The adenosine metabolite inosine is a functional agonist of the adenosine A2A receptor with a unique signaling bias.

Inosine is an endogenous purine nucleoside that is produced by catabolism of adenosine. Adenosine has a short half-life (approximately 10s) and is rapidly deaminated to inosine, a stable metabolite with a half-life of approximately 15h. Resembling adenosine, inosine acting through adenosine receptors (ARs) exerts a wide range of anti-inflammatory and immunomodulatory effects in vivo. The immunomodulatory effects of inosine in vivo, at least in part, are mediated via the adenosine A2A receptor (A2AR), an observation that cannot be explained fully by in vitro pharmacological characterization of inosine at the A2AR. It is unclear whether the in vivo effects of inosine are due to inosine or a metabolite of inosine engaging the A2AR. Here, utilizing a combination of label-free, cell-based, and membrane-based functional assays in conjunction with an equilibrium agonist-binding assay we provide evidence for inosine engagement at the A2AR and subsequent activation of downstream signaling events. Inosine-mediated A2AR activation leads to cAMP production with an EC50 of 300.7µM and to extracellular signal-regulated kinase-1 and -2 (ERK1/2) phosphorylation with an EC50 of 89.38µM. Our data demonstrate that inosine produces ERK1/2-biased signaling whereas adenosine produces cAMP-biased signaling at the A2AR, highlighting pharmacological differences between these two agonists. Given the in vivo stability of inosine, our data suggest an additional, previously unrecognized, mechanism that utilizes inosine to functionally amplify and prolong A2AR activation in vivo.

Topographical heading disorientation: a case study.

We report the case of a patient with selective topographic orientation deficits in both familiar and novel environments after bilateral medial occipital infarctions. Extensive neuropsychological assessment revealed intact functioning in all other cognitive domains. The findings are interpreted in terms of a dissociation between the retrosplenial posterior cingulate and the superior parietal lobule in the right hemisphere.

Predictors of neuropsychological test performance after pediatric traumatic brain injury.

The influence of neurological and demographic variables on neuropsychological test performance was examined in 100 9-to 16-year-old children with traumatic brain injury (TBI). Regression analyses were conducted to determine the relative contributions of coma, neuroimaging findings, ethnicity, socioeconomic status, and gender to variance in performance on the Wechsler Intelligence Scale for Children-Third Edition (WISC-III), California Verbal Learning Test--Children's Version (CVLT-C), and the Children's Category Test. Both neurological and demographic variables contributed to performance on various WISC-III factor index scores as well as the CVLT-C. No evidence for a moderating effect of demographic variables was found, but speed of information processing mediated the effect of neurological and demographic variables on CLVT-C performance. It is concluded that demographic variables have an incremental effect on the neuropsychological test performance of children with TBI above and beyond the influence of injury severity.

Lung inflation with direct injection of agarose: a technique for simultaneous molecular and morphometric measurements.

The usual methods for preparing lungs for morphologic study involve the instillation of fixatives that modifyproteins and RNA such that the tissue is unsuitable for molecular studies. To develop a technique suitable for molecular studies, pieces of adult rat lungs were infiltrated with agarose, glutaraldehyde, or paraformaldehyde and the consistency of alveolar inflation was compared to lungs inflated with 10% formalin. Only direct injection with 1% agarose resulted in comparable inflation of lung tissue and preserved RNA and protein. Thus, this technique enables simultaneous molecular and morphometric analysis of the lung on small pieces of lung tissue in heterogeneous lung diseases.

By binding SIRPalpha or calreticulin/CD91, lung collectins act as dual function surveillance molecules to suppress or enhance inflammation.

Surfactant proteins A and D (SP-A and SP-D) are lung collectins composed of two regions, a globular head domain that binds PAMPs and a collagenous tail domain that initiates phagocytosis. We provide evidence that SP-A and SP-D act in a dual manner, to enhance or suppress inflammatory mediator production depending on binding orientation. SP-A and SP-D bind SIRPalpha through their globular heads to initiate a signaling pathway that blocks proinflammatory mediator production. In contrast, their collagenous tails stimulate proinflammatory mediator production through binding to calreticulin/CD91. Together a model is implied in which SP-A and SP-D help maintain a non/anti-inflammatory lung environment by stimulating SIRPalpha on resident cells through their globular heads. However, interaction of these heads with PAMPs on foreign organisms or damaged cells and presentation of the collagenous tails in an aggregated state to calreticulin/CD91, stimulates phagocytosis and proinflammatory responses.

Analysis of sequential aliquots of hypertonic saline solution-induced sputum from clinically stable patients with cystic fibrosis.

STUDY OBJECTIVES: Sputum induction (SI) is a noninvasive tool for sampling inflamed airways. The purpose of this study was to determine the optimal duration of collection in patients with cystic fibrosis (CF). The hypothesis was that the duration of SI collection would quantitatively and qualitatively alter the content of the induced sputum. METHODS: In 10 clinically stable patients with CF (mean +/- SD age, 28 +/- 7 years; mean FEV(1), 2.6 +/- 0.7 L), SI was performed with 3% hypertonic saline solution at five time points over 20 min. RESULTS: SI was well tolerated, with an average maximum fall in FEV(1) of 7 +/- 7%. The sample volumes, urea concentrations, interleukin-8 concentrations, total cell counts, and nonsquamous cell counts remained constant (p > 0.05). The percentage of neutrophils decreased from 89 +/- 5% to 86 +/- 4% (p = 0.03), and the percentage of alveolar macrophages increased 5 +/- 2% to 8 +/- 4% (p < 0.01). The mean quantitative microbiological counts of nonmucoid Pseudomonas aeruginosa and Staphylococcus aureus decreased over the 20-min time period each by half a log (p = 0.05 and p < 0.01, respectively). Surfactant protein-A concentration increased from 1.6 +/- 0.3 to 2.4 +/- 0.4 ng/mL (log(10); p < 0.001). CONCLUSIONS: We conclude that aliquots of induced sputum are similar in clinically stable patients with CF during 4-min intervals, although there is more alveolar sampling after 20 min. When induced-sputum samples are fractionated for research monitoring of inflammatory or microbiologic indexes, power calculations accounting for these variations over time are required.

Prognostic value of surfactant proteins A and D in patients with acute lung injury.

OBJECTIVE: The primary objective of this study was to test the hypothesis that in patients intubated for acute lung injury, lower concentrations of surfactant proteins A and D in the pulmonary edema fluid and higher concentrations in the plasma are associated with more severe lung injury and worse clinical outcomes. DESIGN: Observational study. SETTING: Intensive care unit patients in a tertiary university hospital and a university-affiliated city hospital. PATIENTS: Thirty-eight intubated, mechanically ventilated intensive care unit patients with acute lung injury or acute respiratory distress syndrome as defined by the North American European Consensus Conference. INTERVENTIONS: Undiluted pulmonary edema fluid and plasma samples were collected within 24 hrs of endotracheal intubation in all patients. MEASUREMENTS AND MAIN RESULTS: The concentrations of surfactant proteins A and D were measured in pulmonary edema fluid and in plasma. Plasma surfactant protein A, but not surfactant protein D, was higher in patients with fewer days of unassisted ventilation (p = .03) and in patients with an absence of intact alveolar fluid clearance (p =.03). In contrast, pulmonary edema fluid surfactant protein D, but not surfactant protein A, was lower in patients with worse oxygenation, as measured by the alveolar-arterial oxygen difference (p = .01) and was lower in the patients who died (2646 ng/mL) compared with those who survived (5503 ng/mL; p = .02). CONCLUSIONS: These results demonstrate that reduced pulmonary edema fluid surfactant protein D and elevated plasma surfactant protein A concentrations at the onset of acute lung injury may be associated with more severe disease and worse clinical outcome and may serve as valuable biochemical markers of prognosis.

Surfactant protein A differentially regulates peripheral and inflammatory neutrophil chemotaxis.

Surfactant protein A (SP-A), a pulmonary lectin, plays an important role in regulating innate immune cell function. Besides accelerating pathogen clearance by pulmonary phagocytes, SP-A also stimulates alveolar macrophage chemotaxis and directed actin polymerization. We hypothesized that SP-A would also stimulate neutrophil chemotaxis. With the use of a Boyden chamber assay, we found that SP-A (0.5-25 microg/ml) did not stimulate chemotaxis of rat peripheral neutrophils or inflammatory bronchoalveolar lavage (BAL) neutrophils isolated from LPS-treated lungs. However, SP-A affected neutrophil chemotaxis toward the bacterial peptide formyl-met-leu-phe (fMLP). Surprisingly, the effect was different for the two neutrophil populations: SP-A reduced peripheral neutrophil chemotaxis toward fMLP (49 +/- 5% fMLP alone) and enhanced inflammatory BAL neutrophil chemotaxis (277 +/- 48% fMLP alone). This differential effect was not seen for the homologous proteins mannose binding lectin and complement protein 1q but was recapitulated by type IV collagen. SP-A bound both neutrophil populations comparably and did not alter formyl peptide binding. These data support a role for SP-A in regulating neutrophil migration in pulmonary tissue.

The different faces of intimate violence: implications for assessment and treatment.

Current research about violence in intimate relationships suggests that at least two qualitatively distinct types of violence exist. This new knowledge challenges the dominant conceptualization of intimate violence as solely a manifestation of patriarchal male dominance. Following a review of the research and analysis of illustrative clinical examples, a conceptual framework is presented that assists couple therapists in answering three salient questions: What type of violence am I most likely to be working with? How can I assess the differences between types of violence? And how might I proceed with treatment for different types of violence?

Role of surfactant proteins A, D, and C1q in the clearance of apoptotic cells in vivo and in vitro: calreticulin and CD91 as a common collectin receptor complex.

Removal of cells dying by apoptosis is essential to normal development, maintenance of tissue homeostasis, and resolution of inflammation. Surfactant protein A (SP-A) and surfactant protein D (SP-D) are high abundance pulmonary collectins recently implicated in apoptotic cell clearance in vitro. Other collectins, such as mannose-binding lectin and the collectin-like C1q, have been shown to bind to apoptotic cells and drive ingestion through interaction with calreticulin and CD91 on the phagocyte in vitro. However, only C1q has been shown to enhance apoptotic cell uptake in vivo. We sought to determine the relative importance of SP-A, SP-D, and C1q in pulmonary clearance of apoptotic cells using knockout and overexpressing mice, and to determine the role of calreticulin and CD91 in this process. SP-A, SP-D, and C1q all enhanced apoptotic cell ingestion by resident murine and human alveolar macrophages in vitro. However, only SP-D altered apoptotic cell clearance from the naive murine lung, suggesting that SP-D plays a particularly important role in vivo. Similar to C1q and mannose-binding lectin, SP-A and SP-D bound to apoptotic cells in a localized, patchy pattern and drove apoptotic cell ingestion by phagocytes through a mechanism dependent on calreticulin and CD91. These results suggest that the entire collectin family of innate immune proteins (including C1q) works through a common receptor complex to enhance removal of apoptotic cells, and that collectins are integral, organ-specific components of the clearance machinery.

Latent structure of the Children's Category Test after pediatric traumatic head injury.

The performance of 100 9-16-year-old children with traumatic head injury (THI) on the Children's Category Test (CCT-2; Boll, 1993) was examined to determine the underlying factor structure. Exploratory principal factor analysis with oblique rotation identified a two-factor solution. Factor 1 was composed primarily of subtests IV, V, and VI, whereas Factor 2 was defined primarily by subtests III and VI. Age and Full Scale IQ, as measured by the Wechsler Intellectual Scale for Children-Third Edition (WISC-III; Wechsler, 1991), were significantly related to both factors. Factor 1, but not Factor 2, demonstrated clear sensitivity to severity of THI. It is concluded that interpretation of the CCT-2 with children who have sustained a THI should consider the multifactorial nature of the instrument, and that exclusive reliance on the summary total error score may impede diagnostic accuracy.