Persistence of colicinogenic Escherichia coli in the mouse gastrointestinal tract

Background: The ability of a bacterial strain to competitively exclude or displace other strains can be attributed to the production of narrow spectrum antimicrobials, the bacteriocins. In an attempt to evaluate the importance of bacteriocin production for Escherichia coli strain residence in the gastrointestinal tract, a murine model experimental evolution study was undertaken. Results: Six colicin-producing, yet otherwise isogenic, E. coli strains were administered and established in the large intestine of streptomycin-treated mice. The strains\u27 persistence, population density, and doubling time were monitored over a period of 112 days. Early in the experiment only minor differences in population density between the various colicin-producing and the nonproducing control strains were detected. However, over time, the density of the control strains plummeted, while that of the colicin-producing strains remained significantly higher (F(7,66) = 2.317; P \u3c 0.0008). Conclusion: The data presented here support prior claims that bacteriocin production may play a significant role in the colonization of E. coli in the gastrointestinal tract. Further, this study suggests that the ability to produce bacteriocins may prove to be a critical factor in determining the success of establishing probiotic E. coli in the gastrointestinal tract of humans and animals

The pharmacokinetics of continuous subcutaneous levodopa/carbidopa infusion: Findings from the ND0612 clinical development program

BACKGROUND: While treatment with levodopa remains the cornerstone of Parkinson\u27s disease (PD) management, chronic oral therapy is often associated with the development of motor complications, that correlate to fluctuating levodopa plasma concentrations, limiting its clinical utility. Continuous infusion is considered to be the optimal delivery route for treating PD patients with motor fluctuations, but current infusion systems require invasive surgery. Subcutaneous infusion of (SC) levodopa has the potential to provide a better tolerated and more convenient route of continuous levodopa delivery. ND0612 is in development as a combination product providing continuous levodopa/carbidopa via a minimally invasive, subcutaneous delivery system for PD patients experiencing motor response fluctuations. We present pharmacokinetic results from a series of studies that analyzed plasma concentrations after SC levodopa delivery with ND0612 to inform the clinical development program. METHODS: We performed a series of six Phase I and II studies to characterize the pharmacokinetics of levodopa and carbidopa derived from ND0612 infusion with/without adjunct oral therapy of the same ingredients. These studies were conducted in healthy volunteers and in PD patients experiencing motor response fluctuations while on their current levodopa therapy regimen. RESULTS: Taken together, the results demonstrate dose-proportionality dependent on rate of subcutaneous levodopa infusion leading to stable and sustained plasma concentrations of levodopa. Subcutaneous infusion of ND0612 administered with oral levodopa/carbidopa maintained near-constant, therapeutic levodopa plasma concentrations, thereby avoiding the troughs in levodopa plasma concentrations that are associated with OFF time in PD. The data generated in this series of studies also confirmed that a levodopa/carbidopa dose ratio of 8:1 would be the most reasonable choice for ND0612 development. CONCLUSIONS: This series of clinical pharmacokinetic studies have demonstrated that ND0612, administered continuously with a levodopa concentration of 60 mg/ml combined with carbidopa 7.5 mg/ml, and complemented with oral levodopa/carbidopa, is suitable for 24 h continuous administration in patients with PD. The stable plasma concentrations of levodopa achieved predict utility of ND0612 as a parenteral formulation for achieving clinically useful delivery of levodopa for PD patients

A multi-lab experimental assessment reveals that replicability can be improved by using empirical estimates of genotype-by-lab interaction.

The utility of mouse and rat studies critically depends on their replicability in other laboratories. A widely advocated approach to improving replicability is through the rigorous control of predefined animal or experimental conditions, known as standardization. However, this approach limits the generalizability of the findings to only to the standardized conditions and is a potential cause rather than solution to what has been called a replicability crisis. Alternative strategies include estimating the heterogeneity of effects across laboratories, either through designs that vary testing conditions, or by direct statistical analysis of laboratory variation. We previously evaluated our statistical approach for estimating the interlaboratory replicability of a single laboratory discovery. Those results, however, were from a well-coordinated, multi-lab phenotyping study and did not extend to the more realistic setting in which laboratories are operating independently of each other. Here, we sought to test our statistical approach as a realistic prospective experiment, in mice, using 152 results from 5 independent published studies deposited in the Mouse Phenome Database (MPD). In independent replication experiments at 3 laboratories, we found that 53 of the results were replicable, so the other 99 were considered non-replicable. Of the 99 non-replicable results, 59 were statistically significant (at 0.05) in their original single-lab analysis, putting the probability that a single-lab statistical discovery was made even though it is non-replicable, at 59.6%. We then introduced the dimensionless Genotype-by-Laboratory (GxL) factor-the ratio between the standard deviations of the GxL interaction and the standard deviation within groups. Using the GxL factor reduced the number of single-lab statistical discoveries and alongside reduced the probability of a non-replicable result to be discovered in the single lab to 12.1%. Such reduction naturally leads to reduced power to make replicable discoveries, but this reduction was small (from 87% to 66%), indicating the small price paid for the large improvement in replicability. Tools and data needed for the above GxL adjustment are publicly available at the MPD and will become increasingly useful as the range of assays and testing conditions in this resource increases

A spatiotemporal analysis of gait freezing and the impact of pedunculopontine nucleus stimulation

Gait freezing is an episodic arrest of locomotion due to an inability to take normal steps. Pedunculopontine nucleus stimulation is an emerging therapy proposed to improve gait freezing, even where refractory to medication. However, the efficacy and precise effects of pedunculopontine nucleus stimulation on Parkinsonian gait disturbance are not established. The clinical application of this new therapy is controversial and it is unknown if bilateral stimulation is more effective than unilateral. Here, in a double-blinded study using objective spatiotemporal gait analysis, we assessed the impact of unilateral and bilateral pedunculopontine nucleus stimulation on triggered episodes of gait freezing and on background deficits of unconstrained gait in Parkinson’s disease. Under experimental conditions, while OFF medication, Parkinsonian patients with severe gait freezing implanted with pedunculopontine nucleus stimulators below the pontomesencephalic junction were assessed during three conditions; off stimulation, unilateral stimulation and bilateral stimulation. Results were compared to Parkinsonian patients without gait freezing matched for disease severity and healthy controls. Pedunculopontine nucleus stimulation improved objective measures of gait freezing, with bilateral stimulation more effective than unilateral. During unconstrained walking, Parkinsonian patients who experience gait freezing had reduced step length and increased step length variability compared to patients without gait freezing; however, these deficits were unchanged by pedunculopontine nucleus stimulation. Chronic pedunculopontine nucleus stimulation improved Freezing of Gait Questionnaire scores, reflecting a reduction of the freezing encountered in patients’ usual environments and medication states. This study provides objective, double-blinded evidence that in a specific subgroup of Parkinsonian patients, stimulation of a caudal pedunculopontine nucleus region selectively improves gait freezing but not background deficits in step length. Bilateral stimulation was more effective than unilateral

Measuring movement fluency during the sit-to-walk task

Restoring movement fluency is a key focus for physical rehabilitation; it's measurement, however, lacks objectivity. The purpose of this study was to find whether measurable movement fluency variables differed between groups of adults with different movement abilities whilst performing the sit-to-walk (STW) movement. The movement fluency variables were: (1) hesitation during movement (reduction in forward velocity of the centre of mass; CoM), (2) coordination (percentage of temporal overlap of joint rotations) and (3) smoothness (number of inflections in the CoM jerk signal)

West Nile encephalitis in Israel, 1999: the New York connection.

We describe two cases of West Nile (WN) encephalitis in a married couple in Tel Aviv, Israel, in 1999. Reverse transcription-polymerase chain reaction performed on a brain specimen from the husband detected a WN viral strain nearly identical to avian strains recovered in Israel in 1998 (99.9% genomic sequence homology) and in New York in 1999 (99.8%). This result supports the hypothesis that the 1999 WN virus epidemic in the United States originated from the introduction of a strain that had been circulating in Israel

Genomic characterization of murine monocytes reveals C/EBPβ transcription factor dependence of Ly6C(-) cells

Monocytes are circulating, short-lived mononuclear phagocytes, which in mice and man comprise two main subpopulations. Murine Ly6C(+) monocytes display developmental plasticity and are recruited to complement tissue-resident macrophages and dendritic cells on demand. Murine vascular Ly6C(-) monocytes patrol the endothelium, act as scavengers, and support vessel wall repair. Here we characterized population and single cell transcriptomes, as well as enhancer and promoter landscapes of the murine monocyte compartment. Single cell RNA-seq and transplantation experiments confirmed homeostatic default differentiation of Ly6C(+) into Ly6C(-) monocytes. The main two subsets were homogeneous, but linked by a more heterogeneous differentiation intermediate. We show that monocyte differentiation occurred through de novo enhancer establishment and activation of pre-established (poised) enhancers. Generation of Ly6C(-) monocytes involved induction of the transcription factor C/EBP{beta} and C/EBP{beta}-deficient mice lacked Ly6C(-) monocytes. Mechanistically, C/EBP{beta} bound the Nr4a1 promoter and controlled expression of this established monocyte survival factor

A simple method to assess freezing of gait in Parkinson's disease patients

Freezing of gait (FOG) can be assessed by clinical and instrumental methods. Clinical examination has the advantage of being available to most clinicians; however, it requires experience and may not reveal FOG even for cases confirmed by the medical history. Instrumental methods have an advantage in that they may be used for ambulatory monitoring. The aim of the present study was to describe and evaluate a new instrumental method based on a force sensitive resistor and Pearson's correlation coefficient (Pcc) for the assessment of FOG. Nine patients with Parkinson's disease in the "on" state walked through a corridor, passed through a doorway and made a U-turn. We analyzed 24 FOG episodes by computing the Pcc between one "regular/normal" step and the rest of the steps. The Pcc reached +/- 1 for "normal" locomotion, while correlation diminished due to the lack of periodicity during FOG episodes. Gait was assessed in parallel with video. FOG episodes determined from the video were all detected with the proposed method. The computed duration of the FOG episodes was compared with those estimated from the video. The method was sensitive to various types of freezing; although no differences due to different types of freezing were detected. The study showed that Pcc analysis permitted the computerized detection of FOG in a simple manner analogous to human visual judgment, and its automation may be useful in clinical practice to provide a record of the history of FOG

Combined STN/SNr-DBS for the treatment of refractory gait disturbances in Parkinson's disease: study protocol for a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Severe gait disturbances in idiopathic Parkinson's disease (PD) are observed in up to 80% of all patients in advanced disease stages with important impact on quality of life. There is an unmet need for further symptomatic therapeutic strategies, particularly as gait disturbances generally respond unfavourably to dopaminergic medication and conventional deep brain stimulation of the subthalamic nucleus in advanced disease stages. Recent pathophysiological research pointed to nigro-pontine networks entrained to locomotor integration. Stimulation of the pedunculopontine nucleus is currently under investigation, however, hitherto remains controversial. The substantia nigra pars reticulata (SNr) - entrained into integrative locomotor networks - is pathologically overactive in PD. High-frequent stimulation of the substantia nigra pars reticulata preferentially modulated axial symptoms and therefore is suggested as a novel therapeutic candidate target for neuromodulation of refractory gait disturbances in PD.</p> <p>Methods</p> <p>12 patients with idiopathic Parkinson's disease and refractory gait disturbances under best individual subthalamic nucleus stimulation and dopaminergic medication will be enroled into this double-blind 2 × 2 cross-over clinical trial. The treatment consists of two different stimulation settings using <it>(i) </it>conventional stimulation of the subthalamic nucleus [STNmono] and <it>(ii) </it>combined stimulation of distant electrode contacts located in the subthalamic nucleus and caudal border zone of STN and substantia nigra pars reticulata [STN+SNr]. The primary outcome measure is the change of the cumulative 'axial score' (UPDRS II items '13-15' and UPRDS III items '27-31') at three weeks of constant stimulation in either condition. Secondary outcome measures include specific scores on freezing of gait, balance function, quality of life, non-motor symptoms, and neuropsychiatric symptoms. The aim of the present trial is to investigate the efficacy and safety of a three week constant combined stimulation on [STN+SNr] compared to [STNmono]. The results will clarify, whether stimulation on nigral contacts additional to subthalamic stimulation will improve therapeutic response of otherwise refractory gait disturbances in PD.</p> <p>Trial registration</p> <p>The trial was registered with the clinical trials register of <url>http://www.clinicaltrials.gov</url> (<a href="http://www.clinicaltrials.gov/ct2/show/NCT01355835">NCT01355835</a>)</p

Functional polymorphisms in the P2X7 receptor gene are associated with stress fracture injury

Context: Military recruits and elite athletes are susceptible to stress fracture injuries. Genetic predisposition has been postulated to have a role in their development. The P2X7 receptor (P2X7R) gene, a key regulator of bone remodelling, is a genetic candidate that may contribute to stress fracture predisposition. Objective: To evaluate the putative contribution of P2X7R to stress fracture injury in two separate cohorts, military personnel and elite athletes. Methods: In 210 Israeli Defence Forces (IDF) military conscripts, stress fracture injury was diagnosed (n=43) based on symptoms and a positive bone scan. In a separate cohort of 518 elite athletes, self-reported medical imaging scan-certified stress fracture injuries were recorded (n=125). Non-stress fracture controls were identified from these cohorts who had a normal bone scan or no history or symptoms of stress fracture injury. Study participants were genotyped for functional SNPs within the P2X7R gene using proprietary fluorescence-based competitive allele-specific PCR assay. Pearson Chi-square (χ2) tests, corrected for multiple comparisons, were used to assess associations in genotype frequencies. Results: The variant allele of P2X7R SNP rs3751143 (Glu496Ala- loss of function) was associated with stress fracture injury, while the variant allele of rs1718119 (Ala348Thr- gain of function) was associated with a reduced occurrence of stress fracture injury in military conscripts (P<0.05). The association of the variant allele of rs3751143 with stress fractures was replicated in elite athletes (P<0.05), whereas the variant allele of rs1718119 was also associated with reduced multiple stress fracture cases in elite athletes (P<0.05). Conclusions: The association between independent P2X7R polymorphisms with stress fracture prevalence supports the role of a genetic predisposition in the development of stress fracture injury