Best Practices for Telehealth in Nurse-Led Care Settings-A Qualitative Study

The COVID-19 pandemic in the US prompted a sudden shift to telehealth in nurse-led care sites which provide services to diverse geolocations. Using a lens of intersectionality, this study characterizes provider and patient-perceived best and promising practices emerging from geographical variation. The aim of this study was to identify best practices of implementing telehealth in nurse-led care models in Colorado through patient and provider experiences of the sudden implementation of telehealth that can enhance health equity. In this exploratory/descriptive qualitative study, a purposive sample of 18 providers and 30 patients were interviewed using a guide informed by the RE-AIM implementation and evaluation framework to capture the contextual experiences related to the sudden shift to telehealth. Textual theme analysis and reflexive team strategies guided the interpretation. Four primary themes of perceived best practices were identified: using multiple modalities, tailoring triage and scheduling, cultivating safety through boundaries and expectations, and differentiating established versus new patient relationships. The findings suggest that telehealth is a flexible and powerful tool to enhance the delivery of equitable care through nurse-led care models within diverse communities such as the one represented in this study. Nurse leaders are positioned to participate in innovative research and create policies and protocols to ensure telehealth is a viable resource to deliver equitable, safe, and accessible high-quality healthcare.

Perinatal Telehealth: Meeting Patients Where They Are

INTRODUCTION

Prior to the coronavirus disease 2019 (COVID-19) pandemic, studies of innovative telehealth perinatal care models showed similar clinical outcomes and perceived quality of care between groups receiving a combination of virtual video and in-person visits. However, these studies included primarily White, English-speaking participants, excluding those who were economically disenfranchised or did not speak English. The purpose of this qualitative study was to describe perinatal patients' and providers' experiences with telehealth during and after the acute phase of the COVID-19 pandemic to inform future utilization of telehealth to drive the delivery of high-quality, accessible, and equitable perinatal care to diverse communities.

METHODS

This descriptive qualitative study included a purposive sample of 14 patients and 17 providers who received or provided perinatal care via telehealth in either a certified nurse-midwifery practice or the nurse-family partnership care model between March 2020 and April 2022. Maximum variation sampling offered a diverse population based on race, ethnicity, and rurality. Researchers conducted 2 rounds of semistructured interviews with a focus on understanding social and geographic context.

RESULTS

Six themes were identified through inductive analysis: (1) unexpected advantages of telehealth, (2) patient empowerment, (3) providers' fear of adverse outcomes, (4) concern for equitable care, (5) strategies to enhance the telehealth experience, and (6) strategies to address access to perinatal telehealth. Patients appreciated the increased ease and reduced cost of accessing visits, which led to fewer missed appointments. Health care providers saw great opportunity in telehealth but expressed concerns about accessibility for patients with language barriers or limited resources.

DISCUSSION

This study provides insight into priorities for continued telehealth utilization focused on providing equitable access to perinatal care. Rather than returning to practices from before the COVID-19 pandemic formed from longstanding routines and perceived limitations, providers are encouraged to capitalize on the rapid innovations in telehealth to build a more effective, equitable, and patient-centered approach to perinatal care.

Effects of a QI intervention on pediatric asthma treatment using patient outcomes and workflow in an emergency department

OBJECTIVE

Evaluate a nurse-initiated quality improvement (QI) intervention aimed at enhancing asthma treatment in a pediatric emergency department (ED), utilizing outcomes and workflow.

METHODS

We evaluated the impact of QI interventions for pediatric patients presenting to the ED with asthma with pre-post analysis. A pediatric asthma score (PAS) of >8 indicated moderate to severe asthma. This secondary analysis of the electronic health record (EHR), evaluated on 1) patient outcomes (time to clinical treatment, ED length of stay [EDLOS], admissions and discharges home), 2) clinical workflow.

RESULTS

We compared 886 visits occurring between 01/01/2015 and 09/27/2015 (pre-implementation period) with 752 visits between 01/01/2016 and 09/27/2016 (post-implementation). Time to first documentation of PAS was decreased post-intervention (p<.001) by >30 min (75 ± 57 to 39 ± 54 min). There were significant decreases in time to treatment with both steroid and bronchodilator administration (both p<.001). EDLOS did not significantly change. Based on acuity level, those discharged home from the ED with high acuity (PAS score ≥8), had a significant decrease in time to initial PAS, steroid and bronchodilator use and EDLOS. Of those with high acuity who were admitted to the hospital, there was a difference pre- to post-implementation, in time to first PAS (p<.05), but not to treatment. Workflow visualization provided additional insights and detailed (task level) comparisons of the timing of ED activities.

CONCLUSIONS

Nurse-initiated ED interventions, can significantly improve the timeliness of pediatric asthma evaluation and treatment. Examining workflow along with the outcomes, can better inform QI evaluations and clinical management.

Patient and Provider Perceptions of COVID-19-Driven Telehealth Use From Nurse-Led Care Models in Rural, Frontier, and Urban Colorado Communities

The purpose of this study was to characterize the patient and provider engagement in the sudden telehealth implementation that occurred with the onset of the COVID-19 pandemic. Patients and providers from 3 nurse-led models of care (federally qualified health centers, nurse midwifery practices, and the Nurse-Family partnership program) in Colorado were surveyed. Data from the Patient Attitude toward Telehealth survey and Provider Perceptions about Telehealth were collected. Patient respondents (n = 308) who resided primarily in rural or frontier communities were female, white, and Hispanic. Patients in urban areas used telehealth more frequently than in rural or frontier areas (P < .001). Rural/Frontier patients had significantly lower attitude scores than urban patients across each of 5 domains assessed. Telehealth modality differed across location (P < .023), with video calls, used more frequently by urban providers, and phone calls used by rural/frontier providers. Our data highlight differences in telehealth access and attitudes across rurality. These findings may contribute to future policy while addressing barriers to telehealth access and delivery.

Outcomes from the medication assisted treatment pilot program for adults with opioid use disorders in rural Colorado

BACKGROUND

As Colorado ranked among the top nationally in non-medical use of opioids, a pilot medication for opioid use disorder (MOUD) program was developed to increase the number of NPs and PAs providing MOUD in order to bring this evidence- based treatment to 2 counties showing disproportionally high opioid overdose deaths. Over the first 18 months, the MOUD Pilot Program led to 15 new health care providers receiving MOUD waiver training and 1005 patients receiving MOUD from the 3 participating organizations. Here we evaluate patient centered clinical and functional outcomes of the pilot MOUD program implemented in 2 rural counties severely affected by the opioid crisis.

METHODS

Under state-funded law (Colorado Senate Bill 17-074), three rural agencies submitted de-identified patient-level data at baseline (N = 1005) and after 6 months of treatment (N = 190, 25%) between December 2017 and January 2020. The Addiction Severity Index, PhQ9 and GAD-7 with McNemar-Bowker, and Wilcoxon Signed Rank tests analysis were used to measure patient outcomes across after participation in the program. .

RESULTS

Patients in treatment reported using less heroin (52.1% vs 20.4%), opioids (22.3% vs 11.0%), and alcohol (28.6% vs 13.1%, all P < 0.01). Patients reported improved health (53.4% vs. 68.2%, P = 0.04), less frequency of disability (8.69 vs. 6.51, P = 0.02), symptoms (29.8% vs 21.3%), pain (67.5% to 53.6), worry (45.3% vs 62.3%), anxiety (49.7% vs 23.2%), depression (54.1% vs 23.3%, all P < 0.02) after treatment.

CONCLUSIONS

This study shows decreased substance use, improved physical and mental health, and reduced symptoms after 6 months of MOUD. Although more research on retention and long-term effects is needed, data shows improved health outcomes after 6 months of MOUD. Lessons learned from implementing this pilot program informed program expansion into other rural areas in need to address some of Colorado' major public health crises.

Analysis of medication patterns for pediatric asthma patients in emergency department: Does the sequence placement of glucocorticoids administration matter?

Objectives: Timely glucocorticoid administration is associated with decreased admission rate and is thus a common quality metric for ED asthma care; less is known about the impact of the timing of glucocorticoids in the context of the sequence of asthma medications administered. Therefore, we investigated the distribution of asthma medication sequences in one ED and analyzed the effect of the sequence placement of glucocorticoids administration on treatment outcomes.Methods: A retrospective study using five-year electronic health record data obtained from an academic urban children's hospital ED was conducted. We clustered the sequences of medication administration using an exact string-matching algorithm to identify the most frequently used asthma medication sequences. Then, we used the identified patterns to perform statistical tests to examine the effect of the sequence placement of glucocorticoids administration on the outcomes length-of-stay and ED disposition.Results: A total of 4,844 encounters were included in our study. The ten most common treatment sequences accounted for 43% of all encounters. Stratified analyses confirmed that treatment sequences pattern was correlated with patient severity, but ED crowding does not impact treatment sequences. In multivariable models, glucocorticoids administration earlier in the treatment sequence was associated with shorter length of stay and lower hospital admission rates.Conclusions: By analyzing medication sequence patterns for the ED encounter of pediatric asthma, we found that the earlier sequence placement of glucocorticoids administration is associated with improved outcomes. Our findings can help inform quality improvement and clinical guideline development related to ED asthma care for children.

Correlates of Physical Activity and Sedentary Behaviors Among Overweight Hispanic School-aged Children

PURPOSE

The purpose of this study was to explore potential correlates of physical activity and sedentary screen time behaviors among overweight Hispanic school-aged children, ages 7 to 14years.

DESIGN AND METHODS

We conducted an exploratory correlation analysis using baseline data of 40 child-parent dyads from the "Mind Exercise Nutrition Do It!" program conducted in the Western United States.

RESULTS

Child self-esteem and parental vegetable intake were moderately associated with physical activity, while parental vegetable intake and child fruit intake were strongly associated with physical activity among males. Physical activity was not significantly associated with body mass index percentile, sedentary screen time behaviors, or body esteem. Only decreased body esteem in males was correlated with sedentary screen time behaviors.

CONCLUSIONS AND PRACTICE IMPLICATIONS

Understanding the correlates of physical activity and sedentary screen time behaviors in this underrepresented population allows nurses to better understand the connections between physical activity and other aspects of well-being in children. Further investigation is needed to determine how these relationships can be incorporated into physical activity interventions that improve the health of overweight Hispanic school-aged children.

B cell subsets contribute to renal injury and renal protection after ischemia/reperfusion

Ischemia/reperfusion (I/R) triggers a robust inflammatory response within the kidney. Numerous components of the immune system contribute to the resultant renal injury, including the complement system. We sought to identify whether natural Abs bind to the postischemic kidney and contribute to complement activation after I/R. We depleted peritoneal B cells in mice by hypotonic shock. Depletion of the peritoneal B cells prevented the deposition of IgM within the glomeruli after renal I/R and attenuated renal injury after I/R. We found that glomerular IgM activates the classical pathway of complement, but it does not cause substantial deposition of C3 within the kidney. Furthermore, mice deficient in classical pathway proteins were not protected from injury, indicating that glomerular IgM does not cause injury through activation of the classical pathway. We also subjected mice deficient in all mature B cells (μMT mice) to renal I/R and found that they sustained worse renal injury than wild-type controls. Serum IL-10 levels were lower in the μMT mice. Taken together, these results indicate that natural Ab produced by peritoneal B cells binds within the glomerulus after renal I/R and contributes to functional renal injury. However, nonperitoneal B cells attenuate renal injury after I/R, possibly through the production of IL-10.

CXCR2 agonists in ADPKD liver cyst fluids promote cell proliferation

Autosomal dominant polycystic kidney disease (ADPKD) is a highly prevalent genetic disease that results in cyst formation in kidney and liver. Cytokines and growth factors secreted by the cyst-lining epithelia are positioned to initiate autocrine/paracrine signaling and promote cyst growth. Comparative analyses of human kidney and liver cyst fluids revealed disparate cytokine/growth factor profiles. CXCR2 agonists, including IL-8, epithelial neutrophil-activating peptide (ENA-78), growth-related oncogene-alpha (GRO-alpha), are potent proliferative agents that were found at high levels in liver but not kidney cyst fluids. Liver cysts are lined by epithelial cells derived from the intrahepatic bile duct (i.e., cholangiocytes). In polarized pkd2(WS25/-) mouse liver cyst epithelial monolayers, CXCR2 agonists were released both apically and basally, indicating that they may act both on the endothelial and epithelial cells within or lining the cyst wall. IL-8 and human liver cyst fluid induced cell proliferation of HMEC-1 cells, a human microvascular endothelial cell line, and Mz-ChA1 cells, a human cholangiocyte cell model. IL-8 expression can be regulated by specific stresses. Hypoxia and mechanical stretch, two likely stressors acting on the liver cyst epithelia, significantly increased IL-8 secretion and promoter activity. AP-1, c/EBP, and NF-kappaB were required but not sufficient to drive the stress-induced increase in IL-8 transcription. An upstream element between -272 and -1,481 bp allowed for the stress-induced increase in IL-8 transcription. These studies support the hypothesis that CXCR2 signaling promotes ADPKD liver cyst growth.

VEGF receptor inhibition blocks liver cyst growth in pkd2(WS25/-) mice

Proliferation of cyst-lining epithelial cells is an integral part of autosomal dominant polycystic kidney disease (ADPKD) cyst growth. Cytokines and growth factors within cyst fluids are positioned to induce cyst growth. Vascular endothelial growth factor (VEGF) is a pleiotropic growth factor present in ADPKD liver cyst fluids (human 1,128 +/- 78, mouse 2,787 +/- 136 pg/ml) and, to a lesser extent, in ADPKD renal cyst fluids (human 294 +/- 41, mouse 191 +/- 90 pg/ml). Western blotting showed that receptors for VEGF (VEGFR1 and VEGFR2) were present in both normal mouse bile ducts and pkd2(WS25/-) liver cyst epithelial cells. Treatment of pkd2(WS25/-) liver cyst epithelial cells with VEGF (50-50,000 pg/ml) or liver cyst fluid induced a proliferative response. The effect on proliferation of liver cyst fluid was inhibited by SU-5416, a potent VEGF receptor inhibitor. Treatment of pkd2(WS25/-) mice between 4 and 8 mo of age with SU-5416 markedly reduced the cyst volume density of the liver (vehicle 9.9 +/- 4.3%, SU-5416 1.8 +/- 0.7% of liver). SU-5416 treatment between 4 and 12 mo of age markedly protected against increases in liver weight [pkd2(+/+) 4.8 +/- 0.2%, pkd2(WS25/-)-vehicle 10.8 +/- 1.9%, pkd2(WS25/-)-SU-5416 4.8 +/- 0.4% body wt]. The capacity of VEGF signaling to induce in vitro proliferation of pkd2(WS25/-) liver cyst epithelial cells and inhibition of in vivo VEGF signaling to retard liver cyst growth in pkd2(WS25/-) mice indicates that the VEGF signaling pathway is a potentially important therapeutic target in the treatment of ADPKD liver cyst disease.

Regulated ion transport in mouse liver cyst epithelial cells

Derived from bile duct epithelia (BDE), secretion by liver cyst-lining epithelia is positioned to drive cyst expansion but the responsible ion flux pathways have not been characterized. Cyst-lining epithelia were isolated and cultured into high resistance monolayers to assess the ion secretory pathways. Electrophysiologic studies showed a marked rate of constitutive transepithelial ion transport, including Cl(-) secretion and Na(+) absorption. Na(+) absorption was amiloride-sensitive, suggesting the activation of epithelial sodium channels (ENaC). Further, both cAMP(i) and extracellular ATP induced robust secretory responses. Western blotting and immunohistologic analysis of liver cyst epithelia demonstrated expression of P2X4, a potent purinergic receptor in normal BDE. Luminometry and bioassaying measured physiologically relevant levels of ATP in a subset of liver cyst fluid samples. Liver cyst epithelia also displayed a significant capacity to degrade extracellular ATP. In conclusion, regulated ion transport pathways are present in liver cyst epithelia and are positioned to direct fluid secretion into the lumen of liver cysts and promote increases in liver cyst expansion and growth.

Inhibited neurogenesis in JNK1-deficient embryonic stem cells

The JNKs are components of stress signaling pathways but also regulate morphogenesis and differentiation. Previously, we invoked a role for the JNKs in nerve growth factor (NGF)-stimulated PC12 cell neural differentiation (L. Marek et al., J. Cell. Physiol. 201:459-469, 2004; E. Zentrich et al., J. Biol. Chem. 277:4110-4118, 2002). Herein, the role for JNKs in neural differentiation and transcriptional regulation of the marker gene, NFLC, modeled in mouse embryonic stem (ES) cells was studied. NFLC-luciferase reporters revealed the requirement for NFLC promoter sequences encompassing base pairs -128 to -98 relative to the transcriptional start site as well as a proximal cyclic AMP response element-activating transcription factor binding site at -45 to -38 base pairs for transcriptional induction in NGF-treated PC12 cells and neurally differentiated ES cells. The findings reveal common promoter sequences that integrate conserved signal pathways in both PC12 cell and ES cell systems. To test the requirement for the JNK pathway in ES cell neurogenesis, ES cell lines bearing homozygous disruptions of the jnk1, jnk2, or jnk3 genes were derived and submitted to an embryoid body (EB) differentiation protocol. Neural differentiation was observed in wild-type, JNK2(-/-), and JNK3(-/-) cultures but not in JNK1(-/-) EBs. Rather, an outgrowth of cells with epithelial morphology and enhanced E-cadherin expression but low NFLC mRNA and protein was observed in JNK1(-/-) cultures. The expression of wnt-4 and wnt-6, identified inhibitors of ES cell neurogenesis, was significantly elevated in JNK1(-/-) cultures relative to wild-type, JNK2(-/-), and JNK3(-/-) cultures. Moreover, the Wnt antagonist, sFRP-2, partially rescued neural differentiation in JNK1(-/-) cultures. Thus, a genetic approach using JNK-deficient ES cells reveals a novel role for JNK1 involving repression of Wnt expression in neural differentiation modeled in murine ES cells.

Lipopolyamines: novel antiendotoxin compounds that reduce mortality in experimental sepsis caused by gram-negative bacteria

The interactions of lipopolyamines, a class of structurally unique compounds currently being used as transfection (lipofection) agents, with lipopolysaccharide (LPS) have been characterized. Our studies have demonstrated that 1,3-di-oleoyloxy-2-(6-carboxyspermyl)-propylamide), available commercially as DOSPER, binds to purified LPS with an affinity of about 1/10 that of polymyxin B. This essentially nontoxic compound inhibits, in a dose-dependent manner, LPS-induced activation of the Limulus clotting cascade and the production of tumor necrosis factor alpha (TNF-alpha) interleukin-6 (IL-6), and nitric oxide from LPS-stimulated J774.A1 cells, a murine macrophage-like cell line. Cytokine inhibition is paralleled by decreased steady-state levels of TNF-alpha and IL-6 mRNA and inhibits the nuclear translocation of nuclear factor kappa B. These findings suggest that the lipopolyamine compound sequesters LPS, thereby blocking downstream cellular activation events that lead to the production of proinflammatory mediators. Administration of DOSPER to D-galactosamine-sensitized mice challenged either with LPS or with Escherichia coli organisms provided significant protection against lethality both with and without antibiotic chemotherapy. Partial protection is evident in LPS-challenged mice treated with DOSPER as late as 2 to 4 h following the endotoxin challenge. A greater degree of protection is observed in E. coli-challenged animals receiving ceftazidime than in those receiving imipenem, which is probably attributable to the higher levels of LPS released in vivo by the former antibiotic. Potent antiendotoxic activity, low toxicity, and ease of synthesis render the lipopolyamines candidate endotoxin-sequestering agents of potential significant therapeutic value.

Mechanisms involved in the pathogenesis of sepsis are not necessarily reflected by in vitro cell activation studies

It is thought that lipopolysaccharide (LPS) from gram-negative bacteria contributes significantly to the pathogenesis of septic shock. In vitro studies to address the mechanisms involved in this process have often investigated human monocytes or mouse macrophages, since these cells produce many of the mediators found in septic patients. Targeting of these mediators, especially tumor necrosis factor alpha (TNF-alpha), has been pursued as a means of reducing mortality in sepsis. Two experimental approaches were designed to test the assumption that in vitro studies with macrophages accurately predict in vivo mechanisms of LPS pathogenesis. In the first approach, advantage was taken of the fact that on consecutive days after injection of thioglycolate into mice, increased numbers of macrophages could be harvested from the peritoneum. These cells manifested markedly enhanced levels of in vitro TNF-alpha, interleukin 6 (IL-6), and nitric oxide production in response to LPS. In D-galactosamine-sensitized mice, however, thioglycolate treatment significantly decreased mortality due to LPS, as well as levels of circulating TNF-alpha and IL-6. Anti-TNF-alpha treatment confirmed this cytokine's role in the observed lethality. In a second experimental approach, we compared the mouse macrophage-stimulating potencies of different LPS preparations with their lethalities to mice. In these studies, the in vitro macrophage-stimulating profiles presented by rough-LPS and smooth-LPS preparations were the reverse of their relative lethal potencies in vivo. In conclusion, peritoneal macrophages appear not to be the major cells responsible for the overall host response during endotoxic shock. These findings underscore the importance of verifying the correlation of in vivo systems with in vitro systems when attributing specific functions to a cell type.

Differential regulation of lipopolysaccharide (LPS) activation pathways in mouse macrophages by LPS-binding proteins

LPS binding to its receptor(s) on macrophages induces the synthesis of inflammatory mediators involved in septic shock. While the signaling mechanism(s) remains to be fully defined, the human LPS-binding protein (LBP) is known to regulate responses to LPS by facilitating its binding to CD14 on human monocytes. The structurally related bactericidal permeability increasing protein (BPI) differs from LBP by inhibiting LPS-induced human monocyte activation. We have demonstrated that, unlike the human monocyte response to LPS, both LBP and BPI inhibited LPS-stimulated TNF-alpha production in mouse peritoneal macrophages. In contrast, LPS-dependent nitric oxide release was not affected by LBP. LPS induces the phosphorylation of a number of proteins in a dose and time-dependent manner, however, the pattern of LPS-induced phosphorylation was not reduced by either LBP or BPI under conditions that result in selective TNF-alpha inhibition. Further, activation of the transcription factor NF-kappaB in response to LPS was also not modified by either LBP or BPI. Finally, no differences were detected in TNF-alpha or inducible nitric oxide synthase mRNA accumulations induced by LPS in the presence or absence of either protein, whereas a slight decreased mRNA stability was observed in the group with LPS treatment. These results would suggest that many of the early signaling events contribute to LPS-induced macrophage signaling at a point preceding the divergence of pathways that differentially regulate TNF-alpha and NO production.

Differential Regulation of Lipopolysaccharide (LPS) Activation Pathways in Mouse Macrophages by LPS-Binding Proteins

LPS binding to its receptor(s) on macrophages induces the synthesis of inflammatory mediators involved in septic shock. While the signaling mechanism(s) remains to be fully defined, the human LPS-binding protein (LBP) is known to regulate responses to LPS by facilitating its binding to CD14 on human monocytes. The structurally related bactericidal permeability increasing protein (BPI) differs from LBP by inhibiting LPS-induced human monocyte activation. We have demonstrated that, unlike the human monocyte response to LPS, both LBP and BPI inhibited LPS-stimulated TNF-α production in mouse peritoneal macrophages. In contrast, LPS-dependent nitric oxide release was not affected by LBP. LPS induces the phosphorylation of a number of proteins in a dose and time-dependent manner, however, the pattern of LPS-induced phosporylation was not reduced by either LBP or BPI under conditions that result in selective TNF-α inhibition. Further, activation of the transcription factor NF-κB in response to LPS was also not modified by either LBP or BPI. Finally, no differences were detected in TNF-α or inducible nitric oxide synthase mRNA accumulations induced by LPS in the presence or absence of either protein, whereas a slight decreased mRNA stability was observed in the group with LPS treatment. These results would suggest that many of the early signaling events contribute to LPS-induced macrophage signaling at a point preceding the divergence of pathways that differentially regulate TNF-α and NO production.

Two functionally independent pathways for lipopolysaccharide-dependent activation of mouse peritoneal macrophages

We have investigated the effects of human LPS-binding protein (LBP) and human bactericidal/permeability-increasing protein (BPI) on LPS-dependent activation of mouse thioglycolate-elicited peritoneal macrophages in vitro, in comparison with human PBMCs. Confirming earlier published studies, BPI inhibited, and LBP enhanced, the ability of LPS to stimulate PBMC production of the cytokines TNF-alpha and IL-6. In marked contrast to these results, under identical conditions of in vitro culture, both LBP and BPI suppressed, in a dose-dependent manner, the ability of LPS to stimulate cytokine production in mouse macrophages. Further, while human BPI also suppressed LPS-dependent NO secretion in mouse macrophages, human LBP had no inhibitory effect on NO secretion under conditions that inhibited TNF-alpha secretion. These data provide the first direct evidence that mouse macrophages may utilize two independent pathways in response to LPS, thus leading to different phenotypic responses.

Two functionally independent pathways for lipopolysaccharide-dependent activation of mouse peritoneal macrophages

We have investigated the effects of human LPS-binding protein (LBP) and human bactericidal/permeability-increasing protein (BPI) on LPS-dependent activation of mouse thioglycolate-elicited peritoneal macrophages in vitro, in comparison with human PBMCs. Confirming earlier published studies, BPI inhibited, and LBP enhanced, the ability of LPS to stimulate PBMC production of the cytokines TNF-alpha and IL-6. In marked contrast to these results, under identical conditions of in vitro culture, both LBP and BPI suppressed, in a dose-dependent manner, the ability of LPS to stimulate cytokine production in mouse macrophages. Further, while human BPI also suppressed LPS-dependent NO secretion in mouse macrophages, human LBP had no inhibitory effect on NO secretion under conditions that inhibited TNF-alpha secretion. These data provide the first direct evidence that mouse macrophages may utilize two independent pathways in response to LPS, thus leading to different phenotypic responses.

Tumor necrosis factor alpha plus interleukin 1 beta treatment protects granulocytopenic mice from Pseudomonas aeruginosa lung infection: role of an unusual inflammatory response

We have recently demonstrated that treatment with interleukin 1 beta (IL-1 beta) plus tumor necrosis factor alpha (TNF alpha) protects granulocytopenic hosts from Pseudomonas aeruginosa aerosol challenge. In this study we characterized the inflammatory response induced by P. aerugionsa in granulocytopenic mice treated with 2,000 U IL-1 beta plus 2,000 U TNF alpha. Treatment with the nonsteroidal anti-inflammatory agent piroxicam abolished both the protective effect of cytokine treatment and the increase in myeloperoxidase (MPO) pulmonary activity. Histopathological studies revealed that, after aerosol challenge with P. aeruginosa, treatment with these cytokines induced migration and extravasation of mononuclear cells of immature appearance into the lung parenchyma. These cells contained MPO in their cytoplasm and displayed phagocytic capacity. Resident alveolar macrophages exhibited signs of activation and appeared in reduced numbers in bronchoalveolar lavage fluid. We suggest that the inflammatory response promoted by low TNF alpha plus IL-1 beta doses may be one mechanism responsible for protection of granulocytopenic hosts from P. aeruginosa aerosol challenge.

Modulation of human polymorphonuclear leukocyte chemotaxis and superoxide anion production by Pseudomonas aeruginosa exoproducts, IL-1 beta and piroxicam

Whereas addition of 200 ng ml-1 exotoxin A (exoA) did not modify PMNL chemotaxis, 20 U ml-1 human recombinant interleukin-1 beta (hrIL-1 beta) primed polymorphonuclear leukocytes (PMNL) for migration towards Pseudomonas aeruginosa peptide chemotactins (PAPCs). Piroxicam (100 micrograms ml-1), a non-steroidal anti-inflammatory agent (NSAIA), inhibited PMNL chemotaxis and abolished the priming effect of hrIL-1 beta. Both PAPCs and exoA induced PMNL superoxide anion production, but neither hrIL-1 beta nor piroxicam modified significantly PMNL superoxide anion production induced by PAPCs. The fact that hrIL-1 beta can prime PMNL for chemotaxis towards PAPCs and that piroxicam can abolish activation by primed PMNL are findings relevant to the pharmacological control of lung tissue damage during P. aeruginosa pneumonia.

The effect of treatment with interleukin-1 and tumor necrosis factor on Pseudomonas aeruginosa lung infection in a granulocytopenic mouse model

The efficacy of treatment with interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF alpha) on Pseudomonas aeruginosa pneumonia was evaluated in a granulocytopenic mouse model. Combined intravenous administration of 2000 U IL-1 beta plus 2000 U TNF alpha significantly diminished mortality from aerosol challenge with P. aeruginosa. Mice treated with IL-1 beta, TNF alpha, or both also exhibited a significant enhancement in pulmonary clearance of P. aeruginosa. Combined cytokine administration induced an increase in the pulmonary content of myeloperoxidase activity. Mature leukocytes were not detected in either circulation or bronchoalveolar lavage fluid from granulocytopenic, cytokine-treated mice. In conclusion, IL-1 beta and TNF alpha treatment exhibited a synergistic protective effect from pulmonary P. aeruginosa challenge in granulocytopenic hosts, probably due to enhancement of nonspecific antibacterial mechanisms.

The effect of a cyclooxygenase inhibitor on the in vivo polymorphonuclear leukocyte migration to Pseudomonas aeruginosa peptide chemotactins

Pseudomonas aeruginosa chemotactic peptides (PAPCs) induced migration of polymorphonuclear leukocytes (PMNL) into the lungs when administered by the aerosol route. Migration of PMNL into the lungs and total protein content of lung lavage fluids in response to PAPCs aerosol challenge, and mortality from lethal challenge with P. aeruginosa were decreased by piroxicam treatment.

Piroxicam-copper complexes: inhibition of polymorphonuclear leukocyte migration to Pseudomonas aeruginosa chemotactins in vivo and superoxide dismutase-like activity in vitro

Piroxicam-copper (Cu2+) complexes, formed spontaneously by mixing solutions of piroxicam and CuSO4 (1:1 Cu2+:piroxicam), inhibited the superoxide anion-catalyzed reduction of ferricytochrome C in a dose-related fashion. Addition of ethylenediaminetetraacetate to the mixture decreased in a dose-related manner the superoxide dismutase (SOD)-like activity of piroxicam-Cu2+. Piroxicam alone (10(-5) M, final concentration) did not display SOD-like activity but 10(-5) M Cu2+ exhibited significant activity, similar to that of piroxicam-Cu2+. Intraperitoneal treatment of mice with either 0.64 mg/kg piroxicam or its Cu2+ complexes (0.64 mg/kg piroxicam + 0.12 mg/kg Cu2+) was equally effective in diminishing both the migration of polymorphonuclear leukocytes (PMNL) to the airways and the content of myeloperoxidase activity in the lungs, induced by aerosol challenge with Pseudomonas aeruginosa peptide chemotactins. Therefore, piroxicam-Cu2+ complexes may provide both the anti-inflammatory activity of piroxicam plus the SOD-like activity of Cu2+.

Treatment with a non-steroidal anti-inflammatory agent delays the growth of spontaneous pulmonary metastases of a mammary adenocarcinoma of non-detected immunogenicity

Previous reports showed that treatment with non-steroidal anti-inflammatory agents (NSAIA) can alter the growth profile of a variety of tumours. In this study, the effect of NSAIA treatment on the growth of the primary tumour and the appearance of spontaneous pulmonary metastases, was investigated. A mammary adenocarcinoma of non-detected immunogenicity, C7HI, was grafted subcutaneously in the lateral flank of Balb/c mice. Oral treatment with approximately 1 mg kg-1 day-1 piroxicam delayed both tumour growth and the growth of pulmonary metastases. Survival of mice bearing the primary tumour was significantly lengthened by anti-inflammatory treatment. Similarly, in separate experiments, after surgical removal of the primary tumour by day 34 after grafting, the group of mice treated orally with piroxicam also exhibited a higher survival rate than the control group. Upon surgical removal of the primary tumour 34 days after grafting, piroxicam treatment significantly decreased both the number and size of pulmonary metastases. The results of this study lends support to the hypothesis that inhibition or modulation of inflammation may delay tumour organisation and growth. It is suggested that piroxicam treatment may be an appropriate adjunct therapy to delay the appearance of pulmonary metastases and to increase life-expectancy in a host whose primary tumour has to be surgically removed.

Preliminary characterization of Pseudomonas aeruginosa peptide chemotactins for polymorphonuclear leukocytes

In a previous report, we showed that supernatants of Pseudomonas aeruginosa cultures exhibit chemotactic activity for polymorphonuclear leukocytes (PMNL). In this study, P. aeruginosa chemotactins were isolated, purified, and partially characterized. The organisms were cultured in Vogel-Bonner defined medium, and cultures were stopped in late log phase. Chemotactins withstood heating, remained unaltered after acid or alkali treatment in a pH range from 4 to 10, and resisted digestion by trypsin or carboxypeptidase, but chemotactic activity was decreased by 73% after incubation with pronase. Only 2% of the total chemotactic activity of culture supernatants could be extracted with chloroform. Chemotactins with molecular sizes less than 3 kDa constituted the largest contribution to the chemotactic activity of culture supernatants. Pretreatment of PMNL with 10(-5) M formylmethionyl-leucyl-phenylalanine (FMLP) inhibited chemotaxis towards FMLP and P. aeruginosa culture supernatants but not towards complement component C5a. In conclusion, the total chemotactic activity for PMNL of P. aeruginosa culture supernatants was due, almost exclusively, to chemotactins that have properties similar, if not identical, to those exhibited by formylmethionyl peptides.