Use of a computerized C-reactive protein (CRP) based sepsis evaluation in very low birth weight (VLBW) infants: a five-year experience

BACKGROUND

Serial C-reactive protein (CRP) values may be useful for decision-making regarding duration of antibiotics in neonates. However, established standard of practice for its use in preterm very low birth weight (<1500 g, VLBW) infants are lacking.

OBJECTIVE

Evaluate compliance with a CRP-guided computerized decision support (CDS) algorithm and compare characteristics and outcomes of compliant versus non-compliant cases. Measure correlation between CRPs and white blood count (WBC) indices.

METHODS

We examined 3 populations: 1) all preterm VLBW infants born at Vanderbilt 2006-2011 - we assessed provider compliance with CDS algorithm and measured relevant outcomes; 2) all patients with positive blood culture results admitted to the Vanderbilt NICU 2006-2012 - we tested the correlation between CRP and WBC results within 7 days of blood culture phlebotomy; 3) 1,000 randomly selected patients out of the 7,062 patients admitted to the NICU 2006-2012 - we correlated time-associated CRP values and absolute neutrophil counts.

RESULTS

Of 636 VLBW infants in cohort 1), 569 (89%) received empiric antibiotics for suspected early-onset sepsis. In 409 infants (72%) the CDS algorithm was followed; antibiotics were discontinued ≤48 hours in 311 (55%) with normal serial CRPs and continued in 98 (17%) with positive CRPs, resulting in significant reduction in antibiotic exposure (p<0.001) without increase in complications or subsequent infections. One hundred sixty (28%) were considered non-compliant because antibiotics were continued beyond 48 hours despite negative serial CRPs and blood cultures. Serial CRPs remained negative in 38 (12%) of 308 blood culture-positive infants from cohort 2, but only 4 patients had clinically probable sepsis with single organisms and no immunodeficiency besides extreme prematurity. Leukopenia of any cell type was not linked with CRPs in cohorts 2 and 3.

CONCLUSIONS

CDS/CRP-guided antibiotic use is safe and effective in culture-negative VLBW infants. CRP results are not affected by low WBC indices.

The Role of skn-1 in methylmercury-induced latent dopaminergic neurodegeneration

Mercury (Hg) is a persistent environmental bioaccumulative metal, with developmental exposure to methylmercury (MeHg) resulting in long-term health effects. We examined the impact of early-life exposure to MeHg and knockdown of skn-1 on dopaminergic (DAergic) neurodegeneration in the nematode Caenorhabditis elegans. SKN-1, a the major stress-activated cytoprotective transcription factors, promotes the transcription of enzymes that scavenge free radicals, synthesizes glutathione and catalyzes reactions that increase xenobiotic excretion. Deletions or mutations in this gene suppress stress resistance. Thus, we hypothesized that the extent of MeHg's toxicity is dependent on intact skn-1 response; therefore skn-1 knockout (KO) worms would show heightened sensitivity to MeHg-induced toxicity compared to wildtype worms. In this study we identified the impact of early-life MeHg exposure on Hg content, stress reactivity and DAergic neurodegeneration in wildtype, and skn-1KO C. elegans. Hg content, measured by Inductively Coupled Plasma Mass Spectrometry, showed no strain-dependent differences. Reactive oxygen species generation was dramatically increased in skn-1KO compared to wildtype worms. Structural integrity of DAergic neurons was microscopically assessed by visualization of fluorescently-labeled neurons, and revealed loss of neurons in skn-1KO and MeHg exposed worms compared to wildtype controls. Dopamine levels detected by High-performance liquid chromatography, were decreased in response to MeHg exposure and decreased in skn-1KO worms, and functional behavioral assays showed similar findings. Combined, these studies suggest that knockdown of skn-1 in the nematode increases DAergic sensitivity to MeHg exposure following a period of latency.

Adverse neurodevelopmental outcomes after exposure to phenobarbital and levetiracetam for the treatment of neonatal seizures

OBJECTIVE

Compare neurodevelopment after levetiracetam (LEV) and phenobarbital (PB) for neonatal seizures.

STUDY DESIGN

Retrospective study of infants who received antiepileptic drugs (AEDs) for neonatal seizures. Effect of cumulative exposure to LEV and PB on outcomes of death, cerebral palsy (CP) and Bayley Scales of Infant Development (BSID) scores were evaluated at 24 months corrected age. Analyses were adjusted for number of electrographic seizures and gestational age.

RESULT

In 280 infants with comparable seizure etiology and cranial imaging results, increased exposure to PB was associated with worse BSID cognitive and motor scores (8.1- and 9-point decrease per 100 mg kg(-1); P=0.01). The effect was less with LEV (2.2- and 2.6-point decrease per 300 mg kg(-1) LEV (P=0.01)). CP probability increased by 2.3-fold per 100 mg kg(-1) PB and was not associated with increasing LEV.

CONCLUSION

Increased exposure to PB is associated with worse neurodevelopmental outcomes than LEV. Prospective studies of outcomes of neonatal exposure to AEDs are essential.

Early prediction of cerebral palsy after neonatal intensive care using motor development trajectories in infancy

Neonatal intensive care unit (NICU) patients are at high risk for developmental disabilities such as cerebral palsy (CP). Early identification of CP is essential to effective rehabilitation, but diagnosis is often delayed, especially in preterm infants. We hypothesized that through the longitudinal evaluation of motor trajectories in the NICU follow-up clinic, we could distinguish infants who develop CP by 3 years of age.

STUDY DESIGN AND SUBJECTS

This was a retrospective study of 606 patients in the NICU Follow-up Clinic at Vanderbilt University with birth weight < 1500g or a diagnosis of hypoxic ischemic encephalopathy.

OUTCOMES MEASURES

Assessments included neurologic exams, the Developmental Assessment of Young Children (DAYC), the Bayley Scales of Infant Development (BSID) and the Gross Motor Function Classification Scale.

RESULTS

A decrease in DAYC scores between 6 and 12 months was present in preterm and term infants later diagnosed with CP, but not in children without CP (-23 vs. +1.5, p<0.001). DAYC score decreases in infancy were highly predictive of later CP (p<0.001). BSID scores quantified severe motor delays but did not add to prediction of CP diagnosis.

CONCLUSION

Standardized assessments of motor milestones quantitatively predict the risk of CP in former NICU patients by 12 months, allowing for timely diagnosis, counseling and therapy in high-risk infants.

The role of impedance monitoring in patients with extraesophageal symptoms

OBJECTIVES/HYPOTHESIS

Ambulatory esophageal impedance monitoring is commonly employed to assess for nonacid reflux in patients with extraesophageal reflux. We aimed to determine if on therapy impedance data can be predicted from off therapy upper endoscopy, manometry, or pH parameters.

STUDY DESIGN

Prospective Cohort Study.

METHODS

Patients with extraesophageal reflux symptoms and either partial- or nonresponders to twice-daily PPI underwent impedance monitoring on twice-daily PPI, as well as manometry, upper endoscopy, and 48-hour wireless pH monitoring off acid-suppressive medications for 1 week. Percent time pH < 4 and number of reflux episodes were obtained. Multivariable linear regression was used to determine association between the impedance data on therapy and upper endoscopy, manometry, and pH parameters measured off therapy.

RESULTS

Seventy-five patients (77% female, median BMI 29, 38% with hiatal hernia, and 19% with esophagitis) were studied both on and off therapy. Thirty-five percent had abnormal impedance monitoring on therapy and 84% had abnormal pH testing off therapy. There was no significant (P = 0.184) overall correlation between total number of impedance events and the baseline physiologic parameters of hiatal hernia, degree of acid reflux, or manometric findings, with only weak correlation (r = 0.54, P = 0.045) with % time pH < 4 among patients with esophagitis.

CONCLUSIONS

In patients with suspected extraesophageal reflux refractory to PPI therapy, impedance measures on therapy cannot be predicted from traditional baseline esophageal physiologic parameters. We recommend caution regarding over-interpretation of impedance data.

LEVEL OF EVIDENCE

2b.

High economic burden of caring for patients with suspected extraesophageal reflux

OBJECTIVES

Extraesophageal symptoms are common manifestations of gastroesophageal reflux disease (GERD). Lack of a definitive diagnostic or treatment standards complicate management, which often leads to multiple specialty consultations, procedures, pharmaceuticals and diagnostic tests. The aim of this study was to determine the economic burden associated with extraesophageal reflux (EER).

METHODS

Direct costs of evaluation were estimated for patients referred with symptoms attributed to EER between 2007 and 2011. Medicare payment for evaluation and management and pharmaceutical prices was used to calculate first year and overall costs of evaluating and treating extraesophageal symptoms attributed to reflux.

RESULTS

Overall, 281 patients were studied (cough (50%), hoarseness (23%), globus/post-nasal drainage (15%), asthma (9%), and sore throat (3%)). Over a median (interquartile range) of 32 (16-46) months follow-up, patients had a mean (95% confidence interval) of 10.1 (9.4-10.9) consultations with specialists and underwent 6.4 (3-9) diagnostic procedures. Overall, the mean initial year direct cost was $5,438 per patient being evaluated for EER. Medical and non-medical components contributed $5,154 and $283. Of the overall cost, 52% were attributable to the use of proton pump inhibitors. During the initial year, direct costs were 5.6 times higher than those reported for typical GERD ($971). A total of 54% of patients reported improvement of symptoms. Overall cost per improved patient was $13,700.

CONCLUSIONS

EER contributes substantially to health-care expenditures. In this cohort, the cost for initial year's evaluation and treatment of EER symptoms was quintuple that of typical GERD. Prescription costs and, in particular, proton pump inhibitors were the single greatest contributor to the cost of EER management.

Directional distribution of neoplasia in Barrett's esophagus is not influenced by distance from the gastroesophageal junction

BACKGROUND

Accurate endoscopic detection and staging are critical for appropriate management of Barrett's esophagus (BE)-associated neoplasia. Prior investigation has demonstrated that the distribution of endoscopically detectable early neoplasia is not uniform but instead favors specific directional distributions within a short BE segment; however, it is unknown whether the directional distribution of neoplasia differs with increasing distance from the gastroesophageal junction, including in patients with long-segment BE.

OBJECTIVE

To identify whether directional distribution of BE-associated neoplasia is influenced by distance from the gastroesophageal junction.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care referral center.

PATIENTS

Patients with either short-segment or long-segment BE undergoing EMR.

INTERVENTION

EMR.

MAIN OUTCOME MEASUREMENTS

Directional distribution of BE-associated neoplasia stratified by distance from gastroesophageal junction.

RESULTS

EMR was performed on 60 lesions meeting study criteria during the specified time period. Pathology demonstrated low-grade dysplasia in 22% (13/60), high-grade dysplasia in 38% (23/60), intramucosal (T1a) adenocarcinoma in 23% (14/60), and invasive (≥ T1b) adenocarcinoma in 17% (10/60). Directional distribution of lesions was not uniform (P < .001), with 62% of lesions (37/60) located between the 1 o'clock and 5 o'clock positions. When circular statistics methodology was used, there was no difference in the directional distribution of neoplastic lesions located within 3 cm of the gastroesophageal junction compared with ≥ 3 cm from the gastroesophageal junction.

LIMITATIONS

Single-center study may limit external validity.

CONCLUSION

The directional distribution of neoplastic foci within a BE segment is not influenced by distance of the lesion from the gastroesophageal junction. Mucosa between the 1 o'clock and 5 o'clock locations merits careful attention and endoscopic inspection in individuals with both short-segment BE and long-segment BE.

TR3 modulates platinum resistance in ovarian cancer

In metastatic ovarian cancer, resistance to platinum chemotherapy is common. Although the orphan nuclear receptor TR3 (nur77/NR4A1) is implicated in mediating chemotherapy-induced apoptosis in cancer cells, its role in ovarian cancer has not been determined. In an ovarian cancer tissue microarray, TR3 protein expression was elevated in stage I tumors, but downregulated in a significant subset of metastatic tumors. Moreover, TR3 expression was significantly lower in platinum-resistant tumors in patients with metastatic disease, and low TR3 staining was associated with poorer overall and progression-free survival. We have identified a direct role for TR3 in cisplatin-induced apoptosis in ovarian cancer cells. Nucleus-to-cytoplasm translocation of TR3 was observed in cisplatin-sensitive (OVCAR8, OVCAR3, and A2780PAR) but not cisplatin-resistant (NCI/ADR-RES and A2780CP20) ovarian cancer cells. Immunofluorescent analyses showed clear overlap between TR3 and mitochondrial Hsp60 in cisplatin-treated cells, which was associated with cytochrome c release. Ovarian cancer cells with stable shRNA- or transient siRNA-mediated TR3 downregulation displayed substantial reduction in cisplatin effects on apoptotic markers and cell growth in vitro and in vivo. Mechanistic studies showed that the cisplatin-induced cytoplasmic TR3 translocation required for apoptosis induction was regulated by JNK activation and inhibition of Akt. Finally, cisplatin resistance was partially overcome by ectopic TR3 overexpression and by treatment with the JNK activator anisomycin and Akt pathway inhibitor, wortmannin. Our results suggest that disruption of TR3 activity, via downregulation or nuclear sequestration, likely contributes to platinum resistance in ovarian cancer. Moreover, we have described a treatment strategy aimed at overcoming platinum resistance by targeting TR3.

Reactive oxygen species-reducing strategies improve pulmonary arterial responses to nitric oxide in piglets with chronic hypoxia-induced pulmonary hypertension

AIMS

There are no effective treatments for chronic pulmonary hypertension in infants with cardiopulmonary disorders associated with hypoxia, such as those with chronic lung disease. These patients often have poor or inconsistent pulmonary dilator responses to inhaled nitric oxide (iNO) therapy for unknown reasons. One possible explanation for poor responsiveness to iNO is reduced NO bioavailability caused by interactions between reactive oxygen species (ROS) and NO. Our major aim was to determine if strategies to reduce ROS improve dilator responses to the NO donor, S-nitroso-N-acetyl-penicillamine (SNAP), in resistance pulmonary arteries (PRAs) from a newborn piglet model of chronic pulmonary hypertension.

RESULTS

The dilation to SNAP was significantly impaired in PRAs from piglets with chronic hypoxia-induced pulmonary hypertension. ROS scavengers, including cell-permeable and impermeable agents to degrade hydrogen peroxide (H(2)O(2)), improved dilation to SNAP in PRAs from chronically hypoxic piglets. Treatment with agents to inhibit nitric oxide synthase and NADPH oxidase, potential enzymatic sources of ROS, also improved dilation to SNAP in PRAs from hypoxic piglets.

INNOVATION

Our studies are the first to utilize a newborn model of chronic pulmonary hypertension to evaluate the impact of a number of potential therapeutic strategies for ROS removal on responses to exogenous NO in the vessels most relevant to the regulation of pulmonary vascular resistance (PRA).

CONCLUSIONS

Strategies aimed at reducing ROS merit further evaluation and consideration as therapeutic approaches to improve responses to iNO in infants with chronic pulmonary hypertension.

An oropharyngeal pH monitoring device to evaluate patients with chronic laryngitis

BACKGROUND

Diagnostics for gastro-esophageal reflux disease (GERD) are suboptimal because of limited sensitivity. We performed in vitro and in vivo studies to systematically assess the performance characteristics of an oropharyngeal pH probe.

METHODS

In vitro studies compared the oropharyngeal probe with a standard pH catheter in liquid and aerosolized solutions, pH 1-7. The accuracy of measurements, deviation from target pH, and time to equilibrium pH were determined. Simultaneous distal esophageal pH measurements were obtained in 11 patients with GERD. Oropharyngeal and distal esophageal reflux parameters were measured for controls (n = 20), patients with GERD (n = 17), and patients with chronic laryngitis (n = 10).

KEY RESULTS

In the liquid phase, at pH 4-5, the oropharyngeal probe had less deviation from the target value than the standard catheter; deviation in the vapor phase was similar (0.4 pH units). Median (interquartile) time to reach equilibrium pH was significantly (P < 0.001) faster with the oropharyngeal than the standard probe. In comparing simultaneous distal esophageal pH characteristics, 96% of recordings with the new and standard probes were in agreement to within ± 1.0 pH unit; 71% of recordings were in agreement within ± 0.5 pH units. Patients with chronic laryngitis had significantly higher levels of oropharyngeal acid exposure at pH <4, <5, and <6, in the upright position than patients with GERD or controls (P < .001).

CONCLUSIONS & INFERENCES

Oropharyngeal pH monitoring appears to be more sensitive than traditional pH monitoring in evaluation of patients with extraesophageal reflux. It is a promising tool in evaluation of this difficult group of patients.

Early-life exposure to methylmercury in wildtype and pdr-1/parkin knockout C. elegans

We examined the impact of early-life exposure to methylmercury (MeHg) on Caenorhabditis elegans (C. elegans) pdr-1 mutants, addressing gene-environment interactions. We tested the hypothesis that early-life exposure to MeHg and knockout (KO) of pdr-1 (mammalian: parkin/PARK2) exacerbates MeHg toxicity and damage to the dopaminergic (DAergic) system. pdr-1KO worms showed increased lethality and decreased lifespan following MeHg exposure. Mercury (Hg) content, measured with inductively coupled plasma-mass spectrometry was increased in pdr-1KO worms compared to wildtype (N2) controls. 2'7' dichlorodihydrofluorescein diacetate assay revealed a significant increase in reactive oxygen species in both strains following MeHg exposure; however, while N2 worms showed an increase in skn-1 transcript levels following MeHg exposure, there was no difference in skn-1 induction in pdr-1KO worms. Dopamine-dependent behavioral analysis revealed an effect of MeHg on N2 wildtype worms, but no effect on pdr-1KO worms. Taken together, these results suggest that pdr-1KO worms are more sensitive to MeHg than wildtype worms, but MeHg does not exacerbate behavioral changes related to the absence of pdr-1.

A pilot study of Biotene OralBalance® gel for oral care in mechanically ventilated preterm neonates

BACKGROUND

Neonatal ventilator-associated pneumonia (VAP) is associated with increased morbidity and mortality. In adults on mechanical ventilation, timed oral care decreases the frequency of VAP, but this approach has not been studied in neonates.

OBJECTIVES

To evaluate the feasibility of a randomized trial of timed oral care with Biotene OralBalance® gel and estimate the required sample size for such a trial.

METHODS

Infants were eligible for enrollment if they were born before 28 weeks of gestation, and were mechanically ventilated between 7 and 10 postnatal days. Infants were randomized to receive timed oral care with Biotene OralBalance® gel or sterile water. All subjects were treated with a standard bundle of procedures to reduce the risk of VAP.

RESULTS

We enrolled 41 of 46 eligible infants (89%). Compliance with timed oral care protocol was 97%. No local oral side effects of Biotene OralBalance® gel were observed. There were no significant group differences in mortality or short-term outcomes, except length of hospital stay which was significantly shorter in the Sterile water group (p = 0.02). A lower rate of VAP was found in the Biotene group, although the difference was not statistically significant (9/1000 ventilator-days versus 17/1000 ventilator-days in the Sterile water group, respectively; p = 0.16).

CONCLUSIONS

The results of this pilot study support the feasibility of a randomized trial of timed oral care with Biotene OralBalance® gel for prevention of VAP in mechanically ventilated neonates.

Cimetidine-associated patent ductus arteriosus is mediated via a cytochrome P450 mechanism independent of H2 receptor antagonism

Persistent patency of the ductus arteriosus (PDA) is a common problem in preterm infants. The antacid cimetidine is a potent antagonist of the H2 histamine receptor but it also inhibits certain cytochrome P450 enzymes (CYPs), which may affect DA patency. We examined whether cimetidine contributes to PDA and is mediated by CYP inhibition rather than H2 blockade. Analysis of a clinical trial to prevent lung injury in premature infants revealed a significant association between cimetidine treatment and PDA. Cimetidine and ranitidine, both CYP inhibitors as well as H2 blockers, caused relaxation of the term and preterm mouse DA. CYP enzymes that are inhibited by cimetidine were expressed in DA subendothelial smooth muscle. The selective CYP3A inhibitor ketoconazole induced greater DA relaxation than cimetidine, whereas famotidine and other H2 antagonists with less CYP inhibitory effects caused less dilation. Histamine receptors were developmentally regulated and localized in DA smooth muscle. However, cimetidine caused DA relaxation in histamine-deficient mice, consistent with CYP inhibition, not H2 antagonism, as the mechanism for PDA. Oxygen-induced DA constriction was inhibited by both cimetidine and famotidine. These studies show that antacids and other compounds with CYP inhibitory properties pose a significant and previously unrecognized risk for PDA in critically ill newborn infants.

Iron deficiency accelerates Helicobacter pylori-induced carcinogenesis in rodents and humans

Gastric adenocarcinoma is strongly associated with Helicobacter pylori infection; however, most infected persons never develop this malignancy. H. pylori strains harboring the cag pathogenicity island (cag+), which encodes CagA and a type IV secretion system (T4SS), induce more severe disease outcomes. H. pylori infection is also associated with iron deficiency, which similarly augments gastric cancer risk. To define the influence of iron deficiency on microbial virulence in gastric carcinogenesis, Mongolian gerbils were maintained on iron-depleted diets and infected with an oncogenic H. pylori cag+ strain. Iron depletion accelerated the development of H. pylori-induced premalignant and malignant lesions in a cagA-dependent manner. H. pylori strains harvested from iron-depleted gerbils or grown under iron-limiting conditions exhibited enhanced virulence and induction of inflammatory factors. Further, in a human population at high risk for gastric cancer, H. pylori strains isolated from patients with the lowest ferritin levels induced more robust proinflammatory responses compared with strains isolated from patients with the highest ferritin levels, irrespective of histologic status. These data demonstrate that iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer.

Iron deficiency accelerates Helicobacter pylori-induced carcinogenesis in rodents and humans

Gastric adenocarcinoma is strongly associated with Helicobacter pylori infection; however, most infected persons never develop this malignancy. H. pylori strains harboring the cag pathogenicity island (cag+), which encodes CagA and a type IV secretion system (T4SS), induce more severe disease outcomes. H. pylori infection is also associated with iron deficiency, which similarly augments gastric cancer risk. To define the influence of iron deficiency on microbial virulence in gastric carcinogenesis, Mongolian gerbils were maintained on iron-depleted diets and infected with an oncogenic H. pylori cag+ strain. Iron depletion accelerated the development of H. pylori-induced premalignant and malignant lesions in a cagA-dependent manner. H. pylori strains harvested from iron-depleted gerbils or grown under iron-limiting conditions exhibited enhanced virulence and induction of inflammatory factors. Further, in a human population at high risk for gastric cancer, H. pylori strains isolated from patients with the lowest ferritin levels induced more robust proinflammatory responses compared with strains isolated from patients with the highest ferritin levels, irrespective of histologic status. These data demonstrate that iron deficiency enhances H. pylori virulence and represents a measurable biomarker to identify populations of infected persons at high risk for gastric cancer.

Use of direct, endoscopic-guided measurements of mucosal impedance in diagnosis of gastroesophageal reflux disease

BACKGROUND & AIMS

Diagnostic tests for gastroesophageal reflux disease (GERD) are constrained because measurements are made at a single time point, so the long-term effects on the mucosa cannot be determined. We developed a minimally invasive system to assess changes in esophageal mucosal impedance (MI), a marker of reflux. We measured the extent of changes in MI along the esophagus and show that the device to assess MI can be used to diagnose patients with GERD.

METHODS

A single-channel MI catheter composed of a unique sensor array was designed to easily traverse the working channel of an upper endoscope. We performed a prospective longitudinal study of patients with erosive esophagitis (n = 19), nonerosive but pH-positive GERD (n = 23), and those without GERD (n = 27). MI was measured at the site of esophagitis as well as 2, 5, and 10 cm above the squamocolumnar junction. The MI values were compared among groups, at different levels along the esophageal axis.

RESULTS

Median MI values were significantly lower at the site of erosive mucosa (811 Ω; range, 621-1272 Ω) than other nonerosive regions (3723 Ω; range, 2421-4671 Ω; P = .001), and were significantly lower at 2 cm above the squamocolumnar junction in patients with GERD (2096 Ω; range, 1415-2808 Ω), compared with those without GERD (3607 Ω; range, 1973-4238 Ω; P = .008). There was a significant and graded increase in MI along the axis of the distal to proximal esophagus in patients with GERD that was not observed in individuals without reflux (P = .004).

CONCLUSIONS

Measurements of MI along the esophagus can be used to identify patients with GERD. ClinicalTrials.gov, number NCT01194323.

Nonlinear relationship between body mass index and esophageal acid exposure in the extraesophageal manifestations of reflux

BACKGROUND & AIMS

Obesity is believed to be an important etiologic factor in gastroesophageal reflux disease. However, it is not clear how obesity might affect esophageal acid exposure in patients with extraesophageal manifestations of reflux.

METHODS

We conducted a cross-sectional study of 223 patients with extraesophageal symptoms suspected of being related to reflux. Participants underwent endoscopy and 48-hour wireless pH testing. The percentage of time at a pH of less than 4 (total, upright, and supine) was measured for each patient, and data were compared with corresponding body mass index (BMI), as continuous and categoric variables (normal, 18.5 to <25; overweight, 25 to <30; and obese, >30). Multivariable linear regression was used to identify variables associated with percentage of total time at a pH less than 4. The primary predictor of interest was BMI; age, sex, esophagitis, and hiatal hernia status were considered potential confounders or precision variables.

RESULTS

Esophageal acid exposure was associated significantly (P < .001) with BMI. The percentage of time at a pH less than 4 and total symptomatic reflux events increased significantly (P = .005) with increasing BMI. The relationship between percentage of time at a pH less than 4 and BMI was nonlinear and S-shaped. With BMI ranges, the percentage of time at a pH less than 4 increased by 0.23% (normal BMI), 0.75% (overweight), and 0.07% (obese) for every 1-kg/m(2) increase in BMI (P < .001).

CONCLUSIONS

Increases in esophageal acid exposure are greatest among overweight patients and plateau in obese patients. The findings have implications for benefit of weight loss in patients with suspected extraesophageal manifestations of gastroesophageal reflux disease.

Isoprostanes as physiological mediators of transition to newborn life: novel mechanisms regulating patency of the term and preterm ductus arteriosus

BACKGROUND

Increased oxygen tension at birth regulates physiologic events that are essential to postnatal survival, but the accompanying oxidative stress may also generate isoprostanes. We hypothesized that isoprostanes regulate ductus arteriosus (DA) function during postnatal vascular transition.

METHODS

Isoprostanes were measured by gas chromatography-mass spectrometry. DA tone was assessed by pressure myography. Gene expression was measured by quantitative PCR.

RESULTS

Oxygen exposure was associated with increased 8-iso-prostaglandin (PG)F2α in newborn mouse lungs. Both 8-iso-PGE2 and 8-iso-PGF2α induced concentration-dependent constriction of the isolated term DA, which was reversed by the thromboxane A2 (TxA2) receptor antagonist SQ29548. SQ29548 pretreatment unmasked an isoprostane-induced DA dilation mediated by the EP4 PG receptor. Exposure of the preterm DA to 8-iso-PGE2 caused unexpected DA relaxation that was reversed by EP4 antagonism. In contrast, exposure to 8-iso-PGF2α caused preterm DA constriction via TxA2 receptor activation. Further investigation revealed the predominance of the TxA2 receptor at term, whereas the EP4 receptor was expressed and functionally active from mid-gestation onward.

CONCLUSION

This study identifies a novel physiological role for isoprostanes during postnatal vascular transition and provide evidence that oxidative stress may act on membrane lipids to produce vasoactive mediators that stimulate physiological DA closure at birth or induce pathological patency of the preterm DA.

Rapid salivary pepsin test: blinded assessment of test performance in gastroesophageal reflux disease

OBJECTIVE/HYPOTHESIS

Pepsin lateral flow device (LFD) is a rapid noninvasive test to detect salivary pepsin as a surrogate marker for gastroesophageal reflux disease (GERD). We aimed to establish the test sensitivity, specificity, positive and negative predictive values (PPV, NPV) in patients with symptomatic and objective evidence of GERD compared to healthy controls.

STUDY DESIGN

Prospective, blinded, controlled cohort study.

METHODS

A total of 230 samples were analyzed. In vitro bench testing was conducted on 52 gastric juice and 54 sterile water samples to assess test sensitivity and specificity. Saliva was collected from 58 patients with GERD and 51 controls. All patients with GERD underwent esophagogastroduodenoscopy (EGD) and wireless 48-hour pH monitoring off acid suppressive therapy. PPV and NPV were calculated based on disease definition of esophagitis and/or abnormal pH monitoring.

RESULTS

Receiver operating characteristics analysis of in vitro samples found assay sensitivity and a specificity of 87%. There were 6/51 (12%) control subjects and 13/58 (22%) patients with GERD who tested positive for salivary pepsin (P = .25). There was a step-wise increase in the prevalence of positive salivary pepsin: esophagitis (55%), abnormal pH monitoring (43%), GERD symptoms only (24%) (P < .001). Salivary pepsin test showed a PPV of 81% and NPV of 78% for those with objective evidence of GERD (abnormal pH and/or esophagitis).

CONCLUSIONS

Rapid LFD for salivary pepsin has acceptable test characteristics in patients with GERD. A positive salivary pepsin test in this group may obviate the need for more expensive diagnostic testing by EGD or pH monitoring.

Feasibility of Dual Wireless Esophageal pH Monitoring

Objective

Wireless pH monitoring is currently employed in the distal esophagus. There are no controlled studies on the feasibility/safety of proximal esophageal wireless pH capsule placement. We tested the hypothesis that there will be no difference in patient perception of a more proximally placed pH capsule.

Study Design

Randomized single-blinded sham-controlled trial.

Setting

Tertiary care center.

Subjects and Methods

All patients had a wireless pH capsule positioned 6 cm proximal to the gastroesophageal junction. They were randomized into intervention or sham groups after distal capsule placement. The delivery introducer was positioned 10 cm proximal to the distal esophageal capsule, and a second capsule was either deployed (intervention) or not (sham) based on group allocation. Patients were blinded to group assignment. Modified Edmonton Score was used to assess for chest pain, dysphagia, and odynophagia. The primary endpoints were (1) required endoscopic removal because of discomfort and (2) change in chest pain scores, controlling for baseline pain.

Results

Patients were randomized to either the intervention, proximal esophageal capsule (n = 11), or sham (n = 11). Patients with proximal pH probes had higher odds of having their chest pain (odds ratio [OR], 8.44; 95% confidence interval [CI], 1.35-52.6; P = .02), odynophagia (OR, 49.5; 95% CI, 4.70-520; P = .001), and dysphagia (OR, 14.3; 95% CI, 2.12-96.6; P = .006) exacerbated. Two (2/11; 18%) proximally deployed probes required endoscopic removal because of patient intolerance or discomfort.

Conclusion

A proximal esophageal wireless pH monitor placement is feasible but results in increased chest pain, odynophagia, and dysphagia that can be severe enough to require endoscopic removal. These limitations preclude its potential clinical benefit.

Paneth cell ablation in the presence of Klebsiella pneumoniae induces necrotizing enterocolitis (NEC)-like injury in the small intestine of immature mice

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in premature infants. During NEC pathogenesis, bacteria are able to penetrate innate immune defenses and invade the intestinal epithelial layer, causing subsequent inflammation and tissue necrosis. Normally, Paneth cells appear in the intestinal crypts during the first trimester of human pregnancy. Paneth cells constitute a major component of the innate immune system by producing multiple antimicrobial peptides and proinflammatory mediators. To better understand the possible role of Paneth cell disruption in NEC, we quantified the number of Paneth cells present in infants with NEC and found that they were significantly decreased compared with age-matched controls. We were able to model this loss in the intestine of postnatal day (P)14-P16 (immature) mice by treating them with the zinc chelator dithizone. Intestines from dithizone-treated animals retained approximately half the number of Paneth cells compared with controls. Furthermore, by combining dithizone treatment with exposure to Klebsiella pneumoniae, we were able to induce intestinal injury and inflammatory induction that resembles human NEC. Additionally, this novel Paneth cell ablation model produces NEC-like pathology that is consistent with other currently used animal models, but this technique is simpler to use, can be used in older animals that have been dam fed, and represents a novel line of investigation to study NEC pathogenesis and treatment.

Significance and degree of reflux in patients with primary extraesophageal symptoms

OBJECTIVES/HYPOTHESIS

Patients with extraesophageal symptoms are often suspected of having gastroesophageal reflux disease (GERD). However, the true prevalence and severity of reflux disease is not well studied. In this group of patients, the objectives of our study were to determine the prevalence and severity of esophageal acid exposure and classify the endoscopic findings.

STUDY DESIGN

Prospective cohort study.

METHODS

One hundred twenty-eight patients with extraesophageal symptoms underwent 48 hours of Bravo pH monitoring. Percent of time that pH was <4 (total upright and supine) was measured. Severity of reflux was categorized by the percent of total time pH was <4, with mild = >4.2% but <10%, moderate = 10% to 20%, and severe>20%. Endoscopic signs of esophagitis and Barrett's esophagus were determined.

RESULTS

There were 104/128 (81%) patients who had abnormal esophageal acid exposure, 44% in the upright and supine position, 38% in the upright position only, and 18% in the supine position only. There were 59/128 (46%) patients with mild reflux, 40/128 (31%) with moderate, and only 5/128 (4%) patients with severe reflux. 23/128 (18%) patients had evidence of esophagitis. Only 1/128 (0.8%) patients had pathologic Barrett's esophagus. Prevalence of abnormal esophageal acid exposure was similar in those with (75%) or without (66%) concomitant heartburn and/or regurgitation (P = .3).

CONCLUSIONS

Abnormal esophageal pH is common in patients with extraesophageal symptoms. Most have only mild (46%) to moderate (31%) reflux with a low prevalence of esophagitis (18%) or Barrett's esophagus (0.8%). The degree of esophageal acid reflux cannot be predicted from baseline presence or absence of typical GERD symptoms.

Caution about overinterpretation of symptom indexes in reflux monitoring for refractory gastroesophageal reflux disease

BACKGROUND & AIMS

Symptom index (SI) and symptom association probability (SAP) are indexes used to analyze data collected from ambulatory pH and/or impedance monitoring and quantify the association between symptoms and reflux events. However, their characteristics are not well defined. We measured factors that affect SI and SAP values to determine their utility in assessing patients with refractory gastroesophageal reflux disease (GERD).

METHODS

We conducted a cross-sectional study of 254 patients with poor responses to proton pump inhibitor (PPI) therapy. Participants underwent esophagogastroduodenoscopy and wireless pH (n = 127) or impedance/pH monitoring when they were not receiving PPI therapy (n = 41) or impedance/pH monitoring while they received twice-daily PPI therapy (n = 86). SI and SAP values were calculated individually; ranges of values for each cell in the 2 × 2 contingency table were determined. Monte Carlo simulation was conducted to determine how varying reflux and symptom rates within the contingency table impacted the expected value and variability in SI and SAP.

RESULTS

At best, only 33% of patients who were refractory to PPI therapy had positive SI or SAP scores for acid or nonacid reflux events. Abnormal SAP (>95%) and SI (>50%) scores required high rates of reflux. At reflux rates less than 10%, observed in 70% of the studied population, SI and SAP values were largely determined by chance occurrences, rather than the relationship between symptoms and reflux. The values for each index varied significantly day-to-day.

CONCLUSIONS

SI or SAP indexes can be overinterpreted, unless patients with gastroesophageal reflux disease who are refractory to PPI therapy have high rates of reflux.