Evaluation of Acanthamoeba Myosin-IC as a Potential Therapeutic Target

Members of the genus Acanthamoeba are facultative pathogens of humans, causing a sight-threatening keratitis and a fatal encephalitis. We have targeted myosin-IC by using small interfering RNA (siRNA) silencing as a therapeutic approach, since it is known that the function of this protein is vital for the amoeba. In this work, specific siRNAs against the Acanthamoeba myosin-IC gene were developed. Treated and control amoebae were cultured in growth and encystment media to evaluate the induced effects after myosin-IC gene knockdown, as we have anticipated that cyst formation may be impaired. The effects of myosin-IC gene silencing were inhibition of cyst formation, inhibition of completion of cytokinesis, inhibition of osmoregulation under osmotic stress conditions, and death of the amoebae. The finding that myosin-IC silencing caused incompletion of cytokinesis is in agreement with earlier suggestions that the protein plays a role in cell locomotion, which is necessary to pull daughter cells apart after mitosis in a process known as “traction-mediated cytokinesis”. We conclude that myosin-IC is a very promising potential drug target for the development of much-needed antiamoebal drugs and that it should be further exploited for Acanthamoeba therapy.     

Attitudes and knowledge regarding influenza vaccination among hospital health workers caring for women and children

This cross-sectional study of 340 obstetrics/gynecology, 123 neonatology, and 244 pediatric health care workers (HCWs) was designed to evaluate compliance with recommendations concerning the use of influenza vaccine during pregnancy and among pediatric subjects. The results clearly show that only a marginal number of the HCWs in all three fields currently recommend vaccine use for pregnant women and healthy young children. Moreover, all of the HCWs were seriously deficient in terms of their general knowledge of influenza prevention and their own personal vaccination coverage was low. Extensive and sustained efforts to overcome cultural limitations concerning influenza and its prevention are urgently required among HCWs caring for women and children in order to ensure effective compliance with the current recommendations.     

Room-temperature magnetic properties of oxy- and carbonmonoxyhemoglobin

The magnetic susceptibility and the density of human oxy-(HbO₂) and carbonmonoxyhemoglobin (HbCO) solutions of various concentrations have been measured at room temperature, with pure water used as a calibrant. Solutions of unstripped and stripped HbO₂ at pH 7.2 in unbuffered water solvent were always found to be less diamagnetic than pure water, whereas solutions of HbCO in identical conditions were always found to be more diamagnetic than pure water. After correcting for concentration-dependent density changes and assuming the HbCO samples to be fully diamagnetic, the paramagnetic reduction of the diamagnetic susceptibility of HbO₂ corresponds to a molar susceptibility per heme (χ_M^heme) of 2460 ± 600 × 10^-6 cgs/mol.     

Injectable and self-curing composites of acrylic/bioactive glass and drug systems. A histomorphometric analysis of the behaviour in rabbits

Injectable self-curing systems based on PMMA, phosphate-free bioactive glasses and the drug fosfosal, a phosphate derivative of salicylic acid with analgesic and moderate anti-inflammatory properties, have been tested in vivo to evaluate their biocompatibility. The model consisted of the injection of dough of cement into a defect created in the femur of rabbits, and the cure of the cement in situ after implantation. The biological response was studied in the short and long terms by macroscopic, radiological and histopathological examination, and quantitatively by histomorphometric and statistical analysis considering the most representative variables at the bone-cement interface: cement, bone marrow, newly formed bone and connective tissue. All bioactive formulations presented resorption of the cement at the end of the experiment in contrast to the control of PMMA, due to the presence of resorbable components. The presence or absence of the phosphate group added by the drug fosfosal influenced mainly on the new bone formation process. The cement formulated with bioactive glasses and in absence of fosfosal produced the maximum amount of neoformed bone at 2 weeks, and then it resorbed at 4 weeks to give a higher amount of neoformed bone at the end of the experiment, compared with the formulation containing only fosfosal. The presence of fosfosal and bioactive glass together affected the ossification process strongly. The osseous tissue was produced more gradually but it continuously increased giving rise to a more stable bone at the end of the experiment.     

Morning blood pressure surge as a destabilizing factor of atherosclerotic plaque: role of ubiquitin-proteasome activity

Whether morning blood pressure surge influences the molecular mechanisms of plaque progression toward instability is not known. Recently, we have demonstrated enhanced activity of the ubiquitin-proteasome system in human plaques and evidenced that it is associated with inflammatory-induced plaque rupture. We evaluated the inflammatory infiltration and ubiquitin-proteasome activity in asymptomatic carotid plaques of hypertensive patients with different patterns of morning blood pressure surge. Plaques were obtained from 32 hypertensive patients without morning blood pressure surge and 28 with morning blood pressure surge enlisted to undergo carotid endarterectomy for extracranial high-grade (>70%) internal carotid artery stenosis. Plaques were analyzed for macrophages, T-lymphocytes, human leukocyte antigen-DR+cells, ubiquitin-proteasome activity, nuclear factor-kappaB, inhibitor kB-beta, tumor necrosis factor-alpha, nitrotyrosine, matrix metalloproteinase-9, and collagen content (immunohistochemistry and ELISA). Compared with plaques obtained from hypertensive patients without morning blood pressure surge, plaques from with morning blood pressure surge had more macrophages, T-lymphocytes, human leukocyte antigen-DR+cells (P<0.001), ubiquitin-proteasome activity, tumor necrosis factor-alpha, nuclear factor-kB (P<0.001), nitrotyrosine, and matrix metalloproteinase-9 (P<0.01), along with a lesser collagen content and IkB-beta levels (P<0.001). Enhanced ubiquitin-proteasome activity in atherosclerotic lesions of patients with morning blood pressure surge is associated with inflammatory-dependent unstable plaque phenotype. These data suggest a potential interplay between morning blood pressure surge and ubiquitin-proteasome activity in atherosclerosis pathophysiology.     

Neuroendocrine gastric carcinoma expressing somatostatin： A highly malignant, rare tumor

Poorly differentiated gastric neuroendocrine carcinomas, although rare, deserve particular attention, as they are aggressive and have an extremely poor prognosis. In this report we describe a gastric neuroendocrine carcinoma with rapidly fatal outcome. Immunohistological staining of the resected specimens revealed that the tumor was an endocrine carcinoma. The tumor disclosed intense immunoreactivity to pan-neuroendocrine markers and diffuse somatostatin immunoreactivity. There were no psammoma bodies and no demonstrable association with von Recklinghausen's neurofibromatosis. In the gastrointestinal tract, neuroendocrine tumors producing predominantly somatostatin have been described only in the duodenum. To the best of our knowledge, the present report is the second case report of a neuroendocrine gastric carcinoma expressing diffusely somatostatin as the only neuroendocrine regulatory peptide.     

Epifluorescent direct counts of bacteria and viruses from topsoil of various desert dust storm regions

Topsoil from arid regions is the main source of dust clouds that move through the earth's atmosphere, and microbial communities within these soils can survive long-range dispersion. Microbial abundance and chemical composition were analyzed in topsoil from various desert regions. Statistical analyses showed that microbial direct counts were strongly positively correlated with calcium concentrations and negatively correlated with silicon concentrations. While variance between deserts was expected, it was interesting to note differences between sample sites within a given desert region, illustrating the ‘patchy’ nature of microbial communities in desert environments.