Arginine: at the crossroads of nitrogen metabolism.

L-arginine is the most nitrogen-rich amino acid, acting as a key precursor for the synthesis of nitrogen-containing metabolites and an essential intermediate in the clearance of excess nitrogen. Arginine's side chain possesses a guanidino group which has unique biochemical properties, and plays a primary role in nitrogen excretion (urea), cellular signaling (nitric oxide) and energy buffering (phosphocreatine). The post-translational modification of protein-incorporated arginine by guanidino-group methylation also contributes to epigenetic gene control.

Cellular ATP demand creates metabolically distinct subpopulations of mitochondria.

Mitochondria serve a crucial role in cell growth and proliferation by supporting both ATP synthesis and the production of macromolecular precursors. Whereas oxidative phosphorylation (OXPHOS) depends mainly on the oxidation of intermediates from the tricarboxylic acid cycle, the mitochondrial production of proline and ornithine relies on reductive synthesis. How these competing metabolic pathways take place in the same organelle is not clear.

Lactate activates the mitochondrial electron transport chain independently of its metabolism.

Lactate has long been considered a cellular waste product. However, we found that as extracellular lactate accumulates, it also enters the mitochondrial matrix and stimulates mitochondrial electron transport chain (ETC) activity. The resulting increase in mitochondrial ATP synthesis suppresses glycolysis and increases the utilization of pyruvate and/or alternative respiratory substrates.

Lactate activates the mitochondrial electron transport chain independent of its metabolism.

Lactate has long been considered a cellular waste product. However, we found that as extracellular lactate accumulates, it also enters the mitochondrial matrix and stimulates mitochondrial electron transport chain (ETC) activity. The resulting increase in mitochondrial ATP synthesis suppresses glycolysis and increases the utilization of pyruvate and/or alternative respiratory substrates.

The multiple links between actin and mitochondria.

Actin plays many well-known roles in cells, and understanding any specific role is often confounded by the overlap of multiple actin-based structures in space and time. Here, we review our rapidly expanding understanding of actin in mitochondrial biology, where actin plays multiple distinct roles, exemplifying the versatility of actin and its functions in cell biology. One well-studied role of actin in mitochondrial biology is its role in mitochondrial fission, where actin polymerization from the endoplasmic reticulum through the formin INF2 has been shown to stimulate two distinct steps.

Mitochondrial dysfunction triggers actin polymerization necessary for rapid glycolytic activation.

Mitochondrial damage represents a dramatic change in cellular homeostasis. One rapid response is perimitochondrial actin polymerization, termed acute damage-induced actin (ADA). The consequences of ADA are not understood.

Parallel kinase pathways stimulate actin polymerization at depolarized mitochondria.

Mitochondrial damage (MtD) represents a dramatic change in cellular homeostasis, necessitating metabolic changes and stimulating mitophagy. One rapid response to MtD is a rapid peri-mitochondrial actin polymerization termed ADA (acute damage-induced actin). The activation mechanism for ADA is unknown.

Ultrasound-guided platelet-rich plasma injections for post-traumatic greater occipital neuralgia: study protocol for a pilot randomized controlled trial.

Background: Post-traumatic headaches (PTH) are a common sequelae of traumatic brain injury (TBI) and greatly impact patient function and quality of life. Post-traumatic greater occipital neuralgia (GON) is a type of post-traumatic headache. Conventional treatment includes steroid/anesthetic injections which typically alleviate pain but have a short duration of effect.

Characterizing Physical Activity and Sedentary Behavior in Adults With Persistent Postconcussive Symptoms After Mild Traumatic Brain Injury.

Objective: To evaluate physical activity (PA) and sedentary behavior and their associations with symptom and quality of life outcomes in adults with persistent postconcussive symptoms (PPCS) after mild traumatic brain injury (mTBI).

Design: Cross-sectional cohort study.

Setting: Outpatient brain injury clinic.

Growth hormone deficiency testing and treatment following mild traumatic brain injury.

Pituitary dysfunction, specifically growth hormone (GH) deficiency, can occur following traumatic brain injury. Our objective was to characterize the prevalence of GH deficiency (GHD) testing and response to recombinant human GH (rhGH) treatment in adults with persistent symptoms following mild traumatic brain injury (mTBI) referred for assessment of pituitary dysfunction. A retrospective chart review was conducted of patients seen at an outpatient brain injury clinic with a diagnosis of mTBI and persistent post-concussive symptoms who were referred to endocrinology.

Improving symptom burden in adults with persistent post-concussive symptoms: a randomized aerobic exercise trial protocol.

Background: Persistent post-concussive symptoms (PPCS) affect up to 30% of individuals following mild traumatic brain injury. PPCS frequently includes exercise intolerance. Sub-symptom threshold aerobic exercise has been proposed as a treatment option for symptom burden and exercise intolerance in this population.

Regulation of INF2-mediated actin polymerization through site-specific lysine acetylation of actin itself.

INF2 is a formin protein that accelerates actin polymerization. A common mechanism for formin regulation is autoinhibition, through interaction between the N-terminal diaphanous inhibitory domain (DID) and C-terminal diaphanous autoregulatory domain (DAD). We recently showed that INF2 uses a variant of this mechanism that we term "facilitated autoinhibition," whereby a complex consisting of cyclase-associated protein (CAP) bound to lysine-acetylated actin (KAc-actin) is required for INF2 inhibition, in a manner requiring INF2-DID.

Two distinct actin filament populations have effects on mitochondria, with differences in stimuli and assembly factors.

Recent studies show that mitochondria and actin filaments work together in two contexts: (1) increased cytoplasmic calcium induces cytoplasmic actin polymerization that stimulates mitochondrial fission and (2) mitochondrial depolarization causes actin assembly around mitochondria, with roles in mitophagy. It is unclear whether these two processes utilize similar actin assembly mechanisms. Here, we show that these are distinct actin assembly mechanisms in the acute phase after treatment (<10 min).

A complex containing lysine-acetylated actin inhibits the formin INF2.

Inverted formin 2 (INF2) is a member of the formin family of actin assembly factors. Dominant missense mutations in INF2 are linked to two diseases: focal segmental glomerulosclerosis, a kidney disease, and Charcot-Marie-Tooth disease, a neuropathy. All of the disease mutations map to the autoinhibitory diaphanous inhibitory domain.

Arab female and male perceptions of factors facilitating and inhibiting their physical activity: Findings from a qualitative study in the Middle East.

Objectives: Physical inactivity is a leading global risk to health by contributing to obesity and other chronic diseases. Many chronic non-communicable diseases, such as cancer, diabetes, and cardiovascular diseases (CVDs), can be prevented and controlled by modifying lifestyle behaviors such as physical activity [PA]. However, prevalence of insufficient physical activity and obesity is high in the Middle East Region.

The Effects of Exercise on Physical and Psychological Outcomes in Cancer Caregivers: Results From the RECHARGE Randomized Controlled Trial.

Background: Family caregivers to cancer patients are at risk for physical and psychological morbidity as a direct result of being in the caregiver role. Exercise as an intervention to support caregiver health and well-being has been tested in other caregiver populations; however, no randomized controlled trials testing the effects of an aerobic and resistance training program have been conducted where cancer caregivers only have participated.

Purpose: To examine the effects of a 12-week exercise program on quality of life (Short Form 36 v2), psychological outcomes, physical activity levels, and physical fitness in caregivers to cancer patients.

Fostering active living and healthy eating through understanding physical activity and dietary behaviours of Arabic-speaking adults: a cross-sectional study from the Middle East.

Objectives: Physical inactivity and unhealthy diets increase the risk for diabetes, cardiovascular diseases and cancer. Many people in Qatar are sedentary and consume diets high in fats, salt and sugar. The purpose of this study was to determine physical activity levels, food habits and understand the variables that might predict physical activity and healthy eating behaviours among Arabic-speaking adults living in the State of Qatar.

Perceptions of masculinity and body image in men with prostate cancer: the role of exercise.

Purpose: The goal of this study was to explore the association between levels of exercise and patterns of masculinity, body image, and quality of life in men undergoing diverse treatment protocols for prostate cancer.

Methods: Fifty men with prostate cancer (aged 42-86) completed self-report measures. Self-reported measures included the following: the Godin Leisure Time Exercise Questionnaire (GLTEQ), Masculine Self-esteem Scale (MSES), Personal Attributes Questionnaire (PAQ), Body Image Scale (BIS), and the Functional Assessment of Cancer Therapy-Prostate (FACT-P).

Comparison of Polar M600 Optical Heart Rate and ECG Heart Rate during Exercise.

Purpose: The purpose of this study was to evaluate the accuracy of the Polar M600 optical heart rate (OHR) sensor compared with ECG heart rate (HR) measurement during various physical activities.

Methods: Thirty-six subjects participated in a continuous 76-min testing session, which included rest, cycling warm-up, cycling intervals, circuit weight training, treadmill intervals, and recovery. HR was measured using a three-lead ECG configuration and a Polar M600 Sport Watch on the left wrist.

Dietary Intake and Associated Body Weight in Canadian Undergraduate Students Enrolled in Nutrition Education.

The primary purpose of this study was to describe dietary intakes among Canadian undergraduate students enrolled in an Introductory Nutrition course. A secondary objective was to determine food group servings associated with meeting more Dietary Reference Intakes (DRIs) of select nutrients and with a lower body mass index (BMI). Participants (n = 124, 20.

Patient-reported outcomes, body composition, and nutrition status in patients with head and neck cancer: Results from an exploratory randomized controlled exercise trial.

Background: Patients with head and neck cancer experience loss of weight and muscle mass, decreased functioning, malnutrition, depression, and declines in quality of life during and after treatment. The purpose of this exploratory randomized study was to determine the optimal timing for the initiation of a lifestyle and progressive resistance exercise training intervention (during or after radiation therapy), as determined by intervention adherence and by comparing between-group outcomes across 24 weeks.

Methods: Sixty patients with head and neck cancer were randomized to engage in a 12-week lifestyle intervention and progressive resistance-training program either during radiation treatment or immediately after completion.

A Simple and Facile Approach to Aliphatic N-Substituted Functional Eight-Membered Cyclic Carbonates and Their Organocatalytic Polymerization.

Aliphatic N-substituted functional eight-membered cyclic carbonates were synthesized from N-substituted diethanolamines by intramolecular cyclization. On the basis of the N-substituent, three major subclasses of carbonate monomers were synthesized (N-aryl, N-alkyl and N-carbamate). Organocatalytic ring opening polymerization (ROP) of eight-membered cyclic carbonates was explored as a route to access narrowly dispersed polymers of predictable molecular weights.