Search results for "C3"
showing 10 items of 1295 documents
Myelin pathology: Involvement of molecular chaperones and the promise of chaperonotherapy
2019
The process of axon myelination involves various proteins including molecular chaperones. Myelin alteration is a common feature in neurological diseases due to structural and functional abnormalities of one or more myelin proteins. Genetic proteinopathies may occur either in the presence of a normal chaperoning system, which is unable to assist the defective myelin protein in its folding and migration, or due to mutations in chaperone genes, leading to functional defects in assisting myelin maturation/migration. The latter are a subgroup of genetic chaperonopathies causing demyelination. In this brief review, we describe some paradigmatic examples pertaining to the chaperonins Hsp60 (HSPD1,…
The Properdin System: Composition and Function
1978
. This article summarizes the physicochemical data on the factors which compose the properdin system in guinea pig and man. The following other topics are discussed: (1) Activation of the properdin system; (2) Formation of the initiating and amplification C3 convertases; (3) Formation of the C5 convertase, and (4) Regulatory control mechanisms of the properdin system.
Retinol encapsulated into amorphous Ca2+ polyphosphate nanospheres acts synergistically in MC3T3-E1 cells
2015
Both the quality and quantity of collagen, the major structural component of the skin, decrease in aging skin. We succeeded to encapsulate retinol into amorphous inorganic polyphosphate (polyP) nanoparticles together with calcium ions ("aCa-polyP-NP"), under formation of amorphous Ca-polyP/retinol nanospheres ("retinol/aCa-polyP-NS"). The globular nanospheres are not cytotoxic, show an almost uniform size of ≈ 45 nm and have a retinol content of around 25%. Both components of those nanospheres, retinol and the aCa-polyP-NP, if administered together, caused a strong increase in proliferation of mouse calvaria MC3T3 cells. The expressions of collagen types I, II and III genes, but not the exp…
Binding and activation of human and mouse complement by Cryptosporidium parvum (Apicomplexa) and susceptibility of C1q- and MBL-deficient mice to inf…
2008
Cryptosporidium parvum is a protozoan parasite (Apicomplexa) that causes gastrointestinal disease in animals and humans. Whereas immunocompetent hosts can limit the infection within 1 or 2 weeks, immunocompromised individuals develop a chronic, life-threatening disease. The importance of the adaptive cellular immune response, with CD4+ T-lymphocytes being the major players, has been clearly demonstrated. Several non-adaptive immune mechanisms have been suggested to contribute to the host defence, such as interferon-gamma (IFN-gamma) from NK cells, certain chemokines, beta-defensins and pro-inflammatory cytokines, but the influence of the complement systems has been less well studied. We ana…
Multimodal Simulation of a Novel Device for a Safe and Effective External Ventricular Drain Placement
2021
BackgroundExternal ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD varies widely in literature, ranging from 12.3 to 60%. The purpose of this simulation study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement.MethodsWe used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans. The data sets were used to conduct three-dimensional computer-based and combined navigation and augmented reality-based simulations using pla…
Genotoxicity characteristics of reverse diol-epoxides of chrysene.
2017
Trans-3,4-dihydroxy-3,4-dihydrochrysene (chrysene-3,4-diol), a major metabolite of chrysene, is further metabolized by rat liver enzymes to products which effectively revert the his- Salmonella typhimurium strain TA98 to histidine prototrophy, but are only weakly mutagenic in strain TA100 and in Chinese hamster V79 cells (acquisition of resistance to 6-thioguanine). The liver enzyme mediated mutagenicity of chrysene-3,4-diol is substantially enhanced in the presence of 1,1,1-trichloropropene 2,3-oxide, an inhibitor of microsomal epoxide hydrolase. The predominant metabolites of chrysene-3,4-diol, namely the anti- and syn-isomers of its 1,2-oxide (termed reverse diol-epoxides), proved to be …
Cerebral Dynamics during the Observation of Point-Light Displays Depicting Postural Adjustments
2017
Objective: As highly social creatures, human beings rely part of their skills of identifying, interpreting, and predicting the actions of others on the ability of perceiving biological motion. In the present study, we aim to investigate the electroencephalographic (EEG) cerebral dynamics involved in the coding of postural control and examine whether upright stance would be codified through the activation of the temporal-parietal cortical network classically enrolled in the coding of biological motion. Design: We registered the EEG activity of 12 volunteers while they passively watched point light displays (PLD) depicting quiet stable (QB) and an unstable (UB) postural situations and their r…
Microwave-assisted chemical modification of g-C3N4 for photoinduced processes: organic degradation, hydrogen production and selective oxidation of al…
2023
g-C3N4 powders were treated by means of the microwave technique in three different aqueous and organic media (HNO3, NaOH and N,N-dimethylformamide). All powders were analyzed by XRD reveling that g-C3N4 maintains its structure. The morphology of the samples was analyzed with scanning electron microscopy, where the micrographs reveals that the modifcation occurs on the surface of the g-C3N4. The photocatalytic activity of the samples was evaluated in the degradation of ciprofoxacin, hydrogen production and for the selective partial oxidation of 4-methoxybenzylalcohol (4-MBA) to its aldehyde. The sample treated with HNO3 (C3N4-HNO3) shows the best photocatalytic performance in the degradation…
Tributo al professor Miguel F. Refojo, PhD, DSc (1928---2016)
2016
[Excerpt] July 21, 2016, Professor Miguel F. Refojo passed away at the age of 88 in Needham (Massachusetts). Saying that Miguel was one of the most renowned Spanish scientists of the second half of the XXth Century does not resembles its actual scientific size. Indeed, Miguel (or “Migüel” as most of his American friends pronounced his name) was a World Class scientist and inventor that will be forever linked to the advances in polymer science applied to the ophthalmic environment. His contributions in the biomedical field start “officially” in 1967 according to the National Library of Medline database (Pubmed-Medline). [...]
Alpha- and gamma-interferon (IFNα, IFNγ) but not interleukin-1 (IL-1) modulate synthesis and secretion of β2-microglobulin by hepatocytes
1988
Soluble serum beta 2-microglobulin has been thought to result from membrane shedding by activated T-lymphocytes. This hypothesis could explain the increase of beta 2-microglobulin serum levels during virally induced mononucleosis, but not elevated levels as observed in other virally induced and in malignant diseases. In this paper we demonstrate that beta 2-microglobulin is a true secretory protein, and that its synthesis in hepatocytes is modulated by IFNs but not by IL-1. While the 45,000 MW HLA antigen can be found only in cell lysates, beta 2-microglobulin is shown to be secreted also into the culture medium like other secretory proteins (e.g. albumin-factor B-complement C3). Furthermor…