Rotator cuff tears are a common injury impacting a large and diverse group of patients and refer to a partial or full discontinuation of one or more of the muscles or tendons comprising the shoulder complex. It may occur as a result of traumatic injury, applied weight, overuse, or intrinsic degeneration over a period of years. The incidence of rotator cuff tears has been found to increase with age. Though not a life-threatening condition, rotator cuff tears adversely affect the quality of one's lifestyle causing significant pain, weakness, and limitation of motion that hinders a person from performing routine daily activities as adequately and frequently as desired. Data from cadaveric studies suggest that as many as 65% of individuals over the age of 70 have a partial-thickness rotator cuff tear. Oftentimes, rotator cuff tears are asymptomatic which can make diagnosis and early treatment challenging. The decision to pursue operative versus conservative management is often controversial. Though surgical intervention may provide more immediate pain relief and functional improvement, it portends a higher risk of morbidity than conservative measures, particularly with an older demographic of patients. Moreover, surgical repair is often followed by long recovery periods and has variable outcomes. A number of conservative treatment options are currently being utilized for the management of partial rotator cuff tears including oral medication, corticosteroid injection, and targeted physical therapy. This review seeks to assess an innovative, biologic approach to treating partial rotator cuff tears using autologous platelet-rich plasma (PRP). The use of PRP for the conservative management of both degenerative and acutely injured tissues is quickly becoming a more popular option within the clinical community. PRP treatment has received significant attention from the media and has been used by several professional athletes as a means of expediting the healing process. The appeal of PRP stems from the fact that it is produced from a patient's own blood. After a blood sample is obtained, it is placed into a centrifuge, a tool used to separate the blood into its many components. A large concentration of platelet-enriched plasma can then be collected and augmented before administration to an injured area of bone or soft tissue, such as a tendon or ligament. Platelets contain an abundance of growth factors essential for cellular recruitment, proliferation, and specialization required for the healing process. PRP is given to a patient via an injection, often under ultrasound assistance for more precise placement. This study reviewed a collection of current literature on the efficacy of PRP in rotator cuff repair. Published studies have generally illustrated a general trend towards effectiveness, suggesting PRP may improve patient outcomes and prevent the need for surgery in patients with partial rotator cuff tears. Study designs and results have proved to be inconsistent at times. However, further clinical investigation is required to validate the use of PRP as an additional non-surgical treatment option.

When prions are transmitted between species, there can be a delay in pathogenesis due to a phenomenon referred to as the transmission barrier. Some species also show very low susceptibility to prion disease. In this study I hypothesized that the susceptibility of species to prion disease is proportional to the tendency of their endogenous prion protein, PrP, to adopt the β-state, an oligomeric form of misfolded recombinant PrP that is rich in β sheet. Using a novel method of two-wavelength CD analysis, it could be shown that recombinant PrP from prion-susceptible species have a higher propensity to refold to the β-state than resistant species. The crystal structure of rabbit PrPC 121-230 revealed a helix-cap motif at the N-terminus of helix-2 that contributes to the reduced β-state propensity of rabbit PrP. Single amino acid changes in the sequence of PrP can lead to a transmission barrier and/or resistance in species. Mutating single residues in rabbit PrPC to those found in corresponding positions in hamster PrPC, ablated the helix-cap observed in the wild-type and caused an increase in the β-state propensity of rabbit PrP. Conversely, a decrease in β-state propensity was observed when rabbit mutations were introduced into PrP of hamster, a susceptible species. A dimeric association is hypothesized to be involved in the function of PrP and/or the conversion mechanism to infectious prion. In the structures of the wild-type and mutant rabbit PrPCs a dimeric arrangement was observed in the asymmetric unit of the crystals. Using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC), a dimer of rabbit and hamster PrPC was crosslinked in solution. The dimer crosslink was specific and dependent on the tertiary structure of PrPC. Crosslinking of the β-state octamer with EDC showed that similar contacts may be present in this oligomeric form. Together these data provide strong evidence that species susceptibility is linked to β-state propensity.

When prions are transmitted between species, there can be a delay in pathogenesis due to a phenomenon referred to as the transmission barrier. Some species also show very low susceptibility to prion disease. In this study I hypothesized that the susceptibility of species to prion disease is proportional to the tendency of their endogenous prion protein, PrP, to adopt the β-state, an oligomeric form of misfolded recombinant PrP that is rich in β sheet. Using a novel method of two-wavelength CD analysis, it could be shown that recombinant PrP from prion-susceptible species have a higher propensity to refold to the β-state than resistant species. The crystal structure of rabbit PrPC 121-230 revealed a helix-cap motif at the N-terminus of helix-2 that contributes to the reduced β-state propensity of rabbit PrP. Single amino acid changes in the sequence of PrP can lead to a transmission barrier and/or resistance in species. Mutating single residues in rabbit PrPC to those found in corresponding positions in hamster PrPC, ablated the helix-cap observed in the wild-type and caused an increase in the β-state propensity of rabbit PrP. Conversely, a decrease in β-state propensity was observed when rabbit mutations were introduced into PrP of hamster, a susceptible species. A dimeric association is hypothesized to be involved in the function of PrP and/or the conversion mechanism to infectious prion. In the structures of the wild-type and mutant rabbit PrPCs a dimeric arrangement was observed in the asymmetric unit of the crystals. Using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC), a dimer of rabbit and hamster PrPC was crosslinked in solution. The dimer crosslink was specific and dependent on the tertiary structure of PrPC. Crosslinking of the β-state octamer with EDC showed that similar contacts may be present in this oligomeric form. Together these data provide strong evidence that species susceptibility is linked to β-state propensity.

No description available.

Research on all tested vertebrates indicates that geometric information plays a special role when organisms reorient in their environment. Some researchers have argued that geometric information is processed automatically, while landmark information is processed more slowly. These conclusions of the course of reorientation processing have been drawn from research that tested organisms accuracy in locating targets in experimental environments. However, inferences of the course of processing are not logical extensions of physical reorientation paradigms. To this end, the present research employs the psychological refractory period paradigm to investigate, over two experiments, the precise stages of processing that humans utilize when encoding an environment. The data confirm previous research by demonstrating an underadditive effect of response time across stimulus onset asynchrony (SOA) for geometric trials and an additive effect for landmark trials, suggesting that geometric information is processed during the first stage of processing, and landmark information during the second.

Platelet-rich plasma (PRP) can be widely used in veterinary medicine in different areas. Studies using PRP frequently use different methodologies making for difficult comparison. The objective of this study was to evaluate the purity and platelet activation of a PRP protocol. A total of 18 blood samples were drawn from six dogs, collected once per week over a total of three weeks. Blood samples were centrifuged six times at 300g for 5 min. Ultra-pure PRP (OP) was obtained by adding PRP a Optiprep 1.063g/mL density barrier and centrifuged at 350g for 15 min. Mean platelet recovery from whole blood was 62.90% in PRP and 45.24% in OP. PRP and OP showed high platelet purity; blood cell contamination <0.01%. Flow cytometry for platelet activation markers was consistent with minimal platelet activation. This study describes the optimization of PRP protocol with high platelet purity, minimal platelet activation, high reliability and reproducibility.

Abstract In silico analysis showed that Arabidopsis thaliana gene AT5G09530 encodes a uniquely repetitive, proline-enriched protein that is conserved across species, and is likely secreted to the cell wall. Based on its most common amino acid repeat motif, I named the gene PELPK1 and its putative paralog PELPK2 (AT5G09520). Reporter (GUS) expression showed that the PELPK1 upstream genomic region is sufficient for expression in the aleurone layer during seed germination, and is induced throughout the plant by biotic factors (especially Pseudomonas syringae infection), defense chemicals (MeJa, salicylic acid), and mechanical wounding, consistent with the presence of conserved regulatory elements. Sub-cellular localization of a translational fusion of PELPK1 with GFP showed that the protein was secreted into seed-coat aleurone cells and to the cell walls of other tissues. Based on these results, it was concluded that the PELPK1 is a cell wall-associated protein and is most actively transcribed during radicle penetration of the seed coat and during pathogen and wounding responses. A proteomic survey of aleurone proteins failed to identify PELPK1, although several proteins not previously associated with this tissue were identified. Mutational analysis demonstrated that RNAi silencing significantly down-regulated the transcript abundance of PELPK1. Phenotypic analysis showed that RNAi plants exhibited significantly slower germination and root growth when the medium was supplemented with sucrose (100mM). Conversely, constitutive overexpression (OX) of PELPK1 enhanced seed germination and root elongation as compared to wild-type (WT). Analysis of soil-grown plants showed slower emergence and slower vegetative growth for RNAi lines, while OX plants exhibited faster emergence and enhanced vegetative growth and flowering as compared to WT. However, PELPK1 RNAi and OX lines did not differ from WT in response to treatment with pathogens. These results show that the abundance of PELPK1 is positively correlated with plant growth rate under some conditions. PELPK1 may influence growth through CW modification or other independent pathways. / Plant Biology

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No description available.

The phenomenon where small numbers produce faster left than right responses and large numbers produce faster right than left responses (The SNARC effect) has been used as evidence for obligatory activations of magnitude. In two experiments, I used the SNARC effect to examine crosstalk using a psychological refractory period (PRP) paradigm. In Experiment 1, subjects made a parity judgment to the second number, while ignoring the first number in session 1 or performing a magnitude judgment on the number in session 2. In Experiment 2, subjects performed a magnitude judgment on the second number. They ignored the first number in session 1 or performed a parity judgment on the number in session 2. The results supported two conclusions. First, presentation of a number produced obligatory representations of magnitude even if the number was to be ignored. Second, early representations of magnitude resulted in crosstalk on processing of the subsequent number.