Increase in cardiac myosin binding protein-C plasma levels is a sensitive and cardiac-specific biomarker of myocardial infarction

Earlier studies have shown that cardiac myosin binding protein-C (cMyBP-C) is easily releasable into the circulation following myocardial infarction (MI) in animal models and patients. However, since its release kinetics has not been clearly demonstrated, no parameters are available to judge its efficacy as a bona fide biomarker of MI in patients with MI. To make this assessment, plasma levels of cMyBP-C and six known biomarkers of MI were determined by sandwich enzyme-linked immunosorbent assay in patients with MI who had before and after Percutaneous Transcoronary Angioplasty (PTCA), as well as healthy controls. Compared to healthy controls (22.3 ± 2.4 ng/mL (n=54)), plasma levels of cMyBP-C were significantly increased in patients with MI (105.1 ± 8.8 ng/mL (n=65), P<0.001). Out of 65 patients, 24 had very high levels of plasma cMyBP-C (116.5 ± 13.3 ng/mL), indicating high probability of MI. Importantly, cMyBP-C levels were significantly decreased in patients (n=40) at 12 hours post-PTCA (41.2 ± 9.3 ng/mL, P<0.001), compared to the patients with MI. Receiver operating characteristic analysis revealed that a plasma cMyBP-C reading of 68.1 ng/mL provided a sensitivity of 66.2% and a specificity of 100%. Also, myoglobin, carbonic anhydrase and creatine kinase-MB levels were significantly increased in MI patients who also had higher cMyBP-C levels. In contrast, levels of cardiac troponin I, glycogen phosphorylase and heart-type fatty acid binding protein were not significantly changed in the samples, indicating the importance of evaluating the differences in release kinetics of these biomarkers in the context of accurate diagnosis. Our findings suggest that circulating cMyBP-C is a sensitive and cardiac-specific biomarker with potential utility for the accurate diagnosis of MI.

Bubble and ventilator-derived nasal continuous positive airway pressure in premature infants: work of breathing and gas exchange

OBJECTIVE

During bubble nasal continuous positive airway pressure (B-NCPAP), gas flows through the expiratory limb of CPAP tubing submerged underwater to a depth in centimeters considered equal to the desired end expiratory pressure. Ventilator-derived NCPAP (V-NCPAP) controls the delivered pressure at the expiratory orifice. Limited data exist comparing the two forms of NCPAP on work of breathing (WOB) and other short-term respiratory outcomes. We compared WOB and gas exchange between B-NCPAP and V-NCPAP at equivalent delivered nasal prong pressures among a cohort of preterm infants on NCPAP.

STUDY DESIGN

We performed a randomized crossover study in 18 premature infants <1500 g (BW 1101±254 g, GA 28±2 weeks, study age 13±8 days (means±s.d.)), who were already on NCPAP for mild respiratory distress, comparing B-NCPAP to V-NCPAP. Each infant was studied at a constant flow rate and varying pressures of 3, 5, 7, 4 and 2 cm H(2)O in that order. Tidal volumes were obtained by calibrated respiratory inductance plethysmography. Intrapleural pressure was estimated by an esophageal catheter. WOB (inspiratory, elastic and resistive) was calculated from pressure volume data. Breathing asynchrony was assessed with phase angle. Comparisons of respiratory rate, heart rate, tidal volume, minute ventilation, breathing asynchrony, lung compliance, oxygen saturation and transcutaneous (Tc) O(2) and CO(2) were also made.

RESULT

WOB and most respiratory parameters were not different between B-NCPAP and V-NCPAP. TcO(2) was higher with B-NCPAP compared to V-NCPAP (P=0.01). TcCO(2) was not different. None of the other measured parameters was significantly different between the two devices.

CONCLUSION

WOB and ventilation with B-NCPAP and V-NCPAP are similar when equivalent delivered prong pressures are assured. Improved oxygenation with B-NCPAP is intriguing and requires further investigation.

Can FDG-PET reduce the need for mediastinoscopy in potentially resectable nonsmall cell lung cancer?

BACKGROUND

Few fluoro-deoxy-glucose (FDG)-positron emission tomography (PET) nonsmall cell lung cancer (NSCLC) trials have had sufficient patients to adequately evaluate PET for mediastinal staging. We question whether once PET is performed, is mediastinoscopy necessary?

METHODS

We performed a 5-year retrospective analysis of operable patients with known or suspicious NSCLC. Standard PET techniques were used. Inclusion criteria were (1) surgical mediastinal nodal sampling by mediastinoscopy within 31 days of the PET and (2) definitive diagnosis.

RESULTS

There were 237 patients who met the evaluation criteria; ninety-nine patients with NSCLC and 138 with suspicious lesions (137 men and 100 women; aged 20 to 88 years). The PETs were performed from 0 to 29 days before mediastinoscopy (median, 7 days). The standardized uptake value for the primary lesion was 0 to 24.6 (7.9+/-5.0). Nine primary lesions had no FDG uptake (1 benign, 8 NSCLCs). Seventy-one patients (31%) had mediastinal PET positive disease, and 44 patients (19%) had histologic positive mediastinal disease; N2 41 patients (17%) and N3 9 patients (4%). In 6 patients (3%), the initial frozen sections were negative, but PET positivity encouraged further biopsies that were positive for cancer. The PET sensitivity was 82%, specificity 82%, accuracy 82%, negative predictive value 95%, and positive predictive value was 51%. All primary lesions with a standardized uptake value less than 2.5 and a negative mediastinal PET were negative histologically (n = 29). Logistic regression analysis resulted in 100% specificity for PET in this group.

CONCLUSIONS

In NSCLC PET may reduce the necessity for mediastinoscopy when the primary lesion standardized uptake value is less than 2.5 and the mediastinum is PET negative. Accepting this approach in our patient population, the need for mediastinoscopy would have been reduced by 12%.

Attitudes of New York City high school students regarding firearm violence

OBJECTIVES

To assess prevalence of gun possession, attitudes regarding gun possession and gun violence, knowledge and influences of gun violence, and the potential role of physicians in gun violence prevention education among adolescents.

METHODS

An anonymous questionnaire was distributed to 9th through 12th grade high school students at 3 public high schools in New York City.

RESULTS

Three hundred forty-two surveys were distributed and returned. The prevalence of guns in the homes was 19.6%. Of respondents, 43.2% thought it was okay for anyone to have guns, and 57.3% had been injured or have had a relative injured by a gun. Although 11.6% of adolescents had felt the need to talk to an adult about guns, only 3.0% listed their physicians as one of these adults. However, if asked by their physician, 63.8% would discuss the issue with them. Only 5.7% of adolescents have had a physician speak to them about guns.

CONCLUSIONS

The adolescent population surveyed is frequently exposed to gun violence. Although physicians rarely counsel adolescents regarding gun violence and firearm safety, many adolescents would be receptive to this mode of intervention.adolescence, attitude, firearm ownership, firearm violence, physician role.

Variation among neonatal intensive care units in narcotic administration

OBJECTIVES

To compare rates of narcotic administration for medically treated neonates in different neonatal intensive care units (NICUs) and to compare treated and untreated neonates to assess whether narcotics provided advantages or disadvantages for short-term outcomes, such as cardiovascular stability (ie, blood pressure and heart rate), hyperbilirubinemia, duration of respiratory support, growth, and the incidence of intraventricular hemorrhage.

STUDY DESIGN

The medical charts of neonates weighing less than 1500 g, admitted to 6 NICUs (A-F), were abstracted. Neonates who had a chest tube or who had undergone surgery were excluded from the study, leaving the records of 1171 neonates. We modeled outcomes by linear or logistic regression, controlling for birth weight (<750, 750-999, and 1000-1499 g) and illness severity (low, 0-9; medium, 10-19; high, > or =20) using the Score for Neonatal Acute Physiology (SNAP), and adjusted for NICU.

RESULTS

Narcotic use varied by birth weight (<750 g, 21%; 750-999 g, 13%; and 1000-1499 g, 8%), illness severity (low, 9%; medium, 19%; and high, 37%), day (1, 11%; 3, 6%; and 14, 2%), and NICU. We restricted analyses to the 1018 neonates who received mechanical ventilation on day 1. Logistic regression, adjusting for birth weight and SNAP, confirmed a 28.6-fold variation in narcotic administration (odds ratios, 4.1-28.6 vs NICU A). Several short-term outcomes also were associated with narcotic use, including more than 33 g of fluid retention on day 3 and a higher direct bilirubin level (6.8 micromol/L higher [0.4 mg/dL higher], P = .03). There were no differences in weight gain at 14 and 28 days or mechanical ventilatory support on days 14 and 28. Narcotic use was not associated with differences in worst blood pressure or heart rate or with increased length of hospital stay.

CONCLUSIONS

Our study found a 28.6-fold variation among NICUs in narcotic administration in very low-birth-weight neonates. We were unable to detect any major advantages or disadvantages of narcotic use. We did not assess iatrogenic abstinence syndrome or long-term outcomes. These results indicate the need for randomized trials to rationalize these widely differing practices.

Similar breast cancer cell contamination of single-day peripheral-blood progenitor-cell collections obtained after priming with hematopoietic growth factor alone or after cyclophosphamide followed by growth factor

PURPOSE

To evaluate tumor-cell contamination of peripheral-blood progenitor-cell (PBPC) collections obtained after priming with granulocyte colony-stimulating factor (G-CSF).

PATIENTS AND METHODS

Immunocytochemical (ICC) and tumor clonogenic (TCA) assays were used to analyze tumor-cell contamination of pretreatment peripheral-blood (PB) and bone marrow (BM) samples, and of PBPC collection samples obtained after priming with G-CSF 5 micrograms/kg/d for 5 or 7 days in 38 women with advanced breast cancer undergoing high-dose chemotherapy (HDC). Results were compared with 37 historical control patients who underwent PBPC mobilization with cyclophosphamide (4 g/m2) followed by granulocyte-macrophage colony-stimulating factor (GM-CSF) 5 micrograms/kg/d for 14 days.

RESULTS

Before PBPC priming with G-CSF, only one of 37 (3%) PB and four of 36 (11%) BM samples had tumor cells detected by ICC. Tumor-cell contamination of PBPC collections obtained after 5 or 7 days of G-CSF priming was observed in only three of 38 patients (8%). All patients with tumor cells detected in the PBPC collection had stage IV disease. Cells with in vitro clonogenic potential were detected only in the pretreatment BM sample in one patient, and another two patients had ICC- and TCA-positive PBPC samples despite tumor-negative PB and BM before priming. These results are similar to those previously reported for PBPC primed with cyclophosphamide and GM-CSF.

CONCLUSION

In patients with advanced breast cancer responsive to cytotoxic chemotherapy, tumor-cell contamination is not increased in PBPC collected after 5 or 7 days priming with G-CSF and appears similar to that seen when PBPC are primed with cyclophosphamide followed by GM-CSF.