Chief complaints and computed tomography results in the emergency department: a three-year retrospective cohort study.

BACKGROUND: Computed tomography (CT) is frequently performed in the patients who admitted to the emergency department (ED), discharged but returned to ED within 72 h. It is unknown whether the main complaints of patients assist physicians to use CT effectively. This study aimed to find the association between chief complaints and the CT results. METHODS: This three-year retrospective cohort study was conducted in the ED of a tertiary medical center. Adult patients who returned to the ED after the index visit were included from 2019 to 2021. Demographics, pre-existing diseases, chief complaints, and CT region were recorded by independent ED physicians. A logistic regression model with an odds ratio (OR) and 95% confidence interval (CI) was used to determine the relationship between chief complaints and positive CT results. RESULTS: In total, 7,699 patients revisited ED after the index visit; 1,202 (15.6%) received CT. The top chief complaints in patients who received CT were abdominal pain, dizziness, and muscle weakness. Patients with abdominal pain or gastrointestinal symptoms had a significantly higher rate of positive abdominopelvic CT than those without it (OR 2.83, 95% CI 1.98-4.05, p < 0.001), while the central nervous system and cardiopulmonary chief complaints were not associated (or negatively associated) with new positive CT findings. CONCLUSION: Chief complaints of patients on revisit to the ED are associated with different yields of new findings when CT scans of the chest, abdomen and head are performed. Physicians should consider these differential likelihoods of new positive findings based on these data.

Epidemiology and Prehospital Care of Pediatric Unintentional Injuries Among Countries with Different Economic Status in Asia: A Cross-National, Multi-Center Observational Study.

OBJECTIVE: Injury is a major cause of morbidity and mortality in children. However, the epidemiology and prehospital care for pediatric unintentional injuries in Asia are still unclear. METHODS: A total of 9,737 pediatric patients aged <18 years with unintentional injuries cared for at participating centers of the Pan-Asian Trauma Outcome Study (PATOS) from October 2015 to December 2020 were reviewed retrospectively. Patients were divided into two groups: those <8 and those ≥8 years of age. Variables such as patient demographics, injury epidemiology, Injury Severity Score (ISS), and prehospital care were collected. Injury severity and administered prehospital care stratified by gross national income were also analyzed. RESULTS: Pediatric unintentional injuries accounted for 9.4% of EMS-transported trauma cases in the participating Asian centers, and the mortality rate was 0.88%. The leading cause of injury was traffic injuries in older children aged ≥8 years (56.5%), while falls at home were common among young children aged <8 years (43.9%). Compared with younger children, older children with similar ISS tended to receive more prehospital interventions. Uneven disease severity was found in that older children in lower-middle and upper-middle-income countries had higher ISS compared with those in high-income countries. The performance of prehospital interventions also differed among countries with different gross national incomes. Immobilizations were the most performed prehospital intervention followed by oxygen administration, airway management, and pain control; only one patient received prehospital thoracentesis. Procedures were performed more frequently in high-income countries than in upper-middle-income and lower-middle-income countries. CONCLUSIONS: The major cause of injury was road traffic injuries in older children, while falls at home were common among young children. Prehospital care in pediatric unintentional injuries in Asian countries was not standardized and might be insufficient, and the economic status of countries may affect the implementation of prehospital care.

Differences in the characteristics and patterns of adult emergency department return visits before and after the coronavirus disease 2019 outbreak.

BACKGROUND: Data about changes in the characteristics of ED return visits before and after the COVID-19 outbreak are limited. This study aimed to report the differences on utility in ED return visits after the COVID-19 outbreak. METHODS: This retrospective cohort study was conducted from 2019 to 2020. Adult patients with ED return visits were included in the analysis. Variables including demographic characteristics, pre-comorbidities, triage levels, vital signs, chief complaints, management, and diagnosis were recorded and confirmed via a manual assessment. RESULTS: The proportion of patients with ED visits decreased by 23%. Hence, that of patients with ED return visits also reduced from 2580 to 2020 patients (22%) after the COVID-19 outbreak. The average age (60-57.8 years) of patients with return visits was significantly younger, and the proportion of female patients decreased remarkably. Further, the proportion of patients with chronic pre-existing diseases at the return visit significantly differed after the COVID-19 outbreak. The proportion of patients with chief complaints including dizziness, dyspnea, cough, vomiting, diarrhea, and chills during the return visits significantly differed before and after the COVID-19 pandemic. In the multivariable logistic regression model, age, high triage level were significantly associated with unfavorable outcome return visit. CONCLUSION: The use of services in the ED has changed since the COVID-19 outbreak. Hence, the proportion of patients with unplanned return visits within 72 h decreased. After the COVID-19 outbreak, people are now cautious whether they should return to the ED, as in the pre-pandemic situation, or just treat conservatively at home.

COVID-19 stigma associates with burnout among healthcare providers: Evidence from Taiwanese physicians and nurses.

BACKGROUND/PURPOSE: During pandemics like SARS-CoV-2, healthcare providers' well-being and morale are in particular at stake. Burnout may substantially hinder the well-being and morale of healthcare providers, challenging our efforts at disease containment. This study investigated the relationship between perceived COVID-19 stigma and burnout symptoms among physicians and nurses. We further aimed to identify potential factors that may moderate this relationship, including profession, clinical contact with COVID-19 patients, and prior experience with 2003 SARS-CoV-1. METHODS: We used a web-based, structured survey from March 12th to 29th, 2020 to collect cross-sectional, self-reported data. Participants were provided with a link to the survey which took them on average 5-8 minutes. Survey consisted of demographic characteristics, clinical experiences, perceived COVID-19 related stigma, and burnout symptoms. Linear regression with bootstrapping techniques was adopted to test the relations between stigma and burnout, as well as other potential moderators, while adjusting for demographic and clinical factors. RESULTS: Of the 1421 consented respondents, 357 identified as physicians while 1064 identified as nurses. Participants reported some levels of stigma, and noticeable burnout symptoms. Burnout symptoms were positively correlated with COVID-19 stigma, profession, and currently care for confirmed/suspected COVID-19 patients. The interaction between stigma and profession (Stigma × Nurses) but no other interaction terms reached the significance level, suggesting that the slope for nurses was flatter than the slope for physicians. CONCLUSION: The study results suggest that COVID-19 stigma may contribute to burnout among physicians and nurses, and this relation may not vary across clinical roles and experiences but profession.

Tissue-guided LASSO for prediction of clinical drug response using preclinical samples.

Prediction of clinical drug response (CDR) of cancer patients, based on their clinical and molecular profiles obtained prior to administration of the drug, can play a significant role in individualized medicine. Machine learning models have the potential to address this issue but training them requires data from a large number of patients treated with each drug, limiting their feasibility. While large databases of drug response and molecular profiles of preclinical in-vitro cancer cell lines (CCLs) exist for many drugs, it is unclear whether preclinical samples can be used to predict CDR of real patients. We designed a systematic approach to evaluate how well different algorithms, trained on gene expression and drug response of CCLs, can predict CDR of patients. Using data from two large databases, we evaluated various linear and non-linear algorithms, some of which utilized information on gene interactions. Then, we developed a new algorithm called TG-LASSO that explicitly integrates information on samples' tissue of origin with gene expression profiles to improve prediction performance. Our results showed that regularized regression methods provide better prediction performance. However, including the network information or common methods of including information on the tissue of origin did not improve the results. On the other hand, TG-LASSO improved the predictions and distinguished resistant and sensitive patients for 7 out of 13 drugs. Additionally, TG-LASSO identified genes associated with the drug response, including known targets and pathways involved in the drugs' mechanism of action. Moreover, genes identified by TG-LASSO for multiple drugs in a tissue were associated with patient survival. In summary, our analysis suggests that preclinical samples can be used to predict CDR of patients and identify biomarkers of drug sensitivity and survival.

History of Cholecystectomy and Risk of Clostridium Difficile Infection.

BACKGROUND: Cholecystectomy affects bile acid physiology. There is growing evidence that both primary and secondary bile acids play a role in the pathogenesis of Clostridium difficile infections (CDIs). AIMS: The aim of this study is to elucidate the relationship and risk of CDI in patients with cholecystectomy. METHODS: We performed a matched cohort study of patients in an integrated healthcare system in Northern California from January 2000 to December 2018. Patients with cholecystectomy (cases, n = 12,617) identified based on Current Procedure Terminology codes were age- and sex-matched to patients without cholecystectomy (controls, n = 37,851). We excluded those with history of CDI at baseline and calculated the hazard ratio (HR) for development of CDI after adjusting for confounders. RESULTS: We found total of 351 incident CDI during average of 4.66 years of follow-up among cases and controls. In multivariate analysis, cholecystectomy was associated with elevated risk of CDI (HR 1.53, 95% confidence interval 1.14-2.04) compared with controls. Stratified analysis shows this effect does not differ according use of proton pump inhibitors (Pinteraction = 0.142), antibiotics (Pinteraction = 0.387), and hospitalization (Pinteraction = 0.252). CONCLUSIONS: Cholecystectomy is associated with mild increased risk of incident CDI, but this effect is not influenced by use of proton pump inhibitors, antibiotics, or hospitalization. Future prospective studies should be conducted to validate these findings and evaluate bile acid changes after a cholecystectomy.

Strategies on locations of public access defibrillator: A systematic review.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is a critical condition with poor outcomes. Although the survival rate increases in those who undergo defibrillation, the utility of on-time defibrillation among bystanders remained low. An evaluation of the deployment strategy for public access defibrillators (PADs) is necessary to increase their use and accessibility. This study was to conduct a systematic review for deployment strategies of PADs. METHODS: Two authors independently searched for articles published before October 2019 from PubMed, Embase, Web of Science, and Cochrane Library. An independent librarian provided the search strategy and assisted the literature research. We included articles that were focused on the main topic, but excluded those which were missing results or that used an unclear definition. The qualitative outcomes were the utility and OHCA coverage of PADs. We performed a qualitative analysis across the studies, but a quantitative analysis was not available due to the studies' heterogeneity in design and variety of outcomes. RESULTS: We eventually included 15 studies. Three strategies were presented: guidelines-based, grid-based, and landmark-based. The guidelines-based deployment was common fit for OHCA events. The grid-based method increased the use of bystander defibrillation 3-fold, and 30-day survival doubled. The top 3 landmarks in the landmark-based strategy were offices (18.6%), schools (13.3%), and sports facilities (12.9%). Utility of PADs might increase if we optimize PAD location by mathematical modeling and evaluation feedback. CONCLUSION: Three deployment strategies were presented. Although the optimal method could not be fully identified, a more efficient PAD deployment could benefit the population in terms of OHCA coverage and survival among patients with OHCA.

Associations of thoracic cage size and configuration with outcomes of adult in-hospital cardiac arrest: A retrospective cohort study.

BACKGROUND: To analyse the association of thoracic cage size and configuration with outcomes following in-hospital cardiac arrest (IHCA). METHODS: A single-centred retrospective study was conducted. Adult patients experiencing IHCA during 2006-2015 were screened. By analysing computed tomography images, we measured thoracic anterior-posterior and transverse diameters, circumference, and both anterior and posterior subcutaneous adipose tissue (SAT) depths at the level of the internipple line (INL). We also recorded the anatomical structure located immediately posterior to the sternum at the INL. RESULTS: A total of 649 patients were included. The median thoracic circumference was 88.6 cm. The median anterior and posterior thoracic SAT depths were 0.9 and 1.5 cm, respectively. The ascending aorta was found to be the most common retrosternal structure (57.6%) at the INL. Multivariate logistic regression analyses indicated that anterior thoracic SAT depth of 0.8-1.6 cm (odds ratio [OR]: 2.98, 95% confidence interval [CI]: 1.40-6.35; p-value = 0.005) and thoracic circumference of 83.9-95.0 cm (OR: 2.48, 95% CI: 1.16-5.29; p-value = 0.02) were positively associated with a favourable neurological outcome while left ventricular outflow track or aortic root beneath sternum at the level of INL was inversely associated with a favourable neurological outcome (OR: 0.37, 95% CI: 0.15-0.91; p-value = 0.03). CONCLUSION: Thoracic circumference and anatomic configuration might be associated with IHCA outcomes. This proof-of-concept study suggested that a one-size-fits-all resuscitation technique might not be suitable. Further investigation is needed to investigate the method of providing personalized resuscitation tailored to patient needs.

Barriers to bystanders defibrillation: A national survey on public awareness and willingness of bystanders defibrillation☆.

BACKGROUND: After years of setting up public automated external defibrillators (AEDs), the rate of bystander AED use remains low all over the world. This study aimed to assess the public awareness and willingness of bystanders to use AEDs and to investigate the awareness on the Good Samaritan Law (GSL) and the factors associated with the low rate of bystander AED use. METHODS: Using stratified random sampling, national telephone interviews were conducted using an author-designed structured questionnaire. The results were weighted to match the census data in Taiwan. The factors associated with public awareness and willingness of bystanders to use AEDs were analysed by logistic regression. RESULTS: Of the 1073 respondents, only 15.2% had the confidence to recognise public AEDs, and 5.3% of them had the confidence to use the AED. Concerns on immature technique and legal issues remain the most common barriers to AED use by bystanders. Moreover, only 30.8% thought that the public should use AEDs at the scene. Few respondents (9.6%) ever heard of the GSL in Taiwan, and less than 3% understood the meaning of GSL. Positive awareness on AEDs was associated with high willingness of bystanders to use AEDs. Respondents who were less likely to use AEDs as bystanders were healthcare personnel and women. CONCLUSION: The importance of active awareness and the barriers to the use of AEDs among bystanders seemed to have been underestimated in the past years. The relatively low willingness to use AEDs among bystander healthcare providers and women needs further investigation.

Association between prehospital time and outcome of trauma patients in 4 Asian countries: A cross-national, multicenter cohort study.

BACKGROUND: Whether rapid transportation can benefit patients with trauma remains controversial. We determined the association between prehospital time and outcome to explore the concept of the "golden hour" for injured patients. METHODS AND FINDINGS: We conducted a retrospective cohort study of trauma patients transported from the scene to hospitals by emergency medical service (EMS) from January 1, 2016, to November 30, 2018, using data from the Pan-Asia Trauma Outcomes Study (PATOS) database. Prehospital time intervals were categorized into response time (RT), scene to hospital time (SH), and total prehospital time (TPT). The outcomes were 30-day mortality and functional status at hospital discharge. Multivariable logistic regression was used to investigate the association of prehospital time and outcomes to adjust for factors including age, sex, mechanism and type of injury, Injury Severity Score (ISS), Revised Trauma Score (RTS), and prehospital interventions. Overall, 24,365 patients from 4 countries (645 patients from Japan, 16,476 patients from Korea, 5,358 patients from Malaysia, and 1,886 patients from Taiwan) were included in the analysis. Among included patients, the median age was 45 years (lower quartile [Q1]-upper quartile [Q3]: 25-62), and 15,498 (63.6%) patients were male. Median (Q1-Q3) RT, SH, and TPT were 20 (Q1-Q3: 12-39), 21 (Q1-Q3: 16-29), and 47 (Q1-Q3: 32-60) minutes, respectively. In all, 280 patients (1.1%) died within 30 days after injury. Prehospital time intervals were not associated with 30-day mortality. The adjusted odds ratios (aORs) per 10 minutes of RT, SH, and TPT were 0.99 (95% CI 0.92-1.06, p = 0.740), 1.08 (95% CI 1.00-1.17, p = 0.065), and 1.03 (95% CI 0.98-1.09, p = 0.236), respectively. However, long prehospital time was detrimental to functional survival. The aORs of RT, SH, and TPT per 10-minute delay were 1.06 (95% CI 1.04-1.08, p < 0.001), 1.05 (95% CI 1.01-1.08, p = 0.007), and 1.06 (95% CI 1.04-1.08, p < 0.001), respectively. The key limitation of our study is the missing data inherent to the retrospective design. Another major limitation is the aggregate nature of the data from different countries and unaccounted confounders such as in-hospital management. CONCLUSIONS: Longer prehospital time was not associated with an increased risk of 30-day mortality, but it may be associated with increased risk of poor functional outcomes in injured patients. This finding supports the concept of the "golden hour" for trauma patients during prehospital care in the countries studied.

Identification of pathways associated with chemosensitivity through network embedding.

Basal gene expression levels have been shown to be predictive of cellular response to cytotoxic treatments. However, such analyses do not fully reveal complex genotype- phenotype relationships, which are partly encoded in highly interconnected molecular networks. Biological pathways provide a complementary way of understanding drug response variation among individuals. In this study, we integrate chemosensitivity data from a large-scale pharmacogenomics study with basal gene expression data from the CCLE project and prior knowledge of molecular networks to identify specific pathways mediating chemical response. We first develop a computational method called PACER, which ranks pathways for enrichment in a given set of genes using a novel network embedding method. It examines a molecular network that encodes known gene-gene as well as gene-pathway relationships, and determines a vector representation of each gene and pathway in the same low-dimensional vector space. The relevance of a pathway to the given gene set is then captured by the similarity between the pathway vector and gene vectors. To apply this approach to chemosensitivity data, we identify genes whose basal expression levels in a panel of cell lines are correlated with cytotoxic response to a compound, and then rank pathways for relevance to these response-correlated genes using PACER. Extensive evaluation of this approach on benchmarks constructed from databases of compound target genes and large collections of drug response signatures demonstrates its advantages in identifying compound-pathway associations compared to existing statistical methods of pathway enrichment analysis. The associations identified by PACER can serve as testable hypotheses on chemosensitivity pathways and help further study the mechanisms of action of specific cytotoxic drugs. More broadly, PACER represents a novel technique of identifying enriched properties of any gene set of interest while also taking into account networks of known gene-gene relationships and interactions.

Synergy theory for murine Harderian gland tumours after irradiation by mixtures of high-energy ionized atomic nuclei.

Experimental studies reporting murine Harderian gland (HG) tumourigenesis have been a NASA concern for many years. Studies used particle accelerators to produce beams that, on beam entry, consist of a single isotope also present in the galactic cosmic ray (GCR) spectrum. In this paper synergy theory is described, potentially applicable to corresponding mixed-field experiments, in progress, planned, or hypothetical. The "obvious" simple effect additivity (SEA) approach of comparing an observed mixture dose-effect relationship (DER) to the sum of the components' DERs is known from other fields of biology to be unreliable when the components' DERs are highly curvilinear. Such curvilinearity may be present at low fluxes such as those used in the one-ion HG experiments due to non-targeted ('bystander') effects, in which case a replacement for SEA synergy theory is needed. This paper comprises in silico modeling of published experimental data using a recently introduced, arguably optimal, replacement for SEA: incremental effect additivity (IEA). Customized open-source software is used. IEA is based on computer numerical integration of non-linear ordinary differential equations. To illustrate IEA synergy theory, possible rapidly-sequential-beam mixture experiments are discussed, including tight 95% confidence intervals calculated by Monte-Carlo sampling from variance-covariance matrices. The importance of having matched one-ion and mixed-beam experiments is emphasized. Arguments are presented against NASA over-emphasizing accelerator experiments with mixed beams whose dosing protocols are standardized rather than being adjustable to take biological variability into account. It is currently unknown whether mixed GCR beams sometimes have statistically significant synergy for the carcinogenesis endpoint. Synergy would increase risks for prolonged astronaut voyages in interplanetary space.

Public knowledge, attitudes and willingness regarding bystander cardiopulmonary resuscitation: A nationwide survey in Taiwan.

BACKGROUND: A low bystander cardiopulmonary resuscitation (CPR) rate is one of the factors associated with low cardiac arrest survival. This study aimed to assess knowledge, attitudes, and willingness towards performing CPR and the barriers for implementation of bystander-initiated CPR. METHODS: Telephone interviews were conducted using an author-designed and validated structured questionnaire in Taiwan. After obtaining a stratified random sample from the census, the results were weighted to match population data. The factors affecting bystander-initiated CPR were analysed using logistic regression. RESULTS: Of the 1073 respondents, half of them stated that they knew how to perform CPR correctly, although 86.7% indicated a willingness to perform CPR on strangers. The barriers to CPR performance reported by the respondents included fear of legal consequences (44%) and concern about harming patients (36.5%). Most participants expressed a willingness to attend only an hour-long CPR course. Respondents who were less likely to indicate a willingness to perform CPR were female, healthcare providers, those who had no cohabiting family members older than 65 years, those who had a history of a stroke, and those who expressed a negative attitude toward CPR. CONCLUSION: The expressed willingness to perform bystander CPR was high if the respondents possessed the required skills. Attempts should be made to recruit potential bystanders for CPR courses or education, targeting those respondent subgroups less likely to express willingness to perform CPR. The reason for lower bystander CPR willingness among healthcare providers deserves further investigation.

The Effect of Successful Intubation on Patient Outcomes After Out-of-Hospital Cardiac Arrest in Taipei.

STUDY OBJECTIVE: The effect of out-of-hospital intubation in patients with out-of-hospital cardiac arrest remains controversial. The Taipei City paramedics are the earliest authorized to perform out-of-hospital intubation among Asian areas. This study evaluates the association between successful intubation and out-of-hospital cardiac arrest survival in Taipei. METHODS: We analyzed 6 years of Utstein-based registry data from nontrauma adult patients with out-of-hospital cardiac arrest who underwent out-of-hospital airway management including intubation, laryngeal mask airway, or bag-valve-mask ventilation. The primary analysis was intubation success on patient outcomes. The primary outcome was survival to discharge and the secondary outcomes included sustained return of spontaneous circulation and favorable neurologic survival. Sensitivity analysis was performed with intubation attempts rather than intubation success. Subgroup analysis of advanced life support-serviced districts was also performed. RESULTS: A total of 10,853 cases from 2008 to 2013 were analyzed. Among out-of-hospital cardiac arrest patients receiving airway management, successful intubation, laryngeal mask airway, and bag-valve-mask ventilation was reported in 1,541, 3,099, and 6,213 cases, respectively. Compared with bag-valve-mask device use, successful out-of-hospital intubation was associated with improved chances of sustained return of spontaneous circulation (adjusted odds ratio [aOR] 1.91; 95% confidence interval [CI] 1.66 to 2.19), survival to discharge (aOR 1.98; 95% CI 1.57 to 2.49), and favorable neurologic outcome (aOR 1.44; 95% CI 1.03 to 2.03). The results were comparable in sensitivity and subgroup analyses. CONCLUSION: In nontrauma adult out-of-hospital cardiac arrest in Taipei, successful out-of-hospital intubation was associated with improved odds of sustained return of spontaneous circulation, survival to discharge, and favorable neurologic outcome.

Performance of a simplified termination of resuscitation rule for adult traumatic cardiopulmonary arrest in the prehospital setting.

OBJECTIVE: The prehospital termination of resuscitation (TOR) guidelines for traumatic cardiopulmonary arrest (TCPA) was proposed in 2003. Its multiple descriptors of cases where efforts can be terminated make it complex to apply in the field. Here we proposed a simplified rule and evaluated its predictive performance. METHODS: We analysed Utstein registry data for 2009-2013 from a Taipei emergency medical service to test a simplified TOR rule that comprises two criteria: blunt trauma injury and the presence of asystole. Enrolees were adults (≥18 years) with TCPA. The predicted outcome was in-hospital death. We compared the areas under the curve (AUC) of the simple rule with each of four descriptors in the guidelines and with a combination of all four to assess their discriminatory ability. Test characteristics were calculated to assess predictive performance. RESULTS: A total of 893 TCPA cases were included. Blunt trauma occurred in 459 (51.4%) cases and asystole in 384 (43.0%). In-hospital mortality was 854 (95.6%) cases. The simplified TOR rule had greater discriminatory ability (AUC 0.683, 95% CI 0.618 to 0.747) compared with any single descriptor in the 2003 guidelines (range of AUC: 0.506-0.616) although the AUC was similar when all four were combined (AUC 0.695, 95% CI 0.615 to 0.775). The specificity of the simplified rule was 100% (95% CI 88.8% to 100%) and positive predictive value 100% (95% CI 96.8% to 100%). The false positive value, false negative value and decreased rate of unnecessary transport were 0% (95% CI 0% to 3.2%), 94.8% (95% CI 92.9% to 96.2%) and 16.4% (95% CI 14.1% to 19.1%), respectively. CONCLUSIONS: The simplified TOR rule appears to accurately predict non-survivors in adults with TCPA in the prehospital setting.

The ground state of innate immune responsiveness is determined at the interface of genetic, epigenetic, and environmental influences.

Monocytes and macrophages form the major cellular component of the innate immune system, with roles in tissue development, homeostasis, and host defense against infection. Environmental factors were shown to play a significant part in determining innate immune responsiveness, and this included systemic conditions, such as circulating glucose levels, gut microflora, time of year, and even diurnal rhythm, which had a direct impact on innate immune receptor expression. Although the underlying molecular processes are just beginning to emerge, it is clear that environmental factors may alter epigenetic states of peripheral blood monocytes and resident tissue macrophages. We conclude that some measure of cellular ground state must become an essential part of the analysis of myeloid responsiveness or infectious susceptibility.