Publications by authors named "Jorge Velarde"

Determining the true availability of resources and understanding the level of training of surgeons involved in the treatment of patients with pelvic fractures and haemorrhagic shock is critical. In the herein study, the availability of technical, technological, and human resources for the care of this injury in Latin America region was analysed, and the preferences of orthopaedic trauma surgeons when performing interventions for the diagnosis and treatment of patients with pelvic trauma and associated haemorrhagic shock was described. A cross sectional web-based survey containing questions on knowledge, attitudes, and practices with respect to imaging resources, emergency pelvic stabilization methods, and interventions used for bleeding control was sent to 948 Latin America orthopaedic trauma surgeons treating pelvic fractures in the emergency department.

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Objective: The aim of this study was to evaluate the Latin American orthopaedic trauma surgeons preference regarding knee positioning and entry portals for IM nailing and identify the reasons of these preferences.

Methods: Using the AO Trauma database, 22.285 surveys were distributed by email to Latin American orthopaedic surgeons.

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Postoperative bone infection is a severe complication in the treatment of fractures. The management of this pathology is challenging, but recent advances have been made to achieve standardization that can help diagnosis and decision-making. However, we are unaware of studies validating these models in Latin America.

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Article Synopsis
  • The severity of invasive Streptococcus pyogenes infections varies based on the interaction between host STING genotype and bacterial NADase activity.
  • The bacterial NADase variants can suppress the immune response regulated by STING, which is activated by the c-di-AMP produced by the bacteria.
  • A specific STING genotype that fails to effectively bind c-di-AMP, combined with high NADase activity, leads to severe infection outcomes, highlighting the complexity of host-pathogen interactions in disease variability.
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Nicotinamide adenine dinucleotide (NAD+) is an essential co-factor for cellular metabolism and serves as a substrate in enzymatic processes. NAD+ is produced by de novo synthesis or salvage pathways in nearly all bacterial species. Haemophilus influenzae lacks the capacity for de novo synthesis, so it is dependent on import of NAD+ from the external environment or salvage biosynthetic pathways for recycling of NAD+ precursors and breakdown products.

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The emergence and continued dominance of a Streptococcus pyogenes (group A Streptococcus, GAS) M1T1 clonal group is temporally correlated with acquisition of genomic sequences that confer high level expression of cotoxins streptolysin O (SLO) and NAD-glycohydrolase (NADase). Experimental infection models have provided evidence that both toxins are important contributors to GAS virulence. SLO is a cholesterol-dependent pore-forming toxin capable of lysing virtually all types of mammalian cells.

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The orphan regulator RocA plays a critical role in the colonization and pathogenesis of the obligate human pathogen group A Despite multiple lines of evidence supporting a role for RocA as an auxiliary regulator of the control of virulence two-component regulatory system CsrRS (or CovRS), the mechanism of action of RocA remains unknown. Using a combination of and techniques, we now find that RocA interacts with CsrS in the streptococcal membrane via its N-terminal region, which contains seven transmembrane domains. This interaction is essential for RocA-mediated regulation of CsrRS function.

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Tuberculosis is the leading killer among infectious diseases worldwide. Increasing multidrug resistance has prompted new approaches for tuberculosis drug development, including targeted inhibition of virulence determinants and of signaling cascades that control many downstream pathways. We used a multisystem approach to determine the effects of a potent small-molecule inhibitor of the essential Ser/Thr protein kinases PknA and PknB.

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The globally dominant, invasive M1T1 strain of group A (GAS) harbors polymorphisms in the promoter region of an operon that contains the genes encoding streptolysin O (SLO) and NAD-glycohydrolase (NADase), resulting in high-level expression of these toxins. While both toxins have been shown experimentally to contribute to pathogenesis, many GAS isolates lack detectable NADase activity. DNA sequencing of such strains has revealed that reduced or absent enzymatic activity can be associated with a variety of point mutations in , the gene encoding NADase; a commonly observed polymorphism associated with near-complete abrogation of activity is a substitution of aspartic acid for glycine at position 330 (G330D).

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A global increase in invasive infections due to group A Streptococcus (S. pyogenes or GAS) has been observed since the 1980s, associated with emergence of a clonal group of strains of the M1T1 serotype. Among other virulence attributes, the M1T1 clone secretes NAD+-glycohydrolase (NADase).

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Group A Streptococcus (GAS) responds to subinhibitory concentrations of LL-37 by up-regulation of virulence factors through the CsrRS (CovRS) two-component system. The signaling mechanism, however, is unclear. To determine whether LL-37 signaling reflects specific binding to CsrS or rather a nonspecific response to LL-37-mediated membrane damage, we tested LL-37 fragments for CsrRS signaling and for GAS antimicrobial activity.

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Enteroaggregative Escherichia coli (EAEC), increasingly recognized as an important cause of infant and travelers' diarrhoea, exhibits an aggregative, stacked-brick pattern of adherence to epithelial cells. Adherence is mediated by aggregative adherence fimbriae (AAFs), which are encoded on the pAA virulence plasmid. We recently described a highly prevalent pAA plasmid-borne gene, aap, which encodes a protein (nicknamed dispersin) that is secreted to the bacterial cell surface.

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A wild injured Iberian lynx (Lynx pardinus) was taken from the Sierra Morena population. During the health check small intraerythrocytic piroplasms, morphologically indistinguishable from other feline piroplasms, were observed in Wright-Giemsa-stained blood films. Amplification by polymerase chain reaction of a portion of the 18S nuclear small subunit (NSS) rRNA gene and sequencing revealed similarity of the unknown organism with sequences obtained from Pallas's cat from Mongolia and from a domestic cat in Spain.

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The autotransporter family of proteins is an important class of Gram-negative secreted virulence factors. Their secretion mechanism comprises entry to the periplasm via the Sec apparatus, followed by formation of an outer membrane beta barrel, which allows the N-terminal passenger domain to pass to the extracellular space. Several groups have identified a region immediately upstream of the beta domain that is important for outer membrane translocation, the so-called linker region.

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