Spatially restricted activation of the SAX receptor by SCW modulates DPP/TKV signaling in Drosophila dorsal-ventral patterning

Dorsal-ventral patterning within the embryonic ectoderm of Drosophila requires two TGFbeta ligands, DPP and SCW, and two type I TGFbeta receptors, TKV and SAX. In embryos lacking dpp signaling, increasing the level of TKV activity promotes progressively more dorsal cell types, while activation of SAX alone has no phenotypic consequences. However, SAX activity synergizes with TKV activity to promote dorsal development. Functional experiments suggest the two receptors have different ligands: DPP acts through TKV, and SCW acts through SAX. Furthermore, SOG, a negative regulator of this patterning process, preferentially blocks SCW activity. We propose that spatial regulation of the SAX pathway modulates TKV signaling to create positional information over the embryonic ectoderm.     

Biphasic spiral computed tomography versus digital subtraction angiography for evaluation of arterial thrombosis after orthotopic liver transplantation

Aseptic loosening of implant components is a common and important complication of both cemented and uncemented prosthetic joint replacements. Wear particles derived from organic polymer and metal implant biomaterials are commonly found within macrophages and macrophage polykaryons in the fibrous membrane between loose implant components and the host bone undergoing resorption. In order to determine whether biomaterial particle-containing, foreign-body macrophages may contribute to periprosthetic bone resorption, we cultured murine monocytes that had phagocytosed particles of biomaterials commonly employed in bone implant surgery [polymethylmethacrylate (PMMA), ultra-high molecular weight polyethylene (PE), titanium and chromium-cobalt] on bone slices and glass coverslips with UMR 106 osteoblast-like stromal cells in the presence of 1,25-dihydroxy-vitamin D3. Under these conditions, all biomaterial particle-containing, foreign-body macrophages differentiated into osteoclastic cells, i.e. tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells capable of extensive lacunar bone resorption. This study shows that particle phagocytosis by macrophages does not abrogate the ability of these cells to undergo osteoclast differentiation. These findings emphasise the importance of the foreign-body macrophage response to biomaterial wear particles in the pathogenesis of aseptic loosening.     

Prolactin, growth hormone and the immune system in humans

Prolactin (PRL) and growth hormone (GH) qualify as lymphoid growth and differentiation factors. Yet, long-standing hyper- or hyposecretion of PRL or GH does not induce any significant alteration of the immune system. Subclinical changes in laboratory parameters (such as chemotaxis or phagocytosis by granulocytes or macrophages or natural killer cell activity) have been reported in some of these conditions. The GH-insulin-like growth factor (IGF)-I axis is dysregulated in ageing, in catabolic states and in critical illness. Immune parameters, such as infection rate, are being monitored during clinical trials with GH or IGF-I. Hyperprolactinaemia may play an aggravating role in systemic lupus erythematosus, in autoimmune thyroiditis and in other autoimmune diseases. The patient may benefit from increased alertness about interactions between the endocrine and immune systems.     

Synthesis and structure elucidation of estrogen quinones conjugated with cysteine, N-acetylcysteine, and glutathione

A micromechanical model for predicting the densification of particulate matter under hydrostatic loading was developed to account for the time-dependent response of materials to applied loads. Viscoelastic material response used in the analysis was based upon a standard three-parameter rheological model. Compaction data under closed die conditions were collected using an Instron analyzer for different rates of applied load. Densification during the loading phase of PMMA/coMMA powder, a pharmaceutical polymeric coating material, was well predicted by the proposed algorithm, which contrasts with the prediction implied through a static indentation model. Secondary factors which affect compaction such as die-wall friction are also briefly discussed.     

What causes prostate cancer? A brief summary of the epidemiology

Epoetin alfa is the cornerstone of anemia therapy in patients with end-stage renal disease. In addition to stimulating erythropoiesis, Epoetin alfa has been demonstrated to affect hemostasis. Such effects may be important because patients with chronic renal failure have a bleeding diathesis that is multifactorial in origin. Therefore, a computer literature search on the relationship between Epoetin alfa therapy for anemia in patients with end-stage renal disease and platelets, coagulation, coagulation inhibitors, and fibrinolysis was performed. All articles and abstracts reporting original data in the English language on Epoetin alfa and its effect on hemostasis were reviewed. The literature suggests that the effects of Epoetin alfa on the coagulation cascade are of minimal clinical importance. However, Epoetin alfa transiently increases the number of circulating platelets and improves platelet function, and these effects are associated with a return of the bleeding time towards normal.     

Time to dP/dtmax reflects both inotropic and chronotropic properties of cardiac contraction: a conscious dog study

The value of protective gloves in the health care environment is well known. However, these gloves are not perfect. Some are permeable to microorganisms and various chemicals, and/or result in side effects for health care professionals. Gloves that offer the greatest protection and least side effects are highly desirable. Protection against microorganisms and protection against chemicals used in health care are described in Part II of this three-part series.     

Specific cleavage of chromosomal and plasmid DNA strands in gram-positive and gram-negative bacteria can be detected with nucleotide resolution

A sensitive and precise in vitro technique for detecting DNA strand discontinuities produced in vivo has been developed. The procedure, a form of runoff DNA synthesis on molecules released from lysed bacterial cells, mapped precisely the position of cleavage of the plasmid pMV158 leading strand origin in Streptococcus pneumoniae and the site of strand scission, nic, at the transfer origins of F and the F-like plasmid R1 in Escherichia coli. When high frequency of recombination strains of E. coli were examined, DNA strand discontinuities at the nic positions of the chromosomally integrated fertility factors were also observed. Detection of DNA strand scission at the nic position of F DNA in the high frequency of recombination strains, as well as in the episomal factors, was dependent on sexual expression from the transmissable element, but was independent of mating. These results imply that not only the transfer origins of extrachromosomal F and F-like fertility factors, but also the origins of stably integrated copies of these plasmids, are subject to an equilibrium of cleavage and ligation in vivo in the absence of DNA transfer.