Investigating the Therapeutic Potential of a Probiotic in a Rat Model for Infection Following Fracture Fixation

Background: Staphylococcus aureus (S. aureus) is the most common pathogen responsible for osteomyelitis. Objectives: Our objective was to investigate the potential of a probiotic as a treatment for S. aureus-induced infection following fracture fixation in a rat model. Methods: Fifty male Sprague-Dawley rats were assigned to five groups (Control, S. aureus, S. aureus +ceftriaxone, S. aureus + once weekly probiotic, and S. aureus + twice weekly probiotic). Lactobacillus casei subsp. casei (ATCC: 39392) was selected from eight strains of probiotic bacteria with anti-staphylococcal activity. Infection was induced by inoculation with106 colony-forming units (CFU) of S. aureus in a closed femur fracture model stabilized with an intramedullary pin. Three weeks after the surgery, the development of infection and response to the therapy was documented using radiographs, microbiological and histopathological analysis. Results: No bacteria were recovered from rats in the Control group. The analysis of variance revealed a significant difference in the CFU/femur (P < 0.001) and CFU/pin (P = 0.001) across all five treatment groups. When the results were compared, the CFU/femur was significantly lower in the S. aureus + Probiotic twice weekly in comparison with S. aureus (P = 0.008) and the S. aureus + ceftriaxone (P = 0.012) groups. Repeated measure ANOVA to test the radiographic scores during the follow-up time between the intervention groups revealed no significant differences (P = 0.179). Conclusions: Parenteral administration of viable L. casei inhibits S. aureus-induced infection as shown by the bacteriologic analysis, but makes no difference to the radiological union rates. This could be the first step towards developing an effective, biologic adjunctive therapy for the management of osteomyelitis following fracture fixation

Intracellular Trafficking and Synaptic Function of APL-1 in Caenorhabditis elegans

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder primarily characterized by the deposition of b-amyloid plaques in the brain. Plaques are composed of the amyloid-b peptide derived from cleavage of the amyloid precursor protein (APP). Mutations in APP lead to the development of Familial Alzheimer’s Disease (FAD), however, the normal function of this protein has proven elusive. The organism Caenorhabditis elegans is an attractive model as the amyloid precursor-like protein (APL-1) is the single ortholog of APP, and loss of apl-1 leads to a severe molting defect and early larval lethality. Methodology/Principal Findings: We report here that lethality and molting can be rescued by full length APL-1, C-terminal mutations as well as a C-terminal truncation, suggesting that the extracellular region of the protein is essential for viability. RNAi knock-down of apl-1 followed by drug testing on the acetylcholinesterase inhibitor aldicarb showed that loss of apl-1 leads to aldicarb hypersensitivity, indicating a defect in synaptic function. The aldicarb hypersensitivity can be rescued by full length APL-1 in a dose dependent fashion. At the cellular level, kinesins UNC-104/KIF-1A and UNC-116/kinesin-1 are positive regulators of APL-1 expression in the neurons. Knock-down of the small GTPase rab-5 also leads to a dramatic decrease in the amount of apl-1 expression in neurons, suggesting that trafficking from the plasma membrane to the early endosome is important for apl-1 function. Loss of function of a different small GTPase, UNC-108, on the contrary, leads t

The Intracellular Threonine of Amyloid Precursor Protein That Is Essential for Docking of Pin1 Is Dispensable for Developmental Function

Background: Processing of Ab-precursor protein (APP) plays an important role in Alzheimer’s Disease (AD) pathogenesis. Thr residue at amino acid 668 of the APP intracellular domain (AID) is highly conserved. When phosphorylated, this residue generates a binding site for Pin1. The interaction of APP with Pin1 has been involved in AD pathogenesis. Methodology/Principal Findings: To dissect the functions of this sequence in vivo, we created an APP knock-in allele, in which Thr 668 is replaced by an Ala (T 668 A). Doubly deficient APP/APP-like protein 2 (APLP2) mice present postnatal lethality and neuromuscular synapse defects. Previous work has shown that the APP intracellular domain is necessary for preventing early lethality and neuromuscular junctions (NMJ) defects. Crossing the T 668 A allele into the APLP2 knockout background showed that mutation of Thr 668 does not cause a defective phenotype. Notably, the T 668 A mutant APP is able to bind Mint1. Conclusions/Significance: Our results argue against an important role of the Thr 668 residue in the essential function of APP in developmental regulation. Furthermore, they indicate that phosphorylation at this residue is not functionally involved i

Scientific imperatives, clinical implications, and theoretical underpinnings for the investigation of the relationship between genetic variables and patient-reported quality-of-life outcomes

Objectives There is emerging evidence for a genetic basis of patient-reported quality-of-life (QOL) outcomes that can ultimately be incorporated into clinical research and practice. Objectives are (1) to provide arguments for the timeliness of investigating the genetic basis of QOL given the scientific advances in genetics and patient-reported QOL research; (2) to describe the clinical implications of such investigations; (3) to present a theoretical foundation for investigating the genetic underpinnings of QOL; and (4) to describe a series of papers resulting from the GENEQOL Consortium that was established to move this work forward. Methods Discussion of scientific advances based on relevant literature. Results In genetics, technological advances allow for increases in speed and efficiency and decreases in costs in exploring the genetic underpinnings of disease processes, drug metabolism, treatment response, and survival. In patient-based research, advances yield empirically based and stringent approaches to measurement that are scientifically robust. Insights into the genetic basis of QOL will ultimately allow early identification of patients susceptible to QOL deficits and to target care. The Wilson and Cleary model for patient-reported outcomes was refined by incorporating the genetic underpinnings of QOL. Conclusions This series of papers provides a path for QOL and genetics researchers to work together to move this field forward and to unravel the intricate interplay of the genetic underpinnings of patient-reported QOL outcomes. The ultimate result will be a greater understanding of the process relating disease, patient, and doctor that will have the potential to lead to improved survival, QOL, and health services deliver

Pharmacological characterisation of capsaicin-induced relaxations in human and porcine isolated arteries

Capsaicin, a pungent constituent from red chilli peppers, activates sensory nerve fibres via transient receptor potential vanilloid receptors type 1 (TRPV1) to release neuropeptides like calcitonin gene-related peptide (CGRP) and substance P. Capsaicin-sensitive nerves are widely distributed in human and porcine vasculature. In this study, we examined the mechanism of capsaicin-induced relaxations, with special emphasis on the role of CGRP, using various pharmacological tools. Segments of human and porcine proximal and distal coronary arteries, as well as cranial arteries, were mounted in organ baths. Concentration response curves to capsaicin were constructed in the absence or presence of the CGRP receptor antagonist olcegepant (BIBN4096BS, 1 μM), the neurokinin NK1 receptor antagonist L-733060 (0.5 μM), the voltage-sensitive calcium channel blocker ruthenium red (100 μM), the TRPV1 receptor antagonist capsazepine (5 μM), the nitric oxide synthetase inhibitor Nω-nitro-l-arginine methyl ester HCl (l-NAME; 100 μM), the gap junction blocker 18α-glycyrrhetinic acid (10 μM), as well as the RhoA kinase inhibitor Y-27632 (1 μM). Further, we also used the K+ channel inhibitors 4-aminopyridine (1 mM), charybdotoxin (0.5 μM) + apamin (0.1 μM) and iberiotoxin (0.5 μM) + apamin (0.1 μM). The role of the endothelium was assessed by endothelial denudation in distal coronary artery segments. In distal coronary artery segments, we also measured levels of cyclic adenosine monophosphate (cAMP) after exposure to capsaicin, and in human segments, we also assessed the amount of CGRP released in the organ bath fluid after exposure to capsaicin. Capsaicin evoked concentration-dependent relaxant responses in precontracted arteries, but none of the above-mentioned inhibitors did affect these relaxations. There was no increase in the cAMP levels after exposure to capsaicin, unlike after (exogenously administered) α-CGRP. Interestingly, there were significant increases in CGRP levels after exposure to vehicle (ethanol) as well as capsaicin, although this did not induce relaxant responses. In conclusion, the capsaicin-induced relaxations of the human and porcine distal coronary arteries are not mediated by CGRP, NK1, NO, vanilloid receptors, voltage-sensitive calcium channels, K+ channels or cAMP-mediated mechanisms. Therefore, these relaxant responses to capsaicin are likely to be attributed to a non-specific, CGRP-independent mechanism

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Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62838/1/nature02168.pd