Endothelial microparticles released in thrombotic thrombocytopenic purpura express von Willebrand factor and markers of endothelial activation

It has been suggested that endothelial apoptosis is a primary lesion in the pathogenesis of thrombotic thrombocytopenic purpura (TTP). We tested this hypothesis by examining the phenotypic signatures of endothelial microparticles (EMP) in TTP patients. In addition, the effect of TTP plasma on microvascular endothelial cells (MVEC) in culture was further delineated. EMP released by endothelial cells (EC) express markers of the parent EC; EMP released in activation carry predominantly CD54 and CD62E, while those in apoptosis CD31 and CD105. We investigated EMP release in vitro and in TTP patients. Following incubation of MVEC with TTP plasma, EMP and EC were analysed by flow cytometry for the expression of CD31, CD51, CD54, CD62E, CD105, CD106 and von Willebrand factor (VWF) antigen. EMP were also analysed in 12 TTP patients. In both EC and EMP, CD62E and CD54 expression were increased 3- to 10-fold and 8- to 10-fold respectively. However, CD31 and CD105 were reduced 40-60% in EC but increased twofold in EMP. VWF expression was found in 55 +/- 15% of CD62E(+) EMP. Markers of apoptosis were negative. In TTP patients, CD62E(+) and CD31(+)/CD42b(-) EMP were markedly elevated, and preceded and correlated well with a rise in platelet counts and a fall in lactate dehydrogenase. CD62E(+) EMP (60 +/- 20%) co-expressed VWF and CD62E. The ratio of CD31(+)/42b(-) to CD62E(+) EMP exhibited a pattern consistent with activation. In conclusion, our studies indicate endothelial activation in TTP. EMP that co-express VWF and CD62E could play a role in the pathogenesis of TTP.

A Constant-Factor Approximation Algorithm for Embedding Unweighted Graphs into Trees

We present a constant-factor approximation algorithm for computing an embedding of the shortest path metric of an unweighted graph into a tree, that minimizes the multiplicative distortion.

Capillary zone electrophoresis investigation of interactions between granulocyte-colony stimulating factor and dextran sulfate/carrageenan oligosaccharide

The interactions between granulocyte-colony stimulating factor (G-CSF) and dextran sulfate/kappa-carrageenan oligosaccharide were studied by capillary zone electrophoresis. Dextran sulfate could strongly interact with G-CSF and the complex was detected. The binding constant and stoichiometry were determined to be 1.2x10(6) (mol/L)(-1) and 3:1, respectively. However, the interaction between K-carrageenan oligosaccharide and G-CSF was not found.

The lack of associations between alleles at the hypoxia-Inducible factor 1A C1772T loci and responses to acute hypoxia.

Objective The aim of this study was to investigate the associations between alleles of the hypoxia-inducible factor 1A (HIF1A) C1772T polymorphism and several physiological responses to hypoxia, including the hypoxic ventilatory response (HVR), and serum erythropoietin (EPO), arterial oxygen saturation (Sao2), and acute mountain sickness (AMS) responses during 8 hours of exposure to normobaric hypoxia. Methods A total of 76 males participated in the study; 52 participants completed an 8-hour exposure to 12.7% oxygen, during which time Sao2, EPO concentrations, and AMS scores were measured, while 62 individuals took part in an HVR trial (in total 38 individuals completed both protocols). DNA was obtained from leukocytes, and a 346-bp fragment of the HIF1A gene containing the C1772T polymorphism was amplified using polymerase chain reaction. Fragments were sequenced to reveal individual genotypes, and the associations between HIF1A genotype and EPO, Sao2, AMS responses to hypoxia and HVR were examined. Results The magnitude of the hypoxic responses was highly variable between individuals. The increase in participants' EPO responses ranged from 89% to 388% of baseline values following hypoxia, while Sao2 values during the exposure ranged from 71% to 89%. The HVR ranged from −0.04 to +2.18 L · min−1 · Sao2%−1 among participants. No significant differences in EPO, Sao2, AMS, or HVR results were observed between the HIF1A CC genotype and the combined CT/TT genotype group. Conclusion In this study, the HIF1A C1772T polymorphism does not appear to influence EPO, Sao2, or AMS responses during acute hypoxic exposure, or the magnitude of the HVR.

The effect of the product cost factor on error handling in industrial robots

N.W. Hardy and M.H. Lee. The effect of the product cost factor on error handling in industrial robots. In Maria Gini, editor, Detecting and Resolving Errors in Manufacturing Systems. Papers from the 1994 AAAI Spring Symposium Series, pages 59-64, Menlo Park, CA, March 1994. The AAAI Press. Technical Report SS-94-04, ISBN 0-929280-60-1.

A role for LH in the regulation of expression of mRNAs encoding components of the insulin-like growth factor (IGF) system in the ovine corpus luteum

P.M. Hastie and W. Haresign (2006). A role for LH in the regulation of expression of mRNAs encoding components of the insulin-like growth factor (IGF) system in the ovine corpus luteum. Animal Reproduction Science, 96(1-2), 196-209. Sponsorship: DEFRA RAE2008

The rpf gene of Micrococcus luteus encodes an essential secreted growth factor

Galina V. Mukamolova, Obolbek A. Turapov, Konstantin Kazarian, Miroslav Telkov, Arseny S. Kaprelyants, Douglas B. Kell and Michael Young (2002). The rpf gene of Micrococcus luteus encodes an essential secreted growth factor. Molecular Microbiology, 46 (3), 611-621. Sponsorship: BBSRC / Russian Foundation for Basic Research (grant 00-04-48691)/ WHO Global Programme for Vaccines and Immunization / Wellcome Trust RAE2008

The role of the dopaminergic neurotrophin growth/differentiation factor-5 in the developing rat ventral midbrain

Growth differentiation factor-5 (GDF-5) is a member of the transforming growth factor-β superfamily, a family of proteins that play diverse roles in many aspects of cell growth, proliferation and differentiation. GDF-5 has also been shown to be a trophic factor for embryonic midbrain dopaminergic neurons in vitro (Krieglstein et al. 1995) and after transplantation to adult rats in vivo (Sullivan et al. 1998). GDF-5 has also been shown to have neuroprotective and neurorestorative effects on adult dopaminergic neurons in the substantia nigra in animal models of Parkinson’s disease (Sullivan et al. 1997, 1999; Hurley et al. 2004). This experimental evidence has lead to GDF-5 being proposed as a neurotrophic factor with potential for use in the treatment of Parkinson’s disease. However, it is not know if GDF-5 is expressed in the brain and whether it plays a role in dopaminergic neuron development. The experiments presented here aim to address these questions. To that end this thesis is divided into five separate studies each addressing a particular question associated with GDF-5 and its expression patterns and roles during the development of the rat midbrain. Expression of the GDF-5 in the developing rat ventral mesencephalon (VM) was found to begin at E12 and peak on E14, the day that dopaminergic neurons undergo terminal differentiation. In the adult rat, GDF-5 was found to be restricted to heart and brain, being expressed in many areas of the brain, including striatum and midbrain. This indicated a role for GDF-5 in the development and maintenance of dopaminergic neurons. The appropriate receptors for GDF-5 (BMPR-II and BMPR-Ib) were found to be expressed at high levels in the rat VM at E14 and BMPR-II expression was demonstrated on dopaminergic neurons in the E13 mouse VM. GDF-5 resulted in a three-fold increase in the numbers of dopaminergic neurons in cultures of E14 rat VM, without affecting the numbers of neurones or total cells. GDF-5 was found to increase the proportion of neurons that were dopaminergic. The numbers of Nurr1-positive cells were not affected by GDF-5 treatment, but GDF-5 did increase the numbers of Nurr1- positive cells that expressed tyrosine hydroxylase (TH). Taken together this data indicated that GDF-5 increases the conversion of Nurr1-positive, TH-negative cells to Nurr1-positive, TH-positive cells. In GDF-5 treated cultures, total neurite length, neurite arborisation and somal area of dopaminergic were all significantly increased compared to control cultures. Thus this study showed that GDF-5 increased the numbers and morphological differentiation of VM dopaminergic neurones in vitro. In order to examine if GDF-5 could induce a dopaminergic phenotype in neural progenitor cells, neurosphere cultures prepared from embryonic rat VM were established. The effect of the gestational age of the donor VM on the proportion of cell types generated from neurospheres from E12, E13 and E14 VM was examined. Dopaminergic neurons could only be generated from neurospheres which were prepared from E12 VM. Thus in subsequent studies the effect of GDF-5 on dopaminergic induction was examined in progentior cell cultures prepared from the E12 rat VM. In primary cultures of E12 rat VM, GDF-5 increased the numbers of TH-positive cells without affecting the proliferation or survival of these cells. In cultures of expanded neural progenitor cells from the E12 rat VM, GDF-5 increased the expression of Nurr1 and TH, an action that was dependent on signalling through the BMPR-Ib receptor. Taken together, these experiments provide evidence that GDF-5 is expressed in the developing rat VM, is involved in both the induction of a dopaminergic phenotype in cells of the VM and in the subsequent morphological development of these dopaminergic neurons

The gut microbiota as a contributing factor to antipsychotic-induced weight gain and metabolic dysfunction

Schizophrenia represents one of the world’s most devastating illnesses due to its often lifelong course and debilitating nature. The treatment of schizophrenia has vastly improved over recent decades with the discovery of several antipsychotic compounds; however these drugs are not without adverse effects that must be addressed to maximize their therapeutic value. Newer, atypical, antipsychotics are associated with a compilation of serious metabolic side effects including weight gain, insulin resistance, fat deposition, glucose dysregulation and ensuing co-morbidities such as type II diabetes mellitus. The mechanisms underlying these side effects remain to be fully elucidated and adequate interventions are lacking. Further understanding of the factors that contribute these side effects is therefore required in order to develop effective adjunctive therapies and to potentially design antipsychotic drugs in the future with reduced impact on the metabolic health of patients. We investigated if the gut microbiota represented a novel mechanism contributing to the metabolic dysfunction associated with atypical antipsychotics. The gut microbiota comprises the bacteria that exist symbiotically within the gastrointestinal tract, and has been shown in recent years to be involved in several aspects of energy balance and metabolism. We have demonstrated that administration of certain antipsychotics in the rat results in an altered microbiota profile and, moreover, that the microbiota is required for the full scale of metabolic dysfunction to occur. We have further shown that specific antibiotics can attenuate certain aspects of olanzapine and risperidone–induced metabolic dysfunction, in particular fat deposition and adipose tissue inflammation. Mechanisms underlying this novel link appear to involve energy utilization via expression of lipogenic genes as well as reduced inflammatory tone. Taken together, these data indicate that the gut microbiota is an important factor involved in the myriad of metabolic complications associated with antipsychotic therapy. Furthermore, these data support the future investigation of microbial-based therapeutics for not only antipsychotic-induced weight gain but also for tackling the global obesity epidemic.

The role of glucocorticoid-induced tumour necrosis factor receptor in developing mouse sympathetic neurons

Hereditary sensory autonomic neuropathy IV (HSAN IV) is an autosomal recessive disorder characterised by inability to feel pain and anhidrosis and is a consequence of defective NGF/TrkA signalling and growth of sensory and sympathetic neurons. Glucocortiocoid-induced tumour necrosis factors receptor (GITR), a transmembrane protein, activated by its specific ligand, GITRL, is well known for its role in the regulation of innate and acquired immune system responses. Recently, GITR was found to be required for NGF-dependant and extracellular signal-related kinase 1/2 (ERK1/2)-induced neurite growth and target innervation in the developing sympathetic nervous system (SNS). Given this novel role of GITR, it is possible that strategies targeting GITR have potential therapeutic benefit in promoting neurite growth in autonomic neuropathies such as HSAN IV. Using P1 mouse SCG neurons as a model, in addition to various SCG cell treatments, knock down models and transfection methods, we investigated whether GITR increases the sensitivity of sympathetic neurons to NGF; the region of GITR required for the enhancement of NGF-promoted growth, the signalling pathways downstream of GITR and how extensively GITR is involved in regulating peripheral innervation of the SNS. Results indicate that the region responsible for the growth promoting effects of GITR lies in its juxtamembrane intracellular region (here termed the growth promoting domain (GPD)) of GITR. The GPD of GITR activates ERK1/2 and inhibits nuclear factor kappa B (NF-κB) in an inverse fashion to provide an optimal cellular growth environment for P1 SCG neurons. While deleting the GPD of GITR had no effect on TrkA expression, constitutive phosphorylation of specific sites in the GPD reduced TrkA expression indicating a possible role for GITR in increasing the sensitivity of SCG neurons to NGF by the regulation of these sites, TrkA expression and subsequent NGF/TrkA binding. GITR appears to be heterogeneously required for NGF-promoted target innervation of SCG neurons in some organs, implying additional factors are involved in extensive NGF-target innervation of the SNS. In conclusion, this study answers basic biological questions regarding the molecular mechanism behind the role of GITR in the development of the SNS, and provides a basis for future research if GITR modulation is to be developed as a strategy for promoting axonal growth.

HER2: a 'predictive factor' ready to use in the daily management of breast cancer patients?

The past few years have witnessed an exponential increase in studies trying to identify molecular markers in patients with breast tumours that might predict for the success or failure of hormonal therapy or chemotherapy. HER2, a tyrosine kinase membrane receptor of the epidermal growth factor receptor family, has been the most widely studied marker in this respect. This paper attempts to critically review to what extent HER2 may improve 'treatment individualisation' for the breast cancer patient. Copyright (C) 2000.