Neuron-Based Heredity and Human Evolution

It is widely recognized that human evolution has been driven by two systems of heredity: one DNA-based and the other based on the transmission of behaviorally acquired information via nervous system functions. The genetic system is ancient, going back to the appearance of life on Earth. It is responsible for the evolutionary processes described by Darwin. By comparison, the nervous system is relatively newly minted and in its highest form, responsible for ideation and mind-to-mind transmission of information. Here the informational capabilities and functions of the two systems are compared. While employing quite different mechanisms for encoding, storing and transmission of information, both systems perform these generic hereditary functions. Three additional features of neuron-based heredity in humans are identified: the ability to transfer hereditary information to other members of their population, not just progeny; a selection process for the information being transferred; and a profoundly shorter time span for creation and dissemination of survival-enhancing information in a population. The mechanisms underlying neuron-based heredity involve hippocampal neurogenesis and memory and learning processes modifying and creating new neural assemblages changing brain structure and functions. A fundamental process in rewiring brain circuitry is through increased neural activity (use) strengthening and increasing the number of synaptic connections. Decreased activity in circuitry (disuse) leads to loss of synapses. Use and disuse modifying an organ to bring about new modes of living, habits and functions are processes in line with Neolamarckian concepts of evolution (Packard, 1901). Evidence is presented of bipartite evolutionary processes-Darwinian and Neolamarckian-driving human descent from a common ancestor shared with the great apes

Distal Insertional Footprint of the Brachialis Muscle: 3D Morphometric Study

Objective. The purpose of this study is to describe the three-dimensional morphometry of the brachialis muscle at its distal attachment to the ulna. Methods. Fifty cadaveric elbows were dissected and the brachialis distal insertion was isolated on the ulna bone and probed with a three-dimensional digitizer, to create a three-dimensional model of the footprint. Measurements and analysis of each footprint shape were recorded and compared based on gender and size. Results. There was significant gender difference in the surface length (P = 0.002) and projected length (P = 0.001) of the brachialis footprint. The shapes of the footprint also differed among the specimens. Conclusion. The shape of the brachialis muscle insertion differed among all the specimens without significant variation in gender or sides. There was also a significant difference in muscle length between males and females with little difference in the width and surface area. Significance. The information obtained from this study is important for kinematic understanding and surgical procedures around the elbow joint as well as the understanding of the natural age related anatomy of the brachialis footprint morphology

Caudal Vertebral Body Articular Surface Morphology Correlates with Functional Tail Use in Anthropoid Primates

Prehensile tails, capable of suspending the entire body weight of an animal, have evolved in parallel in New World monkeys (Platyrrhini): once in the Atelinae (Alouatta, Ateles, Brachyteles, Lagothrix), and once in the Cebinae (Cebus, Sapajus). Structurally, the prehensile tails of atelines and cebines share morphological features that distinguish them from non-prehensile tails, including longer proximal tail regions, well-developed hemal processes, robust caudal vertebrae resistant to higher torsional and bending stresses, and caudal musculature capable of producing higher contractile forces. The functional significance of shape variation in the articular surfaces of caudal vertebral bodies, however, is relatively less well understood. Given that tail use differs considerably among prehensile and non-prehensile anthropoids, it is reasonable to predict that caudal vertebral body articular surface area and shape will respond to use-specific patterns of mechanical loading. We examine the potential for intervertebral articular surface contour curvature and relative surface area to discriminate between prehensile- and nonprehensile-tailed platyrrhines and cercopithecoids. The proximal and distal intervertebral articular surfaces of the first (Ca1), transitional (TV) and longest (LV) caudal vertebrae were examined for individuals representing 10 anthropoid taxa with differential patterns of tail-use. Study results reveal significant morphological differences consistent with the functional demands of unique patterns of tail use for all vertebral elements sampled. Prehensile-tailed platyrrhines that more frequently use their tails in suspension (atelines) had significantly larger and more convex intervertebral articular surfaces than all nonprehensile-tailed anthropoids examined here, although the intervertebral articular surface contour curvatures of large, terrestrial cercopithecoids (i.e. Papio) converge on the ateline condition. Prehensile-tailed platyrrhines that more often use their tails in tripodal bracing postures (cebines) are morphologically intermediate between atelines and nonprehensile tailed anthropoids.The authors would like to thank Bill Stanley, the Field Museum and the University of Texas at Austin for access to specimens and curatorial assistance as well as the Louisville Zoo and Dr. Roy Burns for their generous donation of Lagothrix lagotricha cadavers. Thanks also to Matthew Tocheri for access to curve fitting software and technical guidance, John Kappelman for the use of his desktop laser scanner and Brett Nachman for technical assistance

Comparisons between intragastric and small intestinal delivery of enteral nutrition in the critically ill: a systematic review and meta-analysis

INTRODUCTION: The largest cohort of critically ill patients evaluating intragastric and small intestinal delivery of nutrients was recently reported. This systematic review included recent data to compare the effects of small bowel and intragastric delivery of enteral nutrients in adult critically ill patients. METHODS: This is a systematic review of all randomised controlled studies published between 1990 and March 2013 that reported the effects of the route of enteral feeding in the critically ill on clinically important outcomes. RESULTS: Data from 15 level-2 studies were included. Small bowel feeding was associated with a reduced risk of pneumonia (Relative Risk, RR, small intestinal vs. intragastric: 0.75 (95% confidence interval 0.60 to 0.93); P = 0.01; I(2 )= 11%). The point estimate was similar when only studies using microbiological data were included. Duration of ventilation (weighted mean difference: -0.36 days (-2.02 to 1.30); P = 0.65; I(2 )= 42%), length of ICU stay (WMD: 0.49 days, (-1.36 to 2.33); P = 0.60; I(2 )= 81%) and mortality (RR 1.01 (0.83 to 1.24); P = 0.92; I(2 )= 0%) were unaffected by the route of feeding. While data were limited, and there was substantial statistical heterogeneity, there was significantly improved nutrient intake via the small intestinal route (% goal rate received: 11% (5 to 16%); P = 0.0004; I(2 )= 88%). CONCLUSIONS: Use of small intestinal feeding may improve nutritional intake and reduce the incidence of ICU-acquired pneumonia. In unselected critically ill patients other clinically important outcomes were unaffected by the site of the feeding tube

Stimulation of the tibial nerve: a protocol for a multicentred randomised controlled trial for urinary problems associated with Parkinson’s disease—STARTUP

Introduction Parkinson’s disease is the second most common chronic neurodegenerative condition with bladder dysfunction affecting up to 71%. Symptoms affect quality of life and include urgency, frequency, hesitancy, nocturia and incontinence. Addressing urinary dysfunction is one of the top 10 priority research areas identified by the James Lind Alliance and Parkinson’s UK. Objectives Conduct a randomised controlled trial (RCT) targeting people with Parkinson’s disease (PwP) who have self-reported problematic lower urinary tract symptoms, investigating the effectiveness of transcutaneous tibial nerve stimulation (TTNS) compared with sham TTNS. Implement a standardised training approach and package for the correct application of TTNS. Conduct a cost-effectiveness analysis of TTNS compared with sham TTNS. Methods and analysis An RCT of 6 weeks with twice weekly TTNS or sham TTNS. Participants will be recruited in 12 National Health Service neurology/movement disorder services, using a web-based randomisation system, and will be shown how to apply TTNS or sham TTNS. Participants will receive a weekly telephone call from the researchers during the intervention period. The trial has two coprimary outcome measures: International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form and the International Prostate Symptom Score. Secondary outcomes include a 3-day bladder diary, quality of life, acceptability and fidelity and health economic evaluation. Outcomes will be measured at 0, 6 and 12 weeks. A sample size of 208 randomised in equal numbers to the two arms will provide 90% power to detect a clinically important difference of 2.52 points on the Internatioanl Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF) and of 3 points in the International Prostate Symptom Score total score at 12 weeks at 5% significance level, based on an SD of 4.7 in each arm and 20% attrition at 6 weeks. Analysis will be by intention to treat and pre defined in a statistical analysis plan Ethics and dissemination East of Scotland Research Ethics Service (EoSRES), 18/ES00042, obtained on 10 May 2018. The trial will allow us to determine effectiveness, safety, cost and acceptability of TTNS for bladder dysfunction in PWP. Results will be published in open access journals; lay reports will be posted to all participants and presented at conferences. Trial registration number ISRCTN12437878; Pre-results

Viewing pre‐lab gross anatomy demonstration videos correlates positively with student performance when total dissection time is limited by Covid‐19 restrictions

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Posterior interosseous nerve localization within the proximal forearm - a patient normalized parameter

AIM To provide a “patient-normalized” parameter in the proximal forearm. METHODS Sixty-three cadaveric upper extremities from thirty-five cadavers were studied. A muscle splitting approach was utilized to locate the posterior interosseous nerve (PIN) at the point where it emerges from beneath the supinator. The supinator was carefully incised to expose the midpoint length of the nerve as it passes into the forearm while preserving the associated fascial connections, thereby preserving the relationship of the nerve with the muscle. We measured the transepicondylar distance (TED), PIN distance in the forearm’s neutral rotation position, pronation position, supination position, and the nerve width. Two individuals performed measurements using a digital caliper with inter-observer and intra-observer blinding. The results were analyzed with the Wilcoxon-Mann-Whitney test for paired samples. RESULTS In pronation, the PIN was within two confidence intervals of 1.0 TED in 95% of cases (range 0.7-1.3 TED); in neutral, within two confidence intervals of 0.84 TED in 95% of cases (range 0.5-1.1 TED); in supination, within two confidence intervals of 0.72 TED in 95% of cases (range 0.5-0.9 TED). The mean PIN distance from the lateral epicondyle was 100% of TED in a pronated forearm, 84% in neutral, and 72% in supination. Predictive accuracy was highest in supination; in all cases the majority of specimens (90.47%-95.23%) are within 2 cm of the forearm position-specific percentage of TED. When comparing right to left sides for TEDs with the signed Wilcoxon-Mann-Whitney test for paired samples as well as a significance test (with normal distribution), the P-value was 0.0357 (significance - 0.05) indicating a significant difference between the two sides. CONCLUSION This “patient normalized” parameter localizes the PIN crossing a line drawn between the lateral epicondyle and the radial styloid. Accurate PIN localization will aid in diagnosis, injections, and surgical approaches

Inner Synovial Membrane Footprint of the Anterior Elbow Capsule: An Arthroscopic Boundary

Introduction. The purpose of this study is to describe the inner synovial membrane (SM) of the anterior elbow capsule, both qualitatively and quantitatively. Materials and Methods. Twenty-two cadaveric human elbows were dissected and the distal humerus and SM attachments were digitized using a digitizer. The transepicondylar line (TEL) was used as the primary descriptor of various landmarks. The distance between the medial epicondyle and medial SM edge, SM apex overlying the coronoid fossa, the central SM nadir, and the apex of the SM insertion overlying the radial fossa and distance from the lateral epicondyle to lateral SM edge along the TEL were measured and further analyzed. Gender and side-to-side statistical comparisons were calculated. Results. The mean age of the subjects was 80.4 years, with six male and five female cadavers. The SM had a distinctive double arched attachment overlying the radial and coronoid fossae. No gender-based or side-to-side quantitative differences were noted. In 18 out of 22 specimens (81.8%), an infolding extension of the SM was observed overlying the medial aspect of the trochlea. The SM did not coincide with the outer fibrous attachment in any specimen. Conclusion. The humeral footprint of the synovial membrane of the anterior elbow capsule is more complex and not as capacious as commonly understood from the current literature. The synovial membrane nadir between the two anterior fossae may help to explain and hence preempt technical difficulties, a reduction in working arthroscopic volume in inflammatory and posttraumatic pathologies. This knowledge should allow the surgeon to approach this aspect of the anterior elbow compartment space with the confidence that detachment of this synovial attachment, to create working space, does not equate to breaching the capsule. Alternatively, stripping the synovial attachment from the anterior humerus does not constitute an anterior capsular release