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Background: Current knowledge of the impact of socioeconomic factors on the risk of admission to the pediatric intensive care unit (PICU) for asthma is limited. Using composite measures of social vulnerability—Social Vulnerability Index (SVI) and Child Opportunity Index (COI) 2.0—we compared patients admitted for status asthmaticus to the PICU and pediatric ward at Children's Hospital Los Angeles (CHLA). We hypothesized patients with a high SVI and low COI are at higher risk for PICU admission. Methods: Patients were identified using ICD‐10 codes for asthma. Primary outcome was admission to PICU versus ward for status asthmaticus. Patient‐registered residential street addresses were geocoded and spatially joined to SVI and COI 2.0 data at the census tract level. Univariate and regression analyses using the patient's SVI, COI 2.0, and admission location were conducted. Results: From January 2017 to March 2022, there were 2458 admissions matched to addresses from 1983 distinct patients. The overall median SVI for all patients was 0.86 (IQR 0.6, 0.9). Overall median COI was 25.0 (IQR 10, 50). There was no difference in SVI or COI for admission to the PICU versus the ward. However, children requiring multiple hospital admissions for asthma were associated with higher SVI and lower COI. Conclusions: Children admitted to CHLA for asthma had an elevated SVI and low COI. There was no difference between admission locations based on SVI or COI scores. This indicates we care for children at increased socioeconomic risk, but this did not increase PICU use for asthma. [ABSTRACT FROM AUTHOR]

Introduction: Neonates have a high incidence of respiratory and cardiac perioperative events. Disease severity and indications for surgical intervention often dovetail with an overall complex clinical course and predispose these infants to adverse long‐term neurodevelopmental outcomes and increased length of stay. Our aims were to describe severe and nonsevere early postoperative complications to establish a baseline of care outcomes and to identify subgroups of surgical neonates and procedures for future prospective studies. Methods: Electronic health record data were examined retrospectively for a cohort of patients who had general anesthesia from January 26, 2015 to August 31, 2018. Inclusion criteria were full‐term infants with postmenstrual age less than 44 weeks or premature infants less than 60 weeks postmenstrual age undergoing nonimaging, noncardiac surgery. Severe postoperative complications were defined as mortality, reintubation, positive blood culture, and surgical site infection. Nonsevere early postoperative outcomes were defined as hypoglycemia, hyperglycemia, hypothermia, hyperthermia, and readmission within 30 days. Results: About 2569 procedures were performed in 1842 neonates of which 10.9% were emergency surgeries. There were 120 postoperative severe complications and 965 nonsevere postoperative outcomes. Overall, 30‐day mortality was 1.8% for the first procedure performed, with higher mortality seen on subgroup analysis for patients who underwent exploratory laparotomy (10.3%) and congenital lung lesion resection (4.9%). Postoperative areas for improvement included hyperglycemia (13.9%) and hypothermia (7.9%). Discussion: The mortality rate in our study was comparable to other studies of neonatal surgery despite a high rate of emergency surgery and a high prevalence of prematurity in our cohort. The early outcomes data identified areas for improvement, including prevention of postoperative glucose and temperature derangements. Conclusions: Neonates in this cohort were at risk for severe and nonsevere adverse postoperative outcomes. Future studies are suggested to improve mortality and adverse event rates. [ABSTRACT FROM AUTHOR]

Antibiotic prophylaxis for total joint replacement surgery: results of a survey of Canadian orthopedic surgeons. Joint replacement surgery is the most common major elective surgical procedure performed in Australia and New Zealand, with approximately 119 620 joint replacements performed in Australia in 2020[1] and 22 229 in New Zealand.[2] Based on projected population growth, epidemiological models have estimated that the incidence of total knee arthroplasties and total hip arthroplasties due to osteoarthritis may increase by 276% and 208% respectively by 2030.[3] All arthroplasties performed in Australia and New Zealand are recorded in the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the New Zealand Orthopaedic Association (NZOA) Joint Registry respectively. Antimicrobial-loaded bone cement use is highly variable in joint replacement surgery: a survey of Australian arthroplasty surgeons Acute kidney injury when treating periprosthetic joint infections after total knee arthorplasties with antibiotic-loaded spacers. [Extracted from the article]

Background: Despite the prevalence of colorectal cancer in the elderly, there has been a lack of recent studies examining surgical outcomes in these patients. Post‐operative outcomes of colorectal cancer surgeries in those aged 80 and above will be compared to those younger than 80. Methods: A retrospective study was conducted of adults receiving surgical resections at a single tertiary centre for colorectal cancer diagnosed between January 2017 and December 2019. Patient demographics, mode of presentation, tumour demographics, operative data and post‐operative outcomes were investigated. Results: Of the 326 patients included, 56 were aged 80 and above. Older patients were more likely to be female (P = 0.02), present with surgical emergencies or from other workup rather than through screening (P = 0.002), have more locally advanced cancers (P = 0.009) and receive less neoadjuvant therapy (P = 0.016). Despite this, they had comparable outcomes to those younger than 80 in terms of length of stay (P = 0.21) and rates of complications including mortality (P = 0.67). Conclusion: With appropriate patient selection and management, elderly patients can achieve comparable post‐operative outcomes to their younger counterparts. [ABSTRACT FROM AUTHOR]

Background: Children routinely undergo inhalational induction of general anesthesia. Intravenous line placement typically occurs after induction of anesthesia and can be challenging, particularly in infants and young children. Aims: We conducted a retrospective observational study to determine whether there was an association between clear liquid fasting time and the number of peripheral intravenous catheter insertion attempts in anesthetized children. The secondary aim was to identify factors associated with multiple attempts to insert intravenous lines. Methods: After institutional research board approval, we retrieved a data set of all children between 0 months and 18 years who received general anesthesia at our hospital between January 1, 2016, and September 30, 2017. Data included age, gender, weight, race, ASA status, gestational age, number of peripheral intravenous catheter insertion attempts, any assistive device for insertion, and insertion site. Inclusion criteria were mask induction, ASA status 1 or 2, nonemergency, ambulatory surgical procedures, and placement of a single intravenous line during the anesthetic. Results: A total of 9693 patients were included in the study. Of which 8869 patients required one insertion attempt and 824 underwent multiple insertion attempts. 50% of patients in the single insertion attempt group had clear liquid fasting time <6.9 hours compared to 51.8% of patients requiring multiple attempts. Logistic regression model adjusted for age, ASA status, gender, and BMI did not find an association between duration of clear liquid fasting time and rate of multiple insertion attempts for intravenous catheters (OR: 0.99, 95% CI: 0.98‐1.01, P =.47). Conclusion: Clear liquid fasting time was not associated with multiple insertion attempts for intravenous line insertion in children receiving general anesthesia. Factors such as patient age, ethnicity, time of day of induction of anesthesia, and American Society of Anesthesiologists Physical Status classification show a greater association with the risk of multiple intravenous line insertion attempts. [ABSTRACT FROM AUTHOR]

Background: The Snoring, Trouble Breathing, and Un‐Refreshed (STBUR) questionnaire is a five‐question screening tool for pediatric sleep‐disordered breathing and risk for perioperative respiratory adverse events in children. The utility of this questionnaire as a preoperative risk‐stratification tool has not been investigated. In view of limited availability of screening tools for preoperative pediatric sleep‐disordered breathing, we evaluated the questionnaire's performance for postanesthesia adverse events that can impact postanesthesia care and disposition. Methods: The retrospective study protocol was approved by the institutional research board. The data were analyzed using two different definitions for a positive screening based on a five‐point scale: low threshold (scores 1 to 5) and high threshold (score of 5). The primary outcome was based on the following criteria: (a) supplemental oxygen therapy following postanesthesia care unit (PACU) stay until hospital discharge, (b) greater than two hours during phase 1 recovery, (c) anesthesia emergency activation in the PACU, and (d) unplanned hospital admission. Results: About 6025 patients completed the questionnaire during the preoperative evaluation. And 1522 patients had a low threshold score and 270 had a high‐threshold score. We found statistically significant associations in three outcomes based on the low threshold score: supplemental oxygen therapy (negative‐predictive value [NPV] 0.97, 95% CI 0.97‐98), PACU recovery time (NPV 0.99, 95% CI 0.99‐0.99) and escalation of care (NPV 0.98, 95% CI 0.97‐0.98). Positive‐predictive values were statistically significant for all outcomes except anesthesia emergency in the PACU. Conclusion: The Snoring, Trouble Breathing, and Un‐Refreshed questionnaire identified patients at higher risk for prolonged phase 1 recovery, oxygen therapy requirement, and escalation of care. The questionnaire's high‐negative predictive value and specificity may make it useful as a screening tool to identify patients at low risk for prolonged stay in PACU. [ABSTRACT FROM AUTHOR]

All missions to Mars which have attempted to detect organic molecules have detected simple chlorohydrocarbons, the source of which has yet to be firmly established. This study assessed the likelihood of these chlorinated molecules being indigenous to the sedimentary units in which they were detected or if they were chlorinated during analysis. The survivability of 1‐chloronapthalene was examined via hydrous pyrolysis experiments and its dechlorination kinetics were determined. The results of these experiments were used to model the survivability of this simple chlorohydrocarbon under Mars‐relevant diagenetic conditions using the Sheepbed mudstone unit as a case study. It was found that 1‐chloronapthalene was rapidly dechlorinated under Noachian conditions, and thus, the detected Martian chlorohydrocarbons are unlikely to be ancient and probably formed within the rover's sample handling chain during analysis. Plain Language Summary: The search for past or present life on Mars is centered on the detection of organic molecules. Most attempts to detect organic molecules on Mars have only found simple chlorinated compounds. The source of these chlorinated compounds has not been firmly established. It has been hypothesized that chlorinated organic compounds could form on the Martian surface via reactions between chlorine‐bearing salts and organic compounds delivered by meteorites. This study examined the ability of simple chlorinated organic molecules to survive the high pressures and temperatures associated with burial over geological time scales. Our aim was to calculate whether chlorinated molecules detected on Mars could be ancient and preserved in the rock units, or if they formed during the analysis process, as other studies have assumed. It was found that, on a warmer ancient Mars when the sediments the chlorinated molecules were detected in were deposited, the increased surface temperatures would have promoted the loss of chlorine relatively rapidly, and the intact chlorinated organic molecules would not have survived the burial and exhumation processes to the present day. The chlorinated organics detected on Mars are therefore likely to have been formed recently, most probably through reactions with chlorine‐bearing salts when heated during analysis. Key Points: The survivability of 1‐chloronapthalene during diagenesis has been modeled for Mars‐relevant conditionsChlorohydrocarbons are unlikely to survive until present under Noachian diagenetic conditionsChlorohydrocarbons detected by MSL appear likely to have been chlorinated during analysis [ABSTRACT FROM AUTHOR]

This essay surveys the varieties of liberation theologies that have emerged in different religious communities across Asia. It explores how Asian liberation theologians from across the major religious traditions of Asia have sought answers from within their own religious traditions and social locations to the endemic persistence of mass poverty, exploitative socio-economic structures, and oppressive political systems that often deny basic human and democratic rights to the poor and marginalized masses in Asia. The article's basic premise is that liberation and social justice are not monopolies of Christianity, but are found across the great religious traditions of Asia, and it highlights examples such as Mahatma Gandhi in Indian Hinduism, B. R. Ambedkar in Indian Buddhism, and Buddhadasa Bhikkhu in Thai Buddhism. Christian examples include Aloysius Pieris (Sri Lanka), Dalit and indigenous tribal theologies from India, and Minjung theology from Korea. [ABSTRACT FROM AUTHOR]

Aim: Caudal epidural anesthesia has been shown to reduce stress response and shorten the time to extubation in children after cardiac surgery. Combined with general anesthesia, regional anesthesia has been proven to be safe and efficacious in the pediatric population. It is not known, however, whether the use of caudal anesthesia actually reduces postoperative pain scores and decreases postoperative opioid use. Methods: We retrospectively analyzed the charts of 199 children who underwent repair for atrial septal defect (ASD), ventricular septal defect (VSD), and Tetralogy of Fallot (TOF) at a major academic children's hospital between 2010 and 2013. Results: Eighty-six patients underwent preoperative placement of caudal anesthesia (bupivacaine 0.25% 1 ml·kg-1 up to 20 ml + clonidine 2mcg·kg-1 + Duramorph 40 mcg·kg-1 up to 2.5 mg) and 113 patients did not have a caudal block. Postoperative cardiac intensive care pain scores were analyzed according to standard nurse-recorded patient-appropriate pain scales ranging from 0 to 10 (CRIES for neonates and FLACC for 2 months–7 years). There was no statistical difference between caudal and noncaudal groups with respect to postoperative pain scores or with postoperative opioid requirements. There was a statistical significance with regard to intraoperative opioid use as noncaudal patients invariably received more opioid during the procedure. Conclusion: Although regional anesthesia reduced intraoperative opioid usage, there was no difference in postoperative opioid usage or pain scores. [ABSTRACT FROM AUTHOR]

Ablation of micrometeoroids during atmospheric entry yields volatile gases such as water, carbon dioxide, and sulfur dioxide, capable of altering atmospheric chemistry and hence the climate and habitability of the planetary surface. While laboratory experiments have revealed the yields of these gases during laboratory simulations of ablation, the reactions responsible for the generation of these gases have remained unclear, with a typical assumption being that species simply undergo thermal decomposition without engaging in more complex chemistry. Here, pyrolysis-Fourier transform infrared spectroscopy reveals that mixtures of meteorite-relevant materials undergo secondary reactions during simulated ablation, with organic matter capable of taking part in carbothermic reduction of iron oxides and sulfates, resulting in yields of volatile gases that differ from those predicted by simple thermal decomposition. Sulfates are most susceptible to carbothermic reduction, producing greater yields of sulfur dioxide and carbon dioxide at lower temperatures than would be expected from simple thermal decomposition, even when mixed with meteoritically relevant abundances of low-reactivity Type IV kerogen. Iron oxides were less susceptible, with elevated yields of water, carbon dioxide, and carbon monoxide only occurring when mixed with high abundances of more reactive Type III kerogen. We use these insights to reinterpret previous ablation simulation experiments and to predict the reactions capable of occurring during ablation of carbonaceous micrometeoroids in atmospheres of different compositions. [ABSTRACT FROM AUTHOR]

Background/Aims Endoscopic screening for high-risk gastro-oesophageal varices ( GOV) is recommended for compensated cirrhotic patients with transient elastography identifying increasing numbers of patients with cirrhosis without portal hypertension. Using liver stiffness measurement ( LSM) ± platelet count, the aim was to develop a simple clinical rule to exclude the presence of high-risk GOV in patients with Child-Pugh A cirrhosis. Methods A retrospective analysis of 71 patients with Child-Pugh A cirrhosis diagnosed by transient elastography ( LSM >13.6 kPa) who underwent screening gastroscopy was conducted. A predictive model using LSM ± platelet count was assessed to exclude the presence of high-risk GOV (diameter >5 mm and/or the presence of high-risk stigmata) and validated using a second cohort of 200 patients from two independent centres. Results High-risk GOV were present in 10 (15%) and 16 (8%) of the training and validation cohorts, respectively, which was associated with LSM and Pl count ( P < 0.05). A combined model based on LSM and Pl count was more accurate for excluding the presence of high-risk GOV than either alone (training cohort AUROC: 0.87 [0.77-0.96] vs. 0.78 [0.65-0.92] for LSM and 0.71 [0.52-0.90] for platelets) with the combination of LSM ≤25 kPa and Pl ≥100 having a NPV of 100% in both the training and validation cohorts. A total of 107 (39%) patients meet this criterion. Conclusion The combination of LSM ≤25 kPa and Pl ≥100 can be used in clinical practice to exclude the presence of high-risk GOV in patients with Child-Pugh A cirrhosis. [ABSTRACT FROM AUTHOR]

An independent 87-year-old female presented to a regional hospital in Western Australia with a 2-day history of left hip pain and erythema. An urgent colorectal review was obtained and computed tomography revealed a colocutaneous fistula arising from the left colon, extending through an area of eroded left iliac crest (Fig. Her past medical history revealed a background of chronic left hip osteomyelitis, which was treated with fusion of the left hip at age 12. [Extracted from the article]

The Gram-negative bacterial endotoxin lipopolysaccharide ( LPS) is a potent inflammatory mediator and a leading cause of bacterial sepsis. While LPS is known to activate antigen-presenting cells, here we find that LPS down-regulates expression of CD11c and CD11b on splenic dendritic cell subsets, thus confounding the ability to identify these subsets following treatment. This has implications with regard to tracking the response to LPS in terms of the cell subsets involved, and should be considered whenever such studies are undertaken. [ABSTRACT FROM AUTHOR]

A novel dendritic-like cell subset termed L- DC was recently identified in murine spleen based on marker expression of a homogeneous cell population derived from long-term culture of neonatal spleen. The function of L- DC is distinct from other splenic dendritic and myeloid cell subsets because of their high endocytic capacity and their ability to cross-present antigen to CD8+ T cells. This paper shows the subset to be unique to spleen and blood, with a similar, but possibly functionally distinct subset also present in bone marrow. The prevalence of the subset is low; ~6% of all dendritic and myeloid cells in the spleen and ~5% in blood. However, they are a distinct cell type on the basis of marker expression, and endocytic and T-cell stimulatory capacity. Attempts to identify an enriched population of these cells in mutant mouse strains with reported increases in myelopoiesis showed either a lack of L- DC or an altered phenotype reflective of the phenotype of the mouse strain. [ABSTRACT FROM AUTHOR]

Antigen-presenting cells (APC), like dendritic cells (DC), are essential for T-cell activation, leading to immunity or tolerance. Multiple DC subsets each play a unique role in the immune response. Here, a novel splenic dendritic-like APC has been characterized in mice that has immune function and cell surface phenotype distinct from other, described DC subsets. These were identified as a cell type continuously produced in spleen long-term cultures (LTC) and have an in vivo equivalent cell type in mice, namely 'L-DC'. This study characterizes LTC-DC in terms of marker phenotype and function, and compares them with L-DC and other known splenic DC and myeloid subsets. L-DC display a myeloid dendritic-like phenotype equivalent to LTC-DC as CD11cCD11bMHC-IICD8α cells, distinct by high accessibility and endocytic capacity for blood-borne antigen. Both LTC-DC and L-DC have strong antigen cross-presentation ability leading to strong activation of CD8 T cells, particularly after exposure to lipopolysaccharide. However, they have weak ability to stimulate CD4 T cells in antigen-specific responses. Evidence is presented here for a novel DC type produced by in vitro haematopoiesis which has distinct antigen-presenting potential and reflects a DC subset present also in vivo in spleen. [ABSTRACT FROM AUTHOR]

Objective: To evaluate trends in the incidence and serotype profile of invasive pneumococcal disease (IPD) in Australian children under 2 years of age after the introduction of the 7-valent pneumococcal conjugate vaccine (7vPCV).Design and Setting: Analysis of incidence rates calculated using IPD surveillance data (including age, Indigenous status and serotype of the pneumococcal isolate) from 2002 to 2007 obtained from the National Notifiable Diseases Surveillance System and population estimates obtained from the Australian Bureau of Statistics.Main Outcome Measures: Trends in IPD incidence among Indigenous and non-Indigenous children between 2002 and 2007; change in the serotype profile of IPD in non-Indigenous children after the introduction of universal 7vPCV vaccination in 2005.Results: Overall incidence of IPD decreased by 74% in all children < 2 years of age between 2002 and 2007 (P < 0.001). While the incidence of IPD caused by 7vPCV serotypes decreased significantly among both Indigenous and non-Indigenous children, the incidence of non-7vPCV serotype IPD increased significantly in non-Indigenous children (from 9.7 to 15.7 per 100 000, P < 0.001). Compared with a pre-vaccination period (2002-2004), the 2007 incidence of serotype 19A IPD in non-Indigenous children increased significantly (from 2.7 to 8.6 per 100 000, P < 0.001). In 2007, 19A was the predominant serotype causing IPD (37.7%) in all children aged < 2 years.Conclusions: The overall incidence of IPD decreased from 2002 to 2007, primarily driven by a reduction in IPD caused by 7vPCV serotypes. However, this was partially offset by a significant increase in the incidence of IPD caused by non-7vPCV serotypes, particularly 19A, in non-Indigenous children. [ABSTRACT FROM AUTHOR]

Dendritic cells (DC) are known to develop from macrophage dendritic progenitors (MDP) in bone marrow (BM), which give rise to conventional (c)DC and monocytes, both dominant antigen presenting cell (APC) subsets in spleen. This laboratory has however defined a distinct dendritic-like cell subset in spleen (L-DC), which can also be derived in long-term cultures of spleen. In line with the restricted in vitro development of only L-DC in these stromal cultures, we questioned whether self-renewing HSC or progenitors exist in spleen with restricted differentiative capacity for only L-DC. Neonatal spleen and BM were compared for their ability to reconstitute mice and to give rise to L-DC, as well as other splenic APC. Neonatal spleen cells were transplanted into allotype-distinct lethally irradiated hosts along with host-type competitor BM cells, and assayed over 8 to 51 weeks for haematopoietic reconstitution of L-DC and cDC subsets, along with other lymphoid and myeloid cells. In this study, neonatal spleen showed multilineage haematopoietic reconstitution in mouse chimeras, rather than specific or restricted ability to differentiate into L-DC. However, the representation of individual APC subsets was found to be unequal in chimeras partially reconstituted with donor cells, such that more donor-derived progeny were seen for L-DC than for myeloid and cDC subsets. The ability of HSC in spleen to develop into L-DC was indicated by a strong bias in the subset size of these cells over other splenic APC subsets. This type of evidence supports a model whereby spleen represents an important site for haematopoiesis of this distinct DC subset. The conditions under which haematopoiesis of L-DC occurs in spleen, or the progenitors involved, will require further investigation. [ABSTRACT FROM AUTHOR]

We experimentally test the efficacy of indenture as a self-enforced contract device. In an indenture game, the principal signals the intention of payment on delivery by tearing a banknote in half and giving the agent one half of it as "prepayment"; the agent receives the completing half after delivering the service. By forward induction, cooperation is incentive-compatibly self-enforcing. The indenture performs very well. inducing a significantly higher level of cooperation than that in a three-stage centipede game. which we use to benchmark the natural rate of cooperation. The difference between cooperation rates in both games increases over time. [ABSTRACT FROM AUTHOR]

Bone marrow is the main site for hematopoiesis in adults. It acts as a niche for hematopoietic stem cells (HSCs) and contains non‐hematopoietic cells that contribute to stem cell dormancy, quiescence, self‐renewal, and differentiation. HSC also exist in resting spleen of several species, although their contribution to hematopoiesis under steady‐state conditions is unknown. The spleen can however undergo extramedullary hematopoiesis (EMH) triggered by physiological stress or disease. With the loss of bone marrow niches in aging and disease, the spleen as an alternative tissue site for hematopoiesis is an important consideration for future therapy, particularly during HSC transplantation. In terms of harnessing the spleen as a site for hematopoiesis, here the remarkable regenerative capacity of the spleen is considered with a view to forming additional or ectopic spleen tissue through cell engraftment. Studies in mice indicate the potential for such grafts to support the influx of hematopoietic cells leading to the development of normal spleen architecture. An important goal will be the formation of functional ectopic spleen tissue as an aid to hematopoietic recovery following clinical treatments that impact bone marrow. For example, expansion or replacement of niches could be considered where myeloablation ahead of HSC transplantation compromises treatment outcomes. [ABSTRACT FROM AUTHOR]

A letter to the editor regarding the trend of laparoscopic surgery for various operation in pediatric patients is presented.

The article focuses on the case of 88-year-old man with a two weeks history of increasing pain the right upper quadrant of abdomen. It states that a thickened gallbladder wall with multiple stones and dilated intrahepatic ducts were sown in an abdominal computed tomography (CT) scan. It says that an effective decompression of the biliary system was confirmed by magnetic resonance cholangiopancreatography (MRCP).

Dendritic cells (DC) represent a heterogeneous class of antigen presenting cells (APC). Previously we reported a distinct myeloid dendritic-like cell present in spleen, as an in vivo counterpart to cells produced in murine spleen long-term cultures (LTC-DC). These cells, named 'L-DC', were found to be functionally and phenotypically distinct from conventional (c)DC, plasmacytoid (p)DC and monocytes. These results suggested that spleen may represent a niche for development of L-DC from endogenous progenitors. Adult murine spleen has now been investigated for the presence of L-DC progenitors. Lineage-negative (Lin)(-) ckit(lo) and Lin(-) ckit(hi) progenitor subsets were identified as candidate populations, and tested for ability to produce L-DC; in vitro upon co-culture with the spleen stromal line STX3, and in vivo after adoptive therapy into mice. Both subsets colonized STX3 stroma in vitro for L-DC production, indicating that they contained either a common or two distinct progenitors for L-DC. However, only the Lin(-) ckit(hi) subset gave progeny cells after adoptive transfer into lethally irradiated mice. In vivo development was however multilineage and not restricted to L-DC development. Multilineage reconstitution reflects long-term reconstituting haematopoietic stem cells (LT-HSC), suggesting a close relationship between L-DC progenitors and LT-HSC. L-DC were however produced in vivo in much higher number than monocytes/macrophages and cDC, indicating the presence of a specific L-DC progenitor within the Lin(-) ckit(hi) subset. A model is advanced for development of L-DC directly from haematopoietic progenitors in spleen and dependent on the spleen microenvironment., (© 2012 The Authors Journal of Cellular and Molecular Medicine © 2012 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.)