the role of ruminative style in maintaining depressive symptoms associated with caregiving strain. Patient lifetime diagnosis and current episode status were evaluated by the Affective Disorder Evaluation and the Clinical Monitoring Form. Caregivers were evaluated within 30 days of the patient on measures of family strain, depressive symptoms, and ruminative style. RESULTS: Men and women did not differ on depression, caregiver strain, or ruminative style scores. Scores suggest an overall mild level of depression and moderate caregiver strain for the sample. Greater caregiver strain was significantly associated (P<0.05) with rumination and level of depressive symptoms, controlling for patient clinical status and demographic variables. Rumination reduced the apparent association between strain and depression by nearly half. Gender was not significantly associated with depression or rumination. CONCLUSION: Rumination helps explain depressive symptoms experienced by both male and female caregivers of patients with bipolar disorder. Interventions for caregivers targeted at decreasing rumination should be considered.

Treatments for bipolar disorder: can number needed to treat/harm help inform clinical decisions?

OBJECTIVE: To compare bipolar treatment interventions, using number needed to treat (NNT) and number needed to harm (NNH). METHOD: Results of randomized controlled clinical trials were used to assess efficacy (NNT for response and relapse/recurrence prevention vs. placebo) and tolerability (e.g. NNH for weight gain and sedation vs. placebo). RESULTS: United States Food and Drug Administration-approved bipolar disorder pharmacotherapies all have single-digit NNTs (i.e. > 10% advantage over placebo), but NNHs for adverse effects that vary widely. Some highly efficacious agents are as likely to yield adverse effects as therapeutic benefit, but may be interventions of choice in more acute severe illness. In contrast, some less efficacious agents with better tolerability may be interventions of choice in more chronic mild-moderate illness. CONCLUSION: Clinical trials can help inform clinical decision making by quantifying the likelihood of benefit vs. harm. Integrating such data with individual patient circumstances, values, and preferences can help optimize treatment choices.

Biofabrication methods for the patterned assembly and synthesis of viral nanotemplates.

This paper reports on novel methodologies for the patterning and templated synthesis of virus-structured nanomaterials in two- and three-dimensional microfabricated architectures using the Tobacco mosaic virus (TMV). The TMV is a high aspect ratio biological molecule which can be engineered to include amino acids with enhanced binding properties. These modifications facilitate self-assembly of the TMV onto various substrates and enable its use as a template for the synthesis of nanostructured materials. This work focuses on the combination of this bottom-up biologically inspired fabrication method with standard top-down micromachining processes that allow direct integration of the virus-structured materials into batch-fabricated devices. Photolithographic patterning of uncoated as well as nickel-coated TMV nanostructures has been achieved using a lift-off process in both solvent and mild basic solutions and their assembly onto three-dimensional polymer and silicon microstructures is demonstrated. In addition to these patterning techniques, in situ formation of metal oxide TMV coatings in patterned microfabricated environments is shown using atomic layer deposition directly on the nickel-coated viruses. The biofabrication 'process toolbox' presented in this work offers a simple and versatile alternative for the hierarchical patterning and incorporation of biotemplated nanomaterials into micro/nanofabrication schemes.

Structure-function relationship between tobacco mosaic virus coat protein and hypersensitivity in Nicotiana sylvestris.

Alterations in the structure of the tobacco mosaic virus (TMV) coat protein affect the elicitation of the N' gene hypersensitive response (HR) in Nicotiana sylvestris. To investigate this structure-function relationship, amino acid substitutions with predicted structural effects were created throughout the known structure of the TMV coat protein. Substitutions that resulted in the elicitation of the HR resided within and would predictably interfere with interface regions located between adjacent subunits in ordered aggregates of coat protein. Substitutions that did not result in the elicitation of the HR were either conservative or located outside these interface regions. In vitro analysis of coat protein aggregates demonstrated HR-eliciting coat proteins to have reduced aggregate stability in comparison with non-HR-eliciting coat proteins and a correlation existed between the strength of the elicited HR and the ability of a substitution to interfere with ordered aggregate formation. This finding corresponded with the predicted structural effects of HR-eliciting substitutions. Radical substitutions that predictably disrupted coat protein tertiary structure were found to prevent HR elicitation. These findings demonstrate that structural alterations that affect the stability of coat protein quaternary structure but not tertiary structure lead to host cell recognition and HR elicitation. A model for HR elicitation is proposed, in which disassembly of coat protein aggregates exposes a host "receptor" binding site.

Structure of ribgrass mosaic virus at 2.9 A resolution: evolution and taxonomy of tobamoviruses.

Ribgrass mosaic virus (RMV) is a member of the tobamovirus group of plant viruses. The structure has been determined at 2.9 A resolution by fiber diffraction methods, and refined by molecular dynamics methods to an R-factor of 0.095. The carboxyl-carboxylate interactions that drive disassembly in tobamoviruses are present in RMV, but are very different from those in other tobamoviruses. RMV has some of the structural features of a subgroup I tobamovirus, a smaller number from subgroup II, and a number that appear to be unique to the RMV cluster of viruses. The structural studies confirm the evolutionary and taxonomic separation of the RMV cluster from both subgroup I and subgroup II tobamoviruses.

Biophysical characterization of a designed TMV coat protein mutant, R46G, that elicits a moderate hypersensitivity response in Nicotiana sylvestris.

The hypersensitivity resistance response directed by the N' gene in Nicotiana sylvestris is elicited by the tobacco mosaic virus (TMV) coat protein R46G, but not by the U1 wild-type TMV coat protein. In this study, the structural and hydrodynamic properties of R46G and wild-type coat proteins were compared for variations that may explain N' gene elicitation. Circular dichroism spectroscopy reveals no significant secondary or tertiary structural differences between the elicitor and nonelicitor coat proteins. Analytical ultracentrifugation studies, however, do show different concentration dependencies of the weight average sedimentation coefficients at 4 degrees C. Viral reconstitution kinetics at 20 degrees C were used to determine viral assembly rates and as an initial assay of the rate of 20S formation, the obligate species for viral reconstitution. These kinetic results reveal a decreased lag time for reconstitution performed with R46G that initially lack the 20S aggregate. However, experiments performed with 20S initially present reveal no detectable differences indicating that the mechanism of viral assembly is similar for the two coat protein species. Therefore, an increased rate of 20S formation from R46G subunits may explain the differences in the viral reconstitution lag times. The inferred increase in the rate of 20S formation is verified by direct measurement of the 20S boundary as a function of time at 20 degrees C using velocity sedimentation analysis. These results are consistent with the interpretation that there may be an altered size distribution and/or lifetime of the small coat protein aggregates in elicitors that allows N. sylvestris to recognize the invading virus.

Susceptibility and symptom development in Arabidopsis thaliana to Tobacco mosaic virus is influenced by virus cell-to-cell movement.

To identify host factors that regulate susceptibility to Tobacco mosaic virus (TMV), 14 Arabidopsis thaliana ecotypes were screened for their ability to support TMV systemic movement. The susceptibility phenotypes observed included one ecotype that permitted rapid TMV movement accompanied by symptoms, nine ecotypes that allowed a slower intermediate rate of systemic movement without symptoms, and four ecotypes that allowed little or no systemic TMV movement. Molecular comparisons between ecotypes representing the rapid (Shahdara), intermediate (Col-1), and slow (Tsu-1) movement phenotypes revealed a positive correlation between the ability of TMV to move cell to cell and its speed of systemic movement. Additionally, protoplasts prepared from all three ecotypes supported similar levels of TMV replication, indicating that viral replication did not account for differences in systemic movement. Furthermore, induction of the pathogenesis-related genes PR-1 and PR-5 occurred only in the highly susceptible ecotype Shahdara, demonstrating that reduced local and systemic movement in Col-1 and Tsu-1 was not due to the activation of known host defense responses. Genetic analysis of F2 progeny derived from crosses made between Shahdara and Tsu-1 or Col-1 and Tsu-1 showed the faster cell-to-cell movement phenotypes of Shahdara and Col-1 segregated as single dominant genes. In addition, the Shahdara symptom phenotype segregated independently as a single recessive gene. Taken together, these findings suggest that, within Arabidopsis ecotypes, at least two genes modulate susceptibility to TMV.

Comparisons of two breast cancer risk estimates in women with a family history of breast cancer.

There is an increasing need for accurate prediction methods of assessing individual risk for breast cancer for both clinical and research purposes. The purpose of this study is to compare the Gail and Claus model risk estimates of breast cancer among women with a family history of breast cancer. This study presents risk estimates from two models of breast cancer risk in 491 women 18 to 74 years of age with a family history of breast cancer who were recruited to risk counseling clinical trials in Seattle, Washington between 1996 and 1997. These trials included women from the general population and additional samples of Ashkenazi Jewish, African-American, and lesbian women. We estimated and compared lifetime (to age 79) and 5-year risk for developing breast cancer using the National Surgical Adjuvant Breast and Bowel Project adaptation of the Gail model and the Claus model. About one-quarter of participants fell into the Gail "high" risk category (> or =1.7% risk of developing breast cancer in the next 5 years). The average lifetime risk was estimated at 13.2% by the Gail model and 11.2% by the Claus model. Estimates from the two models were moderately and positively correlated (r = 0.55) with the Gail model yielding a higher estimate than the Claus model for most participants. If women with a family history of breast cancer are being counseled regarding decisions on genetic testing, tamoxifen use, or other preventive measures, presenting both Claus and Gail estimates may be the best option.

Fast axonal transport in amyotrophic lateral sclerosis: an intra-axonal organelle traffic analysis.

Fast transport of intra-axonal organelles was studied in motor nerve from amyotrophic lateral sclerosis (ALS) patients. Organelle traffic in ALS nerves demonstrated a significant increase in anterograde mean speed, while retrograde mean speed was decreased compared with that of controls. Retrograde traffic density (organelles per unit time) was also significantly decreased in the ALS specimens. Anterograde transport machinery is therefore intact and may be responding to the increased physiologic demand of larger motor units. Diminished retrograde speed and organelle traffic density are consistent with a defect in retrograde transport and could impair communication between axon terminals and perikarya.

Genetic counseling for women with an intermediate family history of breast cancer.

Women with a family history of breast cancer often over-estimate their personal risk for cancer and may view themselves as candidates for genetic testing even when the likelihood of an informative test result is low. We report here on genetic counseling of women with an intermediate family history of breast cancer, defined as women who have one or more biological relatives with breast cancer but whose pedigree suggests a low likelihood of autosomal dominant transmission. A genetic counseling protocol based on traditional genetic counseling strategies was developed with additional components added to address the needs of women with moderately increased breast cancer risk. These additional components included information about non-genetic risk factors, comparisons of high and moderate risk pedigrees, and evaluation of personal risk based on both genetic and nongenetic risk factors. Most participants liked the genetic counseling and found it useful. At baseline, participants over-estimated both their personal risk of breast cancer and that of the average woman. After counseling, estimates of personal and average risk of breast cancer were lower, although both remained higher than actual risk. Most participants reported that they felt less worried about breast cancer after receiving their personal-risk estimate. At baseline, most women judged themselves to be candidates for genetic testing and expressed interest in testing. The number who considered themselves candidates for testing was reduced after counseling (60% versus 82%) but still constituted a majority. Similarly, interest in testing was partially reduced by counseling (60% versus 91%). We conclude that genetic counseling can help women with an intermediate family history of breast cancer to develop more accurate views of their risk, reduce their breast cancer worry, and aid some of them in developing a more realistic view of genetic testing.

Three dimensional Monte Carlo code for photon migration through complex heterogeneous media including the adult human head.

We describe a novel Monte Carlo code for photon migration through 3D media with spatially varying optical properties. The code is validated against analytic solutions of the photon diffusion equation for semi-infinite homogeneous media. The code is also cross-validated for photon migration through a slab with an absorbing heterogeneity. A demonstration of the utility of the code is provided by showing time-resolved photon migration through a human head. This code, known as 'tMCimg', is available on the web and can serve as a resource for solving the forward problem for complex 3D structural data obtained by MRI or CT.

Algorithms for 3D localization and imaging using near-field diffraction tomography with diffuse light.

We introduce two filtering methods for near-field diffuse light diffraction tomography based on the angular spectrum representation. We then combine these filtering techniques with a new method to find the approximate depth of the image heterogeneities. Taken together these ideas improve the fidelity of our projection image reconstructions, provide an interesting three dimensional rendering of the reconstructed volume, and enable us to identify and classify image artifacts that need to be controlled better for tissue applications. The analysis is accomplished using data derived from numerical finite difference simulations with added noise.

Preventing transmission of blood-borne pathogens: a compelling argument for effective device-selection strategies.

Disease transmission from percutaneous injury occurs in 2% to 40% of health care workers (HCWs) after exposure to the hepatitis B virus (HBV), in 3% to 10% after exposure to the hepatitis C (HCV) virus, and in 0.2% to 0.5% after exposure to the HIV virus. According to a recently published case-control study from the Centers for Disease Control and Prevention, the following factors increase the risk of HIV seroconversion in HCWs after percutaneous exposure to HIV-infected blood: deep injury, visible blood on the device, procedures involving needle placement directly into a vein or artery, and terminal AIDS in the source patient. Postexposure use of zidovudine by HCWs appears to reduce the risk of HIV transmission by 79%. Institutions seeking to reduce the risk of HCW seroconversion should conduct analyses of specific tasks associated with these high-risk factors, and safety interventions should be installed when tasks and devices increase the risk of seroconversion. Although this type of outcome-based strategy may not significantly reduce the total number of needlestick injuries, reducing high-risk exposures minimizes disease transmission and maximizes the cost-effectiveness of the intervention.

Cognitive-behavioral stress management intervention decreases the prevalence of depression and enhances benefit finding among women under treatment for early-stage breast cancer.

The authors tested effects of a 10-week group cognitive-behavioral stress management intervention among 100 women newly treated for Stage 0-II breast cancer. The intervention reduced prevalence of moderate depression (which remained relatively stable in the control condition) but did not affect other measures of emotional distress. The intervention also increased participants' reports that having breast cancer had made positive contributions to their lives, and it increased generalized optimism. Both remained significantly elevated at a 3-month follow-up of the intervention. Further analysis revealed that the intervention had its greatest impact on these 2 variables among women who were lowest in optimism at baseline. Discussion centers on the importance of examining positive responses to traumatic events--growth, appreciation of life, shift in priorities, and positive affect-as well as negative responses.

Three-dimensional diffuse optical tomography in the parallel plane transmission geometry: evaluation of a hybrid frequency domain/continuous wave clinical system for breast imaging.

Three-dimensional diffuse optical tomography (DOT) of breast requires large data sets for even modest resolution (1 cm). We present a hybrid DOT system that combines a limited number of frequency domain (FD) measurements with a large set of continuous wave (cw) measurements. The FD measurements are used to quantitatively determine tissue averaged absorption and scattering coefficients. The larger cw data sets (10(5) measurements) collected with a lens coupled CCD, permit 3D DOT reconstructions of a 1-liter tissue volume. To address the computational complexity of large data sets and 3D volumes we employ finite difference based reconstructions computed in parallel. Tissue phantom measurements evaluate imaging performance. The tests include the following: point spread function measures of resolution, characterization of the size and contrast of single objects, field of view measurements and spectral characterization of constituent concentrations. We also report in vivo measurements. Average tissue optical properties of a healthy breast are used to deduce oxy- and deoxy-hemoglobin concentrations. Differential imaging with a tumor simulating target adhered to the surface of a healthy breast evaluates the influence of physiologic fluctuations on image noise. This tomography system provides robust, quantitative, full 3D image reconstructions with the advantages of high data throughput, single detector-tissue coupling path, and large (1L) imaging domains. In addition, we find that point spread function measurements provide a useful and comprehensive representation of system performance.

In vivo cerebrovascular measurement combining diffuse near-infrared absorption and correlation spectroscopies.

We combine two near-infrared diffuse optical techniques to study variations of blood flow, haemoglobin concentration, and blood oxygen saturation in the functioning rat brain. Diffuse correlation spectroscopy (or flowmetry) monitors changes in the cerebral blood flow, without the use of the principles of tracer clearance, by measuring the optical phase-shifts caused by moving blood cells. Near-infrared absorption spectroscopy concurrently measures tissue absorption at two wavelengths to determine haemoglobin concentration and blood oxygen saturation in this same tissue volume. This optical probe is non-invasive and was employed through the intact skull. The utility of the technique is demonstrated in vivo by measuring the temporal changes in the regional vascular dynamics of rat brain during hypercapnia. Temporal and spatial variations of cerebral blood flow, haemoglobin concentration and blood oxygen saturation during hypercapnia are compared with other measurements in the literature, and a quantitative analysis demonstrating the self-consistency of our combined observations of vascular response is presented.