Hypoxia induces lytic replication of Kaposi sarcoma-associated herpesvirus

There is substantial evidence that Kaposi sarcoma-associated herpesvirus (KSHV) plays an important role in the pathogenesis of all forms of Kaposi sarcoma (KS). It has been noted that KS commonly occurs in locations, such as the feet, where tissue may be poorly oxygenated. On the basis of this observation, the potential role of hypoxia in the reactivation of KSHV replication was explored by studying 2 KSHV-infected primary effusion lymphoma B-cell lines (BC-3 and BCBL-1) latently infected with KSHV. Acute and chronic exposure of these cells to hypoxia (1% O(2)) induced KSHV lytic replication, as indicated by an increase in intracellular lytic protein expression and detection of virus in cell supernatants by Western immunoblotting. In addition, hypoxia increased the levels of secreted viral interleukin-6. Moreover, hypoxia enhanced the lytic replication initiated by the viral inducer 12-O-tetradecanoylphorbol-13-acetate. Desferoxamine and cobalt chloride, 2 compounds that increase the intracellular levels of hypoxia-inducible factor 1, were also able to induce KSHV lytic replication. These studies suggest that hypoxia is an inducer of KSHV replication. This process may play an important role in the pathogenesis of KS.

Rapid sequence intubation for pediatric emergency patients: higher frequency of failed attempts and adverse effects found by video review

STUDY OBJECTIVE

Using video review, we seek to determine the frequencies of first-attempt success and adverse effects during rapid sequence intubation (RSI) in a large, tertiary care, pediatric emergency department (ED).

METHODS

We conducted a retrospective study of children undergoing RSI in the ED of a pediatric institution. Data were collected from preexisting video and written records of care provided. The primary outcome was successful tracheal intubation on the first attempt at laryngoscopy. The secondary outcome was the occurrence of any adverse effect during RSI, including episodes of physiologic deterioration. We collected time data from the RSI process by using video review. We explored the association between physician type and first-attempt success.

RESULTS

We obtained complete records for 114 of 123 (93%) children who underwent RSI in the ED during 12 months. Median age was 2.4 years, and 89 (78%) were medical resuscitations. Of the 114 subjects, 59 (52%) were tracheally intubated on the first attempt. Seventy subjects (61%) had 1 or more adverse effects during RSI; 38 (33%) experienced oxyhemoglobin desaturation and 2 required cardiopulmonary resuscitation after physiologic deterioration. Fewer adverse effects were documented in the written records than were observed on video review. The median time from induction through final endotracheal tube placement was 3 minutes. After adjusting for patient characteristics and illness severity, attending-level providers were 10 times more likely to be successful on the first attempt than all trainees combined.

CONCLUSION

Video review of RSI revealed that first-attempt failure and adverse effects were much more common than previously reported for children in an ED.

Targeted inhibition of calcineurin signaling blocks calcium-dependent reactivation of Kaposi sarcoma-associated herpesvirus

Kaposi sarcoma-associated herpesvirus (KSHV) is associated with KS, primary effusion lymphoma (PEL), and multicentric Castleman disease. Reactivation of KSHV in latently infected cells and subsequent plasma viremia occur before the development of KS. Intracellular signaling pathways involved in KSHV reactivation were studied. In latently infected PEL cells (BCBL-1), KSHV reactivation in single cells was determined by quantitative flow cytometry. Viral particle production was determined by electron microscope analyses and detection of minor capsid protein in culture supernatants. Agents that mobilized intracellular calcium (ionomycin, thapsigargin) induced expression of KSHV lytic cycle-associated proteins and led to increased virus production. Calcium-mediated virus reactivation was blocked by specific inhibitors of calcineurin-dependent signal transduction (cyclosporine, FK506). Similarly, calcium-mediated virus reactivation in KSHV-infected dermal microvascular endothelial cells was blocked by cyclosporine. Furthermore, retroviral transduction with plasmid DNA encoding VIVIT, a peptide specifically blocking calcineurin-NFAT interactions, inhibited calcium-dependent KSHV reactivation. By contrast, chemical induction of lytic-phase infection by the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate was blocked by protein kinase C inhibitors, but not by calcineurin inhibitors. In summary, calcineurin-dependent signal transduction, an important signaling cascade in vivo, induces calcium-dependent KSHV replication, providing a possible target for the design of antiherpesvirus strategies in KSHV-infected patients.

Factors associated with oxyhemoglobin desaturation during rapid sequence intubation in a pediatric emergency department: findings from multivariable analyses of video review data

OBJECTIVES

In a video-based study of rapid sequence intubation (RSI) in a pediatric emergency department (PED), 33% of children experienced oxyhemoglobin desaturation (SpO2 < 90%). To inform targeted improvement interventions, we planned multivariable analyses to identify patient and process variables (including time-based data around performance of key RSI process elements uniquely available from video review) associated with desaturation during pediatric RSI.

METHODS

These were planned analyses of data collected during a retrospective, video-based study of RSI in a high-volume, academic PED. For variables with plausible associations with desaturation, multiple logistic regression and generalized estimating equations were used to identify those characteristics independently associated with desaturation at both the patient and the attempt levels.

RESULTS

The authors analyzed video data from 114 patients undergoing RSI over 12 months. Desaturation was more common in patients 24 months of age and younger (59%) than in patients older than 24 months of age (10%). Variables associated with desaturation in patients 24 months of age and younger were duration of attempts (both individual and cumulative), the occurrence of esophageal intubation, a respiratory indication for intubation, and young age. The receiver operating characteristics curve for the model had an area under the curve of 0.80 (95% confidence interval [CI] = 0.67 to 0.92). Forty-six percent of desaturations occurred after 45 seconds of laryngoscopy, and 82% after 30 seconds. The odds ratio for desaturation on individual attempts lasting longer than 30 seconds (vs. those 30 seconds or less) was 5.7 (95% CI = 2.26 to 14.36).

CONCLUSIONS

For children 24 months of age or younger undergoing RSI in a PED, respiratory indication for intubation, esophageal intubation, and duration of laryngoscopy (both individual and cumulative) were associated with desaturation; the number of attempts was not. Interventions to limit attempt duration in the youngest children may improve the safety of RSI.

Calphostin C, a widely used protein kinase C inhibitor, directly and potently blocks L-type Ca channels

Calphostin C is a widely used inhibitor of protein kinase C; in the past 4 years at least 350 articles have been published using this drug as a selective inhibitor of protein kinase C. In this paper, we show that calphostin C also potently inhibits cardiac L-type Ca channels by a mechanism that does not involve changes in adenosine 3',5'-cyclic monophosphate levels or dephosphorylation. The inhibition requires illumination by visible light during exposure to calphostin C. The Ca current (ICa) that remains after partial inhibition of ICa has the same voltage-dependent characteristics as the control current.

Studying the Safety and Performance of Rapid Sequence Intubation: Data Collection Method Matters

OBJECTIVE

We sought to describe and compare chart and video review as data collection sources for the study of emergency department (ED) rapid sequence intubation (RSI).

METHODS

This retrospective cohort study compares the availability and content of key RSI outcome and process data from two sources: chart and video data from 12 months of pediatric ED RSI. Key outcomes included adverse effects (oxyhemoglobin desaturation, physiologic changes, inadequate paralysis, vomiting), process components (number of laryngoscopy attempts, end-tidal CO₂ detection), and timing data (duration of preoxygenation and laryngoscopy attempts).

RESULTS

We reviewed 566 documents from 114 cases with video data. Video review detected higher rates of adverse effects (67%) than did chart review (46%, p < 0.0001), identifying almost twice the rate of desaturation noted in the chart (34% vs. 18%, p = 0.0002). The performance and timing of key RSI processes were significantly more reliably available via video review (timing and duration of preoxygenation, as well as timing, duration, and number of laryngoscopy attempts, all p < 0.05). Video review identified 221 laryngoscopy attempts, whereas chart review only identified 187.

CONCLUSIONS

When compared with video review for retrospective study of RSI in a pediatric ED, chart review significantly underestimated adverse effects, inconsistently contained data on important RSI process elements, rarely provided time data, and often conflicted with observations made on video review. Interpretation of and design of future studies of RSI should take into consideration the quality of the data source.

Referral to the emergency department by a primary care provider predicts severity of illness

OBJECTIVE

The purpose of this study was to assess whether referral to a pediatric emergency department (PED) by a primary care provider was associated with greater severity of illness, as determined on the basis of clinical measures and increased resource utilization.

METHODS

A retrospective study of data for 121 088 children who presented to a PED with abdominal pain, fever, or respiratory complaints during a 5-year period was performed. Demographic data, referral status, and proxy markers of illness severity were collected from the medical records and analyzed.

RESULTS

A total of 26.3% of all patients seen in the PED presented with these 3 complaint categories. With adjustment for age, gender, race, and insurance class, referred patients were significantly more likely to have high triage acuity designations, higher rates of very abnormal vital signs, and higher admission rates, compared with patients who were self-referred. Referred patients were more likely to undergo testing (laboratory or radiologic), to receive intravenous fluid therapy and pain medications, and to be assigned higher-severity discharge diagnoses, such as appendicitis, septic shock, or status asthmaticus.

CONCLUSIONS

Referral by a primary care provider to a PED was significantly and independently associated with greater severity of illness and resource utilization. Referral status should be considered in algorithms used to triage cases for evaluation in the PED.

Minimal reactivation of Kaposi's sarcoma-associated herpesvirus by corticosteroids in latently infected B cell lines

Corticosteroid use in transplant recipients increases the incidence and severity of Kaposi's sarcoma (KS), a disease associated with KS-associated herpesvirus (KSHV) infection. Recently, the prototypic corticosteroid, hydrocortisone, was shown to directly induce lytic cycle reactivation of KSHV in latently-infected BCBL-1 cells. The purpose of this study was to examine this phenomenon in further detail. After incubation with dexamethasone (<or= 30 microM) or hydrocortisone (<or= 30 microM) for 1-4 days, we evaluated KSHV reactivation in latently infected B cell lines (BC-1, BC-3, and BCBL-1) by assessing early-lytic PF-8 and late-lytic gpK8.1 protein expression using flow cytometry. Viral particle production was monitored by quantifying KSHV minor capsid protein levels in cell culture supernatants. A small increase in the percentage of cells expressing viral lytic proteins was observed in BCBL-1, but not in the other cell lines. In combination with 3 nM 12-O-tetradecanoyl-phorbol-13-acetate, a known chemical inducer of KSHV replication, corticosteroids (0.3 microM) enhanced KSHV reactivation twofold in some cell lines, but not in others. In all experiments, lytic viral protein expression by flow cytometry correlated with production of viral particles in culture supernatants. In summary, we found that corticosteroids were limited inducers of KSHV reactivation in latently infected cells. Thus, our findings suggest that corticosteroids do not enhance the incidence and severity of KS in transplant recipients by direct cellular effects on KSHV reactivation.

Use of intravenous tissue plasminogen activator in a 16-year-old patient with basilar occlusion

Intravenous tissue plasminogen activator (t-PA) is currently approved by the US Food and Drug Administration (FDA) for the treatment of ischemic stroke in patients > 18 years of age who present within 3 hours of stroke onset and meet certain criteria. We report a case of a 16-year-old, previously healthy female who presented with a basilar artery occlusion and pontine ischemic stroke. She was treated with intravenous t-PA approximately 4 hours after the onset of symptoms. The patient demonstrated a remarkable recovery 6 hours after onset of her symptoms and had minimal deficits on discharge from the hospital 1 week later. She was found to have a lupus anticoagulant and was heterozygous for the prothrombin gene G2010A mutation. These were likely contributing causes for her stroke. She was also homozygous for plasminogen activator inhibitor 1 (PAI-1) 4G/4G, which at present is a controversial stroke risk factor.

Measurements of manganese with respect to calcium in histological enamel cross sections: toward a new manganese biomarker

Airborne Mn may become an important route of exposure if the use of Mn-containing gasoline additives becomes more widespread. We report on the measurement of manganese and calcium in histological cross sections of shed deciduous tooth enamel of three human subjects. The goal of this research was to measure Mn in tooth enamel for use as a biomarker in assessing manganese exposure in cross-sectional and longitudinal studies. The histological locations can be time-specific (analogous to examining growth rings in trees). This technique, which may identify critical windows of exposure, can be important for evaluating potential vulnerability of the fetus and neonate to inhaled or ingested Mn.

The Medical Resuscitation Committee: Interprofessional Program Development to Optimize Care for Critically Ill Medical Patients in an Academic Pediatric Emergency Department

ABSTRACT

Provision of optimal care to critically ill patients in a pediatric emergency department is challenging. Specific challenges include the following: (a) patient presentations are highly variable, representing the full breadth of human disease and injury, and are often unannounced; (b) care team members have highly variable experience and skills and often few meaningful opportunities to practice care delivery as a team; (c) valid data collection, for quality assurance/improvement and clinical research, is limited when relying on traditional approaches such as medical record review or self-report; (d) specific patient presentations are relatively uncommon for individual providers, providing few opportunities to establish and refine the requisite knowledge and skill; and (e) unscientific or random variation in care delivery. In the current report, we describe our efforts for the last decade to address these challenges and optimize care delivery to critically ill patients in a pediatric emergency department. We specifically describe the grassroots development of an interprofessional medical resuscitation program. Key components of the program are as follows: (a) a database of all medical patients undergoing evaluation in the resuscitation suite, (b) peer review and education through video-based case review, (c) a program of emergency department in situ simulation, and (d) the development of cognitive aids for high-acuity, low-frequency medical emergencies.

Effectiveness of interventions to improve medication use during rapid-sequence intubation in a pediatric emergency department

PURPOSE

Results of a study to determine whether checklist-based interventions improved the selection and administration of rapid-sequence intubation (RSI) medications in a pediatric emergency department (ED) are reported.

METHODS

A retrospective study of data collected during a quality-improvement project was conducted. Data sources included the electronic health record and video review. The central intervention was use of a 21-item RSI checklist, which included guidance for the physician team leader on medication selection and timing. A quick-reference card was developed to guide staff in preparing RSI medications. The main outcomes were (1) standard selection, defined as administration of indicated medications and avoidance of medications not indicated, and (2) efficient administration, defined as an interval of <30 seconds from sedative to neuromuscular blocker (NMB) infusion.

RESULTS

A total of 253 consecutive patients underwent RSI during 3 consecutive periods: the historical (preimprovement) period (n = 136), the checklist only period (n = 68), and the checklist/card period (n = 49). The rate of standard selection of 3 RSI medications (atropine, lidocaine, and rocuronium) did not improve. The rate of efficient sedative and NMB administration improved from 56% in the historical period to 88% in the checklist period (p = 0.005). The median duration of RSI medication administration decreased from 28 seconds (interquartile range [IQR], 23-44 seconds) in the historical period to 19 seconds (IQR, 15-25 seconds) in the checklist/card period (p = 0.004).

CONCLUSION

In a quality-improvement project in a pediatric ED, a checklist-based intervention improved RSI medication administration technique but not selection.