CXCR4 Antagonism Reduces Cardiac Fibrosis and Improves Cardiac Performance in Dilated Cardiomyopathy

Background: Myocardial fibrosis is a key pathologic finding in the failing heart and is implicated as a cause of increased ventricular stiffness and susceptibility to ventricular arrhythmia. Neurohormonal mediators such as aldosterone and angiotensin II are known to cause fibrosis in experimental models, however, clinical evidence for the reversal of fibrosis with relevant antagonists is limited. Recent studies suggest that inflammatory mediators may contribute to fibrosis. In dilated cardiomyopathy the mechanism for myocardial fibrosis is unclear and its implications on systolic function are not known. Methods and Results: We studied the effect of a highly selective antagonist of SDF-1/CXCR4 signaling, AMD3100, on the development of cardiac fibrosis and cardiac function in mice with dilated cardiomyopathy due to cardiac-specific transgenic overexpression of the stress-kinase, Mst1. AMD3100 significantly attenuated the progression of myocardial fibrosis and this was accompanied by significant improvements in diastolic and systolic performance as evaluated in isolated Langendorff perfused hearts. AMD3100 reduced BNP mRNA expression but did not alter the expression of Ca²⁺ handling genes. CXCR4 antagonism also reduced the abundance of splenic CD4⁺ T cells. Conclusion: This study demonstrates that CXCR4 pathway contributes to pathogenesis of cardiac fibrosis in dilated cardiomyopathy, and it represents a new potential therapeutic target in heart failure. The data also demonstrate that anti-fibrotic strategies can improve systolic performance.

Evidence of hepatitis A virus infection in the patients with acute encephalitis syndrome in Gorakhpur region, North India

The etiological agent remained unidentified in a large number of patients hospitalized for acute encephalitis syndrome (AES) in 2008-2009 in Uttar Pradesh and Bihar, north India. All patients were found to present with fever and altered sensorium, while 28%, 19% and 13% showed hepatomegaly, splenomegaly and meningeal signs, respectively. Involvement mostly of children with abnormal hepatic features prompted us to undertake an exploratory study on viral hepatitis A to determine its association, if any, with hepatic derangements. AES patients (n = 2515) and healthy children (n = 167) were investigated for the presence of serum anti-hepatitis A virus (anti-HAV) IgM and anti-Japanese encephalitis (anti-JE) virus IgM by ELISA. Cerebrospinal fluids (CSFs, n = 595) and rectal swabs (n = 182) were examined for anti-HAV IgM and/or HAV RNA. Anti-HAV IgM was detected in the sera of 14.6% patients as against 6.6% of healthy children (p = 0.0042). Anti-JE virus IgM positivity was Keywords: acute encephalitis syndrome; cerebrospinal fluid; hepatitis A virus; anti-HAV IgM; non-Japanese encephalitis.

Secondhand Smoke Exposure and Preclinical Markers of Cardiovascular Risk in Toddlers

OBJECTIVE

To investigate relationships between secondhand smoke exposure in young children and several preclinical markers of cardiovascular risk that have been established as relevant to adult populations.

STUDY DESIGN

There were 139 children, 2-5 years of age, enrolled in a cross-sectional study. Secondhand smoke exposure was objectively determined by hair nicotine level; a comprehensive panel of clinical markers (morning blood pressure, fasting glucose and insulin, lipid profiles, inflammation) and research markers (markers of oxidation, endothelial stress, and endothelial repair) of cardiovascular risk status were assessed. Univariate and multivariate linear regression were used to evaluate relationships between secondhand smoke exposure and cardiovascular risk markers.

RESULTS

Hair nicotine levels were correlated directly with blood pressure and serum C-reactive protein, and inversely correlated with serum high-density lipoprotein cholesterol and endothelial cell progenitor cell prevalence. In multivariate analyses, these relationships remained when controlled for age, sex, body mass index z-score, maternal education, and method of payment. Additionally, in multivariate analyses, hair nicotine level was significantly negatively correlated with total antioxidant capacity.

CONCLUSIONS

These results support the view that secondhand smoke exposure in the very young has a detectable relationship with several markers of cardiovascular risk, long before the emergence of clinical disease. Further studies to define mechanisms and strategies to prevent and mitigate these risks early in life are warranted.

Early urinary biomarkers of acute kidney injury in preterm infants

BACKGROUND

Acute kidney injury (AKI) in the neonatal intensive care setting is multifactorial and is associated with significant morbidity and mortality. This study evaluates the utility of novel urinary biomarkers to predict the development and/or severity AKI in preterm infants.

METHODS

We performed a case-control study on a prospective cohort of preterm infants (<32 wk), to compare seven urine biomarkers between 25 infants with AKI and 20 infants without AKI.

RESULTS

Infants with AKI had significantly higher neutrophil gelatinase-associated lipocalin (NGAL) (median, control (CTRL) vs. AKI; 0.598 vs. 4.24 µg/ml; P < 0.0001). In contrast, urinary epidermal growth factor (EGF) levels were significantly lower in infants who developed AKI compared to controls (median, CTRL vs. AKI; 0.016 vs. 0.006 µg/ml; P < 0.001). The area under the curve (AUC) for NGAL for prediction of stage I AKI on the day prior to AKI diagnosis (day-1) was 0.91, and for the prediction of stage II/III, AKI was 0.92. Similarly, urine EGF was a predictor of renal injury on day -1 (AUC: 0.97 for stage I and 0.86 for stage II/III AKI).

CONCLUSION

Urinary biomarkers may be useful to predict AKI development prior to changes in serum creatinine (SCr) in preterm infants.

Oxidative Stress in Youth and Adolescents With Elevated Body Mass Index Exposed to Secondhand Smoke

INTRODUCTION

Our objective was to investigate the relationships between secondhand smoke (SHS) exposure and oxidative stress in a group of youth and adolescents with elevated body mass index.

METHODS

Participants in this cross sectional study were healthy nonsmoking youth and adolescents ages 9 to 18 years old. Three-quarters of the participants were either overweight or obese. SHS exposure was determined by survey and hair nicotine level. Markers of oxidation were total antioxidant capacity and protein malondialdehyde adducts (MDA).

RESULTS

Ninety subjects were studied; adequate hair samples were available for 86. The mean hair nicotine level was 0.75ng/mg, the median was 0.58ng/mg and the range was 0.09-2.88ng/mg. There was a significant relationship between MDA and the three survey questions regarding smoke exposure ([mother smokes, r = 0.29, P = .006], [smoker lives in the home, r = 0.31, P = .004], and [number of smokers in the home, r = 0.36, P = .002]). There was a significant positive relationship between log-hair nicotine and MDA (Pearson r = 0.233, P = .031), which remained significant after controlling for age, sex, race, and method of insurance. No relationship was found between log-hair nicotine and total antioxidant capacity. However, there was a significant relationship between number of smokers in the home (r = 0.24, P = .042) and total antioxidant capacity.

CONCLUSIONS

We have demonstrated a significant positive relationship hair nicotine level and MDA in a group of youth with a high proportion of overweight/obese subjects.

IMPLICATIONS

We have shown a significant relationship between objectively measured SHS exposure and one marker of oxidative stress in a sample of youth and adolescents with a high proportion of overweight/obese subjects, and who were nonsmokers with relatively low tobacco exposure. This finding remains significant after controlling for age, sex, race, and type of medical insurance. Since the cardiovascular effects of SHS exposure are related to oxidative stress, this finding adds to our knowledge that the sequence of deleterious effects of tobacco exposure on the cardiovascular system begins long before clinical disease is evident.

The effect of prenatal maternal infection on respiratory function in mouse offspring: evidence for enhanced chemosensitivity

Systemic maternal inflammation is implicated in preterm birth and bronchopulmonary dysplasia (BPD) and may induce morbidities including reduced pulmonary function, sleep-disordered breathing, and cardiovascular disorders. Here we test the hypothesis that antenatal maternal inflammation per se causes altered alveolar development and increased chemoreflex sensitivity that persists beyond infancy. Pregnant C57BL/6 mice were administered lipopolysaccharide (LPS) (150 μg/kg ip) to induce maternal inflammation or saline (SHAM) at embryonic day 16 (randomized). Pups were weighed daily. On days 7, 28, and 60 (D07, D28, and D60), unrestrained wholebody plethysmography quantified ventilation and chemoreflex responses to hypoxia (10%), hypercapnia (7%), and asphyxia (hypoxic hypercapnia). Lungs were harvested to quantify alveolar number, size, and septal thickness. LPS pups had reduced baseline ventilation per unit bodyweight (∼40%, P < 0.001) vs. SHAM. LPS increased ventilatory responses to hypoxia (D07: 66% vs. 28% increase in ventilation; P < 0.001) hypercapnia (170% vs. 88%; P < 0.001), and asphyxia (249% vs. 154%; P < 0.001); hypersensitive hypoxic responsiveness persisted until D60 (P < 0.001). LPS also increased apnea frequency (P < 0.01). LPS caused thicker alveolar septae (D07, P < 0.001), diminished alveolar number (D28, P < 0.001) vs. SHAM, but effects were minimal by D60. Pups delivered from mothers exposed to antenatal inflammation exhibit deficits in lung structure and hypersensitive responses to respiratory stimuli that persist beyond the newborn period. Antenatal inflammation may contribute to impaired gas exchange and unstable breathing in newborn infants and adversely affect long-term health.

Role of mitochondrial dysfunction in hyperglycaemia-induced coronary microvascular dysfunction: Protective role of resveratrol

Microvascular complications are now recognized to play a major role in diabetic complications, and understanding the mechanisms is critical. Endothelial dysfunction occurs early in the course of the development of complications; the precise mechanisms remain poorly understood. Mitochondrial dysfunction may occur in a diabetic rat heart and may act as a source of the oxidative stress. However, the role of endothelial cell-specific mitochondrial dysfunction in diabetic vascular complications is poorly studied. Here, we studied the role of diabetes-induced abnormal endothelial mitochondrial function and the resultant endothelial dysfunction. Understanding the role of endothelial mitochondrial dysfunction in diabetic vasculature is critical in order to develop new therapies. We demonstrate that hyperglycaemia leads to mitochondrial dysfunction in microvascular endothelial cells, and that mitochondrial inhibition induces endothelial dysfunction. Additionally, we show that resveratrol acts as a protective agent; resveratrol-mediated mitochondrial protection may be used to prevent long-term diabetic cardiovascular complications.

Alterations in connexin 43 during diabetic cardiomyopathy: competition of tyrosine nitration versus phosphorylation

BACKGROUND

Cardiac conduction abnormalities are observed early in the progression of type 1 diabetes (T1D), but the mechanism(s) involved are undefined. Connexin 43, a critical component of ventricular gap junctions, depends on tyrosine phosphorylation status to modulate channel conductance; changes in connexin 43 content, distribution, and/or phosphorylation status may be involved in cardiac rhythm disturbances. We tested the hypothesis that cardiac content and/or distribution of connexin 43 is altered in a rat model of T1D cardiomyopathy, investigating a mechanistic role for tyrosine.

METHODS

Electrocardiographic analyses were conducted during the progression of diabetic cardiomyopathy in rats dosed with streptozotocin (STZ; 65 mg/kg) 3, 7, and 35 days after the induction of diabetes. Following functional analyses, we conducted immunohistochemical and immunoprecipitation studies to assess alterations in connexin 43.

RESULTS

There was significant evidence of ventricular conduction abnormalities (QRS complex, Q-T interval) as early as 7 days after STZ, persisting throughout the study. Connexin 43 levels were increased 7 days after STZ and remained elevated throughout the study. Connexin 40 content was unchanged relative to controls throughout the study. Changes in connexin 43 distribution were also observed: connexin 43 staining was dispersed from myocyte short axis junctions. Connexin 43 tyrosine phosphorylation declined during the progression of diabetes, with concurrent increases in tyrosine nitration.

CONCLUSIONS

The data suggest that changes in connexin 43 content and distribution occur during experimental diabetes and likely contribute to alterations in cardiac function, and that oxidative modification of tyrosine-mediated signaling may play a mechanistic role.

Lung development alterations in newborn mice after recovery from exposure to sublethal hyperoxia

Exposure of newborn mice to hyperoxia arrests lung development, with resultant pathological characteristics similar to bronchopulmonary dysplasia in infants born prematurely. We tested the hypothesis that aberrations in lung development caused by 14 days of sublethal hyperoxia would be reversed during 14 days of recovery to room air (RA) when the concentration of oxygen exposure was weaned gradually. Newborn FVB mice were exposed to 85% oxygen or RA for 14 days. Weaning from hyperoxia was by either transfer directly into RA or a decrease in the concentration of oxygen by 10% per days. At 28 days, pups were euthanized, and the lungs were inflation fixed and assessed. At postnatal day 28, lungs of mice weaned abruptly from hyperoxia had fewer (6 ± 0.6 versus 10 ± 0.7; P < 0.001) alveoli per high-powered field and larger alveoli (4050 ± 207 versus 2305 ± 182 μm(2)) than animals weaned gradually; both hyperoxia-exposed groups were different from lungs obtained from air-breathing controls (20 ± 0.5 alveoli per high-powered field; P < 0.001). The results are consistent with the absence of catch-up alveolarization in this model and indicate that the long-term consequences of early exposures to hyperoxia merit closer examination. The effects of abrupt weaning to RA observed further suggest that weaning should be considered in experimental models of newborn exposure to hyperoxia.

Preterm lambs given intravenous dopamine show increased dopamine in their cerebrospinal fluid

AIM

Dopamine is used as an inotropic medication in preterm infants. The preterm human blood brain barrier (BBB) is permeable to intravascular dopamine, and the impact of exogenous dopamine on the preterm brain remains unknown. The preterm lamb model may be suitable for studying the cerebral impact of dopamine therapy whether its BBB permeability is similar to preterm human infants. We aimed to examine BBB permeability to exogenous dopamine in the preterm lamb, by measuring dopamine levels in the cerebrospinal fluid (CSF).

METHODS

Nine preterm foetal lambs (125-130 days, term = 147 days) were given either dopamine at 10 μg/kg/min (dopamine, n = 4) or saline (control, n = 5). CSF, and plasma samples were taken for dopamine assay.

RESULTS

The median (range) baseline CSF dopamine level for the combined control and dopamine groups (n = 9) was 0.10(0.03-0.16) ng/mL, and baseline plasma dopamine was 0.30(0.13-0.84) ng/mL. The dopamine lambs showed increase in CSF dopamine to 3.91(1.87-11.35) ng/mL with plasma dopamine increased to 14.2 (9.1-57.9) ng/mL. No change was found in the control lambs.

CONCLUSION

In the preterm lamb, the BBB permeability and pharmacokinetics to dopamine infusion are similar to findings in the preterm human infant, supporting applicability of the preterm lamb model for studying effects of dopamine infusion in the preterm human brain.

Effects of human endothelial gene polymorphisms on cellular responses to hyperglycaemia: role of NOS3 (Glu298Asp) and ACE (I/D) polymorphisms

The functional relevance of NOS3 and ACE genetic variations to endothelial cell function is largely unstudied. Here we tested the functional relevance of the NOS3 (Glu298Asp) polymorphism and ACE (I/D) polymorphism in endothelial cells in vitro. Our hypothesis was that these genetic polymorphisms alter endothelial cell sensitivity to glucose and 3-nitrotyrosine (3NT). Genotyped HUVECs were incubated with glucose, free 3NT or a combination of these two toxicants. Significant differences in glucose-induced cell death and free 3NT-induced cell death were observed among the NOS3 genotypes. Combined glucose/3NT caused increased toxicity among the NOS3 genotypes. No differences were observed among the ACE genotypes in their responses to glucose/3NT. These data demonstrate that the NOS3 genotype may be an important predictor of, or be mechanistically involved in, endothelial vulnerability, whereas the ACE I/D genotype is apparently less important. Thus this NOS3 genetic variation may play a role in vulnerability to endothelium-dependent diabetic vascular complications.

Inhaled nitric oxide decreases leukocyte trafficking in the neonatal mouse lung during exposure to >95% oxygen

Chronic lung injury in the neonate is termed bronchopulmonary dysplasia (BPD). These patients generally require supplemental oxygen therapy, and hyperoxia has been implicated in the pathogenesis of BPD. The concomitant use of oxygen and inhaled NO (iNO) may result in the generation of reactive nitrogen species or may have an anti-inflammatory effect in the neonatal lung. We tested the hypothesis that exposure to >95% O2 in neonatal mice would increase trafficking of leukocytes into the lung and that the addition of iNO to >95% O2 would decrease this leukocyte trafficking. Hyperoxia resulted in fewer alveoli, increased presence of neutrophils and macrophages, and decreased number of mast cells within the lung parenchyma. Adding iNO to hyperoxia prevented the hyperoxia-induced changes and resulted in the numbers of alveoli, neutrophils, macrophages, and mast cells approximating those found in controls (room air exposure). Intercellular adhesion molecule (ICAM) and monocyte chemotactic protein-1 (MCP-1), two factors responsible for leukocyte recruitment, were up-regulated by hyperoxic exposure, but the addition of iNO to the hyperoxic exposure prevented the hyperoxia-induced up-regulation of ICAM and MCP-1. These data demonstrate that iNO alters the hyperoxia-induced recruitment of leukocytes into the lung.

Pharmacological and biological screening of ascorbigen: protection against glucose-induced endothelial cell toxicity

Cruciferous vegetables contain significant amounts of ascorbigen and related substances with known molecular structures. This study tested the hypothesis that ascorbigen demonstrates antioxidant properties and protects human umbilical cord endothelial cells against hyperglycemic toxicity in vitro. It was observed that ascorbigen, in micromolar concentrations, protected against endothelial cell death from glucose toxicity. Additionally, ascorbigen at 3.0 mm shifted the concentration response curve of l-phenylephrine to the right, with a reduction in the maximal contractile effects of the agonist. This action was not related to alpha-adrenoceptor blockade. Ascorbigen also relaxed the vascular tone induced by l-phenylephrine, which is not mediated by an endothelial cell nitric oxide-dependent mechanism. On the guinea-pig ileum, the spasmogenic effects of carbachol, histamine and serotonin were reduced in the presence of 3 mM ascorbigen. Spasm of the gut induced by the acetylcholinesterase inhibitor, physostigmine, was antagonized by ascorbigen with an IC50 of 286 microM. This natural product also has a weak antiparasitic activity. The cytoprotective effects of ascorbigen may be highly relevant in the optimum physiological regulation of the function and the therapeutic value of this substance in disease settings needs to be further investigated.

Celecoxib-Cyclodextrin Systems: Characterization and Evaluation of In Vitro and In Vivo Advantage

Solid dispersions of Celecoxib were prepared with hydroxypropyl beta cyclodextrin by various methods such as physical mixture, cogrinding, kneading, and coevaporation. The dispersions were characterized by differential scanning calorimetry (DSC), X-ray diffraction patterns, infrared spectroscopy, and nuclear magnetic resonance studies. The DSC thermograms of the dispersions indicated potential of heat-induced interaction between Celecoxib and cyclodextrin that could influence in vitro drug dissolution. The dispersions exhibited faster rates of dissolution compared to that of Celecoxib. The kneaded dispersion with the fastest in vitro dissolution rate when compressed into tablets showed a better release profile compared to the tablets of pure Celecoxib. In vivo studies revealed that the kneaded dispersion provided for quicker response and was more effective in inhibiting rat paw edema as compared to Celecoxib alone, thus confirming the advantage of improved pharmacological activity of Celecoxib when administered as a solid dispersion with cyclodextrin.

Preliminary computational modeling of nitric oxide synthase 3 interactions with caveolin-1: influence of exon 7 Glu298Asp polymorphism

The significance of endothelial nitric oxide synthase 3 (NOS3) activity has been recognized for many years, however it was only recently that the complicated regulation of this constitutively expressed enzyme in endothelial cells was identified. A critical component of the NOS3 regulatory cycle in endothelial cells is its intracellular localization to caveolae. The caveolar coordination of NOS3, more specifically its interaction with caveolin-1 (Cav-1), plays a major role in normal endothelial NOS3 activity and vascular bioavailability of nitric oxide. We have recently shown that the presence of NOS3 exon 7 Glu298Asp polymorphism caused diminished shear-dependent NOS activation, was less extensively associated with caveolae, and had a decreased degree of interaction with Cav-1. Here, we carried out preliminary investigations to identify possible mechanisms of the genotype-dependent endothelial cell responses we observed in our previous investigations. Through this approach we tested the hypothesis that computer simulations could provide insights regarding the contribution of this single nucleotide polymorphism to regulation of the NOS3 isoform. We observed that in the Glu/Asp and Asp/Asp mutant genotypes, the amount of NOS3 associated with Cav-1 was significantly lower. Additionally, we have shown, using a theoretical computational model, that mutation of an amino acid at position 298 might affect the protein-protein interactions and localization of the NOS3 protein. These alterations might also affect the protein function and explain the enhanced disease risk associated with the presence of Glu298Asp polymorphism in the NOS3 protein.

Maturational changes in the regulation of pulmonary vascular tone by nitric oxide in neonatal rats

Nitric oxide (NO) is an important regulator of vasomotor tone in the pulmonary circulation. We tested the hypothesis that the role NO plays in regulating vascular tone changes during early postnatal development. Isolated, perfused lungs from 7- and 14-day-old Sprague-Dawley rats were studied. Baseline total pulmonary vascular resistance (PVR) was not different between age groups. The addition of KCl to the perfusate caused a concentration-dependent increase in PVR that did not differ between age groups. However, the nitric oxide synthase (NOS) inhibitor N(omega)-nitro-L-arginine augmented the K(+)-induced increase in PVR in both groups, and the effect was greater in lungs from 14-day-old rats vs. 7-day-old rats. Lung levels of total endothelial, inducible, and neuronal NOS proteins were not different between groups; however, the production rate of exhaled NO was greater in lungs from 14-day-old rats compared with those of 7-day-old rats. Vasodilation to 0.1 microM of the NO donor spermine NONOate was greater in 14-day lungs than in 7-day lungs, and lung levels of both soluble guanylyl cyclase and cGMP were greater at 14 days than at 7 days. Vasodilation to 100 microM of the cGMP analog 8-(4-chlorophenylthio)guanosine-3',5'-cyclic monophosphate was greater in 7-day lungs than in 14-day lungs. Our results demonstrate that the pulmonary vascular bed depends more on NO production to modulate vascular tone at 14 days than at 7 days of age. The observed differences in NO sensitivity may be due to maturational increases in soluble guanylyl cyclase protein levels.

Chronic cardiac resynchronization therapy and reverse ventricular remodeling in a model of nonischemic cardiomyopathy

While cardiac resynchronization therapy (CRT) has been shown to reduce morbidity and mortality in heart failure (HF) patients, the fundamental mechanisms for the efficacy of CRT are poorly understood. The lack of understanding of these basic mechanisms represents a significant barrier to our understanding of the pathogenesis of HF and potential recovery mechanisms. Our purpose was to determine cellular mechanisms for the observed improvement in chronic HF after CRT. We used a canine model of chronic nonischemic cardiomyopathy. After 15 months, dogs were randomized to continued RV tachypacing (untreated HF) or CRT for an additional 9 months. Six minute walk tests, echocardiograms, and electrocardiograms were done to assess the functional response to therapy. Left ventricular (LV) midmyocardial myocytes were isolated to study electrophysiology and intracellular calcium regulation. Compared to untreated HF, CRT improved HF-induced increases in LV volumes, diameters and mass (p<0.05). CRT reversed HF-induced prolongations in LV myocyte repolarization (p<0.05) and normalized HF-induced depolarization (p<0.03) of the resting membrane potential. CRT improved HF-induced reductions in calcium (p<0.05). CRT did not attenuate the HF-induced increases in LV interstitial fibrosis. Using a translational approach in a chronic HF model, CRT significantly improved LV structure; this was accompanied by improved LV myocyte electrophysiology and calcium regulation. The beneficial effects of CRT may be attributable, in part, to improved LV myocyte function.

Biochemical consequences of the NOS3 Glu298Asp variation in human endothelium: altered caveolar localization and impaired response to shear

Human endothelial nitric oxide synthase (NOS3) gene polymorphism at Exon 7 (Glu298Asp) has been linked to vascular endothelial dysfunction, but the mechanisms are not defined. Shear is a key modulator of NOS3 function in vivo and association with caveolae is important for the control of NOS3 protein activity. Here we tested the hypothesis that altered enrichment of NOS3 in the caveolar membrane defines Glu298Asp genotype-specific responses and NOS3 activity. Basal caveolar membrane enrichment was carried out to quantitate the NOS3 enrichment in caveolae. Cells were subjected to shear and NOS3 protein levels, phosphorylation, enzyme function were investigated. Variant genotypes had lower NOx production pre- and post-shear, but no genotype-dependent alterations in pNOS3 were observed. Asp variants had significantly lower NOS3 enrichment in the caveolar membrane fraction. Further, immunoprecipitation studies demonstrated that Asp variants had substantially less NOS3/Cav-1 association (approximately 40%) during static conditions. Furthermore, acute shear causes impaired NOS3/Cav-1 dissociation in Asp variants. The results from immunoprecipitation studies were in complete agreement with caveolar membrane preparation findings. Collectively, these data demonstrate functional consequences of the Glu298Asp NOS3 variation and further define disruption of NOS3 caveolar localization and shear-induced mobilization as the primary mechanism responsible for these differences.

Children's acquisition and retention of safety skills: the Lifeskills program

OBJECTIVES

Assessment of safety skills performance and knowledge, to evaluate the education offered by the Lifeskills "Learning for Living" village, Bristol, UK which emphasizes interactive learning-by-doing.

DESIGN

Two quasi-experimental matched control group studies. Study 1: knowledge and performance three months post-intervention. Study 2: knowledge pre-intervention and post-intervention at three time points, to distinguish between immediate learning and longer term retention.

SETTING

The Lifeskills training village, Bristol, UK; primary schools in four education authorities in the area.

PARTICIPANTS

Study 1: 145 children aged 10-11 years; 109 from the Lifeskills program, 36 control. Study 2: 671 children aged 10-11 years; 511 Lifeskills, 160 control.

OUTCOME MEASURES

Three areas (road, home, and fire safety). Five performance tests: observation of children's safety skills. Five knowledge tests: pictorial quiz.

RESULTS

Study 1: Lifeskills/intervention children did better than control children on performance and knowledge tests. The knowledge-performance correlation was r = 0.51. Study 2: intervention children did better than control children immediately after the intervention and three months later on all five knowledge tests. On three tests the intervention group showed retention of knowledge from immediately post-intervention to three months, but on two tests there was some loss. This loss was primarily among children from scholastically lower achieving schools. In all other respects the intervention was equally successful for boys and girls, and for children from higher and lower achieving schools.

CONCLUSIONS

The Lifeskills package improved both knowledge and performance but had shortcomings. Complexity of material did not affect knowledge acquisition but did affect its retention.

Calcineurin regulates myocardial function during acute endotoxemia

RATIONALE

Cyclosporin A (CsA) is known to preserve cardiac contractile function during endotoxemia, but the mechanism is unclear. Increased nitric oxide (NO) production and altered mitochondrial function are implicated as mechanisms contributing to sepsis-induced cardiac dysfunction, and CsA has the capacity to reduce NO production and inhibit mitochondrial dysfunction relating to the mitochondrial permeability transition (MPT).

OBJECTIVES

We hypothesized that CsA would protect against endotoxin-mediated cardiac contractile dysfunction by attenuating NO production and preserving mitochondrial function.

METHODS

Left ventricular function was measured continuously over 4 h in cats assigned as follows: control animals (n = 7); LPS alone (3 mg/kg, n = 8); and CsA (6 mg/kg, n = 7), a calcineurin inhibitor that blocks the MPT, or tacrolimus (FK506, 0.1 mg/kg, n = 7), a calcineurin inhibitor lacking MPT activity, followed in 30 min by LPS. Myocardial tissue was then analyzed for NO synthase-2 expression, tissue nitration, protein carbonylation, and mitochondrial morphology and function.

MEASUREMENTS AND MAIN RESULTS

LPS treatment resulted in impaired left ventricular contractility, altered mitochondrial morphology and function, and increased protein nitration. As hypothesized, CsA pretreatment normalized cardiac performance and mitochondrial respiration and reduced myocardial protein nitration. Unexpectedly, FK506 pretreatment had similar effects, normalizing both cardiac and mitochondrial parameters. However, CsA and FK506 pretreatments markedly increased protein carbonylation in the myocardium despite elevated manganese superoxide dismutase activity during endotoxemia.

CONCLUSIONS

Our data indicate that calcineurin is a critical regulator of mitochondrial respiration, tissue nitration, protein carbonylation, and contractile function in the heart during acute endotoxemia.

Primary rhabdomyosarcoma of the seminal vesicle

Sarcomas of the seminal vesicle are very rare and poorly documented; as it is not always possible to pinpoint a truly vesicular origin of the pelvic mass due to local spread at the time of presentation. The purpose of the article is to document and characterize a rhabdomyosarcoma of the seminal vesicle of which to the knowledge of the authors there has been no previous report in the English literature.

Abnormal permeability of inner and outer mitochondrial membranes contributes independently to mitochondrial dysfunction in the liver during acute endotoxemia*

OBJECTIVE

This study was designed to determine the role played by the mitochondrial permeability transition in the pathogenesis of mitochondrial damage and dysfunction in a representative systemic organ during the acute phase of endotoxemia.

DESIGN

A well-established, normotensive feline model was employed to determine whether pretreatment with cyclosporine A, a potent inhibitor of the mitochondrial permeability transition, normalizes mitochondrial ultrastructural injury and dysfunction in the liver during acute endotoxemia.

SETTING

The Ohio State University Medical Center research laboratory.

SUBJECTS

Random source, adult, male conditioned cats.

INTERVENTIONS

Hemodynamic resuscitation and maintenance of acid-base balance and tissue oxygen availability were provided, as needed, to minimize the potentially confounding effects of tissue hypoxia and/or acidosis on the experimental results. Treatment groups received isotonic saline vehicle (control; n = 6), lipopolysaccharide (3.0 mg/kg, intravenously; n = 8), or cyclosporine A (6.0 mg/kg, intravenously; n = 6) or tacrolimus (FK506, 0.1 mg/kg, intravenously; n = 4) followed in 30 mins by lipopolysaccharide (3.0 mg/kg, intravenously). Liver samples were obtained 4 hrs posttreatment, and mitochondrial ultrastructure, function, and cytochrome c, Bax, and ceramide contents were assessed.

MEASUREMENTS AND MAIN RESULTS

As expected, significant mitochondrial injury was apparent in the liver 4 hrs after lipopolysaccharide treatment, despite maintenance of regional tissue oxygen availability. Namely, mitochondria demonstrated high-amplitude swelling and exhibited altered respiratory function. Cyclosporine A pretreatment attenuated lipopolysaccharide-induced mitochondrial ultrastructural abnormalities and normalized mitochondrial respiratory control, reflecting protection against inner mitochondrial membrane damage. However, an abnormal permeability of outer mitochondrial membranes to cytochrome c was observed in all lipopolysaccharide-treated groups and was associated with increased mitochondrial concentrations of Bax and ceramide.

CONCLUSIONS

These studies confirm that liver mitochondria are early targets of injury during endotoxemia and that inner and outer mitochondrial membrane damage occurs through different mechanisms. Inner mitochondrial membrane damage appears to relate to the mitochondrial permeability transition, whereas outer mitochondrial membrane damage can occur independent of the mitochondrial permeability transition. Preliminary evidence suggests that Bax may participate in lipopolysaccharide-induced outer mitochondrial membrane damage, but further investigations are needed to confirm this.

Cyclosporin A ameliorates mitochondrial ultrastructural injury in the ileum during acute endotoxemia

OBJECTIVE

This study was designed to determine the role, if any, of the mitochondrial permeability transition in the pathogenesis of mitochondrial injury in a representative systemic organ during the acute phase of endotoxemia.

DESIGN

A well-established, normotensive feline model was employed to determine whether pretreatment with cyclosporin A, a potent inhibitor of the mitochondrial permeability transition, reduces the severity of mitochondrial injury in the ileum during acute endotoxemia.

SETTING

The Ohio State University Medical Center research laboratory. SUBJECTS Adult, male conditioned cats.

INTERVENTIONS

Volume resuscitation and maintenance of acid/base balance and tissue oxygen availability were provided, as needed, to minimize the potentially confounding effects of tissue hypoxia and/or acidosis on the experimental results. Following isotonic saline vehicle (control; n = 6), lipopolysaccharide (3.0 mg/kg, intravenously; n = 10), or cyclosporin A (6 mg/kg, intravenously; n = 7) followed in 60 mins by lipopolysaccharide (3.0 mg/kg, intravenously) administration, ileal samples were obtained at 4 hrs posttreatment, and mitochondrial ultrastructure was assessed. Objective comparisons of mitochondrial ultrastructural morphology were performed by using digital image analyses.

MEASUREMENTS AND MAIN RESULTS

As expected, significant mitochondrial injury was apparent in the ileal tissues by 4 hrs following LPS treatment, despite maintenance of regional tissue oxygen availability. Objective evaluation of mitochondrial morphology demonstrated characteristics consistent with high-amplitude swelling. Cyclosporin A pretreatment protected against the development of these LPS-induced mitochondrial ultrastructural abnormalities, an effect not attributable to the suppression of lipopolysaccharide-induced tumor necrosis factor-alpha production.

CONCLUSIONS

These investigations are the first to demonstrate a protective effect of cyclosporin A against mitochondrial injury in a representative systemic organ during acute endotoxemia. We propose that mitochondrial injury likely related to induction of the mitochondrial permeability transition may participate in the pathogenesis of systemic organ injury and organ failures during acute sepsis.

In situ measurement of nitric oxide production in cardiac isografts and rejecting allografts by an electrochemical method

A number of previous studies have indirectly (electron paramagnetic resonance, nitrite/nitrate, ribonuclease protection assay for inducible nitric oxide synthase (iNOS) mRNA, l-citrulline assay) demonstrated the production of nitrogen monoxide (NO) during early cardiac allograft rejection. This study reports the first direct, quantitative measurement using an electrochemical method of NO produced from rejecting allograft tissue studied in vitro. A rat heterotopic abdominal transplant preparation was utilized. Day 7 isograft (ACI to ACI) or allograft (Lewis to ACI) transplanted hearts were atraumatically harvested and suspended at 4 degrees C in Ringers-Hepes solution. An electrochemical system highly sensitive and specific for NO consisting of a Nafion-coated platinum disk electrode (lower limit, 50 nM NO) coupled to an analysis system measured ongoing oxidation of NO. Measurements were carried out after inserting the electrode in the tissue block and warming the block to 25 degrees C. Additional measurements were also made after incubation of tissue with aminoguanidine (AG), a relatively selective iNOS inhibitor. Direct measurements (mean +/- SEM) from allograft tissue indicated a fourfold increase in NO as compared with isografts (13.41 +/- 4.40 microM NO vs. 3.43 +/- 2.04 microM NO). Incubation of allograft tissue with AG reduced NO levels to isograft levels (13.41 +/- 4.40 microM NO vs. 5.94 +/- 3.14 microM NO); AG had no effect on measured isograft NO levels. Direct, quantitative measurement of NO from tissue is feasible and reproducible, and discrimination between different levels of NO production can be made. These results confirm the imputed results from the previous studies using this experimental model. This technology promises to be a valuable tool for evaluating specific modulators of NO production studied under a variety of physiologic and pathophysiologic conditions.

Reactive oxygen species mediate tumor necrosis factor alpha-converting, enzyme-dependent ectodomain shedding induced by phorbol myristate acetate

Ectodomain shedding of cell surface membrane-anchoring proteins is an important process in a wide variety of physiological events(1, 2). Tumor necrosis factor alpha (TNF-alpha) converting enzyme (TACE) is the first discovered mammalian sheddase responsible for cleavage of several important surface proteins, including TNF-alpha, TNF p75 receptor, L-selectin, and transforming growth factor-a. Phorbol myristate acetate (PMA) has long been known as a potent agent to enhance ectodomain shedding. However, it is not fully understood how PMA activates TACE and induces ectodomain shedding. Here, we demonstrate that PMA induces both reactive oxygen species (ROS) generation and TNF p75 receptor shedding in Mono Mac 6 cells, a human monocytic cell line, and l-selectin shedding in Jurkat T-cells. ROS scavengers significantly attenuated PMA-induced TNF p75 receptor shedding. Exogenous H2O2 mimicked PMA-induced enhancement of ectodomain shedding, and H2O2-induced shedding was blocked by TAPI, a TACE inhibitor. Furthermore, both PMA and H2O2 failed to cause ectodomain shedding in a cell line that lacks TACE activity. By use of an in vitro TACE cleavage assay, H2O2 activated TACE that had been rendered inactive by the addition of the TACE inhibitory pro-domain sequence. We presume that the mechanism of TACE activation by H2O2 is due to an oxidative attack of the pro-domain thiol group and disruption of its inhibitory coordination with the Zn++ in the catalytic domain of TACE. These results demonstrate that ROS production is involved in PMA-induced ectodomain shedding and implicate a role for ROS in other shedding processes.

Electron microscopy of buffalo green monkey kidney cells persistently infected with hepatitis A virus and immunolocalization of HAV antigens

Studies were carried out to analyse the ultrastructural changes and the distribution of hepatitis A virus (HAV)/antigens at subcellular level in buffalo green monkey kidney (BGMK) cells persistently infected with HM-175 strain of HAV. HAV infected BGMK cells showed distinct abnormalities in the endoplasmic reticulum and cytoplasmic membrane as compared to uninfected cells. The abnormalities were characterized by wavy arrays, structures like myelin, annulate lamellae, cytoplasmic inclusion bodies and vesicles. The wavy arrays within the cytoplasm of the host cells appeared to represent degenerating membranes. A complex myelin like body was found in close association with a group of virus like particles. Annulate lamellae like structures involving single paired membrane were detected infrequently whereas the cytoplasmic vesicles were numerous in these cells. An indirect immunogold technique was utilized to localize the HAV antigenin infected cells. A high density immunogold label for HIV like particles was predominantly detected in cytoplasmic vesicles. These results suggest a strong association of membrane substructure in vesicle forms with the compartmentalized replication of HAV within persistently infected host cells.

Effecting and leading change in health care organizations

BACKGROUND

Understanding change is crucial to implementing quality improvement (QI) initiatives. Widespread change will be required to correct what many consider to be outmoded and deficient systems of care. This article summarizes the current literature--within both health care and the fields of business and management--regarding how change occurs at the individual and organizational levels. Part 1 focuses on changing clinician behavior, which is instrumental to any effort directed in the health care setting. Part 2 examines the culture of change. Part 3 addresses issues of leadership, along with the necessary steps to guide change in an organization. Part 4 summarizes key elements of change. Finally, Part 5 provides three case examples of QI initiatives reported in the recent literature to illustrate how the application of the knowledge of change management can assist in the successful implementation of QI programs.

KEY ELEMENTS OF CHANGE

The knowledge base regarding successful change in health care organizations can be summarized in eight crucial strategies or principles: (1) develop a vision for change, (2) focus on the change process, (3) analyze which individuals in the organization must respond to the proposed change and what barriers exist, (4) build partnerships between physicians and the administration, (5) create a culture of continuous commitment to change, (6) ensure that change begins with leadership, (7) ensure that change is well communicated, and (8) build in accountability for change.

CONCLUSION

A knowledge of change management can help leaders of QI programs in health care organizations successfully apply these concepts to bring about much-needed transformations in health care.

Activation of tumor necrosis factor-alpha-converting enzyme-mediated ectodomain shedding by nitric oxide

Ectodomain shedding of cell surface proteins is an important process in a wide variety of physiological and developmental events. Recently, tumor necrosis factor-alpha-converting enzyme (TACE) has been found to play an essential role in the shedding of several critical surface proteins, which is evidenced by multiple developmental defects exhibited by TACE knockout mice. However, little is known about the physiological activation of TACE. Here, we show that nitric oxide (NO) activates TACE-mediated ectodomain shedding. Using an in vitro model of TACE activation, we show that NO activates TACE by nitrosation of the inhibitory motif of the TACE prodomain. Thus, NO production activates the release of cytokines, cytokine receptors, and adhesion molecules, and NO may be involved in other ectodomain shedding processes.

Soft tissue sarcomas: ultrasonographic evaluation of local recurrences

OBJECTIVE

The diagnosis of early local recurrence of soft tissue sarcomas, especially in those treated with surgery and radiotherapy, is a difficult clinical problem. Financial constraints led us to use ultrasonography instead of CT or MR imaging. The aim of this study was to evaluate the role of ultrasonography (US) in detecting local recurrence.

METHODS AND RESULTS

Fifty patients with previous treatment for soft tissue sarcomas were evaluated prospectively for recurrence by US and histopathology. Seven of the 50 patients were clinically suspected to have recurrent tumour. Ultrasonography showed recurrence in 26, no recurrence in 18, benign disease in four and was indeterminate in two cases. Ultrasonography was instrumental in guiding fine needle aspiration biopsies of small local recurrences and indeterminate lesions in 17 patients. In the sonographically tumour positive patients, histopathology confirmed recurrence in 24; one case had benign disease and one patient refused surgery. Thirteen of the 18 sonographically tumour negative patients were operated upon; all were negative for tumour on histopathology. Both the indeterminate cases showed recurrence on histopathology. The benign cases were confirmed by histopathology correlation. Ultrasound guided fine needle aspiration cytology (FNAC) was positive in 14 out of 17 patients (88%). The sensitivity and specificity of US was 92.30% and 94.4% respectively.

CONCLUSION

Our study concludes that US is an extremely useful and cost effective method in the detection of early local recurrences of soft tissue sarcomas and should therefore be used for initial routine follow-up and guided biopsies.

Digital imaging analysis for the study of endotoxin-induced mitochondrial ultrastructure injury

Primary defects in mitochondrial function have been implicated in over 100 diverse diseases. In situ, mitochondria possess unique and well-defined morphology in normal healthy cells, but diseases linked to defective mitochondrial function are characterized by the presence of morphologically abnormal and swollen mitochondria with distorted cristae. In situ study of mitochondrial morphology is established as an indicator of mitochondrial health but thus far assessments have been via subjective evaluations by trained observers using discontinuous scoring systems. Here we investigated the value of digital imaging analysis to provide for unbiased, reproducible, and convenient evaluations of mitochondrial ultrastructure. Electron photomicrographs of ileal mucosal mitochondria were investigated using a scoring system previously described by us, and also analyzed digitally by using six digital parameters which define size, shape, and electron density characteristics of over 700 individual mitochondria. Statistically significant changes in mitochondrial morphology were detected in LPS treated animals relative to vehicle control using both the subjective scoring system and digital imaging parameters (p < 0.05). However, the imaging approach provided convenient and high throughput capabilities and was easily automated to remove investigator influences. These results illustrate significant changes in ileal mucosal mitochondrial ultrastructure during sepsis and demonstrate the value of digital imaging technology for routine assessments in this setting.

Cellular antioxidant and pro-oxidant actions of nitric oxide

We describe a biphasic action of nitric oxide (NO) in its effects on oxidative killing of isolated cells: low concentrations protect against oxidative killing, while higher doses enhance killing, and these two effects occur by distinct mechanisms. While low doses of NO (from (Z)-1-[N-(3-ammonio propyl)-N-(n-propyl)-amino]-diazen-1-ium-1,2(2) diolate [PAPA/NO] or S-nitroso-N-acetyl-L-penicillamine [SNAP] prevent killing of rat hepatocytes by t-butylhydroperoxide (tBH), further increasing doses result in increased killing. Similar effects occur with rat hepatoma cells treated with PAPA/NO and tBH or H2O2. Increased killing with higher concentrations of NO donor is due to both NO and tBH, because NO donor alone is without effect. Glutathione (GSH) is not involved in either of these actions. Based on measurements of thiobarbituric acid-reactive substances (TBARS) and effects of lipid radical scavenger (DPPD) and deferoxamine, the protective effect, but not the enhancing effect, involves peroxidative chemistry. Fructose has no effect on tBH killing alone but provides substantial protection against killing by higher concentrations of NO plus tBH, suggesting that the enhancing effect involves mitochondrial dysfunction. Hepatocytes, when stimulated to produce NO endogenously, become resistant to tBH killing, indicative of the presence of an NO-triggered antioxidant defensive mechanism. The finding that the protective effects of low concentrations of NO and the harmful effects of high concentrations of NO are fundamentally different in nature suggest that therapeutic interventions could be designed, which selectively prevent its pro-oxidant activity at high concentrations, thus converting NO from a "Janus-faced" modulator of oxidant injury into a "pure" protectant.

Clinical performance improvement series. Classic CQI integrated with comprehensive disease management as a model for performance improvement

BACKGROUND

In recent years, health and disease management has emerged as an effective means of delivering, integrating, and improving care through a population-based approach. Since 1997 the University of Pennsylvania Health System (UPHS) has utilized the key principles and components of continuous quality improvement (CQI) and disease management to form a model for health care improvement that focuses on designing best practices, using best practices to influence clinical decision making, changing processes and systems to deploy and deliver best practices, and measuring outcomes to improve the process. Experience with 28 programs and more than 14,000 patients indicates significant improvement in outcomes, including high physician satisfaction, increased patient satisfaction, reduced costs, and improved clinical process and outcome measures across multiple diseases. DIABETES DISEASE MANAGEMENT: In three months a UPHS multidisciplinary diabetes disease management team developed a best practice approach for the treatment of all patients with diabetes in the UPHS. After the program was pilot tested in three primary care physician sites, it was then introduced progressively to additional practice sites throughout the health system. The establishment of the role of the diabetes nurse care managers (certified diabetes educators) was central to successful program deployment. Office-based coordinators ensure incorporation of the best practice protocols into routine flow processes. A disease management intranet disseminates programs electronically. Outcomes of the UPHS health and disease management programs so far demonstrate success across multiple dimensions of performance-service, clinical quality, access, and value.

DISCUSSION

The task of health care leadership today is to remove barriers and enable effective implementation of key strategies, such as health and disease management. Substantial effort and resources must be dedicated to gain physician buy-in and achieve compliance. The challenge is to provide leadership support, to reward and recognize best practice performers, and to emphasize the use of data for feedback and improvement. As these processes are implemented successfully, and evidence of improved outcomes is documented, it is likely that this approach will be more widely embraced and that organizationwide performance improvement will increase significantly.

CONCLUSIONS

Health care has traditionally invested extraordinary resources in developing best practice approaches, including guidelines, education programs, or other tangible products and services. Comparatively little time, effort, and resources have been targeted to implementation and use, the stage at which most efforts fail. CQI's emphasis on data, rapid diffusion of innovative programs, and rapid cycle improvements enhance the implementation and effectiveness of disease management.