Current autologous transfusion practices. Implications for the future

A questionnaire was distributed to 509 AABB institutional members to evaluate current autologous transfusion practices. Results were returned from 47 blood centers, 108 transfusion services and 64 hospital blood banks (response rate 43%). Results indicate that not all eligible patients are allowed to donate due to unnecessarily strict eligibility criteria. Thirty percent of autologous units are not tested for infectious disease markers. Of those units tested and found positive for anti-HIV or HBsAg, 53 and 72% respectively, of the institutions provide the units to the intended recipient. Forty-seven percent of institutions perform an AHG crossmatch for autologous recipients. Sixty five percent of institutions permit "crossing-over" of autologous units for homologous use. Implications of these findings for the development of standards for autologous transfusion programs are discussed.     

Familial restrictive cardiomyopathy with atrioventricular block without skeletal myopathy

Familial restrictive cardiomyopathy is an autosomal dominant cardiomyopathy histologically characterized by myocyte hypertrophy and interstitial fibrosis. The case of a 54-year-old man diagnosed with restrictive cardiomyopathy is reported. The patient had been implanted with a two-chambered pacemaker for a complete atrioventricular block 12 years before. The family history was positive with several affected members, none of whom had findings of skeletal myopathy. Genetic analysis of the index patient revealed no troponin I mutations.     

Thinking outside the box: Use of the pressure wire to assess intracranial large artery stenoses

• A novel study investigating the utility of the 0.014″ diameter pressure wire to assess the hemodynamic significance of intermediate intracranial stenosis.
• Technical aspects of pressure wire positioning across intracranial arteries are described.
• Further research is required to clarify the assessment of pressure gradients in the cerebral circulation and to define the optimal threshold for intervention.

     

ActA is a dimer

ActA, a surface protein of Listeria monocytogenes, is able to induce continuous actin polymerization at the rear of the bacterium, in the cytosol of the infected cells. Its N-terminal domain is sufficient to induce actin tail formation and movement. Here, we demonstrate, using the yeast two-hybrid system, that the N-terminal domain of ActA may form homodimers. By using chemical cross-linking to explore the possibility that ActA could be a multimer on the surface of the bacteria, we show that ActA is a dimer. Cross-linking experiments on various L. monocytogenes strains expressing different ActA variants demonstrated that the region spanning amino acids 97–126, and previously identified as critical for actin tail formation, is also critical for dimer formation. A model of actin polymerization by L. monocytogenes, involving the ActA dimer, is presented.     

Bioactive Chitosan Nanoparticles Loaded with Retinyl Palmitate: A Simple Route Using Ionotropic Gelation

Nowadays, there is an increasing demand in incorporating antioxidants into biopolymeric nanoparticles (NPs) in order to enlarge their applications in the pharmaceutical and biomedical fields. The challenge of the work is to investigate the feasibility of encapsulating retinyl palmitate (RP) into chitosan (Ch) NP via ionotropic gelation. Two routes are addressed in the preparation of the systems, and they have an influence on the physicochemical properties of the NP in addition to the antioxidant amount loaded. The resulting RP‐encapsulated NP has pseudo spherical morphology, average hydrodynamic diameters between 230 and 350 nm and zeta potential values between +12.5 and +30 mV, depending on RP load and procedure. Encapsulation efficiency ranges from about 35% to 64%, and the loading capacity between 4% and 10%. The antioxidant activity studied by the 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH) assay and cytotoxicity of RP‐loaded NP evaluated against human dermal fibroblasts is dependent on RP content and NP concentration.

     

Adenosine diphosphate sugar pyrophosphatase prevents glycogen biosynthesis in Escherichia coli

An adenosine diphosphate sugar pyrophosphatase (ASPPase, EC ) has been characterized by using Escherichia coli. This enzyme, whose activities in the cell are inversely correlated with the intracellular glycogen content and the glucose concentration in the culture medium, hydrolyzes ADP-glucose, the precursor molecule of glycogen biosynthesis. ASPPase was purified to apparent homogeneity (over 3,000-fold), and sequence analyses revealed that it is a member of the ubiquitously distributed group of nucleotide pyrophosphatases designated as "nudix" hydrolases. Insertional mutagenesis experiments leading to the inactivation of the ASPPase encoding gene, aspP, produced cells with marginally low enzymatic activities and higher glycogen content than wild-type bacteria. aspP was cloned into an expression vector and introduced into E. coli. Transformed cells were shown to contain a dramatically reduced amount of glycogen, as compared with the untransformed bacteria. No pleiotropic changes in the bacterial growth occurred in both the aspP-overexpressing and aspP-deficient strains. The overall results pinpoint the reaction catalyzed by ASPPase as a potential step of regulating glycogen biosynthesis in E. coli.     

Cardiovascular Disease Urban Intervention: Baseline Activities and Findings

Regular exercise, good dietary habits, knowledge of the disease and its warning signs as well as ability to perform CPR (cardiopulmonary resuscitation) are all important to prevent and combat Cardiovascular Disease (CVD) and Stroke. In 2005–2006, an AHA sponsored “Search Your Heart” cardiovascular disease intervention was conducted in 388 urban African-American/black and Latino/Hispanic faith based institutions, all churches of various denominations, to improve members’ knowledge and preparedness about CVD and stroke. The intervention involved (a) distribution of a customized multi-component CVD and stroke related educational and skill development package to 388 “ambassadors” for all participating churches, (b) AHA staff coordinated educational sessions for the ambassadors and (c) 211 Ambassadors coordinating the conduct of at least one CVD educational activities in their churches. In May 2006, a written survey was distributed to 211 ambassadors affiliated with the Heritage affiliate of AHA, which covers New Jersey, Connecticut, Long Island and New York City, to: (a) assess the intervention’s effect, and (b) plan and implement a targeted forward intervention approach based on findings. Survey questions addressed regular exercise, healthy eating, disease knowledge, and warning signs and ability to perform CPR.     

Genetic reductionist approach for dissecting individual roles of GGDEF proteins within the c-di-GMP signaling network in Salmonella

Bacteria have developed an exclusive signal transduction system involving multiple diguanylate cyclase and phosphodiesterase domain-containing proteins (GGDEF and EAL/HD-GYP, respectively) that modulate the levels of the same diffusible molecule, 3′-5′-cyclic diguanylic acid (c-di-GMP), to transmit signals and obtain specific cellular responses. Current knowledge about c-di-GMP signaling has been inferred mainly from the analysis of recombinant bacteria that either lack or overproduce individual members of the pathway, without addressing potential compensatory effects or interferences between them. Here, we dissected c-di-GMP signaling by constructing a Salmonella strain lacking all GGDEF-domain proteins and then producing derivatives, each restoring 1 protein. Our analysis showed that most GGDEF proteins are constitutively expressed and that their expression levels are not interdependent. Complete deletion of genes encoding GGDEF-domain proteins abrogated virulence, motility, long-term survival, and cellulose and fimbriae synthesis. Separate restoration revealed that 4 proteins from Salmonella and 1 from Yersinia pestis exclusively restored cellulose synthesis in a c-di-GMP–dependent manner, indicating that c-di-GMP produced by different GGDEF proteins can activate the same target. However, the restored strain containing the STM4551-encoding gene recovered all other phenotypes by means of gene expression modulation independently of c-di-GMP. Specifically, fimbriae synthesis and virulence were recovered through regulation of csgD and the plasmid-encoded spvAB mRNA levels, respectively. This study provides evidence that the regulation of the GGDEF-domain proteins network occurs at 2 levels: a level that strictly requires c-di-GMP to control enzymatic activities directly, restricted to cellulose synthesis in our experimental conditions, and another that involves gene regulation for which c-di-GMP synthesis can be dispensable.