Plant CLE peptides from two distinct functional classes synergistically induce division of vascular cells

The Clavata3 (CLV3)/endosperm surrounding region (CLE) signaling peptides are encoded in large plant gene families. CLV3 and the other A-type CLE peptides promote cell differentiation in root and shoot apical meristems, whereas the B-type peptides (CLE41–CLE44) do not. Instead, CLE41 inhibits the differentiation of Zinnia elegans tracheary elements. To test whether CLE genes might code for antagonistic or synergistic functions, peptides from both types were combined through overexpression within or application onto Arabidopsis thaliana seedlings. The CLE41 peptide (CLE41p) promoted proliferation of vascular cells, although delaying differentiation into phloem and xylem cell lineages. Application of CLE41p or overexpression of CLE41 did not suppress the terminal differentiation of the root and shoot apices triggered by A-type CLE peptides. However, in combination, A-type peptides enhanced all of the phenotypes associated with CLE41 gain-of-function, leading to massive proliferation of vascular cells. This proliferation relied on auxin signaling because it was enhanced by exogenous application of a synthetic auxin, decreased by an auxin polar transport inhibitor, and abolished by a mutation in the Monopteros auxin response factor. These findings highlight that vascular patterning is a process controlled in time and space by different CLE peptides in conjunction with hormonal signaling.     

Quality of life in elderly patients with acute myeloid leukemia: patients may be more accurate than physicians

Background

The aim of this study was to evaluate changes in quality of life scores and their association with therapy and survival in unselected elderly patients with acute myeloid leukemia.

Design and Methods

From February 2003 to February 2007, 113 patients aged more than 60 years with de novo acute myeloid leukemia were enrolled in a prospective observational study. Two different quality of life instruments were employed: the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire – C30 (EORTC QLQ-C30) and a health-related quality of life questionnaire for patients with hematologic diseases (QOL-E).

Results

Forty-eight patients (42.4%) received intensive chemotherapy and 65 (57.6%) were given palliative treatments. Age greater than 70 years (P=0.007) and concomitant diseases (P=0.019) had a significant impact on treatment allocation. At diagnosis, general quality of life was affected [median QOL-E standardized score 54, interquartile range 46–70; median EORTC global score 50, interquartile range 41–66]. Most patients were given a good ECOG Performance Status (< 2), which did not correlate with the patients’ perception of quality of life. At multivariate analysis, palliative approaches (P=0.016), age more than 70 years (P=0.013) and concomitant diseases (P=0.035) each had an independent negative impact on survival. In a multivariate model corrected for age, concomitant diseases and treatment option, survival was independently predicted by QOL-E functional (P=0.002) and EORTC QLQ-C30 physical function (P=0.030) scores.

Conclusions

Quality of life could have an important role in elderly acute myeloid leukemia patients at diagnosis as a prognostic factor for survival and a potential factor for treatment decisions.     

Molecular imaging in myeloma precursor disease

Multiple myeloma (MM) is consistently preceded by its pre-malignant states, monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering multiple myeloma (SMM). By definition, precursor conditions do not exhibit end-organ disease (anemia, hypercalcemia, renal failure, skeletal lytic lesions, or a combination of these). However, new imaging methods are demonstrating that some patients in the MGUS or SMM category are exhibiting early signs of MM. Although MGUS/SMM patients are currently defined as low-risk versus high-risk based on clinical markers, we currently lack the ability to predict the individual patient's risk of progression from MGUS/SMM to MM. Given that the presence of gross lytic bone lesions is a hallmark of MM, it is reasonable to believe that less severe bone changes defined by more sensitive imaging may be predictive of MM progression. Indeed, since bone disease is such an essential aspect of MM, imaging techniques directed at the detection of early bone lesions, have the potential to become increasingly more useful in the setting of MGUS/SMM. Current guidelines for the radiological assessment of MM still recommend the traditional skeletal survey, although its limitations are well documented, especially in early phases of the disease when radiographs can significantly underestimate the extent of bone lesions and bone marrow involvement. Newer, more advanced imaging modalities, with higher sensitivities, including whole-body low-dose computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) are being employed. Also various imaging techniques have been used to provide an assessment of bone involvement and identify extra-osseous disease. This review emphasizes the current state of the art and emerging imaging methods, which may help to better define high-risk versus low-risk MGUS/SMM. Ultimately, improved imaging could allow more tailored clinical management, and, most likely play an important role in the development of future treatment strategies for high-risk precursor disease.     

Sinusoidal endothelial cell and hepatocyte death following cold ischemia-warm reperfusion of the rat liver

Cold ischemia-warm reperfusion (CI-WR) injury of the liver is characterized by marked alterations of sinusoidal endothelial cells (SECs), whereas hepatocytes appear to be relatively unscathed. However, the time course and mechanism of cell death remain controversial: early versus late phenomenon, necrosis versus apoptosis? We describe the occurrence and nature of cell death after different periods of CI with University of Wisconsin (UW) solution and after different periods of WR in the isolated perfused rat liver model. After 24- and 42-hour CI (viable and nonviable livers, respectively), similar patterns of liver cell death were seen: SEC necrosis appeared early after WR (10 minutes) and remained stable for up to 120 minutes. After 30 minutes of WR, apoptosis increased progressively with WR length. Based on morphological criteria, apoptotic cells were mainly hepatocytes within liver plates or extruded in the sinusoidal lumen. In addition, only after 42-hour CI were large clusters of necrotic hepatocytes found in areas of congested sinusoids. In these same livers, the hepatic microcirculation, evaluated by means of the multiple-indicator dilution technique, revealed extracellular matrix disappearance with no-flow areas. In conclusion, different time courses and mechanisms of cell death occur in rat livers after CI-WR, with early SEC necrosis followed by delayed hepatocyte apoptosis. These processes do not appear to be of major importance in the mechanism of graft failure because they are similar under both nonlethal and lethal conditions; this is not the case for the loss of the extracellular matrix found only under lethal conditions and associated with hepatocyte necrosis.     

Macrophage migration inhibitory factor in systemic lupus erythematosus

OBJECTIVE: To examine associations between serum macrophage migration inhibitory factor (MIF) and disease-related variables and corticosteroid use in patients with systemic lupus erythematosus (SLE). METHODS: Serum MIF concentration was measured by ELISA in 90 female patients with SLE and 279 healthy controls. Univariate and multivariate regression analyses were used to examine the associations between serum MIF concentration and disease-related indices of SLE and corticosteroid use. RESULTS: Serum MIF concentrations were positively associated with SLE disease damage (SLICC/ACR index), and indices of disease damage were greater in SLE patients with serum MIF concentrations above the normal median value. Serum MIF concentration was also observed to be significantly greater in patients with SLICC/ACR damage index (DI) scores >/= 3. Serum MIF was also positively associated with current corticosteroid dose. Significantly higher SLICC/ACR DI scores were observed in patients with values of serum MIF above the normal median, and this remained significant after adjusting for corticosteroid dose. Serum MIF concentration was also predictive of SLICC/ACR index after 3 years of followup, but this association was partly confounded by corticosteroid dose. Serum MIF was also negatively associated with serum creatinine concentration, independent of disease damage and corticosteroid dose. CONCLUSION: MIF is overexpressed in patients with SLE. While this can be partly explained by corticosteroid use, there is evidence of an association between MIF and lupus-related disease damage.     

Factors affecting HIV concordancy in married couples in four African cities

OBJECTIVE: To determine risk factors for HIV transmission within married couples in four urban populations in sub-Saharan Africa. METHODS: Data from a cross-sectional population-based study were used. Representative random samples approximating 1000 men and 1000 women in each of four cities of Kisumu (Kenya), Ndola (Zambia), Cotonou (Benin), and Yaoundé (Cameroon), were interviewed and tested for sexually transmitted infections (STI). Married couples were identified as concordant negative, discordant, or concordant positive for each STI. After excluding concordant HIV negative couples, analysis of behavioural and STI risk factors for HIV positive concordancy was undertaken across the four cities and in each city separately where sample size allowed. RESULTS: Among 221 couples in which at least one member was HIV positive, we found that the only significant risk factor for positive HIV concordancy was herpes simplex type 2 (HSV-2) status. After adjusting for age and city of residence the odds ratio for HIV concordancy compared to couples with neither spouse HSV-2 positive was 3.4 (95% confidence interval, 0.62-18.4) for couples with one partner HSV-2 positive and 8.6 (95% confidence interval, 1.6-45.0) for couples with both partners HSV-2 positive. The same trends were seen in Kisumu and Ndola when they were analysed separately (numbers were small in the other cities). CONCLUSIONS: Although cross-sectional studies are not ideal for delineating the sequence of transmission events, this study adds to the evidence that HSV-2 is a key risk factor in promoting HIV transmission.     

Lack of association between gene sequence variations of platelet membrane receptors and aspirin responsiveness detected by the PFA-100 system in patients with coronary artery disease

Platelet membrane receptors play a pivotal role in thrombus formation. Expression of platelet membrane receptors are under genetic control and gene sequence variations of receptors pivotal to thrombotic formation have been hypothesized to contribute to different degrees of individual response to aspirin. The aim of the present study was to investigate the impact of functional genetic polymorphisms of platelet membrane receptors on aspirin sensitivity assessed by means of the PFA-100 system in patients with coronary artery disease. Gene sequence variations of three platelet membrane receptors (GPIa/IIa, P2Y12, GPIIb/IIIa) pivotal to thrombus formation were assessed in 76 patients with coronary artery disease on chronic aspirin treatment. Patients with reduced sensitivity to aspirin were defined when closure-times of collagen/epinephrine cartridges < or =193 seconds and coined as PFA-100 non-responders. PFA-100 non-responders were observed in 33% of patients. Patients with diabetes mellitus were more frequently PFA-100 non-responders. Closure times of collagen/ADP coated cartridges were reduced in PFA-100 non-responders. The genotype distribution was similar in PFA-100 responder and non-responder patients for all three genotypes and did not vary in contemporaneous carriers of allelic variants. In conclusion, in vitro determined sensitivity to aspirin assessed using PFA-100 is not associated with gene sequence variations of platelet membrane receptors key to thrombus formation.     

Adenosine does not bind to the growth hormone secretagogue receptor type-1a (GHS-R1a)

Ghrelin regulates GH secretion and energy homeostasis through the GH secretagogue receptor type-1a (GHS-R1a). This G-protein coupled receptor shows the peculiarity to transduce information provided not just by ghrelin as well as by adenosine through a supposed binding site different from the characterized ghrelin-binding pocket. Indeed, adenosine triggers intracellular calcium rise through a distinct signaling pathway to the one described for ghrelin, although it fails to stimulate GH secretion. Despite multiple active conformations of GHS-R1a, suggested as an explanation for a ligand-dependent activation of the downstream signaling, the concept of adenosine as agonist for GHS-R1a has been re-evaluated. The results revealed that calcium rise of both ghrelin and adenosine appears to be mediated by receptors that did not show the same sensitivity to protein kinase C (PKC) activity in GHS-R1a-transfected HEK 293 cells (HEK-GHS-R1a cells). The binding analyses showed the same number of adenosine-binding sites in both HEK 293 (B(max) = 2.01 +/- 0.15 fmol/cell) and HEK-GHS-R1a cells (B(max) = 1.90 +/- 0.11 fmol/cell). This binding was unaltered by different GHS-R1a antagonists. Western blot analysis showed a similar endogenous expression of endogenous adenosine receptor type-2b and -3 in both cell lines. The K(d) values for adenosine were 1.78 microM in HEK 293 cells and 6.30 microM in HEK-GHS-R1a cells, pointing to a modification of agonist affinity induced by overexpression of the GHS-R1a. Additionally, adenosine failed to induce the GHS-R1a endocytosis, although it attenuates the ghrelin-induced GHS-R1a endocytosis. In conclusion, adenosine is not an agonist of the GHS-R1a and its action is mediated by the endogenous adenosine receptor type-2b and -3, which is able to partially use the intracellular signaling machinery of HEK-GHS-R1a cells.     

Severe congenital neutropenia in a multigenerational family with a novel neutrophil elastase (<Emphasis Type=Italic>ELANE</Emphasis>) mutation

We have analysed a family with nine congenital neutropenia patients in four generations, several of which we have studied in a long-term follow-up of over 25 years. The patients were mild to severe neutropenic and suffered from various recurrent bacterial infections. Mutations in the genes ELANE, CSF3R and GFI1 have been reported in patients with autosomal dominant congenital neutropenias. Using a small-scale linkage analysis with markers around the ELANE, CSF3R, CSF3 and GFI1 genes, we were able to determine that the disease segregated with markers around the ELANE gene. We identified a novel mutation in the ELANE gene in all of the affected family members that was not present in any of the healthy family members. The mutation leads to an A28S missense mutation in the mature protein. None of these patients developed leukaemia. This is the first truly multigenerational family with mutations in ELANE as unambiguous cause of severe congenital neutropenia SCN.