Generation of the eosinophil chemotactic factor (ECF) from various cell types by melittin

The peptide melittin, the main constituent of bee venom is a potent stimulus for the generation of an eosinophil chemotactic factor (ECF) from human polymorphonuclear neutrophils, rat mast cells and rat peritoneal cells depleted in mast cells. Optimal EFC induction required a sublytic activation of the cells. With each cell type the kinetics of ECF generation were similar in that after an early rise in activity a steep fall off occurred at later times of incubation suggesting a mechanism of inactivation. The induction of ECF by melittin is increased in the presence of calcium. The polar portion of the melittin molecule (aminoacids 20–26) is responsible for the generation of the chemotactic activity. Other peptides of honey bee venom such as the mast cell degranulating peptide (MCD) or apamine do not initiate ECF release. It appears that melittin leads to ECF induction via the phospholipase A₂-arachidonic acid dependent pathway of cell activation. Our data suggests that the lipid mediator ECF can be obtained from phagocytes and mast cells thus indicating the interdependence of inflammatory reactions.     

Plasma fibronectin levels in meningococcal disease

Fibronectin (a glycoprotein which modulates inflammation) may decrease mortality in systemic infection. Children with meningococcal disease (MCD) may have low fibronectin levels. We aimed to compare plasma fibronectin levels in children with MCD and controls, correlate fibronectin levels with interleukin-6 (IL-6), shock and death, and assess fibronectin as an aid to early diagnosis in MCD. Samples were taken on admission from 99 children with MCD and 49 controls. Plasma fibronectin was measured using a turbidimetric immunoassay. Plasma fibronectin was significantly lower in MCD compared to controls (57 μg/ml vs 105 μg/ml; P < 0.005). Children who died had significantly lower levels than survivors (29 μg/ml vs 62 μg/ml; P = 0.01). Fibronectin levels were negatively correlated with IL-6 levels. Fibronectin was a poor predictor of MCD. Conclusion Plasma fibronectin levels are decreased in children with MCD, especially in shock and death. This decrease is associated with high IL-6 levels. Fibronectin could be a novel therapy in severe MCD. Received: 6 June 1996 / Accepted: 16 October 1996     

End-Stage Renal Disease and Mortality Outcomes Across Different Glomerulonephropathies in a Large Diverse US Population

Objective

To compare renal function decline, incident end-stage renal disease (ESRD), and mortality among patients with 5 common glomerular diseases in a large diverse population.

Two cases of DYNC1H1 mutations with intractable epilepsy

BackgroundThe DYNC1H1 gene encodes the heavy chain of cytoplasmic dynein 1, a core structure of the cytoplasmic dynein complex. Dominant DYNC1H1 mutations are implicated in Charcot–Marie–Tooth disease, axonal, type 20, spinal muscular atrophy, lower extremity-predominant 1, and autosomal dominant mental retardation 13 with neuronal migration defects. We report two patients with DYNC1H1 mutations who had intractable epilepsy and intellectual disability (ID), one with and one without pachygyria.Case reportsPatient 1 had severe ID. At the age of 2 months, she presented myoclonic seizures and tonic seizures, and later experienced atonic seizures and focal impaired-awareness seizures (FIAS). EEG showed slow waves in right central areas during myoclonic seizures. Brain MRI revealed pachygyria, predominantly in the occipital lobe. After callosal transection her atonic seizures disappeared, but FIAS remained. Patient 2 was diagnosed with autism spectrum disorder (ASD) and severe ID. At the age of 7 years, he presented generalized tonic–clonic seizures, myoclonic seizures, and FIAS. Interictal EEG showed generalized spike-and-wave complexes, predominantly in the left frontal area. Brain MRI was unremarkable. Exome sequencing revealed novel de novo mutations in DYNC1H1: c.4691A > T, p.(Glu1564Val) in Patient 1 and c.12536 T > C, p.(Leu4179Ser) in Patient 2.ConclusionsDYNC1H1 comprises a stem, stalk, and six AAA domains. Patient 2 is the second report of an AAA6 domain mutation without malformations of cortical development. The p.(Gly4072Ser) mutation in the AAA6 domain was also reported in a patient with ASD. It may be that the AAA6 domain has little effect on neuronal movement of DYNC1H1 along microtubules.     

Ammonium accumulation and chemokine decrease in culture media of Gcdh−/− 3D reaggregated brain cell cultures

Glutaric Aciduria type I (GA-I) is caused by mutations in the GCDH gene. Its deficiency results in accumulation of the key metabolites glutaric acid (GA) and 3-hydroxyglutaric acid (3-OHGA) in body tissues and fluids. Present knowledge on the neuropathogenesis of GA-I suggests that GA and 3-OHGA have toxic properties on the developing brain.We analyzed morphological and biochemical features of 3D brain cell aggregates issued from Gcdh^?/? mice at two different developmental stages, day-in-vitro (DIV) 8 and 14, corresponding to the neonatal period and early childhood. We also induced a metabolic stress by exposing the aggregates to 10 mM l-lysine (Lys).Significant amounts of GA and 3-OHGA were detected in Gcdh^?/? aggregates and their culture media. Ammonium was significantly increased in culture media of Gcdh^?/? aggregates at the early developmental stage. Concentrations of GA, 3-OHGA and ammonium increased significantly after exposure to Lys. Gcdh^?/? aggregates manifested morphological alterations of all brain cell types at DIV 8 while at DIV 14 they were only visible after exposure to Lys. Several chemokine levels were significantly decreased in culture media of Gcdh^?/? aggregates at DIV 14 and after exposure to Lys at DIV 8.This new in vitro model for brain damage in GA-I mimics well in vivo conditions. As seen previously in WT aggregates exposed to 3-OHGA, we confirmed a significant ammonium production by immature Gcdh^?/? brain cells. We described for the first time a decrease of chemokines in Gcdh^?/? culture media which might contribute to brain cell injury in GA-I.     

霉酚酸酯对微小病变肾病治疗作用研究

目的以阿霉素肾病大鼠建立微小病变肾病模型,以霉酚酸酯(MMF)进行干预,检测nephrin的表达,研究霉酚酸酯对微小病变肾病的治疗作用及其机制。方法SD大鼠18只,分为肾病模型组、MMF治疗组、对照组。模型组、治疗组大鼠尾静脉一次性注入阿霉素7.5mg/kg,治疗组大鼠于注药次日开始使用MMF20mg/(kg·d)灌胃。对照组大鼠尾静脉一次性注入等量生理盐水。每组于第28天各取大鼠6只,检测尿蛋白、血生化指标;并用免疫组化、Westernblot方法,检测肾组织内nephrin蛋白水平。结果肾病组尿蛋白第28天达高峰;血清清蛋白明显降低(P<0.01);治疗组第28天尿蛋白、血清甘油三酯、胆固醇较肾病组减少(P<0.01),血清清蛋白较肾病组增加(P<0.01)。免疫组化、Westernblot结果提示肾病组较对照组第28天nephrin蛋白表达升高(P<0.01);治疗组第28天nephrin蛋白表达较肾病组下调(P<0.01)。结论阿霉素诱发的微小病变肾病发生与nephrin表达异常有关,霉酚酸酯可以减少蛋白尿,延缓微小病变型大鼠肾损伤,其作用与影响nephrin的表达有关。     

The role of CNS fuel sensing in energy and glucose regulation

Individual cells must carefully regulate their energy flux to ensure nutrient levels are adequate to maintain normal cellular activity. The same principle holds in multicellular organisms. Thus, for mammals to perform necessary physiological functions, sufficient nutrients need to be available. It is more complex, however, to understand how the energy status of different cells impacts on the overall energy balance of the entire organism. We propose that the central nervous system is the critical organ for the coordination of intracellular metabolic processes that are essential to guarantee energy homeostasis at the organismal level. In particular, we suggest that in specific hypothalamic neurons, evolutionarily conserved fuel sensors, such as adenosine monophosphate-activated protein kinase and mammalian target of rapamycin (mTOR), integrate sensory input from nutrients, including those derived from recently ingested food or those that are stored in adipose tissue, to regulate effector pathways responsible for fuel intake and utilization. The corollary to this hypothesis is that dysregulation of these fuel-sensing mechanisms in the brain may contribute to metabolic dysregulation underlying diseases, such as obesity and type 2 diabetes.