Clarifying the role of belief-motive explanations in multi-stakeholder realist evaluation.

In realist evaluation, where researchers aim to make program theories explicit, they can encounter competing explanations as to how programs work. Managing explanatory tensions from different sources of evidence in multi-stakeholder projects can challenge external evaluators, especially when access to pertinent data, like client records, is mediated by program stakeholders. In this article, we consider two central questions: how can program stakeholder motives shape a realist evaluation project; and how might realist evaluators respond to stakeholders' belief-motive explanations, including those about program effectiveness, based on factors such as supererogatory commitment or trying together in good faith? Drawing on our realist evaluation of a service reform initiative involving multiple agencies, we describe stakeholder motives at key phases, highlighting a need for tactics and skills that help to manage explanatory tensions. In conclusion, the relevance of stakeholders' belief-motive explanations ('we believe the program works') in realist evaluation is clarified and discussed.

Multipolar effects on the dipolar polarizability of magneto-electric antennas.

We show the important role played by the multipolar coupling between the illuminating field and magneto-electric scatterers even in the small particle limit (λ/10). A general multipolar method is presented which, for the case of planar non centrosymmetric particles, generates a simple expression for the polarizability tensor that directly links the dipolar moment to the incident field. The relevancy of this approach is demonstrated by comparing thoroughly the dipolar moments predicted by the method with full numerical calculations.

Hafnia alvei pyelonephritis in a renal transplant recipient: case report and review of an under-recognized nosocomial pathogen.

We describe the first case to our knowledge of Hafnia alvei pyelonephritis in a renal transplant recipient. Clinicians should consider this under-recognized pathogen when clinically evaluating immunosuppressed patients with a history of invasive procedures.

Differences in rapid desensitization of 5-hydroxytryptamine2A and 5-hydroxytryptamine2C receptor-mediated phospholipase C activation.

The serotonin (5-HT)2A and 5-HT2C receptors share a high degree of sequence homology and have very similar pharmacological profiles. Although it is generally believed that the cellular signal transduction mechanisms activated by these receptors are indistinguishable, recent data suggest significant differences in their signaling cascades. In this study we explored differences in the characteristics and mechanisms of rapid desensitization between the 5-HT2A and 5-HT2C receptor systems. For both receptor systems, pretreatment with 5-HT reduced the ability of a maximal concentration of 5-HT to stimulate phospholipase C-mediated inositol phosphate accumulation by about 65%, although the 5-HT2C receptor system was more sensitive to the desensitizing stimulus. Differences in the concentration dependence of the rate constant for desensitization (k(des)) suggested different mechanisms of desensitization for the 5-HT2A and 5-HT2C receptor systems. At very high receptor occupancy (>99%), the responsiveness of the 5-HT2A, but not the 5-HT2C, receptor system returned to control levels despite the continued presence of the agonist. This resensitization was dependent upon the activity of protein kinase C (PKC). Agonist-induced desensitization of the 5-HT2A, but not the 5-HT2C, receptor system was reduced by the PKC inhibitors staurosporine and bisindolylmaleimide, and by down-regulation of PKC. In addition, inhibitors of calmodulin (W-7) or of calmodulin-dependent protein kinase II, reduced 5-HT2A, but not 5-HT2C, desensitization. Desensitization of the 5-HT2C, but not the 5-HT2A, receptor system was dependent on G protein receptor kinase activity. These data further emphasize the major differences in the signaling systems coupled to 5-HT2A/2C receptors.

Transduction of a dominant-negative H-Ras into human eosinophils attenuates extracellular signal-regulated kinase activation and interleukin-5-mediated cell viability.

Inhibition of eosinophil apoptosis by exposure to interleukin-5 (IL-5) is associated with the development of tissue eosinophilia and may contribute to the inflammation characteristic of asthma. Analysis of the signaling events associated with this process has been hampered by the inability to efficiently manipulate eosinophils by the introduction of active or inhibitory effector molecules. Evidence is provided, using a dominant-negative N17 H-Ras protein (dn-H-Ras) and MEK inhibitor U0126, that activation of the Ras-Raf-MEK-ERK pathway plays a determining role in the prolongation of eosinophil survival by IL-5. For these studies, a small region of the human immunodeficiency virus Tat protein, a protein transduction domain known to enter mammalian cells efficiently, was fused to the N-terminus of dn-H-Ras. The Tat-dn-H-Ras protein generated from this construct transduced isolated human blood eosinophils at more than 95% efficiency. When Tat-dn-H-Ras-transduced eosinophils were treated with IL-5, they exhibited a time- and dosage-dependent reduction in extracellular regulated kinase 1 and 2 activation and an inhibition of p90 Rsk1 phosphorylation and IL-5-mediated eosinophil survival in vitro. In contrast, Tat-dn-H-Ras did not inhibit CD11b up-regulation or STAT5 tyrosine phosphorylation. These data demonstrate that Tat dominant-negative protein transduction can serve as an important and novel tool in studying primary myeloid cell signal transduction in primary leukocytes and can implicate the Ras-Raf-MEK-ERK pathway in IL-5-initiated eosinophil survival.

Granulocyte macrophage colony-stimulating factor and interleukin-5 activate STAT5 and induce CIS1 mRNA in human peripheral blood eosinophils.

In these studies, we examined signaling through the transcription factor STAT5 in human peripheral blood eosinophils after treatment with granulocyte macrophage colony-stimulating factor (GM-CSF) or interleukin (IL)-5. In response to either cytokine, STAT5 was rapidly tyrosine phosphorylated and acquired interferon gamma activation site (GAS) DNA binding activity. Tyrosine-phosphorylated STAT5 was associated with both cytosolic and nuclear cell fractions. Consistent with activation, the transcription of a STAT5-dependent gene, cytokine inducible, SH2-containing protein (CIS1), was enhanced after cytokine stimulation. This is the first report of IL-5 regulation of CIS1 gene expression in any cell type. Given its role in cytokine signaling, CIS1 upregulation may serve to attenuate IL-5 and GM-CSF modulation of eosinophil function. These data suggest that active nuclear STAT5 participates in the regulation of IL-5 and GM-CSF--inducible genes in stimulated human peripheral blood eosinophils.

Observations and calculations of light scattering from clusters of spheres.

Two-dimensional angular optical scattering (TAOS) patterns from clusters of polystyrene latex spheres are measured in the near-forward and near-backward directions. In both cases, the scattering pattern contains a rich and complicated structure that is the result of the interaction and interference of light among the primary particles. Calculations are made for aggregates that are similar to those generated experimentally and also demonstrate the rich structure in the scattering pattern. A comparison of the experimental and theoretical TAOS patterns gives good qualitative agreement.

Novel actions of inverse agonists on 5-HT2C receptor systems.

In cell systems where ligand-independent receptor activity is optimized (such as when receptors are overexpressed or mutated), acute treatment with inverse agonists reduces basal effector activity whereas prolonged exposure leads to sensitization of receptor systems and receptor up-regulation. Few studies, however, have reported effects of inverse agonists in systems where nonmutated receptors are expressed at relatively low density. Here, we investigated the effects of inverse agonists at human serotonin (5-HT)2C receptors expressed stably in Chinese hamster ovary cells ( approximately 250 fmol/mg protein). In these cells, there is no receptor reserve for 5-HT and 5-HT2C inverse agonists did not reduce basal inositol phosphate (IP) accumulation nor arachidonic acid (AA) release but behaved as simple competitive antagonists, suggesting that these receptors are not overexpressed. Prolonged treatment (24 h) with inverse agonists enhanced selectively 5-HT2C-mediated IP accumulation but not AA release. The enhancing effect occurred within 4 h of treatment, reversed within 3 to 4 h (after 24-h treatment), and could be blocked with neutral antagonists or weak positive agonists. The enhanced responsiveness was not due to receptor up-regulation but may involve changes in the expression of the G protein, Galphaq/11 and possibly Galpha12 and Galpha13. Interestingly, 24-h exposure to inverse agonists acting at 5-HT2C receptors also selectively enhanced IP accumulation, but not AA release, elicited by activation of endogenous purinergic receptors. These data suggest that actions of inverse agonists may be mediated through effects on receptor systems that are not direct targets for these drugs.

Campaign '92: three more years!

Creative planning and well-executed graphics produced an upbeat approach to preparing staff for a JCAHO accreditation visit. Five humorous and highly visible strategies were used in a coordinated eight-week "campaign." Not only did the institution "pass the test" but there was a consensus among staff nurses that they had felt comfortable, confident and in control during interviews with the JCAHO surveyor.

Late phase bronchoconstriction and eosinophilia as well as methacholine hyperresponsiveness in Ascaris-sensitive rhesus monkeys were reversed by oral administration of U-83836E.

We used the Ascaris-sensitive primate model to assess the effect of oral doses of the 2-aminochroman (U-83836E) lazaroid on the antigen-induced late phase (24 h) bronchoconstriction (LPBC), eosinophilia and methacholine hyperreactivity. Following establishment of consistent lung resistance measurements and bronchoalveolar lavage eosinophilia in 4 Ascaris reactor primates, we determined the baseline aerosol mecholyl provocative challenge for 50% increase (PC50 in mg/ml) in these animals. Twenty-four hours following antigen challenge, we again determined the PC50 (mg/ml). In all 4 animals, there was a statistically significant decrease in PC50 (5.4- to 32-fold, n = 5-7; p < 0.029). Bronchoconstriction at 24 h increased in all 4 (49-86% over saline aerosol, p < 0.05). Eosinophilia increased from 21 to an average of 33% of total cells (p < 0.05 compared to saline). Repeating the antigen challenge in the presence of oral doses of 10 mg/kg U-83836E 18 and 3 h before and 6 h after challenge resulted in 53-70% inhibition of LPBC, 53-81% inhibition of eosinophilia (p < 0.05 compared to Ascaris) and return of the mecholyl PC50 (mg/ml) to before antigen levels (p = NS) thus blocking increased hyperreactivity. These results indicate U-83836E, like steroids, would be an effective drug for asthma and lung inflammation.

Activation of human eosinophils by platelet-derived growth factor.

Activated eosinophils are believed to be major contributors to the chronic inflammatory sequelae of asthma, but the details of the mechanism of eosinophil activation in vivo are unknown. In our search for physiologically important modes of eosinophil activation, we studied the effects of recombinant human platelet-derived growth factor (PDGF) on human peripheral blood eosinophils. We compared two activation end-points: secretion of granule contents, exemplified by the release of eosinophil peroxidase (EPO), and eosinophil-derived neurotoxin (EDN), and the generation of active oxygen metabolites (O2- production). PDGFc-sis dose dependently stimulated the secretion of large amounts of EPO and EDN from eosinophils. Higher concentrations of PDGF induced a dose-dependent O2- production, especially if the cells were first primed with low concentrations of phorbol ester. These activities were not seen with the AA homodimer of PDGF, suggesting that the activation was receptor dependent. However, several attempts to directly demonstrate the existence of such receptors were unsuccessful. The magnitude of the secretory response to PDGF, and the realization that eosinophils could be easily exposed to this substance as they travel towards the lung, suggests the possibility that this growth factor may be a physiologically important activator of eosinophils in the pulmonary inflammation which is associated with asthma.

Myocardial rupture. Your patient's survival may depend on you.

Myocardial rupture is the second leading cause of in-hospital death from acute myocardial infarction. It is most likely to occur in the elderly, women, and patients with transmural infarction and no previous history of angina. A high index of suspicion is critical to the diagnosis. Myocardial rupture should be suspected when recurrent chest pain or hemodynamic instability develops after myocardial infarction. Rapid intervention and appropriate infarct-limiting therapy may reduce the mortality rate of this catastrophic complication.

Biochemical and functional differences between eosinophils from animal species and man.

Eosinophils were isolated from peritoneal lavages of repeated horse serum-injected guinea pigs or rhesus monkeys and from peripheral blood of normal human donors. Eicosanoid metabolism and chemotaxis by these cells were studied by in vitro techniques. Upon calcium ionophore stimulation guinea pig eosinophils released thromboxane B2 (TXB2) and leukotriene B4 (LTB4) while monkey and human cells produced LTC4, LTB4, and 5-HETE. Guinea pig cells do not synthesize sulfidopeptide LTs, because they lack the specific LTA4 glutathione S-transferase. Guinea pig eosinophils exhibit maximal chemotactic responses to LTB4, zymosan activated plasma, and human recombinant C5a, while producing only a negligible response to platelet activating factor (PAF). Monkey and human cells responded maximally to PAF, but exhibit only a weak response to LTB4. These results suggest that the guinea pig eosinophils differ from monkey and human eosinophils in both the synthetic capacity and functional chemotaxis responses to lipid mediators.

Platelet-derived growth factor can activate purified primate, phorbol myristate acetate-primed eosinophils.

We are interested in the physiologic mechanisms of eosinophil activation because of the presumed participation of activated eosinophils in the inflammatory sequelae of asthma. Suspecting that other formed elements of the blood may contribute to such an activation, we examined the capacity of platelet-derived growth factor (PDGF), a product of activated platelets, to activate eosinophils. We found that highly purified monkey and human eosinophils, but not guinea pig eosinophils, were activated by PDGF (superoxide anion production) in a dose-dependent fashion. Moreover, this activation was further dependent on a prior 'priming' of the cells by a brief exposure to subthreshold concentrations of phorbol ester. The response was specific for the BB homodimer of PDGF suggesting it is receptor-dependent.

Speech-language pathologists' opinions on the management of velopharyngeal insufficiency.

A 16-item questionnaire designed to survey opinions on the management of velopharyngeal insufficiency (VPI) was distributed to all members (N = 296) of the American Cleft Palate Association who were speech-language pathologists. Questionnaires were completed by 173 respondents (58.4 percent). There were differences of opinion among speech-language pathologists on various management issues related to VPI, including the value of instrumental assessment of VPI, the importance of oral examination of velopharyngeal function, and the effectiveness of speech therapy in the treatment of VPI. The implications of these findings for clinical training in VPI are discussed.

Ascaris suum ova-induced bronchoconstriction, eosinophilia, and IgE antibody responses in experimentally infected primates did not lead to histamine hyperreactivity.

The hypothesis that active immunization of primates to give airway allergic responses would also confer on them a hyperreactivity to a nonspecific stimulus such as histamine was tested in 29 normal rhesus primates. At 6 wk after immunization, specific primate IgE (Rast) to Ascaris antigen had increased from 0.35 +/- 0.17 to 0.98 +/- 0.35 units/ml x 10(2) (p less than 0.05). Histamine released from bronchial alveolar lavage cells in response to antigen increased from 5.4 +/- 0.67 to 24 +/- 1.8ng/10(6) cells (p less than 0.05). In a subgroup of seven animals, airway resistance RL and compliance before and after feeding embryonated Ascaris ova increased from RL 3.5 +/- 3.1 to 275 +/- 212 cm H2O/L/s (p = 0.02) and Cdyn fell from 81 +/- 10 to 11.3 +/- 12 ml/cm H2O (p less than 0.05). The bronchial lavage fluid contained a very high percentage of eosinophils after infection, 8 +/- 3.1 to 24 +/- 13% per 500 cells counted, and did not increase appreciably upon later antigen challenge, 24 +/- 13 to 31 +/- 11% of the cells at 9.5 h after antigen challenge (p = NS). When a group of seven of these 29 animals were compared for their histamine responsiveness before and after acquired Ascaris airway reactivity, there was no difference in 19 animals. Pulmonary response to histamine delivered from freon canisters at doses of 0.005, 0.01, 0.025, and 0.05% did not change (RL, 141 +/- 102 to 93 +/- 62; Cdyn, 49 +/- 7 to 46 +/- 11% change before and after, respectively) (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Inhibition of the 5-lipoxygenase pathway with piriprost (U-60,257) protects normal primates from ozone-induced methacholine hyperresponsive small airways.

Weekly exposure to ozone in seven normal Rhesus monkeys led to induction of methacholine hypersensitive airways (RL increases 242 +/- 60% and Cdyn decreases 68 +/- 13% of baseline methacholine responses). It took 19 weeks to establish this hyperresponse that persisted for greater than 15 weeks once ozone was stopped. A second exposure led to similar response peaks in 6 weeks. At the peak of the second response, weekly 1% piriprost exposure before ozone led to a return to baseline that was not different between placebo and piriprost treated animals (9.4 +/- 1.0 and 4.3 +/- 2.9 weeks, placebo and treated, respectively P = 0.09 NS). A statistical difference in the mecholyl response in placebo and piriprost treated groups while on ozone was shown only in the Cdyn measurement (Cdyn% change 68 +/- 13 vs 24 +/- 14, placebo and piriprost, respectively P = 0.03). Off ozone (or return to baseline), a statistical difference could be detected both in RL and Cdyn (RL% changed 151 +/- 41 vs 31.1 +/- 49, P = 0.03, and for Cdyn 62.7 +/- 8 vs 9 +/- 10, P = 0.0006, placebo and piriprost, respectively). We conclude tha the primate provides a chronic model of airways reactivity in which the role of lipoxygenase is implicated because of the beneficial role of piriprost, and further that the ozone lesion is primarily in the smaller airways (possibly and alveolitis).

Activity of a novel hydroquinone inhibitor of leukotriene synthesis (U-66,858) in the rhesus monkey Ascaris reactor.

The IgE-mediated hypersensitivity to Ascaris antigen in reactor rhesus primates was used to assess the pharmacologic profile of U-66,858 (1-acetoxy-2-n-butyl-4-methoxy-naphthalene). When the compound was given by the oral route, it showed dose-related inhibition of resistance (RL) and compliance (Cdyn) changes. When the compound was given by the aerosol route, it showed dose independent inhibition. In 15 animals, aerosols (52 +/- 32 to 53 +/- 10% for RL, p = 0.05 and 45 +/- 19 to 28 +/- 19% Cdyn inhibitions, p = 0.05) for 5.0-0.1% aerosol. By the oral route, inhibition was seen at 1-4 h following administration. In 5 animals, oral doses of 10 and 5 mg/kg inhibited (RL by 98 +/- 2 to 78 +/- 1.5%, p = 0.01 and Cdyn by 75 +/- 17 to 60.9 +/- 9.1%, p = 0.05) by 10 and 5 mg/kg U-66,858, respectively. The in vivo demonstration of inhibition of pulmonary bronchoconstriction by this compound, in a model known to be leukotriene sensitive, coupled with its potent in vitro inhibition of 5-lipoxygenase enzymes, suggests this compound may be of use in 5-lypoxygenase-mediated models of asthma.