The GLUT4 glucose transporter resides mostly in perinuclear membranes in unstimulated 3T3-L1 adipocytes and is acutely translocated to the cell surface in response to insulin. Using a novel method to purify intracellular GLUT4-enriched membranes, we identified by mass spectrometry the intermediate filament protein vimentin and the microtubule protein ␣-tubulin as components of these membranes. Immunoelectron microscopy of the GLUT4-containing membranes also revealed their association with these cytoskeletal proteins. Disruption of intermediate filaments and microtubules in 3T3-L1 adipocytes by microinjection of a vimentinderived peptide of the helix initiation 1A domain caused marked dispersion of perinuclear GLUT4 to peripheral regions of the cells. Inhibition of the microtubule-based motor dynein by brief cytoplasmic acidification of cultured adipocytes also dispersed perinuclear GLUT4 and inhibited insulin-stimulated GLUT4 translocation to the cell surface. Insulin sensitivity was restored as GLUT4 was again concentrated near the nucleus upon recovery of cells in physiological buffer. These data suggest that GLUT4 trafficking to perinuclear membranes of cultured adipocytes is directed by dynein and is required for optimal GLUT4 regulation by insulin.Insulin regulates the cellular uptake of glucose in adipose tissue and muscle by acutely controlling the number of glucose transport proteins present in the cell surface membrane (1-4). The major insulin-responsive sugar transporter, GLUT4, recycles in endosomal and exocytic membranes of these cells (5-7) and is mostly sequestered within intracellular membranes in the unstimulated state (8 -10). Insulin acts primarily by enhancing the exocytosis of GLUT4, but the hormone also appears to inhibit endocytosis as well (5-7). Recent studies have revealed that the insulin-regulated intracellular membranes containing GLUT4 are specialized and appear to exclude some other cycling proteins such as the transferrin receptor and the GLUT1 glucose transporter (11, 12). These latter proteins are present at the cell surface in higher abundance than GLUT4 in unstimulated cells and move through a rapid constitutive endosomal recycling pathway (13, 14). Complicating our understanding of the interrelationships between these trafficking systems are findings suggesting that GLUT4 also partially co-localizes with endosomal membranes containing the transferrin receptor and GLUT1 (12,15,16). Because normal glucose homeostasis in humans is dependent upon the dynamics of GLUT4 membrane trafficking, intensive efforts have been directed at understanding the basis for the unique recycling characteristics and regulation of GLUT4.Isolation of the intracellular membranes of adipocytes and muscle that are enriched in GLUT4 has been achieved using immunoadsorption procedures with immobilized antibodies raised against GLUT4 (17, 18). These membranes are likely a mixture of endosomal membrane fractions as well as the specialized insulin-responsive membranes. Many proteins that reside in the intracel...

Study Design Qualitative study to identify themes and explore mechanisms underlying recovery of hand function post stroke for individuals discharged from rehabilitation services. Purpose of the Study Post-stroke hemiparesis frequently results in persistent hand dysfunction; the mechanisms of functional recovery are however poorly understood. We assessed the perspectives of community-dwelling patients with chronic stroke on their hand function limitations and recovery to explore the feasibility of developing a theoretical framework for understanding the process of continued post-stroke recovery. Methods Eight patients with chronic post-stroke hemiparesis were interviewed and videotaped while they performed a battery of 20 upper limb tasks. Qualitative analysis consisted of two investigators independently reviewing the videotapes and reading the transcribed conversations, identifying significant issues and then comparing their observations to determine common themes and develop emerging concepts. Results Four core themes pertaining to impairment and recovery of task-specific ability emerged: 1) Spasticity can be overcome actively through task-specific attempts to use the affected arm and hand; 2) Use of the affected arm can be facilitated by adopting positions that reduce the effect of gravity on the arm or enable gravity to act as a natural assist in the movement; 3) Task-specific skill can be attained by repeatedly attempting specific component movements of tasks in the context of a variety of different tasks; and 4) Frustration impedes task performance but a mental state of ‘detached focus’ can improve the motivation to use the affected arm. Conclusions These themes suggest a therapeutic framework for continued upper limb rehabilitation in patients’ own environment to maximize functional recovery in patients long after their stroke, and generate hypotheses which may lead to the development of new therapeutic protocols.

Over the past decade, significant advances have been made in understanding concussions. Information regarding proper identification, pathophysiology, risks, outcomes, and management protocols has shifted the treatment paradigm from a generalized grading system to an individualized approach. Early identification and timely management of a concussion is necessary to ensure that patients minimize persistent post-concussive symptoms affecting the physical, behavioral, emotional, and cognitive domains. Adolescents are particularly vulnerable to concussions, having greater susceptibility and more prolonged recovery after sustaining an injury. This article aims to inform clinicians on how to improve symptom relief and functional outcomes for adolescent patients with concussion via immediate intervention, neuropsychological management, and pharmacological treatment.

Osteopathic cranial manipulative medicine was considered a safe adjunctive treatment option to improve concussion-related symptoms and recovery.

BackgroundTo determine whether osteopathic medical students, fellows, residents, and practicing physicians differ in their ability to identify inanimate objects and if these skills relate to palpatory experience.MethodsFifteen commonly known objects were fixed to a board and blinded with a cotton cloth. In Part I of testing, participants were asked to identify 9 objects, with choices provided. In Part II participants were asked to identify 6 objects using one word only. Part III consisted of identifying the shape of an object in Part II.ResultsEighty-nine osteopathic medical students, fellows, residents, and practicing physicians participated in the study. Overall, correct identification of objects was higher in Part I with choices than in Part II without choices available. No statistically significant difference was found among osteopathic medical students, fellows, residents, and practicing physicians in the correct identification of the objects.ConclusionsAccuracy in tactile identification of objects among varying levels of palpatory experience was not found. Correlation with clinical palpation cannot be made as it requires a subset of palpatory skills not tested in this study. Accuracy and measurement of palpation should be studied further to demonstrate if palpatory experience improves palpatory accuracy.

No abstract

The purpose of this study was to determine if a change in forward head posture and occipital extension occurred in participants who wore multifocal lenses vs. those persons with non-multifocal lenses while performing an 8-min visual reading task on a visual display unit (VDU). Forty-two healthy human participants were recruited for this study. Thirty-three participants completed the study. Fourteen participants wore multifocal lenses and 19 wore frames with non-multifocal lenses. To evaluate the degree of change of forward head posture and occipital extension digital photographs of cervical posture were taken at four different time intervals: prior to performing the reading task and at 3, 5 and 8 min during the reading task. The digital photographs were analysed utilizing a computer program. Two one-way ANOVA were utilized to determine the degree of change of forward head posture and occipital extension between groups. A significant difference was identified between groups for changes in degrees of forward head posture while performing a visual reading task on a VDU. However, no significant difference between groups was found for occipital extension while performing the same task. Multifocal wearers exhibit greater degrees of change in forward head posture and occipital extension than non-multifocal wearers. These postural changes may place them at a greater risk for musculoskeletal disorders and headaches.

Traumatic brain injuries that occur during sports have gained significant attention in the literature. Despite improved education and research on proper identification, risk management, and treatment, standardized methods for returning an athlete to play after a concussion are lacking in universal applicability. Current return-to-play guidelines are considered appropriate for the majority of athletes who recover within a few weeks. However, applicability of such guidelines becomes difficult when treating those athletes who experience prolonged symptoms or do not have the resources available to adequately manage complex presentations of concussions. Understanding the guidelines with consideration to special populations will assist the treating physician in providing an appropriate and individualized evaluation and treatment plan to safely return an athlete with a concussion back to play without compromising his or her health.