Shiga Toxin Promotes Podocyte Injury in Experimental Hemolytic Uremic Syndrome via Activation of the Alternative Pathway of Complement

Shiga toxin (Stx)–producing Escherichia coli is the offending agent of postdiarrhea-associated hemolytic uremic syndrome (HUS), a disorder of glomerular ischemic damage and widespread microvascular thrombosis. We previously documented that Stx induces glomerular complement activation, generating C3a responsible for microvascular thrombosis in experimental HUS. Here, we show that the presence of C3 deposits on podocytes is associated with podocyte damage and loss in HUS mice generated by the coinjection of Stx2 and LPS. Because podocyte adhesion to the glomerular basement membrane is mediated by integrins, the relevance of integrin-linked kinase (ILK) signals in podocyte dysfunction was evaluated. Podocyte expression of ILK increased after the injection of Stx2/LPS and preceded the upregulation of Snail and downregulation of nephrin and α-actinin-4. Factor B deficiency or pretreatment with an inhibitory antibody to factor B protected mice against Stx2/LPS-induced podocyte dysregulation. Similarly, pretreatment with a C3a receptor antagonist limited podocyte loss and changes in ILK, Snail, and α-actinin-4 expression. In cultured podocytes, treatment with C3a reduced α-actinin-4 expression and promoted ILK-dependent nuclear expression of Snail and cell motility. These results suggest that Stx-induced activation of the alternative pathway of complement and generation of C3a promotes ILK signaling, leading to podocyte dysfunction and loss in Stx-HUS.     

Non‐epileptic myoclonic attacks in infancy: three cases

Since the first cases of abnormal paroxystic movements in normal infants were described, the importance of accurate characterization of this medical condition has been increasingly confirmed in the literature. Non‐epileptic attacks mimic epileptic paroxysms in clinical presentation, but they have a typically benign course and are unresponsive to pharmacological treatment. An evident feature of the syndrome is its extreme variability in clinical manifestation. Here, we describe three normal infants with two similar forms of non‐epileptic paroxysms. Electroclinical manifestations and profile of evolution were investigated. Ictal video‐EEG polygraphic recordings were obtained for each patient. The increasing number of such reported clinical cases in the literature may contribute to high quality systematic reviews and the development of useful guidelines in the future. The clinical heterogeneity of non‐epileptic attacks, together with the relative rarity of the condition, may make differential diagnosis with epileptic attacks very challenging. [Published with video sequences]     

Toward the interpretation of the combined effect of size and body weight on the tribological performance of total knee prostheses

Purpose

The research questions of the present study were: (1) Is total knee prosthesis wear behaviour influenced by implant size, body weight and their combined effect? (2) Are these findings significant and helpful from a clinical point of view?

Methods

Two very different sizes of the same total knee prosthesis (TKP), previously tested with ISO 14243 parameters, were tested on a knee simulator for a further two million cycles using a modified ISO 14243 load waveform. Roughness examination was performed on the metallic components. Gravimetric and micro-Raman spectroscopic analyses were carried out on the polyethylene inserts.

Results

The average volumetric mass loss was 69 ± 3 mm³ and 88 ± 4 mm³ for smaller and bigger size, respectively. Bigger TKPs are little influenced by an increased load, while the wear trend of the smaller TKP showed a redoubled slope, and more significant morphology changes were observed. However, the two sizes seem to behave similarly when subjected to a load increase of 15 %; the slope of the volumetric mass loss trend was comparable for the two sets of inserts, which did not appear significantly different also at the molecular level. Roughness average parameters of the lateral femoral condyle support this evidence.

Conclusions

It can be asserted that the body weight and implant size are relevant to the understanding of TKP wear behaviour. A post-implantation body weight increase in a patient with smaller knee dimensions could results in more critical effects on prosthesis long-term performance.     

Loss of Gsα Early in the Osteoblast Lineage Favors Adipogenic Differentiation of Mesenchymal Progenitors and Committed Osteoblast Precursors

In humans, aging and glucocorticoid treatment are associated with reduced bone mass and increased marrow adiposity, suggesting that the differentiation of osteoblasts and adipocytes may be coordinately regulated. Within the bone marrow, both osteoblasts and adipocytes are derived from mesenchymal progenitor cells, but the mechanisms guiding the commitment of mesenchymal progenitors into osteoblast versus adipocyte lineages are not fully defined. The heterotrimeric G protein subunit G_sα activates protein kinase A signaling downstream of several G protein‐coupled receptors including the parathyroid hormone receptor, and plays a crucial role in regulating bone mass. Here, we show that targeted ablation of G_sα in early osteoblast precursors, but not in differentiated osteocytes, results in a dramatic increase in bone marrow adipocytes. Mutant mice have reduced numbers of mesenchymal progenitors overall, with an increase in the proportion of progenitors committed to the adipocyte lineage. Furthermore, cells committed to the osteoblast lineage retain adipogenic potential both in vitro and in vivo. These findings have clinical implications for developing therapeutic approaches to direct the commitment of mesenchymal progenitors into the osteoblast lineage. © 2014 American Society for Bone and Mineral Research     

The tyrosine kinase inhibitor tyrphostin AG 126 reduces the multiple organ failure induced by zymosan in the rat

OBJECTIVE: To investigate the effects of tyrphostin AG 126, a tyrosine kinase inhibitor, on the multiple organ failure (MOF) caused by zymosan in the rat. DESIGN: Zymosan (500 mg/kg, suspended in saline solution, i.p.) causes an enhanced formation of reactive oxygen species, which contribute to the pathophysiology of MOF. After zymosan or saline administration, animals were monitored for 12 days. MEASUREMENTS AND RESULTS: Treatment of rats with tyrphostin AG 126 (10 mg/kg, 3 mg/kg or 1 mg/kg intraperitoneally, 1 h and 6 h after zymosan) attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan in a dose-dependent fashion. Tyrphostin AG 126 also attenuated the lung, liver, and intestinal injury (histology) as well as the increase in the levels of myeloperoxidase and malondialdehyde caused by zymosan in the lung, liver, and intestine. Immunohistochemical analysis for nitrotyrosine, poly (ADP-ribose) polymerase (PAR), iNOS, and COX-2 revealed a positive staining in lung, liver and intestine from zymosan-treated rats. The degree of staining for nitrotyrosine, PAR, iNOS, and COX-2 were markedly reduced in tissue sections obtained from zymosan-treated rats which had received tyrphostin AG 126. Furthermore, treatment of rats with tyrphostin AG 126 significantly reduced the production of peroxynitrite and of pro-inflammatory cytokines TNF-alpha and IL-1beta. CONCLUSIONS: This study provides the first evidence that the protein kinase inhibitor tyrphostin AG 126 attenuates the degree of MOF associated with zymosan-induced peritonitis in the rat.     

Vaginal cystocele repair and hysteropexy in women with anterior and central compartment prolapse: efficacy and safety after 30 months of follow-up

Introduction and hypothesis

The aim of this study was to assess the safety and efficacy of vaginal native tissue repair and uterine suspension after a follow-up of at least 1 year.

Methods

We included all consecutive women with an anterior vaginal prolapse of stage II or higher and a concomitant uterine prolapse of stage II who underwent this surgical procedure. We considered women with a descensus with maximum point of less than ?1 in any compartment as objectively cured. Overall success was defined as no prolapse symptoms, together with a Patient Global Impression of Improvement (PGI-I) score of 2 or less, prolapse of stage lower than II, and no need for other surgery.

Results

A total of 102 patients underwent this surgical procedure during the study period and met all the inclusion criteria for statistical analysis. The mean follow-up was 31 ± 8.2 months; no patient was lost to follow-up. Five patients (4.9%) showed postoperative complications. In terms of subjective outcomes, at the last available follow-up, failure of this surgical procedure was seen in 2% of patients. The objective cure rate and the overall cure rate were the 95.1%. No significant deterioration in objective cure rates was observed over time (p = 0.6).

Conclusions

Vaginal repair and hysteropexy appear to be an effective and safe option for women with advanced uterovaginal prolapse.