Cutting Edge: Retinoic Acid Promotes Brain-homing of CD8+ T Cells during Congenital Cytomegalovirus Infection.

The most common congenital viral infection is CMV, which leads to numerous neurologic disabilities. Using a mouse model of congenital CMV, we previously determined that Ag-specific CD8+ T cells traffic to the brain in a CCR9-dependent manner. The mechanism by which these CD8+ T cells acquire a CCR9-dependent "brain-tropic" phenotype remains unclear. In this study, we identify the key factor that imprints brain homing specificity on CD8+ T cells, the source of production, and the location where CCR9 expression is induced. Specifically, we discovered that CCR9 is induced on CD8+ T cells by retinoic acid-producing CD8α+ dendritic cells in the cervical lymph node postinfection. We found that retinoic acid is important for CD8+ T cells to establish tissue residency in the brain. Collectively, our data expand the role of retinoic acid during infection and mechanistically demonstrate how CD8+ T cells are primed to protect the brain during congenital viral infection.

Influence of Oxygen-Containing Functional Groups on the Environmental Properties, Transformations, and Toxicity of Carbon Nanotubes.

Carbon nanotubes (CNTs) have unique physical and chemical properties that drive their use in a variety of commercial and industrial applications. CNTs are commonly oxidized prior to their use to enhance dispersion in polar solvents by deliberately grafting oxygen-containing functional groups onto CNT surfaces. In addition, CNT surface oxides can be unintentionally formed or modified after CNTs are released into the environment through exposure to reactive oxygen species and/or ultraviolet irradiation. Consequently, it is important to understand the impact of CNT surface oxidation on the environmental fate, transport, and toxicity of CNTs. In this review, we describe the specific role of oxygen-containing functional groups on the important environmental behaviors of CNTs in aqueous media (e.g., colloidal stability, adsorption, and photochemistry) as well as their biological impact. We place special emphasis on the value of systematically varying and quantifying surface oxides as a route to identifying quantitative structure-property relationships. The role of oxygen-containing functional groups in regulating the efficacy of CNT-enabled water treatment technologies and the influence of surface oxides on other carbon-based nanomaterials are also evaluated and discussed.

Biodegradation of Functionalized Nanocellulose.

Nanocellulose has attracted widespread interest for applications in materials science and biomedical engineering due to its natural abundance, desirable physicochemical properties, and high intrinsic mineralizability (i.e., complete biodegradability). A common strategy to increase dispersibility in polymer matrices is to modify the hydroxyl groups on nanocellulose through covalent functionalization, but such modification strategies may affect the desirable biodegradation properties exhibited by pristine nanocellulose. In this study, cellulose nanofibrils (CNFs) functionalized with a range of esters, carboxylic acids, or ethers exhibited decreased rates and extents of mineralization by anaerobic and aerobic microbial communities compared to unmodified CNFs, with etherified CNFs exhibiting the highest level of recalcitrance. The decreased biodegradability of functionalized CNFs depended primarily on the degree of substitution at the surface of the material rather than within the bulk. This dependence on surface chemistry was attributed not only to the large surface area-to-volume ratio of nanocellulose but also to the prerequisite surface interaction by microorganisms necessary to achieve biodegradation. Results from this study highlight the need to quantify the type and coverage of surface substituents in order to anticipate their effects on the environmental persistence of functionalized nanocellulose.

Anomalous Diffusion Characterization by Fourier Transform-FRAP with Patterned Illumination.

Fourier transform fluorescence recovery after photobleaching (FT-FRAP) with patterned illumination is theorized and demonstrated for quantitatively evaluating normal and anomalous diffusion. Diffusion characterization is routinely performed to assess mobility in cell biology, pharmacology, and food science. Conventional FRAP is noninvasive, has low sample volume requirements, and can rapidly measure diffusion over distances of a few micrometers. However, conventional point-bleach measurements are complicated by signal-to-noise limitations, the need for precise knowledge of the photobleach beam profile, potential for bias due to sample heterogeneity, and poor compatibility with multiphoton excitation because of local heating. In FT-FRAP with patterned illumination, the time-dependent fluorescence recovery signal is concentrated to puncta in the spatial Fourier domain, with substantial improvements in signal-to-noise, mathematical simplicity, representative sampling, and multiphoton compatibility. A custom nonlinear optical beam-scanning microscope enabled patterned illumination for photobleaching through two-photon excitation. Measurements in the spatial Fourier domain removed dependence on the photobleach profile, suppressing bias from imprecise knowledge of the point spread function. For normal diffusion, the fluorescence recovery produced a simple single-exponential decay in the spatial Fourier domain, in excellent agreement with theoretical predictions. Simultaneous measurement of diffusion at multiple length scales was enabled through analysis of multiple spatial harmonics of the photobleaching pattern. Anomalous diffusion was characterized by FT-FRAP through a nonlinear fit to multiple spatial harmonics of the fluorescence recovery. Constraining the fit to describe diffusion over multiple length scales resulted in higher confidence in the recovered fitting parameters. Additionally, phase analysis in FT-FRAP was shown to inform on flow/sample translation.

Stochastic Differential Scanning Calorimetry by Nonlinear Optical Microscopy.

Stochastic phase transformations within individual crystalline particles were recorded by integration of second harmonic generation (SHG) imaging with differential scanning calorimetry (DSC). The SHG activity of a crystal is highly sensitive to the specific molecular packing arrangement within a noncentrosymmetric lattice, providing access to information otherwise unavailable by conventional imaging approaches. Consequently, lattice transformations associated with dehydration/desolvation events were readily observed by SHG imaging and directly correlated to the phase transformations detected by the DSC measurements. Following studies of a model system (urea), stochastic differential scanning calorimetry (SDSC) was performed on trehalose dihydrate, which has a more complex phase behavior. From these measurements, SDSC revealed a broad diversity of single-particle thermal trajectories and direct evidence of a "cold phase transformation" process not observable by the DSC measurements alone.

Spinal subarachnoid diverticula in dogs: A review.

Spinal subarachnoid diverticula are fluid dilations of the subarachnoid space that can cause a compressive myelopathy in dogs. These diverticula are usually associated with high motion areas in the cervical and caudal thoracic spine. The definitive etiopathogenesis has not been determined but likely involves congenital or acquired causes. Pugs, French bulldogs, and Rottweilers are overrepresented breeds. Clinical signs typically include ataxia, paresis, and upper motor neuron urinary and/or fecal incontinence; pain is a less common feature. Diagnosis is based on advanced imaging, with magnetic resonance imaging now being favored given the additional detail of the spinal cord parenchyma that can be obtained. Outcomes are better with surgical intervention than with medical therapies, though there is a lack of long-term data. No superior surgical technique has been identified, and questions remain on the significance of addressing leptomeningeal adhesions at the time of surgery. Clinical signs can recur, though not always due to recurrence of diverticulum formation, and pugs may be less likely to have a successful long-term outcome.

Diverticule subarachnoïdien spinal chez des chiens : une revue. Les diverticules subarachnoïdiens spinaux sont des dilatations liquides de l'espace subarachnoïdien qui peuvent causer une myélopathie compressive chez les chiens. Ces diverticules sont généralement associés à des régions à motion élevée de la colonne vertébrale cervicale et caudale. L'étiopathogénie définitive n'a pas été déterminée mais implique fort probablement des causes congénitales ou acquises. Les carlins, bulldogs français et rottweiler sont des races sur-représentées. Les signes cliniques inclus typiquement de l'ataxie, de la parésie et un neurone moteur supérieur d'incontinence urinaire et/ou fécale; la douleur est une caractéristique moins fréquente. Le diagnostic est basé sur des analyses avancées d'imagerie, avec l'imagerie par résonnance magnétique maintenant favorisée étant donné les détails additionnels du parenchyme de la colonne vertébrale qui peuvent être obtenus. Les résultats sont meilleurs avec l'intervention chirurgicale qu'avec les thérapies médicales, bien qu'il y ait un manque de données à long terme. Aucune technique chirurgicale supérieure n'a été identifiée, et des questions persistent sur l'importance de s'attarder aux adhésions leptoméningées au moment de la chirurgie. Les signes cliniques peuvent réapparaitre, quoique pas toujours à cause de la récurrence de la formation des diverticules, et les carlins pourraient être moins enclin à avoir une issue favorable à long terme.(Traduit par Dr Serge Messier).

Iterative Non-Negative Matrix Factorization Filter for Blind Deconvolution in Photon/Ion Counting.

A digital filter based on non-negative matrix factorization (NMF) enables blind deconvolution of temporal information from large data sets, simultaneously recovering both photon arrival times and the instrument impulse response function (IRF). In general, the measured digital signals produced by modern analytical instrumentation are convolved by the corresponding IRFs, which can complicate quantitative analyses. Common examples include photon counting (PC), chromatography, super resolution imaging, fluorescence imaging, and mass spectrometry. Scintillation counting, in particular, provides a signal-to-noise advantage in measurements of low intensity signals, but has a limited dynamic range due to pulse overlap. This limitation can complicate the interpretation of data by masking temporal and amplitude information on the underlying detected signal. Typical methods for deconvolution of the photon events require advanced knowledge of the IRF, which is not generally trivial to obtain. In this work, a sliding window approach was developed to perform NMF one pixel at a time on short segments of large (e.g., 25 million point) data sets. Using random initial guesses for the IRF, the NMF filter simultaneously recovered both the deconvolved photon arrival times and the IRF. Applying the NMF filter to the analysis of triboluminescence (TL) data traces of active pharmaceutical ingredients enabled discrimination between different hypothesized physical origins of the signal.

Kinetic Modeling of Accelerated Stability Testing Enabled by Second Harmonic Generation Microscopy.

The low limits of detection afforded by second harmonic generation (SHG) microscopy coupled with image analysis algorithms enabled quantitative modeling of the temperature-dependent crystallization of active pharmaceutical ingredients (APIs) within amorphous solid dispersions (ASDs). ASDs, in which an API is maintained in an amorphous state within a polymer matrix, are finding increasing use to address solubility limitations of small-molecule APIs. Extensive stability testing is typically performed for ASD characterization, the time frame for which is often dictated by the earliest detectable onset of crystal formation. Here a study of accelerated stability testing on ritonavir, a human immunodeficiency virus (HIV) protease inhibitor, has been conducted. Under the condition for accelerated stability testing at 50 °C/75%RH and 40 °C/75%RH, ritonavir crystallization kinetics from amorphous solid dispersions were monitored by SHG microscopy. SHG microscopy coupled by image analysis yielded limits of detection for ritonavir crystals as low as 10 ppm, which is about 2 orders of magnitude lower than other methods currently available for crystallinity detection in ASDs. The four decade dynamic range of SHG microscopy enabled quantitative modeling with an established (JMAK) kinetic model. From the SHG images, nucleation and crystal growth rates were independently determined.

Triboluminescence from Pharmaceutical Formulations.

Triboluminescence (TL) is shown to enable selective detection of trace crystallinity within nominally amorphous solid dispersions (ASDs). ASDs are increasingly used for the preparation of pharmaceutical formulations, the physical stability of which can be negatively impacted by trace crystallinity introduced during manufacturing or storage. In the present study, TL measurements of a model ASD consisting of griseofulvin in polyethylene glycol produced limits of detection of 140 ppm. Separate studies of the particle size dependence of sucrose crystals and the dependence on polymorphism in clopidogrel bisulfate particles are both consistent with a mechanism for TL closely linked to the piezoelectric response of the crystalline fraction. Whereas disordered polymeric materials cannot support piezoelectric activity, molecular crystals produced from homochiral molecules adopt crystal structures that are overwhelmingly symmetry-allowed for piezoelectricity. Consequently, TL may provide a broadly applicable and simple experimental route for sensitive detection of trace crystallinity within nominally amorphous materials.

Influence of Cholesterol on the Oxygen Permeability of Membranes: Insight from Atomistic Simulations.

Cholesterol is widely known to alter the physical properties and permeability of membranes. Several prior works have implicated cell membrane cholesterol as a barrier to tissue oxygenation, yet a good deal remains to be explained with regard to the mechanism and magnitude of the effect. We use molecular dynamics simulations to provide atomic-resolution insight into the influence of cholesterol on oxygen diffusion across and within the membrane. Our simulations show strong overall agreement with published experimental data, reproducing the shapes of experimental oximetry curves with high accuracy. We calculate the upper-limit transmembrane oxygen permeability of a 1-palmitoyl,2-oleoylphosphatidylcholine phospholipid bilayer to be 52 ± 2 cm/s, close to the permeability of a water layer of the same thickness. With addition of cholesterol, the permeability decreases somewhat, reaching 40 ± 2 cm/s at the near-saturating level of 62.5 mol % cholesterol and 10 ± 2 cm/s in a 100% cholesterol mimic of the experimentally observed noncrystalline cholesterol bilayer domain. These reductions in permeability can only be biologically consequential in contexts where the diffusional path of oxygen is not water dominated. In our simulations, cholesterol reduces the overall solubility of oxygen within the membrane but enhances the oxygen transport parameter (solubility-diffusion product) near the membrane center. Given relatively low barriers to passing from membrane to membrane, our findings support hydrophobic channeling within membranes as a means of cellular and tissue-level oxygen transport. In such a membrane-dominated diffusional scheme, the influence of cholesterol on oxygen permeability is large enough to warrant further attention.

Incidence of fever in labor and risk of neonatal sepsis.

BACKGROUND: The current recommendation regarding the management of a term newborn delivered of a mother with an intrapartum fever or a diagnosis of clinical chorioamnionitis is that the neonate should have baseline laboratory work drawn along with blood cultures and be universally treated with antibiotics until culture results return. These guidelines report that the rate of intrapartum fever is about 3%; however, a few large studies suggest that the rate is higher at about 7%. OBJECTIVE: We sought to prospectively evaluate the rate of fever during labor in a large number of deliveries and determine the rate of early-onset neonatal sepsis in newborns delivered from mothers with an intrapartum fever compared with newborns delivered from mothers without intrapartum fever. STUDY DESIGN: This was a prospective cohort study of all temperatures obtained in women in labor from Jan. 1, 2011, through June 30, 2014. Every patient with a fever of ≥38°C at ≥36 weeks' gestation was evaluated for gestational age, parity, spontaneous or induced labor, group B streptococcus status, regional anesthesia, mode of delivery, treatment with intrapartum antibiotics, and whether a clinical diagnosis of chorioamnionitis was made by the managing physician. Neonates were assessed for blood culture results, neonatal intensive care unit admission, length of stay, and any major newborn complications. Statistical analysis involved χ2, Fisher exact, and Student t test. RESULTS: A total of 412 patients (6.8%; 95% confidence interval, 6.2-7.5%) developed a fever in 6057 deliveries at ≥36 weeks' gestation. No cases of maternal sepsis occurred. Of the 417 newborns (5 sets of twins), only 1 (0.24%; 95% confidence interval, 0.01-1.3%) developed early-onset neonatal sepsis with a positive blood culture for Escherichia coli. There were 4 cases (0.07%; 95% confidence interval, 0.02-0.18%) of early-onset neonatal sepsis in the 5697 newborns (52 sets of twins) delivered from mothers who were not febrile and this difference was not significant (P = .3). The positive blood cultures in these 4 neonates were 3 group B streptococcus and 1 Enterococcus. The overall rate of early-onset neonatal sepsis in this population of newborns delivered at ≥36 weeks' gestation was 0.82/1000 deliveries. CONCLUSION: The incidence of an intrapartum fever of ≥38°C in pregnancies at ≥36 weeks' gestation is common at 6.8% and this is consistent with the findings of a few other large retrospective studies. The rate of an intrapartum fever occurs in approximately 1 in 15 women in labor. The risk of neonatal sepsis in newborns delivered of mothers with intrapartum fever or a diagnosis of clinical chorioamnionitis is low at 0.24%, a rate that is <1 in 400. The recommendation for universal laboratory work, cultures, and antibiotic treatment pending culture results for this newborn population needs further examination.

Strengthening the role of Community Health Representatives in the Navajo Nation.

BACKGROUND: Strengthening Community Health Worker systems has been recognized to improve access to chronic disease prevention and management efforts in low-resource communities. The Community Outreach and Patient Empowerment (COPE) Program is a Native non-profit organization with formal partnerships with both the Navajo Nation Community Health Representative (CHR) Program and the clinical facilities serving the Navajo Nation. COPE works to better integrate CHRs into the local health care system through training, strengthening care coordination, and a standardized culturally appropriate suite of health promotion materials for CHRs to deliver to high-risk individuals in their homes. METHODS: The objective of this mixed methods, cross sectional evaluation of a longitudinal cohort study was to explore how the COPE Program has effected CHR teams over the past 6 years. COPE staff surveyed CHRs in concurrent years (2014 and 2015) about their perceptions of and experience working with COPE, including potential effects COPE may have had on communication among patients, CHRs, and hospital-based providers. COPE staff also conducted focus groups with all eight Navajo Nation CHR teams. RESULTS: CHRs and other stakeholders who viewed our results agree that COPE has improved clinic-community linkages, primarily through strengthened collaborations between Public Health Nurses and CHRs, and access to the Electronic Health Records. CHRs perceived that COPE's programmatic support has strengthened their validity and reputation with providers and clients, and has enhanced their ability to positively effect health outcomes among their clients. CHRs report an improved ability to deliver health coaching to their clients. Survey results show that 80. 2% of CHRs feel strongly positive that COPE trainings are useful, while 44.6% of CHRs felt that communication and teamwork had improved because of COPE. CONCLUSIONS: These findings suggest that CHRs have experienced positive benefits from COPE through training. COPE may provide a useful programmatic model on how best to support other Community Health Workers through strengthening clinic-community linkages, standardizing competencies and training support, and structuring home-based interventions for high-risk individuals.

Cultural elements underlying the community health representative - client relationship on Navajo Nation.

BACKGROUND: Navajo Nation Community Health Representatives (CHR) are trained community health workers (CHWs) who provide crucial services for patients and families. The success of the CHRs' interventions depends on the interactions between the CHRs and their clients. This research investigates the culturally specific factors that build and sustain the CHR-client interaction. METHODS: In-depth interviews were conducted with 16 CHRs on Navajo Nation. Interviews were transcribed and coded according to relevant themes. Code summaries were organized into a narrative using grounded theory techniques. RESULTS: The analysis revealed four findings critical to the development of a CHR-client relationship. Trust is essential to this relationship and provides a basis for providing quality services to the client. The ability to build and maintain trust is defined by tradition and culture. CHRs must be respectful of the diverse traditional and social practices. Lastly, the passing of clients brings together the CHR, the client's family, and the community. CONCLUSION: Understanding the cultural elements of the CHR-client relationship will inform the work of community partners, clinical providers, and other indigenous communities working to strengthen CHR programs and obtain positive health outcomes among marginalized communities.

Magnification of Cholesterol-Induced Membrane Resistance on the Tissue Level: Implications for Hypoxia.

High cellular membrane cholesterol is known to generate membrane resistance and reduce oxygen (O2) permeability. As such, cholesterol may contribute to the Warburg effect in tumor cells by stimulating intracellular hypoxia that cannot be detected from extracellular oxygen measurements. We probe the tissue-level impact of the phenomenon, asking whether layering of cells can magnify the influence of cholesterol, to modulate hypoxia in relation to capillary proximity. Using molecular dynamics simulations, we affirm that minimally hydrated, adjacent lipid bilayers have independent physical behavior. Combining this insight with published experimental data, we predict linearly increasing impact of membrane cholesterol on oxygen flux across cells layered in tissue.

Anal condyloma treatment and recurrence in HIV-negative men who have sex with men.

BACKGROUND: Men who have sex with men have increased prevalence of both human papillomavirus and anogenital condyloma. OBJECTIVE: Risk factors for multiple treatment and recurrence of anal condyloma were examined. DESIGN: This is a retrospective study of HIV-negative men who have sex with men who were treated for anal condyloma. SETTINGS: This study was conducted in a private surgical practice. PATIENTS: The patients were HIV-negative men who have sex with men, aged 18 years or older. INTERVENTION(S): Ablation with electrocautery or CO2 laser was performed, as well as excision and topical imiquimod condyloma treatment adjuvant. MAIN OUTCOME MEASURES: Primary clearance, defined as 4 months of condyloma-free survival posttreatment, and recurrence, defined as any anal condyloma diagnosis after primary clearance. RESULTS: Of 231 participants, 207 achieved primary clearance (median age, 32.0 years) and were followed (median, 18.2 months) after primary treatment. Most had intra-anal and perianal condyloma (56%), were treated with electrocautery ablation (79.2%), and required 1 treatment (range, 1-6) for clearance. There were 57 recurrences (median, 12 months). One-third each had minimal, moderate, or extensive disease. Forty-six percent of patients received imiquimod posttreatment adjuvant. High-grade dysplasia was found in 31% at presentation and 43% during follow-up. Factors associated with requiring multiple treatments for clearance were participants having moderate disease (adjusted odds ratio, 6.0 (1.7-21.4)) and receiving imiquimod adjuvant (adjusted odds ratio, 4.7 (2.0-10.6)). No single factor predicted recurrence, but those with moderate disease experienced recurrences significantly sooner (median, 25 months of follow-up). LIMITATIONS: This was a retrospective chart review, it was limited to a single practice, and it excluded those who did not achieve primary clearance. CONCLUSIONS: Most men who have sex with men have intra-anal and perianal condyloma and concomitant high-grade dysplasia is common. Most achieved clearance with 1 treatment. Having both intra-anal and perianal condyloma, increased severity of disease, and imiquimod adjuvant were significant predictors of requiring multiple treatments for clearance. No identified risk factors proved a significant predictor of recurrence.

Intermediate lobe immunoreactivity in a patient with suspected lymphocytic hypophysitis.

Lymphocytic hypophysitis is an organ-specific autoimmune disease characterised by destruction of pituitary hormone-secreting cells due to attack by self-reactive T lymphocytes. The spectrum of pituitary autoantibodies characterised by indirect immunofluorescence (IF) in these patients has not been substantially defined. The purpose of this study was to determine the spectrum of pituitary autoantibodies in 16 lymphocytic hypophysitis patients. Pituitary sections were prepared from guinea pigs and sera from 16 lymphocytic hypophysitis patients (13 biopsy proven and 3 suspected cases) and 13 healthy controls were evaluated for immunoreactivity to the pituitary tissue by immunofluorescence. A single patient was found to have high titre pituitary autoantibodies against guinea pig pituitary tissue. Immunoreactivity was directed against cells of the intermediate lobe. We present the case report of the patient who is a 24 year old woman that presented with headaches, polyuria and polydipsia. A uniformly enlarged pituitary mass was visible on MRI and a diagnosis of suspected lymphocytic hypophysitis was made. Based on our IF study, we postulate this patient has an autoimmune process directed towards the major cell type in the intermediate lobe, the melanotroph. Pre-adsorption with peptides representing adrenocorticotropic hormone, α-melanocyte stimulating hormone or ß-endorphin did not affect the IF signal suggesting our patient's pituitary autoantibodies may target some other product of Proopiomelanocortin (POMC) processing, such as corticotrophin-like intermediate peptide or γ-lipoprotein. Alternatively, the autoantibodies may target a peptide completely unrelated to POMC processing.

A sensory subpopulation depends on vesicular glutamate transporter 2 for mechanical pain, and together with substance P, inflammatory pain.

Ablating or functionally compromising sets of sensory neurons has provided important insights into peripheral modality-specific wiring in the somatosensory system. Inflammatory hyperalgesia, cold pain, and noxious mechanosensation have all been shown to depend upon Na(v)1.8-positive sensory neurons. The release of fast-acting neurotransmitters, such as glutamate, and more slowly released neuropeptides, such as substance P (SP), contribute to the diversified responses to external stimuli. Here we show that deleting Vglut2 in Na(v)1.8(Cre)-positive neurons compromised mechanical pain and NGF-induced thermal hyperalgesia, whereas tactile-evoked sensation, thermal, formalin-evoked, and chronic neuropathic pain were normal. However, when Vglut2(f/f);Na(v)1.8(Cre) mice were injected with a SP antagonist before the formalin test, the second phase pain response was nearly completely abolished, whereas in control mice, the pain response was unaffected. Our results suggest that VGLUT2-dependent signaling originating from Na(v)1.8-positive neurons is a principal sensing mechanism for mechanical pain and, together with SP, inflammatory pain. These data define sets of primary afferents associated with specific modalities and provide useful genetic tools with which to analyze the pathways that are activated by functionally distinct neuronal populations and transmitters.