Potential of calcium nitrate to mitigate the aluminum toxicity in Phaseolus vulgaris: effects on morphoanatomical traits,mineral nutrition and photosynthesis

Ecotoxicology - Common bean (Phaseolus vulgaris) cultivation occurs mainly in regions with acidic soils, where high aluminum (Al) concentration is a major constraint to crop production. In this...     

Utilisation of sperm‐binding assay combined with computer‐assisted sperm analysis to evaluate frozen‐thawed bull semen

Due to homologies between the chicken egg perivitelline membrane with mammalian zona pellucida proteins, spermatozoa of several species are able to bind to this membrane. However, adequate standardisation is required to attest possible applications of this technique for semen evaluation of a given species. Therefore, we thawed and divided cryopreserved semen samples into two aliquotes, one kept in water bath at 37 °C (thawed) and the other submitted to snap‐freezing to damage sperm cells (dead spermatozoa). Aliquotes were mixed into different ratios of thawed:dead cells and analysed for motility, membrane and acrosomal integrity, and mitochondrial activity. In parallel, chicken egg perivitelline membranes were inseminated with these ratios, and the number of spermatozoa bound per mm² of membrane was assessed by conventional microscopy (CM) and computer‐assisted sperm analysis (CASA). Linear regression showed high correlation between thawed:dead sperm ratio and number of spermatozoa bound to the membrane (CM: r² = 0.91 and CASA: r² = 0.92 respectively). Additionally, positive correlations were found between the number of spermatozoa bound to the membrane and acrosomal integrity, membrane integrity, mitochondrial activity and motility. These findings indicate that sperm‐egg‐binding assay associated with CASA is a reliable, practical and inexpensive method for examining the fertilising capacity of cryopreserved bull semen.     

B-cell lymphoma after angioimmunoblastic lymphadenopathy: a case with oligoclonal gene rearrangements associated with Epstein-Barr virus

We describe a patient with angioimmunoblastic lymphadenopathy with dysproteinemia (AILD), who subsequently developed large-cell immunoblastic lymphoma of B-cell immunophenotype. At the time of the initial diagnosis, histologic examination of an inguinal lymph node showed typical features of AILD, and there was no evidence of a monoclonal B-cell population by immunohistochemical analysis. In situ hybridization and Southern blot analysis for Epstein-Barr virus (EBV) were negative. At autopsy 2 years later, the patient had widespread lymph node and organ involvement by large-cell immunoblastic lymphoma of B-cell immunophenotype. Southern blot analysis performed on DNA extracted from lymph nodes, liver, and spleen showed two patterns of Ig heavy chain and kappa light chain gene rearrangements. The T-cell receptor beta chain gene was in the germline configuration. Analysis with an EBV terminal repeat region probe showed two clonal populations that paralleled the Ig gene rearrangement studies. Double-labeling immunohistochemistry and in situ hybridization confirmed the presence of EBV within the neoplastic B cells. The data support the hypothesis that EBV was not etiologically related to AILD in this case, and that EBV proliferation may occur after the onset of the disease. Further, the data suggest that some B-cell lymphomas that arise in the setting of AILD resemble EBV-associated B-cell lymphomas that arise in other immunodeficiency states.     

Telavancin In Vitro Activity against a Collection of Methicillin-Resistant Staphylococcus aureus Isolates,Including Resistant Subsets,from the United States

Telavancin had MIC₅₀, MIC₉₀, and MIC₁₀₀ values of 0.03, 0.06, and 0.12 μg/ml, respectively, against methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), and non-multidrug-resistant (non-MDR) and MDR subsets. MRSA with elevated MIC values for vancomycin (2 to 4 μg/ml) or daptomycin (1 to 2 μg/ml) had telavancin MIC₅₀ (0.06 μg/ml) values 2-fold higher than those of isolates with lower MIC results (MIC₅₀, 0.03 μg/ml). However, telavancin had MIC₉₀ and MIC₁₀₀ results of 0.06 and 0.12 μg/ml (100% susceptible), respectively, regardless of the MRSA subset.     

In Vitro Activity of Dalbavancin against Drug-Resistant Staphylococcus aureus Isolates from a Global Surveillance Program

In over a decade (2002 to 2012) of Staphylococcus aureus surveillance testing on 62,195 isolates, dalbavancin was demonstrated to be active against isolates that were either susceptible or nonsusceptible to daptomycin, linezolid, or tigecycline. Nearly all (99.8%) multidrug-resistant methicillin-resistant S. aureus isolates were inhibited by dalbavancin at ≤0.12 μg/ml (MIC_50/90, 0.06/0.06 μg/ml), the current U.S. Food and Drug Administration (U.S. FDA) breakpoint. Overall, only 0.35% of the monitored S. aureus isolates had a dalbavancin MIC of either 0.25 or 0.5 μg/ml (i.e., were nonsusceptible).     

Noninvasive Streptococcus pneumoniae Serotypes Recovered from Hospitalized Adult Patients in the United States in 2009 to 2012

This study was conducted to determine the serotype distribution and trends over time of Streptococcus pneumoniae strains associated with noninvasive infections among adult patients ≥18 years of age in the United States (2009 to 2012). A total of 2,927 S. pneumoniae isolates recovered from patients presenting with respiratory infections and obtained mainly (87.0%) from lower respiratory tract specimens (sputum) were included. The levels of the 7-valent pneumococcal conjugate vaccine (PCV7) serotypes remained stable over the 4-year study period (4.6% to 5.5%; P = 0.953). Overall, 13-valent pneumococcal conjugate vaccine (PCV13) serotypes were identified in 32.7% of samples, declining from 33.7% to 35.5% in 2009 to 2011 to 28.2% in 2012 (P = 0.007), with a significant decrease in the levels of serotypes 7F (P = 0.013) and 6A (P = 0.010). The levels of 19A remained constant (15.8% to 17.1%) during 2009 to 2011, dropping to 12.2% in 2012 (P = 0.089). The prevalence of serotypes associated with the 23-valent pneumococcal polysaccharide vaccine (PPSV23), but not PCV13, remained generally stable; however, the prevalence of serotypes 15B and 15C (15B/15C) increased from 2.7% to 6.3% (P = 0.010). The proportion of nonvaccine serotypes increased gradually during the study period (P = 0.044), particularly for serotype 35B (from 3.6% in 2009 to 8.2% in 2012; P = 0.001). Nonsusceptibility rates for penicillin (susceptible breakpoint, ≤2 μg/ml) and clindamycin against PCV7 serotypes decreased over the period. These results suggest the emergence of indirect effects following introduction of PCV13 for infants and young children; continued surveillance is needed to assess the burden of PCV13 serotypes in the adult population after the implementation of age-based recommendations in the United States.     

Thrombopoietin stimulates megakaryocytopoiesis, myelopoiesis, and expansion of CD34+ progenitor cells from single CD34+Thy-1+Lin- primitive progenitor cells

Thrombopoietin (TPO) or MpI ligand is known to stimulate megakaryocyte (MK) proliferation and differentiation. To identify the earliest human hematopoietic cells on which TPO acts, we cultured single CD34+Thy- 1+Lin- adult bone marrow cells in the presence of TPO alone, with TPO and interleukin-3 (IL-3), or with TPO and c-kit ligand (KL) in the presence of a murine stromal cell line (Sys1). Two distinct growth morphologies were observed: expansion of up to 200 blast cells with subsequent differentiation to large refractile CD41b+ MKs within 3 weeks or expansion to 200-10,000 blast cells, up to 25% of which expressed CD34. The latter blast cell expansions occurred over a 3- to 6-week period without obvious MK differentiation. Morphological staining, analysis of surface marker expression, and colony formation analysis revealed that these populations consisted predominantly of cells committed to the myelomonocytic lineage. The addition of IL-3 to TPO-containing cultures increased the extent of proliferation of single cells, whereas addition of KL increased the percentage of CD34+ cells among the expanding cell populations. Production of multiple colony- forming unit-MK from single CD34+Thy-1+Lin- cells in the presence of TPO was also demonstrated. In limiting dilution assays of CD34+Lin- cells, TPO was found to increase the size and frequency of cobblestone areas at 4 weeks in stromal cultures in the presence of leukemia inhibitory factor and IL-6. In stroma-free cultures, TPO activated a quiescent CD34+Lin-Rhodamine 123lo subset of primitive hematopoietic progenitor cells into cycle, without loss of CD34 expression. These data demonstrate that TPO acts directly on and supports division of cells more primitive than those committed to the MK lineage.