CD248/Endosialin is dynamically expressed on a subset of stromal cells during lymphoid tissue development, splenic remodeling and repair

Studies of stromal cell populations in lymphoid tissue (LT) have been hampered by a lack of selective markers. Here, we show that CD248 (Endosialin/TEM1) is a stromal marker that is differentially expressed on fibroblasts and pericytes in the thymus, lymph node and spleen. Expression is high during LT development but largely disappears in the adult. CD248 is re-expressed in a Salmonella-induced model of splenic enlargement; peak expression corresponding to the peak of splenic enlargement. These results suggest that CD248 expression helps define a subset of LT stromal cells which play a role in remodelling during tissue development, infection and repair.     

Biology and ecology of Nezumia liolepis and N. stelgidolepis from the west coast of North America

Nezumia liolepis and Nezumia stelgidolepis were collected during a National Marine Fisheries Service 1997 groundfish survey along the Pacific coast of North America. Bottom trawling was conducted from 188 to 1260 m depths. Nezumia liolepis were collected from 581 to 1247 m (3·4–5·7°C) and N. stelgidolepis from 285 to 555 m (6·0–8·4°C). The two species had distinct depth and temperature distributions and the majority of the specimens for each species came from narrow depth ranges. Nezumia stelgidolepis attains a larger pre-anal fin length (117 mm) than N. liolepis (83 mm), and age estimates from otolith ring counts indicate ages from 3 to 9 years for N. liolepis and 7 and 13 years for N. stelgidolepis from specimens collected. The gonads of N. liolepis were not reproductively active, and a single N. stelgidolepis possessed eggs of various sizes suggesting batch spawning. N. liolepis and N. stelgidolepis fed benthically, primarily on crustaceans such as amphipods, shrimp, mysids and polychaete worms. Although diet overlap was high, these two species appear to limit competition for resources by habitat separation.     

Temperature extremes: geographic patterns,recent changes,and implications for organismal vulnerabilities

Extreme temperatures can injure or kill organisms and can drive evolutionary patterns. Many indices of extremes have been proposed, but few attempts have been made to establish geographic patterns of extremes and to evaluate whether they align with geographic patterns in biological vulnerability and diversity. To examine these issues, we adopt the CLIMDEX indices of thermal extremes. We compute scores for each index on a geographic grid during a baseline period (1961–1990) and separately for the recent period (1991–2010). Heat extremes (temperatures above the 90th percentile during the baseline period) have become substantially more common during the recent period, particularly in the tropics. Importantly, the various indices show weak geographic concordance, implying that organisms in different regions will face different forms of thermal stress. The magnitude of recent shifts in indices is largely uncorrelated with baseline scores in those indices, suggesting that organisms are likely to face novel thermal stresses. Organismal tolerances correlate roughly with absolute metrics (mainly for cold), but poorly with metrics defined relative to local conditions. Regions with high extreme scores do not correlate closely with regions with high species diversity, human population density, or agricultural production. Even though frequency and intensity of extreme temperature events have – and are likely to have – major impacts on organisms, the impacts are likely to be geographically and taxonomically idiosyncratic and difficult to predict.     

The Effect of Aerobic Exercise on Neuroplasticity within the Motor Cortex following Stroke

Background

Aerobic exercise is associated with enhanced plasticity in the motor cortex of healthy individuals, but the effect of aerobic exercise on neuroplasticity following a stroke is unknown.

Objective

The aim of this study was to compare corticomotoneuronal excitability and neuroplasticity in the upper limb cortical representation following a single session of low intensity lower limb cycling, or a rest control condition.

Methods

We recruited chronic stroke survivors to take part in three experimental conditions in a randomised, cross-over design. Corticomotoneuronal excitability was examined using transcranial magnetic stimulation to elicit motor evoked potentials in the affected first dorsal interosseus muscle. Following baseline measures, participants either cycled on a stationary bike at a low exercise intensity for 30 minutes, or remained resting in a seated position for 30 minutes. Neuroplasticity within the motor cortex was then examined using an intermittent theta burst stimulation (iTBS) paradigm. During the third experimental condition, participants cycled for the 30 minutes but did not receive any iTBS.

Results

Twelve participants completed the study. We found no significant effect of aerobic exercise on corticomotoneuronal excitability when compared to the no exercise condition (P > 0.05 for all group and time comparisons). The use of iTBS did not induce a neuroplastic-like response in the motor cortex with or without the addition of aerobic exercise.

Conclusions

Our results suggest that following a stroke, the brain may be less responsive to non-invasive brain stimulation paradigms that aim to induce short-term reorganisation, and aerobic exercise was unable to induce or improve this response.     

Neuromuscular Effects of Common Krait (Bungarus caeruleus) Envenoming in Sri Lanka

Objective

We aimed to investigate neurophysiological and clinical effects of common krait envenoming, including the time course and treatment response.

Methodology

Patients with definite common krait (Bungarus caeruleus) bites were recruited from a Sri Lankan hospital. All patients had serial neurological examinations and stimulated concentric needle single-fibre electromyography (sfEMG) of orbicularis oculi in hospital at 6wk and 6–9mth post-bite.

Principal Findings

There were 33 patients enrolled (median age 35y; 24 males). Eight did not develop neurotoxicity and had normal sfEMG. Eight had mild neurotoxicity with ptosis, normal sfEMG; six received antivenom and all recovered within 20–32h. Seventeen patients developed severe neurotoxicity with rapidly descending paralysis, from ptosis to complete ophthalmoplegia, facial, bulbar and neck weakness. All 17 received Indian polyvalent antivenom a median 3.5h post-bite (2.8–7.2h), which cleared unbound venom from blood. Despite this, the paralysis worsened requiring intubation and ventilation within 7h post-bite. sfEMG showed markedly increased jitter and neuromuscular blocks within 12h. sfEMG abnormalities gradually improved over 24h, corresponding with clinical recovery. Muscle recovery occurred in ascending order. Myotoxicity was not evident, clinically or biochemically, in any of the patients. Patients were extubated a median 96h post-bite (54–216h). On discharge, median 8 days (4–12days) post-bite, patients were clinically normal but had mild sfEMG abnormalities which persisted at 6wk post-bite. There were no clinical or neurophysiological abnormalities at 6–9mth.

Conclusions

Common krait envenoming causes rapid onset severe neuromuscular paralysis which takes days to recover clinically consistent with sfEMG. Subclinical neuromuscular dysfunction lasts weeks but was not permanent. Antivenom effectively cleared venom but did not prevent worsening or reverse neuromuscular paralysis.