Maladaptation of dentate gyrus mossy cells mediates contextual discrimination deficit after traumatic stress.

Fear overgeneralization is a maladaptive response to traumatic stress that is associated with the inability to discriminate between threat and safety contexts, a hallmark feature of post-traumatic stress disorder (PTSD). However, the neural mechanisms underlying this deficit remain unclear. Here, we show that traumatic stress exposure impairs contextual discrimination between threat and safety contexts in the learned helplessness (LH) model. Mossy cells (MCs) in the dorsal hippocampus are suppressed in response to traumatic stress. Bidirectional manipulation of MC activity in the LH model reveals that MC inhibition is causally linked to impaired contextual discrimination. Mechanistically, MC inhibition increases the number of active granule cells in a given context, significantly overlapping context-specific ensembles. Our study demonstrates that maladaptive inhibition of MCs after traumatic stress is a substantial mechanism underlying fear overgeneralization with contextual discrimination deficit, suggesting a potential therapeutic target for cognitive symptoms of PTSD.

Performance of angle shear connectors for U-shaped steel concrete infilled composite beams.

The current design codes i.e. AISC 360-16, CSA-S16-19, EC-04 etc. provide empirical relationships to estimate the capacity of shear connectors which were developed based on pushout tests of headed studs and channels connectors in exposed type sections. Therefore, these equations may result inaccurate predictions for strength of connectors in infilled-type sections. This study presents a detailed experimental study investigating the performance of angle connectors in composite sections. The testing program consisted two series of pushout tests. A total of 36 specimens were tested, considering the influence of several important parameters i.e. the length (Lc), height (hc), and web-thickness (tw) of angle connector, length of the weld (w) and the direction of shear connector (forward/backward) etc. The tests results demonstrated that with increasing connector height hs, and thickness, the maximum load Pmax and slip δu were increased. The connector direction didn't change much the load-slip behavior. The prediction accuracy of the existing shear capacity models was evaluated by comparing the predictions with experimental results. The current equations were noticed to be highly inconsistent in predicting the shear capacity of angle connectors, especially in case of infilled type sections. When the entire length of connector was taken as the effective length, the models overestimated the shear capacity. While in case when the welding length was taken as effective length in calculations, the models underestimated the shear strength of angle connectors.

Two cases of baclofen-induced encephalopathy in hemodialysis and peritoneal dialysis patients.

Hiccups are a spasmodic contraction of the diaphragm and usually transient phenomenon that affects nearly everyone. When hiccups develop, the patients are administrated antispastic agent, such as baclofen. Baclofen is widely used for the treatment of this spastic movement disorders. Also, baclofen is a gamma-aminobutyric acid (GABA) derivative that induces presynaptic motor neuron inhibition and produces a central antispastic response. Baclofen toxicity is rare and has been reported with intrathecal pump and orally administered baclofen, particularly in patients with poor renal function. Herein, we report two cases of encephalopathy in hemodialysis and peritoneal dialysis patients who received low doses of baclofen for persistent hiccups.

Outcomes of patients with end-stage renal disease (ESRD) under chronic hemodialysis requiring continuous renal replacement therapy (CRRT) and patients without ESRD in acute kidney injury requiring CRRT: a single-center study.

In most continuous renal replacement therapy (CRRT) studies, end-stage renal disease (ESRD) patients were excluded and the outcomes of patients with ESRD treated with chronic hemodialysis (HD) were unknown. The purposes of this study were to (1) evaluate short-term patient survival and (2) compare the survival of conventional HD patients needing CRRT with the survival of non-ESRD patients in acute kidney injury (AKI) requiring CRRT. We evaluated adults (>18 years) requiring CRRT who were treated in the intensive care unit (ICU) at Kosin University Gospel Hospital from January 1, 2009 to December 31, 2010. A total of 100 (24 ESRD, 76 non-ESRD) patients underwent CRRT during the study period. Patients were divided into two major groups: patients with ESRD requiring chronic dialysis and patients without ESRD (non-ESRD) with AKI. We compared the survival of conventional HD patients requiring CRRT with the survival of non-ESRD patients in AKI requiring CRRT. For non-ESRD patients, the 90-day survival rate was 41.6%. For ESRD patients, the 90-day survival rate was 55.3%. Multivariate Cox proportional hazards analyses demonstrated that conventional HD was not a significant predictor of mortality (hazard ratio [HR]: 0.334, 95% confidence interval [CI]: 0.063-1.763, P = 0.196), after adjustment for age, gender, presence of sepsis, APACHE score, use of vasoactive drugs, number of organ failures, ultrafiltration rate, and arterial pH. The survival rates of non-ESRD and ESRD patients requiring CRRT did not differ; ESRD with conventional HD patients may be not a significant predictor of mortality.