Determination of secondary structure of normal fibrin from human peripheral blood

The secondary structure of human fibrin from normal donors and from bovine and suilline plasma was studied by Fourier transform ir spectroscopy and a quantitative analysis of its secondary structure was suggested. For this purpose, a previously experimented spectrum deconvolution procedure based on the use of the Conjugate Gradient Minimisation Algorithm with the addition of suitable constraints was applied to the analysis of conformation-sensitive amide bands. This procedure was applied to amide I and III analysis of bovine and suilline fibrin, obtained industrially, and to amide III analysis of human fibrin clots. The analysis of both amide I and III in the first case was useful in order to test the reliability of the method. We found bovine, suilline, and human fibrin to contain about 30% α-helix (amide I and III components at 1653 cm⁻¹, and 1312 and 1284 cm⁻¹, respectively), 40% β-sheets (amide I and III components at 1625 and 1231 cm⁻¹, respectively) and 30% turns (amide I and III components at 1696, 1680, 1675 cm⁻¹, and 1249 cm⁻¹, respectively). The precision of the quantitative determination depends on the amount of these structures in the protein. Particularly, the coefficient of variation is < 10% for percentage values of amide I and III components > 15 and 5%, respectively. The good agreement of our quantitative data, obtained separately by amide I and amide III analysis, and consistent with a previous fibrinogen (from commercial sources) study that reports only information about fibrin β-sheet content obtained by factor analysis, leads us to believe that the amounts of secondary structures found (α-helix, β-sheets, and turns) are accurate. © 1997 John Wiley & Sons, Inc. Biopoly 41: 545–553, 1997.     

Involvement of fractalkine and macrophage inflammatory protein-1 alpha in moderate-severe depression

Moderate-severe depression (MSD) is linked to overexpression of proinflammatory cytokines and chemokines. Fractalkine (FKN) and macrophage inflammatory protein-1 alpha (MIP-1alpha) are, respectively, members of CX3C and C-C chemokines, and both are involved in recruiting and activating mononuclear phagocytes in the central nervous system. We analysed the presence of FKN and MIP-1alpha in sera of untreated MSD patients and healthy donors. High FKN levels were observed in all MSD patients as compared with values only detectable in 26% of healthy donors. MIP-1alpha was measurable in 20% of patients, while no healthy donors showed detectable chemokine levels. In conclusion, we describe a previously unknown involvement of FKN in the pathogenesis of MSD, suggesting that FKN may represent a target for a specific immune therapy of this disease.     

Genetic heterogeneity at the beta-giardin locus among human and animal isolates of Giardiaduodenalis and identification of potentially zoonotic subgenotypes

Human giardiasis, caused by the intestinal flagellate Giardia duodenalis, is considered a zoonotic infection, although the role of animals in the transmission to humans is still unclear. Molecular characterisation of cysts of human and animal origin represents an objective means to validate or reject this hypothesis. In the present work, cysts were collected in Italy from humans (n=37) and animals (dogs, one cat and calves, n=46), and were characterised by PCR amplification and sequencing of the beta-giardin gene. As expected, only Assemblages A and B were identified among human isolates. The host-specific Assemblages C and D were found in the majority of dog isolates; however, 6 dog isolates were typed as Assemblage A. The cat-specific Assemblage F has been identified in the single feline isolate available. Among calf isolates, most were typed as Assemblages A (n=12) and B (n=5), whereas the host-specific Assemblage E was rarely found (n=3). Sequence heterogeneity in the beta-giardin gene allowed a number of subgenotypes to be identified within Assemblage A (8 subgenotypes), B (6 subgenotypes), D (2 subgenotypes), and E (3 subgenotypes). Five of these subgenotypes, namely A1, A2, A3, A4 and B3, were found to be associated with infections of humans, of dogs and of calves; these data, therefore, supported the role of these animals as a source of infection for humans.     

Associations between Trichinella species and host species in Finland

Examination of 627 wild animals--raccoon dogs (Nyctereutes procyonoides), red foxes (Vulpes vulpes), European lynxes (Lynx lynx), brown bears (Ursus arctos), wolves (Canis lupus), and badgers (Meles meles)--revealed Trichinella spp. The prevalence varied according to geographical region of Finland (north; southwest, SW; and southeast, SE) and was the highest among lynxes (70%, SW). The risk of trichinellosis was higher in the SE (odds ratio, OR, 19.4) and SW regions (OR 14.3), as compared with the northern region (OR 1), with no difference between the former 2 regions. Foxes (OR 2.1) and lynxes (OR 1.9) had a higher risk than raccoon dogs (OR 1) of being infected. The distribution of different Trichinella species was evaluated in 87 wild and domestic mammals by multiplex polymerase chain reaction. Trichinella spiralis was detected more often in domestic and synanthropic animals than in sylvatic hosts. Trichinella nativa was detected only in wildlife. Trichinella pseudospiralis was found both in sylvatic and synanthropic hosts. Trichinella britovi was detected only in mixed infections with other Trichinella species. The raccoon dog was the sole host for all 4 Trichinella species and also carried the most intense infections.     

Update on pathological platelet activation in coronary thrombosis

Although coronary thrombosis (CT) is integral to cardiovascular outcomes, the underlying pathophysiological mechanisms remain unclear. CT may occur in case of atherosclerotic plaque erosion/rupture, or even after stenting implantation. Platelets (PLT) activation is the keystone of atherothrombosis and depends on many dysregulated elements, including endothelial dysfunction, oxidized lipoproteins, and immune response. Besides the classical view of PLT as an effector of hemostatic response, a new repertoire of PLT activities is emerging. PLT lipidome oxidation is a self-maintaining process which promotes PLT reactivity, coagulation cascade, and inflammatory cell activation. PLT-innate immune cell interaction is also sustained by neutrophil extracellular traps and NLRP3 inflammasome pathways. Other noteworthy emerging mechanisms are implicated in the crosstalk between PLT and surrounding cells. Especially, microvesicles (MVs) released from PLT may extend their signaling network far beyond the classical cell−cell interactions. Moreover, the recognition of noncoding RNA in PLT MVs introduce another layer of complexity in terms of intercellular signaling by a direct regulation of messenger RNA profile and gene expression in the recipient cells. The aim of this narrative review is to update the recent advance in CT and intracoronary stent thrombosis, including causal factors and potential translation of experimental evidence into the clinical setting.     

Autoimmune-associated PTPN22 R620W Variation Reduces Phosphorylation of Lymphoid Phosphatase on an Inhibitory Tyrosine Residue

A missense C1858T single nucleotide polymorphism in the PTPN22 gene recently emerged as a major risk factor for human autoimmunity. PTPN22 encodes the lymphoid tyrosine phosphatase (LYP), which forms a complex with the kinase Csk and is a critical negative regulator of signaling through the T cell receptor. The C1858T single nucleotide polymorphism results in the LYP-R620W variation within the LYP-Csk interaction motif. LYP-W620 exhibits a greatly reduced interaction with Csk and is a gain-of-function inhibitor of signaling. Here we show that LYP constitutively interacts with its substrate Lck in a Csk-dependent manner. T cell receptor-induced phosphorylation of LYP by Lck on an inhibitory tyrosine residue releases tonic inhibition of signaling by LYP. The R620W variation disrupts the interaction between Lck and LYP, leading to reduced phosphorylation of LYP, which ultimately contributes to gain-of-function inhibition of T cell signaling.