ArcKR expression modifies synaptic plasticity following epileptic activity: Differential effects with in vitro and in vivo seizure-induction protocols.

OBJECTIVES: Pathological forms of neural activity, such as epileptic seizures, modify the expression pattern of multiple proteins, leading to persistent changes in brain function. One such protein is activity-regulated cytoskeleton-associated protein (Arc), which is critically involved in protein-synthesis-dependent synaptic plasticity underlying learning and memory. In the present study, we have investigated how the expression of ArcKR, a form of Arc in which the ubiquitination sites have been mutated, resulting in slowed Arc degradation, modifies group I metabotropic glutamate receptor-mediated long-term depression (G1-mGluR-LTD) following seizures. METHODS: We used a knock-in mice line that express ArcKR and two hyperexcitation models: an in vitro model, where hippocampal slices were exposed to zero Mg2+, 6 mM K+; and an in vivo model, where kainic acid was injected unilaterally into the hippocampus. In both models, field excitatory postsynaptic potentials (fEPSPs) were recorded from the CA1 region of hippocampal slices in response to Schaffer collateral stimulation and G1-mGluR-LTD was induced chemically with the group 1 mGluR agonist DHPG. RESULTS: In the in vitro model, ArcKR expression enhanced the effects of seizure activity and increased the magnitude of G1-mGluR LTD, an effect that could be blocked with the mGluR5 antagonist MTEP. In the in vivo model, fEPSPs were significantly smaller in slices from ArcKR mice and were less contaminated by population spikes. In this model, the amount of G1-mGluR-LTD was significantly less in epileptic slices from ArcKR mice as compared to wildtype (WT) mice. SIGNIFICANCE: We have shown that expression of ArcKR, a form of Arc in which degradation is reduced, significantly modulates the magnitude of G1-mGluR-LTD following epileptic seizures. However, the effect of ArcKR on LTD depends on the epileptic model used, with enhancement of LTD in an in vitro model and a reduction in the kainate mouse model.

Pilot study of a high-intensity interval training program in older adults: Safety, feasibility, functional fitness and cognitive effects.

Exercise can boost physical and cognitive health in older adults. However, there are a lack of accessible exercise programs that foster adherence among older adults. In this study, we aimed to establish the safety and feasibility of APEX, a new exercise program designed to optimize fitness and cognitive gains for older adults, in addition to evaluating its acute physiological effects, and assessing its possible effects on functional fitness and cognition among healthy older adults. APEX utilizes a multimodal progressive high-intensity interval training (HIIT) design, with high-intensity intervals focused on enhancing cardiovascular fitness and muscle strength, and recovery intervals that incorporate balance and mobility exercises. The APEX training was tested in healthy older adults (n=4) over the course of four weeks. Ultimately, APEX was found to be safe and feasible, with no adverse events and high adherence. Participants met heart rate targets for all of the high-intensity exercises, and all intervals had a significant difference in heart rates between high-intensity and recovery periods in linear effects models (p<0.001). Improvements in functional fitness were observed in aerobic endurance, lower body strength, and balance. The intervention was also associated with positive trends in the cognitive domains of information processing, working memory, executive control, and attention. APEX offers a promising alternative to traditional cardiovascular exercise modalities for older adults with additional benefits for functional fitness and cognition. These results encourage further testing of the APEX program in older adults and different clinical populations.

Arc expression regulates long-term potentiation magnitude and metaplasticity in area CA1 of the hippocampus in ArcKR mice.

Expression of the immediate early gene Arc/Arg3.1 (Arc), a key mediator of synaptic plasticity, is enhanced by neural activity and then reduced by proteasome-dependent degradation. We have previously shown that the disruption of Arc degradation, in an Arc knock-in mouse (ArcKR), where the predominant Arc ubiquitination sites were mutated, reduced the threshold to induce, and also enhanced, the strength of Group I metabotropic glutamate receptor-mediated long-term depression (DHPG-LTD). Here, we have investigated if ArcKR expression changes long-term potentiation (LTP) in CA1 area of the hippocampus. As previously reported, there was no change in basal synaptic transmission at Schaffer collateral/commissural-CA1 (SC-CA1) synapses in ArcKR versus wild-type (WT) mice. There was, however, a significant increase in the amplitude of synaptically induced (with low frequency paired-pulse stimulation) LTD in ArcKR mice. Theta burst stimulation (TBS)-evoked LTP at SC-CA1 synapses was significantly reduced in ArcKR versus WT mice (after 2 h). Group 1 mGluR priming of LTP was abolished in ArcKR mice, which could also potentially contribute to a depression of LTP. Although high frequency stimulation (HFS)-induced LTP was not significantly different in ArcKR compared with WT mice (after 1 h), there was a phenotype in environmentally enriched mice, with the ratio of LTP to short-term potentiation (STP) significantly reduced in ArcKR mice. These findings support the hypothesis that Arc ubiquitination supports the induction and expression of LTP, likely via limiting Arc-dependent removal of AMPA receptors at synapses.

Recurrence quantification analysis of isokinetic strength tests: A comparison of the anterior cruciate ligament reconstructed and the uninjured limb.

BACKGROUND: Despite widespread use of return to sport testing following anterior cruciate ligament reconstruction, studies suggest inadequacy in current testing criteria, such as limb symmetry index calculations, to determine athletes' readiness to return to play. Recurrence quantification analysis, an emerging non-linear data analysis tool, may reveal subtle neuromuscular differences between the injured and uninjured limb that are not captured by traditional testing. We hypothesized that isokinetic torque curve data of the injured limb would demonstrate lower determinism and entropy as compared to the uninjured limb. METHODS: 102 patients (44 M, 58F, 10 ± 1 months post-anterior cruciate ligament reconstruction) underwent isokinetic quadriceps strength testing using a HumacNorm dynamometer. Patients completed maximum effort knee extension and flexion at 60°/sec. Data were post-processed with a MATLAB CRQA Graphical User Interface and determinism and entropy values were extracted. Paired-sample t-tests (α = 0.05) were used to compare data from the injured and uninjured limb. FINDINGS: Determinism and entropy values in the torque curves were lower in the injured limb than the uninjured limb (p < 0.001). Our findings indicate there is less predictability and complexity present in the torque signals of injured limbs. INTERPRETATION: Recurrence quantification analysis can be used to assess neuromuscular differences between limbs in patients who have undergone anterior cruciate ligament reconstruction. Our findings offer further evidence that there are changes to the neuromuscular system which persist following reconstruction. Further investigation is needed to establish thresholds of determinism and entropy values needed for safe return to sport and to evaluate the utility of recurrence quantification analysis as a return to sport criterion.

Pleiotropic effects of a methyl donor diet in a novel animal model.

Folate and other methyl-donor pathway components are widely supplemented due to their ability to prevent prenatal neural tube defects. Several lines of evidence suggest that these supplements act through epigenetic mechanisms (e.g. altering DNA methylation). Primary among these are the experiments on the mouse viable yellow allele of the agouti locus (A(vy)). In the Avy allele, an Intracisternal A-particle retroelement has inserted into the genome adjacent to the agouti gene and is preferentially methylated. To further test these effects, we tested the same diet used in the Avy studies on wild-derived Peromyscus maniculatus, a native North American rodent. We collected tissues from neonatal offspring whose parents were fed the high-methyl donor diet as well as controls. In addition, we assayed coat-color of a natural variant (wide-band agouti = A(Nb)) that overexpresses agouti as a phenotypic biomarker. Our data indicate that these dietary components affected agouti protein production, despite the lack of a retroelement at this locus. Surprisingly, the methyl-donor diet was associated with defects (e.g. ovarian cysts, cataracts) and increased mortality. We also assessed the effects of the diet on behavior: We scored animals in open field and social interaction tests. We observed significant increases in female repetitive behaviors. Thus these data add to a growing number of studies that suggest that these ubiquitously added nutrients may be a human health concern.

Natural genetic variation underlying differences in Peromyscus repetitive and social/aggressive behaviors.

Peromyscus maniculatus (BW) and P. polionotus (PO) are interfertile North American species that differ in many characteristics. For example, PO exhibit monogamy and BW animals are susceptible to repetitive behaviors and thus a model for neurobehavioral disorders such as Autism. We analyzed these two stocks as well as their hybrids, a BW Y(PO) consomic line (previously shown to alter glucose homeostasis) and a natural P. maniculatus agouti variant (A(Nb) = wide band agouti). We show that PO animals engage in far less repetitive behavior than BW animals, that this trait is dominant, and that trait distribution in both species is bi-modal. The A(Nb) allele also reduces such behaviors, particularly in females. PO, F1, and A(Nb) animals all dig significantly more than BW. Increased self-grooming is also a PO dominant trait, and there is a bimodal trait distribution in all groups except BW. The inter-stock differences in self-grooming are greater between males, and the consomic data suggest the Y chromosome plays a role. The monogamous PO animals engage in more social behavior than BW; hybrid animals exhibit intermediate levels. Surprisingly, A(Nb) animals are also more social than BW animals, although A(Nb) interactions led to aggressive interactions at higher levels than any other group. PO animals exhibited the lowest incidence of aggressive behaviors, while the hybrids exhibited BW levels. Thus this group exhibits natural, genetically tractable variation in several biomedically relevant traits.

A structural biology approach enables the development of antimicrobials targeting bacterial immunophilins.

Macrophage infectivity potentiators (Mips) are immunophilin proteins and essential virulence factors for a range of pathogenic organisms. We applied a structural biology approach to characterize a Mip from Burkholderia pseudomallei (BpML1), the causative agent of melioidosis. Crystal structure and nuclear magnetic resonance analyses of BpML1 in complex with known macrocyclics and other derivatives led to the identification of a key chemical scaffold. This scaffold possesses inhibitory potency for BpML1 without the immunosuppressive components of related macrocyclic agents. Biophysical characterization of a compound series with this scaffold allowed binding site specificity in solution and potency determinations for rank ordering the set. The best compounds in this series possessed a low-micromolar affinity for BpML1, bound at the site of enzymatic activity, and inhibited a panel of homologous Mip proteins from other pathogenic bacteria, without demonstrating toxicity in human macrophages. Importantly, the in vitro activity of BpML1 was reduced by these compounds, leading to decreased macrophage infectivity and intracellular growth of Burkholderia pseudomallei. These compounds offer the potential for activity against a new class of antimicrobial targets and present the utility of a structure-based approach for novel antimicrobial drug discovery.

The Protein Maker: an automated system for high-throughput parallel purification.

The Protein Maker is an automated purification system developed by Emerald BioSystems for high-throughput parallel purification of proteins and antibodies. This instrument allows multiple load, wash and elution buffers to be used in parallel along independent lines for up to 24 individual samples. To demonstrate its utility, its use in the purification of five recombinant PB2 C-terminal domains from various subtypes of the influenza A virus is described. Three of these constructs crystallized and one diffracted X-rays to sufficient resolution for structure determination and deposition in the Protein Data Bank. Methods for screening lysis buffers for a cytochrome P450 from a pathogenic fungus prior to upscaling expression and purification are also described. The Protein Maker has become a valuable asset within the Seattle Structural Genomics Center for Infectious Disease (SSGCID) and hence is a potentially valuable tool for a variety of high-throughput protein-purification applications.

Levofloxacin : a review of its use as a high-dose, short-course treatment for bacterial infection.

Levofloxacin (Levaquin) is a fluoroquinolone antibacterial that is the L-isomer of ofloxacin. A high-dose (750 mg) short-course (5 days) of once-daily levofloxacin is approved for use in the US in the treatment of community-acquired pneumonia (CAP), acute bacterial sinusitis (ABS), complicated urinary tract infections (UTI) and acute pyelonephritis (AP). The broad spectrum antibacterial profile of levofloxacin means that monotherapy is often a possibility in patients with CAP at times when other agents may require combination therapy, although levofloxacin can be used in combination therapy when necessary. The high-dose, short-course levofloxacin regimen maximizes its concentration-dependent bactericidal activity and may reduce the potential for resistance to emerge. In addition, this regimen lends itself to better compliance because of the shorter duration of treatment and the convenient once-daily administration schedule. Oral levofloxacin is rapidly absorbed and is bioequivalent to the intravenous formulation; importantly, patients can transition between the formulations, which results in more options in regards to the treatment regimen and the potential for patients with varying degrees of illness to be treated. Levofloxacin has good tissue penetration and an adequate concentration can be maintained in the urinary tract to treat uropathogens. Levofloxacin is generally well tolerated and has good efficacy in the treatment of patients with CAP, ABS, complicated UTI and AP. The efficacy and tolerability of levofloxacin 500 mg once daily for 10 days in patients with CAP, ABS and UTIs is well established, and the high-dose, short-course levofloxacin regimen has been shown to be noninferior to the 10-day regimen in CAP and ABS, and to have a similar tolerability profile. Similarly, the high-dose, short-course levofloxacin regimen is noninferior to ciprofloxacin in patients with complicated UTI or AP. Thus, levofloxacin is a valuable antimicrobial agent that has activity against a wide range of bacterial pathogens; however, its use should be considered carefully so that the potential for resistance selection can be minimized and its usefulness in severe infections and against a range of penicillin- and macrolide-resistant pathogens can be maintained.

Dalbavancin.

Dalbavancin is a semisynthetic glycopeptide antibacterial agent that is active against Gram-positive bacteria associated with complicated skin and skin structure infections (cSSSIs). It is administered as a two-dose regimen intravenously infused over 30 minutes once weekly. The efficacy of dalbavancin (1000 mg on day 1 and 500 mg on day 8) has been examined in two randomized controlled trials in adults with cSSSIs. In each study, the primary efficacy measure was clinical success at the test-of-cure or follow-up visit in clinically evaluable patients. In a randomized, controlled, double-blind, multinational, phase III trial, dalbavancin was noninferior to linezolid, with clinical success rates of 88.9% and 91.2%. In a randomized, open-label, multicentre, phase II trial, clinical success rates were 94% with dalbavancin and 76% with comparator antibacterials. Dalbavancin was generally well tolerated by adult patients with cSSSIs, with most adverse events being of mild or moderate severity.

Nitazoxanide: a review of its use in the treatment of gastrointestinal infections.

Nitazoxanide (Alinia, Daxon, Dexidex, Paramix, Kidonax, Colufase, Annita) has in vitro activity against a variety of microorganisms, including a broad range of protozoa and helminths. Nitazoxanide is effective in the treatment of protozoal and helminthic infections, including Cryptosporidium parvum or Giardia lamblia, in immunocompetent adults and children, and is generally well tolerated. Nitazoxanide is a first-line choice for the treatment of illness caused by C. parvum or G. lamblia infection in immunocompetent adults and children, and is an option to be considered in the treatment of illnesses caused by other protozoa and/or helminths.

Fludarabine: a review of its use in non-Hodgkin's lymphoma.

Fludarabine (Fludara), a purine nucleoside analogue, has been extensively evaluated in the treatment of a number of lymphoproliferative malignancies, including various types of non-Hodgkin's lymphoma. Clinical studies have shown that fludarabine (alone, and particularly as a component of combination therapy) can result in high overall and complete response in adults with various types of non-Hodgkin's lymphoma, including follicular lymphoma. As mono- or combination therapy, intravenous fludarabine is as effective as several other standard treatment regimens in treatment-naive patients and is also effective in patients with recurrent or refractory disease. The efficacy of fludarabine therapy is improved with the use of rituximab, as part of the initial therapeutic regimen or as maintenance therapy, and deserves consideration. The once-daily oral formulation was effective in the treatment of patients with relapsed indolent B-cell non-Hodgkin's lymphoma; however, further studies are required to confirm its role and establish its efficacy relative to that of standard treatment in this patient population. Fludarabine has generally acceptable tolerability; however, it is associated with haematological adverse events, including myelosuppression. Fludarabine, therefore, provides a highly effective first- or second-line option in the treatment of non-Hodgkin's lymphoma.

Spotlight on methylphenidate controlled-delivery capsules (Equasym XL, Metadate CD) in the treatment of children and adolescents with attention-deficit hyperactivity disorder.

Controlled-delivery methylphenidate (methylphenidate CD) [Equasym XL, Metadate CD], an oral stimulant, is approved in the US and EU to treat children aged > or = 6 years who have been diagnosed with attention-deficit hyperactivity disorder (ADHD). Once-daily methylphenidate CD is generally well tolerated and effective in the treatment of children and adolescents with ADHD. Methylphenidate CD resulted in superior control of ADHD symptoms compared with osmotic release oral system (OROS) methylphenidate over a time period corresponding to that of an average school day in a laboratory classroom. In 3-week clinical trials conducted in a community setting, methylphenidate CD was superior to placebo and non-inferior to methylphenidate immediate-release in the treatment of children and adolescents with ADHD. Thus, methylphenidate CD should be considered an important primary treatment on its own or in addition to behavioural and psychosocial interventions, for when a reduction in ADHD symptoms is required during the school day in preference to the evening.

Ramipril: a review of its use in preventing cardiovascular outcomes in high-risk patients.

Ramipril is an oral, non-sulfhydryl ACE inhibitor thought to act in the renin-angiotensin-aldosterone system to decrease vasopressor activity, aldosterone secretion, and bradykinin degradation. Ramipril is generally well tolerated and effective in the treatment of patients aged > or =55 years at high risk for the development of cardiovascular (CV) events, in whom the risk of myocardial infarction (MI), stroke, and CV death can be significantly reduced. The risk of these CV outcomes may also be reduced with ramipril therapy in various subgroups; these include patients with diabetes mellitus, peripheral arterial disease (PAD) or renal insufficiency, and women. Thus, ramipril, in addition to lifestyle interventions, should be considered an important therapy in the prevention of CV outcomes in high-risk patients.

Methylphenidate controlled-delivery capsules (EquasymXL, Metadate CD): a review of its use in the treatment of children and adolescents with attention-deficit hyperactivity disorder.

Controlled-delivery methylphenidate (methylphenidate CD) [EquasymXL, Metadate CD], an oral stimulant, is approved in the US and EU to treat children aged>or=6 years who have been diagnosed with attention-deficit hyperactivity disorder (ADHD). Once-daily methylphenidate CD is generally well tolerated and effective in the treatment of children and adolescents with ADHD. Methylphenidate CD resulted in superior control of ADHD symptoms compared with osmotic release oral system (OROS) methylphenidate over a time period corresponding to that of an average school day in a laboratory classroom. In 3-week clinical trials conducted in a community setting, methylphenidate CD was superior to placebo and noninferior to methylphenidate immediate-release (IR) in the treatment of children and adolescents with ADHD. Thus, methylphenidate CD should be considered an important primary treatment on its own or in addition to behavioral and psychosocial interventions, for when a reduction in ADHD symptoms is required during the school day in preference to the evening.

Methylphenidate transdermal system: In attention-deficit hyperactivity disorder in children.

The methylphenidate transdermal system (MTS) patch is approved by the US FDA for use in children aged 6-12 years with attention-deficit hyperactivity disorder (ADHD). This delivery system permits sustained absorption of the drug through the skin and into the bloodstream. Methylphenidate (MPH) is a CNS agent thought to act on dopamine and noradrenaline (norepinephrine) pathways and thereby blocks the reuptake of these neurotransmitters into the presynaptic neuron. In children with ADHD, MTS patches releasing MPH doses of 10-30 mg over a 9-hour period (12.5-37.5 cm2 patch size) is steadily absorbed, with mean peak plasma concentrations of d-MPH (20-46.5 ng/mL) reached in approximately 8 hours. In well controlled trials in children with ADHD, patients administered MTS patches releasing MPH 10-30 mg over approximately 9 hours showed significantly greater improvements in their ADHD symptoms than placebo recipients. MTS patches are generally well tolerated in paediatric patients with ADHD, with treatment-emergent events being similar in nature to those reported with oral MPH. The majority of adverse events were mild to moderate in intensity.

Pentosan polysulfate: a review of its use in the relief of bladder pain or discomfort in interstitial cystitis.

Pentosan polysulfate (pentosan polysulfate sodium; ELMIRON), a heparin-like, sulfated polysaccharide, is used to manage bladder pain and discomfort in adults with interstitial cystitis (IC). Preliminary clinical models suggest that pentosan polysulfate repairs damaged glycosaminoglycan (GAG) layers lining the urothelium and in vitro data suggest it may provide an anti-inflammatory effect in patients with IC. Pentosan polysulfate shows beneficial effects in a proportion of patients with IC in terms of the improvement of a patient's overall condition and the relief of pain, and it is a generally well tolerated therapy. It is the only US FDA-approved oral treatment for the relief of bladder pain or discomfort associated with IC, and data support its role as an important option in the treatment of patients with IC.