Mucosal antibody quantity but not avidity predicts likelihood of Salmonella infection in red-eared slider turtles (Trachemys scripta).

Natural antibodies (NAbs) are polyreactive, have low avidity, and are a product of B-1 cells. Evidence suggests that NAbs may play a key role in immune defense in turtles, as increased total mucosal antibodies are associated with a decreased number of extracellular intestinal parasites. However, it is unknown if this trend extends to other types of pathogens and if avidity of the NAb to the pathogen is a factor in protection. We examined the relationship between a common intracellular bacteria in turtles-Salmonella-and NAbs. Plasma and mucosal samples were taken from red-eared slider turtles. We measured levels and avidity of antibodies that bound to lipopolysaccharide (LPS), a component of Salmonella cell wall. We examined the relationship between these measures and the ability of plasma to kill Salmonella as well as infection status. Higher mucosal antibody levels were significantly associated with a decrease in likelihood of infection with Salmonella; however, plasma antibody levels were not. There was a trend for bactericidal ability of the plasma to be positively correlated with plasma antibody levels bound to LPS, but not mucosal antibody levels. Avidity was not significantly related to either killing capacity or likelihood of infection suggesting that only increased quantity and not better binding is responsible for the decreased likelihood of infection. These findings suggest that NAb regulation was sufficient to isolate the infection to the gastrointestinal tract of the turtles, allowing it to be cleared with the mucus layer. Our results add further evidence that turtles use a general, nonspecific NAb response to combat pathogens.

Role of Interhemispheric Cortical Interactions in Poststroke Motor Function.

Background/Objective. We investigated interhemispheric interactions in stroke survivors by measuring transcranial magnetic stimulation (TMS)-evoked cortical coherence. We tested the effect of TMS on interhemispheric coherence during rest and active muscle contraction and compared coherence in stroke and older adults. We evaluated the relationships between interhemispheric coherence, paretic motor function, and the ipsilateral cortical silent period (iSP). Methods. Participants with (n = 19) and without (n = 14) chronic stroke either rested or maintained a contraction of the ipsilateral hand muscle during simultaneous recordings of evoked responses to TMS of the ipsilesional/nondominant (i/ndM1) and contralesional/dominant (c/dM1) primary motor cortex with EEG and in the hand muscle with EMG. We calculated pre- and post-TMS interhemispheric beta coherence (15-30 Hz) between motor areas in both conditions and the iSP duration during the active condition. Results. During active i/ndM1 TMS, interhemispheric coherence increased immediately following TMS in controls but not in stroke. Coherence during active cM1 TMS was greater than iM1 TMS in the stroke group. Coherence during active iM1 TMS was less in stroke participants and was negatively associated with measures of paretic arm motor function. Paretic iSP was longer compared with controls and negatively associated with clinical measures of manual dexterity. There was no relationship between coherence and. iSP for either group. No within- or between-group differences in coherence were observed at rest. Conclusions. TMS-evoked cortical coherence during hand muscle activation can index interhemispheric interactions associated with poststroke motor function and potentially offer new insights into neural mechanisms influencing functional recovery.

Improving Geriatric Care Processes on Two Medical-Surgical Acute Care Units: A Pilot Study.

The Acute Care for Elders (ACE) Unit model improves cognitive and functional outcomes for hospitalized elders but reaches a small proportion of patients. To disseminate ACE Unit principles, we piloted the "Virtual ACE Intervention" that standardizes care processes for cognition and function without daily geriatrician oversight on two non-ACE units. The Virtual ACE Intervention includes staff training on geriatric assessments for cognition and function and on nurse-driven care algorithms. Completion of the geriatric assessments by nursing staff in patients aged 65 years and older and measures of patient mobility and prevalence of an abnormal delirium screening score were compared preintervention and postintervention. Postintervention, the completion of the assessments for current functional status and delirium improved (62.5% vs. 88.5%, p < .001) and (4.2% vs. 96.5%, p < .001). In a subsample analysis, in the postintervention period, more patients were up to the chair in the past day (36.4% vs. 63.5%, p = .04) and the prevalence of an abnormal delirium screening score was lower (13.6% vs. 4.8%, p = .16). The Virtual ACE Intervention is a feasible model for disseminating ACE Unit principles to non-ACE Units and may lead to increased adherence to care processes and improved clinical outcomes.

Abnormal EEG Responses to TMS During the Cortical Silent Period Are Associated With Hand Function in Chronic Stroke.

BACKGROUND: Abnormal brain excitability influences recovery after stroke at which time a prolonged transcranial magnetic stimulation (TMS)-induced electromyographic silent period is thought to reflect abnormal inhibitory interneuron excitability. Cortical excitability can be probed directly during the silent period using concurrent electroencephalography (EEG) of TMS-evoked responses. OBJECTIVE: The primary study objectives were to characterize TMS-evoked cortical potentials (TEPs) using EEG and to investigate associations with persistent hand and arm motor dysfunction in individuals with chronic stroke. METHODS: Thirteen participants with chronic stroke-related mild-moderate arm motor impairment and 12 matched controls completed a single TMS-EEG cortical excitability assessment. TEPs recorded from the vertex during cortical silent period (CSP) assessment and while at rest were used to evaluate differences in cortical excitability between stroke and control participants. Associations between TEPs and CSP duration with measures of upper extremity motor behavior were investigated. RESULTS: Significantly increased TEP component peak amplitudes and delayed latencies were observed for stroke participants compared with controls during CSP assessment and while at rest. Delayed early TEP component (P30) peak latencies during CSP assessment were associated with less manual dexterity. CSP duration was prolonged in stroke participants, and correlated with P30 peak latency and paretic arm dysfunction. CONCLUSIONS: Abnormal cortical excitability directly measured by early TMS-evoked EEG responses during CSP assessment suggests abnormal cortical inhibition is associated with hand dysfunction in chronic stroke. Further investigation of abnormal cortical inhibition in specific brain networks is necessary to characterize the salient neurophysiologic mechanisms contributing to persistent motor dysfunction after stroke.