RasGRP4 Is a Novel Ras Activator Isolated from Acute Myeloid Leukemia

Although a number of genetic defects are commonly associated with acute myeloid leukemia (AML), a large percentage of AML cases are cytogenetically normal. This suggests a functional screen for transforming genes is required to identify genetic mutations that are missed by cytogenetic analyses. We utilized a retrovirus-based cDNA expression system to identify transforming genes expressed in cytogenetically normal AML patients. We identified a new member of the Ras guanyl nucleotide-releasing protein (RasGRP) family of Ras guanine nucleotide exchange factors, designating it RasGRP4. Subsequently, cDNA sequences encoding rodent and human RasGRP4 proteins were deposited in GenBank. RasGRP4 contains the same protein domain structure as other members of the RasGRP family, including a Ras exchange motif, a CDC25 homology domain, a C1/diacyglycerol-binding domain, and putative calcium-binding EF hands. We show that expression of RasGRP4 induces anchorage-independent growth of Rat1 fibroblasts. RasGRP4 is a Ras-specific activator and, interestingly, is highly expressed in peripheral blood leukocytes and myeloid cell lines. Unlike other RasGRP proteins, RasGRP4 is not expressed in the brain or in lymphoid cells. We demonstrated that 32D myeloid cells expressing RasGRP4 have elevated levels of activated Ras compared with control cells, and phorbol 12-myristate 13-acetate (PMA) treatment greatly enhanced Ras activation. PMA induced membrane localization of RasGRP4 and 32D cells expressing RasGRP4 were capable of cytokine-independent proliferation in the presence of PMA. We conclude that RasGRP4 is a member of the RasGRP family of Ras guanine nucleotide exchange factors that may play a role in myeloid cell signaling growth regulation pathways that are responsive to diacylglycerol levels

Examination of the role of Mycoplasma bovis in bovine pneumonia and a mathematical model for its evaluation

The authors screened 34 large cattle herds for the presence of Mycoplasma bovis infection by examining slaughtered cattle for macroscopic lung lesions, by culturing M. bovis from lung lesions and at the same time by testing sera for the presence of antibodies against M. bovis. Among the 595 cattle examined, 33.9% had pneumonic lesions, mycoplasmas were isolated from 59.9% of pneumonic lung samples, and 10.9% of sera from those animals contained antibodies to M.bovis. In 25.2% of the cases M. bovis was isolated from lungs with no macroscopic lesions. The proportion of seropositive herds was 64.7%. The average seropositivity rate of individuals was 11.3% but in certain herds it exceeded 50%. A probability model was developed for examining the relationship among the occurrence of pneumonia, the isolation of M. bovis from the lungs and the presence of M. bovis specific antibodies in sera

The social relations of health care and household resource allocation in neoliberal Nicaragua

<p>Abstract</p> <p>Background</p> <p>With the transition to neoliberalism, Nicaragua's once-critically acclaimed health care services have substantially diminished. Local level social formations have been under pressure to try to bridge gaps as the state's role in the provision of health care and other vital social services has decreased. This paper presents a case study of how global and national health policies reverberated in the social relations of an extended network of female kin in a rural community during late 2002 - 2003.</p> <p>Methods</p> <p>The qualitative methods used in this ethnographic study included semi-structured interviews completed during bi-weekly visits to 51 households, background interviews with 20 lay and professional health practitioners working in the public and private sectors, and participant-observation conducted in the region's government health centers. Interviews and observational field notes were manually coded and iteratively reviewed to identify and conceptually organize emergent themes. Three households of extended kin were selected from the larger sample to examine as a case study.</p> <p>Results</p> <p>The ongoing erosion of vital services formerly provided by the public sector generated considerable frustration and tension among households, networks of extended kin, and neighbors. As resource allocations for health care seeking and other needs were negotiated within and across households, longstanding ideals of reciprocal exchange persisted, but in conditions of poverty, expectations were often unfulfilled, exposing the tension between the need for social support, versus the increasingly oppositional positioning of social network members as sources of competition for limited resources.</p> <p>Conclusions</p> <p>In compliance with neoliberal structural adjustment policies mandated by multilateral and bilateral agencies, government-provided health care services have been severely restricted in Nicaragua. As the national safety net for health care has been eroded, the viability of local level social formations and their ability to respond to struggles collectively has been put at risk as well. Bi-lateral and multilateral agencies need to take into account local needs and demands, and implement policies in a manner that respects national laws, and protects both the physical and social well-being of individuals.</p

Team creativity/innovation in culturally diverse teams: A meta‐analysis

This meta-analysis investigates the direction and strength of the relationship between diversity in culturally diverse teams and team creativity/innovation. We distinguish the effects of two diversity levels (i.e., surface- versus deep-level) in culturally diverse teams and examine the moderators suggested by the socio-technical systems framework (i.e., team virtuality and task characteristics in terms of task interdependence, complexity, and intellectiveness). Surface-level diversity in culturally diverse teams is not related to team creativity/innovation, while deep-level diversity in culturally diverse teams is positively related to team creativity/innovation. Moreover, surface-level diversity in culturally diverse teams and team creativity/innovation are negatively related for simple tasks, but unrelated for complex tasks. Deep-level diversity in culturally diverse teams and team creativity/innovation are positively related for collocated teams and interdependent tasks, but unrelated for non-collocated teams and independent tasks. We discuss the theoretical and practical implications

Nck adapter proteins: functional versatility in T cells

Nck is a ubiquitously expressed adapter protein that is almost exclusively built of one SH2 domain and three SH3 domains. The two isoproteins of Nck are functionally redundant in many aspects and differ in only few amino acids that are mostly located in the linker regions between the interaction modules. Nck proteins connect receptor and non-receptor tyrosine kinases to the machinery of actin reorganisation. Thereby, Nck regulates activation-dependent processes during cell polarisation and migration and plays a crucial role in the signal transduction of a variety of receptors including for instance PDGF-, HGF-, VEGF- and Ephrin receptors. In most cases, the SH2 domain mediates binding to the phosphorylated receptor or associated phosphoproteins, while SH3 domain interactions lead to the formation of larger protein complexes. In T lymphocytes, Nck plays a pivotal role in the T cell receptor (TCR)-induced reorganisation of the actin cytoskeleton and the formation of the immunological synapse. However, in this context, two different mechanisms and adapter complexes are discussed. In the first scenario, dependent on an activation-induced conformational change in the CD3ε subunits, a direct binding of Nck to components of the TCR/CD3 complex was shown. In the second scenario, Nck is recruited to the TCR complex via phosphorylated Slp76, another central constituent of the membrane proximal activation complex. Over the past years, a large number of putative Nck interactors have been identified in different cellular systems that point to diverse additional functions of the adapter protein, e.g. in the control of gene expression and proliferation

Discovery and Characterization of Novel Vascular and Hematopoietic Genes Downstream of Etsrp in Zebrafish

The transcription factor Etsrp is required for vasculogenesis and primitive myelopoiesis in zebrafish. When ectopically expressed, etsrp is sufficient to induce the expression of many vascular and myeloid genes in zebrafish. The mammalian homolog of etsrp, ER71/Etv2, is also essential for vascular and hematopoietic development. To identify genes downstream of etsrp, gain-of-function experiments were performed for etsrp in zebrafish embryos followed by transcription profile analysis by microarray. Subsequent in vivo expression studies resulted in the identification of fourteen genes with blood and/or vascular expression, six of these being completely novel. Regulation of these genes by etsrp was confirmed by ectopic induction in etsrp overexpressing embryos and decreased expression in etsrp deficient embryos. Additional functional analysis of two newly discovered genes, hapln1b and sh3gl3, demonstrates their importance in embryonic vascular development. The results described here identify a group of genes downstream of etsrp likely to be critical for vascular and/or myeloid development

Use of the rSpaA415 antigen indicates low rates of Erysipelothrix rhusiopathiae infection in farmed cattle from the United States of America and Great Britain

Background Clinical cases of Erysipelothrix rhusiopathiae, a zoonotic gram-positive bacterium, have been reported in many ruminant species, including in cattle, deer, moose and muskoxen. Fatal cases have been repeatedly reported in cattle over the years but to date there is only one Japanese study investigating the seroprevalence of this bacterium in cattle using the growth agglutination test (GAT). This technique is subjective, time-consuming, expensive and hazardous compared to modern serological tests such as enzyme-linked immunosorbent assays (ELISA) or the newly developed fluorescent microbead-based immunoassays (FMIA). Results The FMIA based on the surface protein SpaA (rSpaA415) antigen of E. rhusiopathiae developed in this study had an almost perfect agreement with the GAT (k = 0.83) and showed a sensitivity of 89.7% and a specificity of 92.9% when compared to the GAT. Overall, detection rates of E. rhusiopathiae antibody positive samples were 13.8% (51/370) in British herds and 6% (12/200) in US herds. Positive cattle were present in 34.3% (24/70) of the investigated British farms and in 34.7% (8/23) of the US farms with an on-farm prevalence of 7.1 to 100% for the British farms and 8.3–30% for the US farms. Conclusions FMIA is a fast, safe and economic alternative to the GAT for the diagnosis of E. rhusiopathiae in cattle. This work is the first seroprevalence study of E. rhusiopathiae in healthy farmed cattle in Great Britain and the US and revealed that infection occurs at a low level. Further investigations to evaluate risks of zoonotic transmission when handling cattle are needed