Periodicity of high-order functions in the CNS Final progress report, year ending 30 Jun. 1971

Analysis of cerebral slow potentials underlying human attentive processes in central nervous syste

Application of the speed-duration relationship to normalize the intensity of high-intensity interval training

The tolerable duration of continuous high-intensity exercise is determined by the hyperbolic Speed-tolerable duration (S-tLIM) relationship. However, application of the S-tLIM relationship to normalize the intensity of High-Intensity Interval Training (HIIT) has yet to be considered, with this the aim of present study. Subjects completed a ramp-incremental test, and series of 4 constant-speed tests to determine the S-tLIM relationship. A sub-group of subjects (n = 8) then repeated 4 min bouts of exercise at the speeds predicted to induce intolerance at 4 min (WR4), 6 min (WR6) and 8 min (WR8), interspersed with bouts of 4 min recovery, to the point of exercise intolerance (fixed WR HIIT) on different days, with the aim of establishing the work rate that could be sustained for 960 s (i.e. 4×4 min). A sub-group of subjects (n = 6) also completed 4 bouts of exercise interspersed with 4 min recovery, with each bout continued to the point of exercise intolerance (maximal HIIT) to determine the appropriate protocol for maximizing the amount of high-intensity work that can be completed during 4×4 min HIIT. For fixed WR HIIT tLIM of HIIT sessions was 399±81 s for WR4, 892±181 s for WR6 and 1517±346 s for WR8, with total exercise durations all significantly different from each other (P<0.050). For maximal HIIT, there was no difference in tLIM of each of the 4 bouts (Bout 1: 229±27 s; Bout 2: 262±37 s; Bout 3: 235±49 s; Bout 4: 235±53 s; P>0.050). However, there was significantly less high-intensity work completed during bouts 2 (153.5±40. 9 m), 3 (136.9±38.9 m), and 4 (136.7±39.3 m), compared with bout 1 (264.9±58.7 m; P>0.050). These data establish that WR6 provides the appropriate work rate to normalize the intensity of HIIT between subjects. Maximal HIIT provides a protocol which allows the relative contribution of the work rate profile to physiological adaptations to be considered during alternative intensity-matched HIIT protocols

Historical trends in survival of hospitalized heart failure patients: 2000 versus 1995

BACKGROUND: Population-based secular trends in survival of patients with congestive heart failure (CHF) are central to public health research on the burden of the syndrome. METHODS: Patients 35–79 years old with a CHF discharge code in 1995 or 2000 were identified in 22 Minneapolis-St. Paul hospitals. A sample of the records was abstracted (50% of 1995 records; 38% of 2000 records). A total of 2,257 patients in 1995 and 1,825 patients in 2000 were determined to have had a CHF-related hospitalization. Each patient was followed for one year to ascertain vital status. RESULTS: The risk profile of the 2000 patient cohort was somewhat worse than that of the 1995 cohort in both sex groups, but the distributions of age and left ventricular ejection fraction were similar. Within one year of admission in 2000, 28% of male patients and 27% of female patients have died, compared to 36% and 27% of their counterparts in 1995, respectively. In various Cox regression models the average year effect (2000 vs. 1995) was around 0.75 for men and 0.95 to 1.00 for women. The use of angiotensin converting-enzyme inhibitors and beta-blockers was associated with substantially lower hazard of death during the subsequent year. CONCLUSION: Survival of men who were hospitalized for CHF has improved during the second half of the 1990s. The trend in women was very weak, compatible with little to no change. Documented benefits of angiotensin converting-enzyme inhibitors and beta-blockers were evident in these observational data in both men and women

Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis

Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFα and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFα antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFα pathways. © 2012 Yi et al

Does time of surgery influence the rate of false-negative appendectomies?:A retrospective observational study of 274 patients

Background Multiple disciplines have described an “after-hours effect” relating to worsened mortality and morbidity outside regular working hours. This retrospective observational study aimed to evaluate whether diagnostic accuracy of a common surgical condition worsened after regular hours. Methods Electronic operative records for all non-infant patients (age > 4 years) operated on at a single centre for presumed acute appendicitis were retrospectively reviewed over a 56-month period (06/17/2012–02/01/2017). The primary outcome measure of unknown diagnosis was compared between those performed in regular hours (08:00–17:00) or off hours (17:01–07:59). Pre-clinical biochemistry and pre-morbid status were recorded to determine case heterogeneity between the two groups, along with secondary outcomes of length of stay and complication rate. Results Out of 289 procedures, 274 cases were deemed eligible for inclusion. Of the 133 performed in regular hours, 79% were appendicitis, compared to 74% of the 141 procedures performed off hours. The percentage of patients with an unknown diagnosis was 6% in regular hours compared to 15% off hours (RR 2.48; 95% CI 1.14–5.39). This was accompanied by increased numbers of registrars (residents in training) leading procedures off hours (37% compared to 24% in regular hours). Pre-morbid status, biochemistry, length of stay and post-operative complication rate showed no significant difference. Conclusions This retrospective study suggests that the rate of unknown diagnoses for acute appendicitis increases overnight, potentially reflecting increased numbers of unnecessary procedures being performed off hours due to poorer diagnostic accuracy. Reduced levels of staffing, availability of diagnostic modalities and changes to workforce training may explain this, but further prospective work is required. Potential solutions may include protocolizing the management of common acute surgical conditions and making more use of non-resident on call senior colleagues

Towards a conceptual framework demonstrating the effectiveness of audiovisual patient descriptions (patient video cases): a review of the current literature

Background: Technological advances have enabled the widespread use of video cases via web-streaming and online download as an educational medium. The use of real subjects to demonstrate acute pathology should aid the education of health care professionals. However, the methodology by which this effect may be tested is not clear. Methods: We undertook a literature review of major databases, found relevant articles relevant to using patient video cases as educational interventions, extracted the methodologies used and assessed these methods for internal and construct validity. Results: A review of 2532 abstracts revealed 23 studies meeting the inclusion criteria and a final review of 18 of relevance. Medical students were the most commonly studied group (10 articles) with a spread of learner satisfaction, knowledge and behaviour tested. Only two of the studies fulfilled defined criteria on achieving internal and construct validity. The heterogeneity of articles meant it was not possible to perform any meta-analysis. Conclusions: Previous studies have not well classified which facet of training or educational outcome the study is aiming to explore and had poor internal and construct validity. Future research should aim to validate a particular outcome measure, preferably by reproducing previous work rather than adopting new methods. In particular cognitive processing enhancement, demonstrated in a number of the medical student studies, should be tested at a postgraduate level

Systematic review of prognostic models in traumatic brain injury

BACKGROUND: Traumatic brain injury (TBI) is a leading cause of death and disability world-wide. The ability to accurately predict patient outcome after TBI has an important role in clinical practice and research. Prognostic models are statistical models that combine two or more items of patient data to predict clinical outcome. They may improve predictions in TBI patients. Multiple prognostic models for TBI have accumulated for decades but none of them is widely used in clinical practice. The objective of this systematic review is to critically assess existing prognostic models for TBI METHODS: Studies that combine at least two variables to predict any outcome in patients with TBI were searched in PUBMED and EMBASE. Two reviewers independently examined titles, abstracts and assessed whether each met the pre-defined inclusion criteria. RESULTS: A total of 53 reports including 102 models were identified. Almost half (47%) were derived from adult patients. Three quarters of the models included less than 500 patients. Most of the models (93%) were from high income countries populations. Logistic regression was the most common analytical strategy to derived models (47%). In relation to the quality of the derivation models (n:66), only 15% reported less than 10% pf loss to follow-up, 68% did not justify the rationale to include the predictors, 11% conducted an external validation and only 19% of the logistic models presented the results in a clinically user-friendly way CONCLUSION: Prognostic models are frequently published but they are developed from small samples of patients, their methodological quality is poor and they are rarely validated on external populations. Furthermore, they are not clinically practical as they are not presented to physicians in a user-friendly way. Finally because only a few are developed using populations from low and middle income countries, where most of trauma occurs, the generalizability to these setting is limited