phosphorus-radioisotopes and Hypoxia

By definition, idiopathic erythrocytosis (IE) applies to a group of patients characterised by having a measured RCM above their predicted normal range (an absolute erythrocytosis) and following investigation do not have a form of primary or secondary erythrocytosis. Patients with IE are heterogenous. The possibilities include physiological variation, 'early' polycythaemia vera (10-15% develop clear features of PV over a few years), unrecognized congenital erythrocytosis, unrecognized or unrecognizable secondary acquired erythrocytosis or a currently undescribed form of primary or secondary erythrocytosis. Patients are more commonly male with a median age at presentation of 55-60 years. Approximately half of the patients present with vascular occlusive complications. Retrospective evidence indicates that vascular occlusion occurs less frequently when the PCV is controlled at normal levels. Venesection is the treatment of choice to lower the PCV. As a general approach to management, all patients with a PCV above 0.54 should be venesected to a PCV less than 0.45. This target PCV should also apply to patients with lesser degrees of raised PCV who have additional other risk factors for vascular occlusion.

Topics: Aged; Arterial Occlusive Diseases; Bone Marrow; Chlorambucil; Diagnosis, Differential; Endocrine System Diseases; Erythrocyte Volume; Erythroid Precursor Cells; Erythropoietin; Genetic Predisposition to Disease; Humans; Hypoxia; Kidney Diseases; Leukemia; Leukemia, Radiation-Induced; Middle Aged; Phosphorus Radioisotopes; Polycythemia; Polycythemia Vera; Receptors, Erythropoietin; Sequence Deletion; Smoking; Stroke

Changes in de novo protein synthesis and protein phosphorylation were monitored during anoxia and recovery in the red-eared slider Trachemys (= Pseudemys) scripta elegans. Time courses of 35S-radiolabeled methionine incorporation into acid-precipitable material showed an increase up to 5 h postinjection and remained constant after this time. Comparison of the total and acid-precipitable 35S label incorporation into tissues from 20-h control, anoxic, and recovering animals showed differences between these groups: total radioactivity in brain was 2.9-fold lower in recovering turtles, whereas protein-associated radioactivity was 2.4-fold higher in anoxic liver, 2.3-fold lower in recovering skeletal muscle, and 3.7-fold lower in recovering brain tissue. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of radiolabeled proteins showed the existence of a newly synthesized protein band (relative molecular mass = 72 kDa) that was apparent only in 20-h recovering liver and skeletal muscle. Use of 32P labeling to monitor changes in protein phosphorylation patterns during anoxia revealed 1.6-, 1.4-, and 1.5-fold increases in 32P incorporation in anoxic brain, heart, and liver, respectively. Changes in protein phosphorylation were localized to the plasma membrane and cytosolic fractions in brain and to the cytosolic fraction in liver.

Topics: Animals; Brain; Hypoxia; Liver; Methionine; Myocardium; Phosphorus Radioisotopes; Phosphorylation; Proteins; Subcellular Fractions; Sulfur Radioisotopes; Turtles

Glycogen phosphorylase (GPase) from the body wall of the lugworm Arenicola marina (Annelida, Polychaeta) probably exists as a phospho-dephospho hybrid (GPase ab). The hybrid was identified by phosphorylation of purified lugworm GPase b (unphosphorylated form) with rabbit muscle GPase kinase and [gamma-32P]ATP. The completeness of phosphorylation was checked on DEAE-Sephacel. Only one GPase form was eluted. Its 32P incorporation was determined to 0.52 +/- 0.08 mol 32P/100,000 x g protein (n = 4). This GPase ab produced by in vitro phosphorylation has shown similar dependences on AMP and caffeine as GPase extracted from the body wall of the lugworm. Its reversible conversion with endogenous phosphatase and kinase to GPase b has also been demonstrated while a completely phosphorylated form (GPase a) was not detected neither in vivo nor in vitro. Lugworm GPase ab has shown a 2.4-fold higher specific activity as GPase b. The Km for P(i) was 16 mmol/l in absence and 13 mmol/l in presence of AMP. Half maximum activation by AMP was reached at 9 mumol/l. IMP up to 10 mmol/l did not activate and ATP up to 4 mmol/l did not inhibit GPase ab in absence of AMP.

Topics: Adenosine Monophosphate; Animals; Buffers; Chromatography, Ion Exchange; DEAE-Cellulose; Enzyme Activation; Hypoxia; Inosine Monophosphate; Kinetics; Phosphorus Radioisotopes; Phosphorylases; Phosphorylation; Polychaeta; Sodium Fluoride

Quantification of 32P in bands after gel electrophoresis was performed using the flat-bed scintillation counter (Betaplate). The most convenient system involved placing fragments of dried gel between two glass fiber sheets, each previously sealed in a thin plastic bag with liquid scintillant. Good pulse-height spectra and counting efficiencies were obtained with low cross talk and background. The method has been used to quantify mRNA in RNA antisense-protection assays that were linear over a wide range (1-20000 cpm). Cross talk and background could be reduced further by an alternative technique utilizing plastic trays with shallow wells in which a solid scintillant had been melted. Fragments were immersed in the molten scintillant (90 degrees C), which was allowed to solidify, by cooling, before counting.

Topics: Animals; Electrophoresis, Agar Gel; Electrophoresis, Polyacrylamide Gel; Erythropoietin; Hypoxia; Kidney; Phosphorus Radioisotopes; Rats; RNA, Messenger; Scintillation Counting

Striatum synaptosomes prepared from adult rats which had been exposed to postnatal hypoxia incorporate 32P-phosphate into phosphatidylinositol-4,5-trisphosphate (PI-4,5-P2) with decreased rate. 32P-incorporation amounted to 57% of the control for PI-4,5-P2 labeling and was slightly diminished for phosphatidic acid and PI-4-P. Exposure to hypoxia of adult rats did not affect inositol phospholipid labeling. The inhibitory effect of dopamine on 32P-phosphate incorporation was reduced only after postnatal hypoxia. 32P-incorporation rates and the dopamine inhibitory effect were not influenced by external calcium. A working hypothesis is suggested for the dopamine action on specific receptors which may be linked to the polyphosphoinositide metabolism and membrane calcium release. The long lasting effects of an early postnatal hypoxia on 32P-incorporation rates into polyphosphoinositides and phosphatidic acid could reflect the role of the proposed dopamine receptor interaction.

Topics: Animals; Animals, Newborn; Calcium; Corpus Striatum; Dopamine; Egtazic Acid; Hypoxia; Kinetics; Male; Phosphatidic Acids; Phosphatidylinositol Phosphates; Phosphatidylinositols; Phosphorus Radioisotopes; Radioisotope Dilution Technique; Rats; Rats, Inbred Strains; Synaptosomes

Topics: Animals; Calcium-Binding Proteins; Coronary Disease; Cyclic AMP; Dogs; Heart; Hypoxia; Microsomes; Myocardium; Phosphorus Radioisotopes; Phosphorylation; Protein Kinases; Trypsin

Polyacrylamide gel electrophoresis was used to reveal in the rabbit bone marrow cells 5 main fractions of histone proteins which are present in other eukaryotic cells. The degree of acetylation and phosphorylation increased after erythropoietin injection or exposure to hypoxia. Phosphorylation was enhanced in every fraction. Stimulation of acetylation was noted in histones rich in arginine. Erythropoietin had no effect on the synthesis of marrow histones in the early period after a hypoxic stimulus.

Topics: Acetylation; Animals; Bone Marrow; Electrophoresis, Polyacrylamide Gel; Erythropoietin; Female; Histones; Hypoxia; Mice; Phosphorus Radioisotopes; Phosphorylation; Rabbits

31P NMR studies on the brains of living rabbits were carried out at 32 MHz in a spectrometer having a 200-mm clear bore. Paralyzed pump-ventilated animals under nitrous oxide analgesia were inserted into the 1.89-T field and signals were focused in the brain by using a 4-cm surface coil. Several conventional physiological variables were monitored together with 31P spectra during induction and reversal of insulin shock and hypoxic hypoxia sufficient to abolish the electroencephalogram and during status epilepticus. A reversible decrease in phosphocreatine stores accompanied by an increase in Pi was detected during hypoglycemia and hypoxia. Similar changes were observed in prolonged status epilepticus but were not reversed. ATP levels fell about 50% in hypoglycemia but only slightly in the other two metabolic stresses. Intracellular pH rose in hypoglycemia; in status epilepticus and hypoxia it fell, but only when cardiovascular function was severely impaired. From the measured NMR parameters and the assumptions (i) that creatine kinase was at equilibrium and (ii) that the creatine/phosphocreatine pool was constant, it was possible to calculate the relative changes in cytoplasmic ADP levels associated with these metabolic disturbances.

Topics: Animals; Brain; Hypoglycemia; Hypoxia; Magnetic Resonance Spectroscopy; Mathematics; Phosphorus Radioisotopes; Rabbits; Seizures

Exposure of adult rats to hypobaric hypoxia caused hypolipidemia, hypotriglyceridemia and hypophospholipidemia. Hypobaric hypoxia produced an increase in liver triglyceride and cholesterol levels and a decrease in lung triglyceride, total phospholipid and phosphatidyl choline. The proportion of phosphatidyl choline in the pulmonary surfactant fraction I phospholipids (responsible for reducing surface tension) decreased (55.2% as compared to 80.4% in control animals). Incorporation of 32-P into liver phosphatidyl ethanolamine was significantly increased, incorporation into lung phosphatidyl choline and phosphatidyl ethanolamine was increased whereas a decreased incorporation into plasma phosphatidyl choline was observed. The data suggest an enhanced lipid synthesis in liver with a probable impairment of mobilization into plasma.

Topics: Animals; Cholesterol; Hypoxia; Liver; Lung; Male; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Phosphorus Radioisotopes; Pulmonary Alveoli; Pulmonary Surfactants; Rats; Triglycerides

Topics: Adenosine Triphosphate; Aerobiosis; Anaerobiosis; Animals; Cerebral Cortex; Female; Glycolysis; Hypoxia; Male; Mitochondria; Oxygen; Oxygen Consumption; Partial Pressure; Phosphorus Radioisotopes; Rats

Topics: Adenylyl Cyclases; Animals; Cobalt; Cyclic AMP; Erythropoiesis; Erythropoietin; Hypoxia; Iron; Iron Radioisotopes; Kidney Cortex; Kidney Medulla; Lactates; Male; NAD; Phosphorus Radioisotopes; Polycythemia; Pyruvates; Rats; Spectrophotometry, Ultraviolet; Stimulation, Chemical; Time Factors; Tritium

Topics: Animals; Aorta, Abdominal; Bacterial Infections; Constriction; Hypoxia; Lung; Macrophages; Male; Mice; Phagocytosis; Phosphorus Radioisotopes; Pneumonia; Pulmonary Alveoli; Pulmonary Edema; Rats; Staphylococcal Infections; Thiourea

Topics: Animals; Endocrine Glands; Hyperoxia; Hypoxia; Oxygen; Phosphorus; Phosphorus Radioisotopes; Phosphorus, Dietary; Rats

Topics: Brain; Hypoxia; Neurochemistry; Phosphorus; Phosphorus Radioisotopes; Phosphorus, Dietary; Radioactivity