glycogen and Hemolysis

Acclimatisation to environmental hypoxia initiates a series of metabolic and musculocardio-respiratory adaptations that influence oxygen transport and utilisation, or better still, being born and raised at altitude, is necessary to achieve optimal physical performance at altitude, scientific evidence to support the potentiating effects after return to sea level is at present equivocal. Despite this, elite athletes continue to spend considerable time and resources training at altitude, misled by subjective coaching opinion and the inconclusive findings of a large number of uncontrolled studies. Scientific investigation has focused on the optimisation of the theoretically beneficial aspects of altitude acclimatisation, which include increases in blood haemoglobin concentration, elevated buffering capacity, and improvements in the structural and biochemical properties of skeletal muscle. However, not all aspects of altitude acclimatisation are beneficial; cardiac output and blood flow to skeletal muscles decrease, and preliminary evidence has shown that hypoxia in itself is responsible for a depression of immune function and increased tissue damage mediated by oxidative stress. Future research needs to focus on these less beneficial aspects of altitude training, the implications of which pose a threat to both the fitness and the health of the elite competitor. Paul Bert was the first investigator to show that acclimatisation to a chronically reduced inspiratory partial pressure of oxygen (P1O2) invoked a series of central and peripheral adaptations that served to maintain adequate tissue oxygenation in healthy skeletal muscle, physiological adaptations that have been subsequently implicated in the improvement in exercise performance during altitude acclimatisation. However, it was not until half a century later that scientists suggested that the additive stimulus of environmental hypoxia could potentially compound the normal physiological adaptations to endurance training and accelerate performance improvements after return to sea level. This has stimulated an exponential increase in scientific research, and, since 1984, 22 major reviews have summarised the physiological implications of altitude training for both aerobic and anaerobic performance at altitude and after return to sea level. Of these reviews, only eight have specifically focused on physical performance changes after return to sea level, the most comprehensive of which was recently written by Wo

Topics: Acclimatization; Altitude; Altitude Sickness; Anaerobic Threshold; Arrhythmias, Cardiac; Buffers; Cardiac Output; Environment; Glycogen; Health Status; Heart; Hematopoiesis; Hemoglobins; Hemolysis; Humans; Hypoxia, Brain; Immune Tolerance; Muscle, Skeletal; Oxidative Stress; Oxygen; Oxygen Consumption; Partial Pressure; Physical Education and Training; Physical Endurance; Physical Fitness; Plasma Volume; Pulmonary Edema; Regional Blood Flow; Respiration; Respiratory Muscles; Sports; Work of Breathing

We developed acid-functionalized glycogen conjugates as supramolecular carriers for efficient encapsulation and inhibition of a model cationic peptide melittin─the main component of honeybee venom. For this purpose, we synthesized and characterized a set of glycogens, functionalized to various degrees by several different acid groups. These conjugates encapsulate melittin up to a certain threshold amount, beyond which they precipitate. Computer simulations showed that sufficiently functionalized conjugates electrostatically attract melittin, resulting in its efficient encapsulation in a broad pH range around the physiological pH. Hemolytic assays confirmed in vitro that the effective inhibition of melittin's hemolytic activity occurs for highly functionalized samples, whereas no inhibition is observed when using low-functionalized conjugates. It can be concluded that functional glycogens are promising carriers for cationic molecular cargos or antidotes against animal venoms under conditions, in which suitable properties such as biodegradability and biocompatibility are crucial.

Topics: Animals; Glycogen; Hemolysis; Melitten

Dendritic macromolecules are potential candidates for nanomedical application. Herein, glycogen, the natural hyperbranched polysaccharide with favorable biocompatibility, is explored as an effective drug vehicle for treating liver cancer. In this system, glycogen is oxidized and conjugated with cancer drugs through a disulfide link, followed by

Topics: Animals; Antineoplastic Agents; Carcinoma, Hepatocellular; Cell Line, Tumor; Combined Modality Therapy; Doxorubicin; Drug Liberation; Glycogen; Hemolysis; Humans; Hyperthermia, Induced; Infrared Rays; Liver Neoplasms; Mice, Inbred BALB C; Nanoparticles; Phospholipids; Photochemotherapy; Polymers; Pyrroles

Tilapia (Oreochromis nilotica L.) skin collagen is a meritorious commercial resource to be exploited. The purpose of this study was to obtain, evaluate, and characterize tilapia skin collagen-derived antioxidant hydrolysates (TSCP). AAPH-induced erythrocyte hemolysis assay and antifatigue test in mice were implemented. It was indicated that TSCP treatment at 1 mg mL-1 could effectively attenuate AAPH-induced erythrocyte hemolysis rate from 56.35 ± 2.46% to 18.78 ± 2.48% (p < 0.01). A 2.5 mg/(10 g d) dose of TSCP intragastric administration could observably prolong the exhaustive swimming time of the loaded mice and its mechanism was multiple, including the decrease in the levels of serum lactic acid, serum urea nitrogen, and creatine kinase activity, thus improving the contents of liver and muscle glycogen and endogenous SOD activity. Five oligopeptides from the antioxidant fraction were identified as Gly-Hyp, Glu-Asp, Asp-Hyp-Gly, Glu-Pro-Pro-Phe, and Lys-Pro-Phe-Gly-Ser-Gly-Ala-Thr and then synthesized. Among them, the octapeptide exhibited the strongest antioxidant capacity. Therefore, tilapia skin-derived collagen is a meritorious edible resource for producing commercial functional foods, thus helping to scavenge radicals, protecting erythrocytes, and further resisting fatigue.

Topics: Animals; Antioxidants; Cichlids; Collagen; Erythrocytes; Fatigue; Fish Proteins; Glycogen; Hemolysis; Humans; Liver; Male; Mice; Muscle, Skeletal; Peptides; Protective Agents; Skin; Superoxide Dismutase

Current methods for the quantitative determination of glycogen in erythrocytes are unsatisfactory.. Erythrocytes were deproteinized with perchloric acid either after haemolysing by freezing and thawing twice or without freezing and thawing, and the glycogen content was determined by an enzymatic method.. Freezing and thawing resulted in a significantly higher glycogen content, and the recovery of added glycogen using this method was nearly 100%. The mean erythrocyte glycogen content in healthy volunteers (n = 17) was 69.5 microg/g haemoglobin, a value much higher than the previously reported values in healthy subjects.. Freezing and thawing improves the assay of erythrocyte glycogen.

Topics: Erythrocytes; Freezing; Glycogen; Hematologic Tests; Hemolysis; Humans; Sensitivity and Specificity

A 29-year-old woman with muscle phosphofructokinase (PFK) deficiency had exercise intolerance, painful cramps, elevation of muscle enzyme levels in the serum and compensated hemolysis. After the restriction of exercise, the creatine kinase level and indirect bilirubin level decreased, and the reticulocyte count and haptoglobin level were normalized. It is suggested that the hemolysis which was accelerated by exercise was improved by restriction of exercise.

Topics: Adult; Bilirubin; Biopsy; Creatine Kinase; Erythrocytes; Exercise; Exercise Test; Female; Glycogen; Glycogen Storage Disease Type VII; Hemolysis; Humans; Muscle, Skeletal; Phosphofructokinase-1

Topics: Adenosine Triphosphate; Amino Acid Sequence; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type V; Glycogen Storage Disease Type VII; Hemolysis; Humans; Molecular Sequence Data; Muscles; Uric Acid

1. The properties of phosphorylase a, phosphorylase b, phosphorylase kinase and phosphorylase phosphatase present in a human haemolysate were investigated. The two forms of phosphorylase have the same affinity for glucose 1-phosphate but greatly differ in Vmax. Phosphorylase b is only partially stimulated by AMP, since, in the presence of the nucleotide, it is about tenfold less active than phosphorylase a. In a fresh human haemolysate phosphorylase is mostly in the b form; it is converted into phosphorylase a by incubation at 20degreesC, and this reaction is stimulated by glycogen and cyclic AMP. Once activated, the enzyme can be inactivated after filtration of the haemolysate on Sephadex G-25. This inactivation is stimulated by caffeine and glucose and inhibited by AMP and fluoride. The phosphorylase kinase present in the haemolysate can also be measured by the rate of activation of added muscle phosphorylase b, on addition of ATP and Mg2+. 2. The activity of phosphorylase kinase was measured in haemolysates obtained from a series of patients who had been classified as suffering from type VI glycogenosis. In nine patients, all boys, an almost complete deficiency of phosphorylase kinase was observed in the haemolysate and, when it could be assayed, in the liver. A residual activity, about 20% of normal, was found in the leucocyte fraction, whereas the enzyme activity was normal in the muscle. These patients suffer from the sex-linked phosphorylase kinase deficiency previously described by others. Two pairs of siblings, each time brother and sister, displayed a partial deficiency of phosphorylase kinase in the haemolysate and leucocytes and an almost complete deficiency in the liver. This is considered as being the autosomal form of phosphorylase kinase deficiency. Other patients were characterized by a low activity of total (a+b) phosphorylase and a normal or high activity of phosphorylase kinase in their haemolysate.

Topics: Adenosine Monophosphate; Adenosine Triphosphate; Adolescent; Caffeine; Child; Child, Preschool; Cyclic AMP; Enzyme Activation; Erythrocytes; Female; Fluorides; Glucose; Glucosephosphates; Glycogen; Glycogen Storage Disease; Glycogen Storage Disease Type VI; Hemolysis; Humans; Infant; Leukocytes; Liver; Male; Muscles; Phosphorylase Kinase; Phosphorylase Phosphatase; Phosphorylases

Topics: Ammonia; Animals; Astrocytes; Axons; Brain; Cell Nucleus; Cerebellum; Copper; Glycogen; Hemolysis; Histocytochemistry; Mitochondria; Myelin Sheath; Poisoning; Sheep; Sheep Diseases; Spinal Cord; Time Factors; Urea; Vacuoles

Topics: Adenosine Triphosphate; Caffeine; Erythrocytes; Galactose; Glucosephosphates; Glucosyltransferases; Glycogen; Glycogen Synthase; Hemolysis; Hexosephosphates; Hot Temperature; Humans; Kinetics; Phosphates; Protein Denaturation; Sulfates; Theophylline; Uridine Diphosphate Sugars

Topics: Animals; Carbon Isotopes; Chemical Precipitation; Clinical Enzyme Tests; Erythrocytes; Glucose; Glucosidases; Glycogen; Glycogen Storage Disease; Glycoside Hydrolases; Hemolysis; Humans; Hydrogen-Ion Concentration; Kinetics; Liver; Methods; Microchemistry; Muscles; Paper; Rabbits; Rats; Time Factors; Tromethamine