Recombinant human interleukin-3 and granulocyte-macrophage colony- stimulating factor show common biological effects and binding characteristics on human monocytes

Two human hemopoietic growth factors involved in monocytopoiesis, interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were studied for their ability to stimulate blood monocytes and to bind to the monocyte membrane. Both cytokines maintained monocyte/macrophage numbers during long-term culture and increased cell size as compared with controls. Effects on cell numbers were present at low cytokine concentrations (6 to 20 pmol/L), whereas enhanced 3H-thymidine incorporation was observed only at higher concentrations (greater than or equal to 60 pmol/L). Autoradiographic studies showed only 1% to 3% of stimulated monocytes with nuclear grains. These results suggest that the primary mechanism for IL-3 and GM-CSF-induced maintenance of monocyte/macrophage numbers in humans is through an effect on cell survival. Surface receptors for both IL-3 and GM-CSF were studied by using 125I-labeled recombinant human (rh) cytokines and performing Scatchard analyses. Both cytokines showed curvilinear Scatchard plots, and computer analyses favored a two-site binding model. High-affinity binding data for 125I rhIL-3 (Kd 7.7 to 38.2 pmol/L; receptor number/cell 95 to 580) and for 125I rhGM-CSF (Kd 4.7 to 38.9 pmol/L; receptor number/cell 8 to 67) show similar binding affinities for the two cytokines but a lower receptor number/cell for 125I rhGM-CSF. Low-affinity binding characteristics for 125I rhIL-3 (Kd 513 to 939 pmol/L; receptor number/cell 179 to 5,274) and for 125I rhGM- CSF (Kd 576 to 1,120 pmol/L; receptor number/cell 130 to 657) show a similar pattern for the two cytokines. Specificity of 125I rhIL-3 and 125I rhGM-CSF binding to monocytes was established by the ability of the homologous cytokine to inhibit binding and the inability of a range of other cytokines to compete at 100-fold excess molar concentration. It is important, however, that binding of 125I rhIL-3 was partially inhibited by rhGM-CSF and that rhIL-3 partially inhibited binding of 125I rhGM-CSF to the monocyte membrane under conditions shown to prevent receptor internalization. The degree of inhibition varied between 25% and 80% in different experiments, and quantitative inhibition experiments showed that 1,000-fold excess concentrations of competitor failed to inhibit binding of the heterologous ligand completely. These results demonstrate that human IL-3 and GM-CSF have similar effects on growth and survival of human monocytes in vitro and suggest that these and other common biological effects may be mediated either through a common receptor or through distinct receptors associated on the monocyte membrane.     

Do clinical characteristics and outcome in nonagenarians with a hip fracture differ from younger patients?

Aim: To compare clinical characteristics and outcome of nonagenarian hip fracture patients with younger patients aged 65–89 years. Methods: This was a cohort follow‐up study of admissions for a hip fracture between 2005–2010 (mean follow up of 3.5 years) in two teaching hospitals in the Netherlands; 230 nonagenarians and 1014 patients aged 65–89 years were included. Clinical characteristics, adverse events, mobility and mortality were compared. Results: Nonagenarians were more likely to be female and anemic (both P < 0.001), and had more trochanteric fractures (P = 0.005). The number of American Society of Anesthesiologists III/VI classified patients did not differ between the two groups. During the hospital stay, adverse events were more frequently observed in nonagenarians compared with younger patients (P < 0.001). The length of stay was significantly longer in nonagenarians (P < 0.001), and the 90‐day readmission rate was similar. Absolute mortality was higher in nonagenarians (P < 0.001), excess mortality, however, was comparable. Before admission, 40.0% of the nonagenarians lived in their own home, and 40.9% had returned 3 months postfracture. The rate of returning to their own home was lower compared with younger patients (P < 0.001). Prefracture mobility was worse in nonagenarians compared with the younger group, but 3 months after discharge, the number of patients that regained prefracture mobility was comparable in both age groups. Conclusions: Nonagenarian hip fracture patients differ significantly from younger patients aged 65–89 years with respect to clinical characteristics and long‐term outcome. However, almost half of the nonagenarians returned to their own home and more than half regained their prefracture level of mobility. Given these findings, prevention strategies for hip fracture and adverse events during hospital stay that focus particularly on frail nonagenarians are highly recommended. Geriatr Gerontol Int 2013; 13: 190–197.     

Correlation of thromboelastography with standard tests of anticoagulation in paediatric patients receiving extracorporeal life support

Children requiring extracorporeal life support (ECLS) are at significant risk for thrombotic and haemorrhagic complications. Thromboelastography (TEG) is increasingly being used to assist in monitoring the coagulation status of critically ill patients. Its role in heparinised children receiving ECLS is unknown.

Methods

A retrospective review of TEG in 27 children (mean age 2 years and 8 months) receiving ECLS in a tertiary paediatric intensive care unit between December 2006 and April 2008. Paired TEG (kaolin and heparinase) analysis was performed on 171 occasions. On all occasions activated partial thromboplastin time (APTT) and platelet count were performed within 4 hours of the TEG (mean 6.5 minutes after TEG). On 158 occasions, the activated clotting time (ACT) was measured simultaneously with TEG.

Results

The TEG (kaolin) sample was not interpretable due to the heparin effect in 89 (52%) samples. There was a weak correlation between TEG (heparinase) variables and APTT, and between TEG and ACT with a stronger correlation between TEG (Maximum amplitude) and platelet count.

Conclusion

TEG monitoring should always include paired samples in heparinised children on ECLS. In this heterogeneous population, weak, and moderate correlations exist between TEG and standard haematological tests. Prospective studies, with simultaneous sampling for TEG and conventional laboratory tests, must be performed in order to establish its absolute utility as a clinical tool in this population.     

A Review of the Cardiac and Cardiovascular Effects of COVID-19 in Adults and Children

Symptomatic coronavirus disease 2019 (COVID-19) typically affects the respiratory system but can involve the cardiovascular system. Cardiac complications of COVID-19 can result directly from myocarditis or indirectly from numerous other mechanisms. Differentiating between primary and secondary cardiovascular involvement—our focus in this review—may help to identify the long-term effects of COVID-19 on the heart in adults and children.     

Dose-dependent localization of TCDD in isolated centrilobular and periportal hepatocytes

Dose-response relationships for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suggest a differential sensitivity of liver cell types to the induction of cytochrome P450 gene expression, and that the induction of hepatic protein CYP1A2 causes sequestration of TCDD. In addition, immunolocalization of hepatic CYP1A1/1B1/1A2 proteins is not uniform after exposure to TCDD. The mechanism for the regio-specific induction of hepatic P450s by TCDD is unknown, but may involve the differential distribution of participants in the AhR-mediated pathway and/or regional P450 isozymes, as well as, non-uniform distribution/sequestration of TCDD. Therefore, this study examined the effects of TCDD in unfractionated, centrilobular and periportal hepatocytes isolated from female Sprague-Dawley rats acutely exposed (3 days) to a single oral dose of 0.01-10.0 microg [3H]TCDD/kg. A dose- dependent increase in concentration of TCDD was accompanied by a dose- dependent increase in CYP1A1, CYP1A2, and CYP1B1 mRNA expression and associated enzymes in all liver-cell populations. Centrilobular hepatocytes showed a 2.7- to 4.5-fold higher concentration of TCDD as compared to the periportal hepatocytes at doses up to 0.3 microg TCDD/kg. Centrilobular hepatocytes also exhibited an elevated MROD activity as compared to the periportal hepatocytes at doses up to 0.3 microg TCDD/kg. Furthermore, centrilobular hepatocytes showed an elevated concentration of induced CYP1A2 and CYP1B1 mRNA as compared to periportal hepatocytes within the 0.01- and 0.3-microg TCDD/kg- treatment groups. This is the first study to demonstrate that a dose- dependent difference in distribution of TCDD exists between centrilobular and periportal cells that might be related to regional differences in P450 induction.      

Nebulized budesonide versus oral steroid in severe exacerbations of childhood asthma

The aim of this study was to assess whether nebulized budesonide may substitute for oral prednisolone in the management of children whose asthma is severe enough to warrant hospital admission, but who have no life threatening features. In a prospective, double-blind, randomized study nebulized budesonide (2 mg 8 hourly) was compared with oral prednisolone (2 mg/kg at entry and again at 24 h) in 46 children admitted to hospital with severe asthma exacerbations. Efficacy variables (including lung function measurements such as the primary outcome variable, Forced Expiratory Volume in 1 second (FEV₁) and symptoms) were measured 24 h after treatment initiation. FEV₁ improved significantly compared to baseline in patients who received nebulized budesonide compared to the prednislone group. The data show nebulized budesonide to be at least as effective as oral steroid in improving lung function and symptom severity in severe exacerbations of childhood asthma.     

一个新型的双二萜生物碱

普格乌头(Aconitum pukeense W.T.Wang)分布于云南东北部和四川西南部,生长在海拔3400～3500米山地谷中竹林边或沟边。因其根部毒性很强,可用作箭毒,在云南巧家药山又称之为弩箭药。民间常将其泡制后用于治疗跌打损伤等症。该植物的化学成