phosphorus-radioisotopes and phosphoric-acid

Phosphorus (P) research still lacks techniques for rapid imaging of P use and allocation in different soil, sediment, and biological systems in a quantitative manner. In this study, we describe a time-saving and cost-efficient digital autoradiographic method for in situ quantitative imaging of

Topics: Autoradiography; Carbon Radioisotopes; Phosphoric Acids; Phosphorus; Phosphorus Radioisotopes; Plant Leaves; Polymers; Triticum; Zea mays

To prepare 32P-based user-friendly mould brachytherpy sources for the treatment of superficial tumors.. 32P as orthophosphoric acid was adsorbed on 15-25 mm (diameter) circular sheets of cellulose-based adsorbent paper to prepare sources containing approximately 37-74 MBq of 32P per cm of strip. The sources were immobilized between plastic sheets of 40 microm thickness. Autoradiography studies were carried out to determine the uniformity of 32P deposition in the source. Dosimetric evaluation of the sources was also carried out. Bioevaluation studies were carried out in C57BL6 mice bearing melanoma using 37-74 MBq sources.. Cellulose-based sources containing 37-74 MBq of 32P per cm2 could be prepared from which no radioactivity leakage could be detected in water or saline. Autoradiography studies revealed 32P to be uniformly distributed in these sources. Dosimetric evaluation showed that the contact dose imparted was 10 Gy/h, sufficient for treatment of superficial tumors. In mice bearing melanoma, complete tumor regression could be achieved with two applications of 37-74 MBq sources, at an interval of 3 days. Histopathological examination of the skin tissue from the treated area proved the absence of tumor as compared with the controls.. Preparation of P sources of various shapes and sizes (based on the tumor size) having uniform 32P activity distribution could be achieved. Efficacy of these sources in treating melanoma tumors could be established in the animal model.

Topics: Animals; Brachytherapy; Dose-Response Relationship, Radiation; Melanoma, Experimental; Mice; Mice, Inbred C57BL; Neoplasm Transplantation; Phosphoric Acids; Phosphorus Radioisotopes; Radiopharmaceuticals

The purpose of this study was to design and evaluate a 32P patch for brachytherapy of skin diseases. We employed Phosphoric-32P-acid and Chromic 32P-phosphate in combination with natural rubber or silicone to produce the patches. Stability studies in vitro to evaluate the leakage of radioactivity, autoradiographic studies to evaluate homogeneity and shielding, as well as therapeutic efficacy in an animal model of skin cancer of the selected 32P patch were performed. The 32P-silicone-patch demonstrated its safety for external application. Tumor growth was arrest and complete regressions of tumors were seen in some other cases with 40 Gy applied in a single-dose scheme. In conclusion, the 32P-silicone-patch is easy to prepare and use in the treatment of skin diseases.

Topics: Animals; Brachytherapy; Chromium Compounds; Drug Delivery Systems; Female; Histocytochemistry; Mice; Mice, Inbred SENCAR; Phosphates; Phosphoric Acids; Phosphorus Radioisotopes; Radiotherapy Planning, Computer-Assisted; Random Allocation; Rubber; Silicones; Skin Neoplasms

The development of clinical treatments involving the use of beta-emitting millimetric and sub-millimetric devices has been a continuing trend in nuclear medicine. Implanted a few nanometers below the surface of endovascular implants, seeds or beads, beta-emitting radioisotopes can be used in a variety of biomedical applications. Recently, new technologies have emerged to enable the rapid and efficient activation of such devices. A pulsed, coaxial electron cyclotron resonance plasma reactor was designed and tested to demonstrate the feasibility of plasma-based radioactive ion implantation (PBRII). It has been shown that such plasma reactors allow for the implantation of radioisotopes (32P) into biomedical devices with higher efficiencies than those obtained with conventional ion beams. Fragments containing radioactive atoms are produced in the implanter by means of a negatively biased solid sputter cathode that is inserted into an argon plasma. Dilute orthophosphoric acid solutions (H3(32)PO4) are used for the fabrication of flat sputter targets, since they offer a high radioisotope content. However, the aggregation of the radioactive solute into highly hygroscopic ring-like deposits rather than flat, thin radioactive films is observed on certain substrates. This article describes the effect of this nonuniform distribution of the radioisotopes on the efficiency of PBRII, and presents a technique which enables a better distribution of 32P by coating the substrates with iron. The iron coating is shown to enable optimal radioisotope sputtering rates, which are essential in 32P-PBRII for the efficient activation of millimetric biomedical devices such as stents or coils.

Topics: Gold; Humans; Iron; Phosphoric Acids; Phosphorus Radioisotopes; Prostheses and Implants; Silicon

Several methods for the chemical synthesis of gamma-32P-labeled and unlabeled nucleoside 5(')-triphosphates and thiamine triphosphate (ThTP) have been described. They often proved unsatisfactory because of low yield, requirement for anhydrous solvents, procedures involving several steps or insufficient specific radioactivity of the labeled triphosphate. In the method described here, all these drawbacks are avoided. The synthesis of [gamma-32P]ThTP was carried out in one step, using 1,3-dicyclohexyl carbodiimide as condensing agent for thiamine diphosphate and phosphoric acid in a dimethyl sulfoxide/pyridine solvent mixture. Anhydrous solvents were not required and the yield reached 90%. After purification, [gamma-32P]ThTP had a specific radioactivity of 11Ci/mmol and was suitable for protein phosphorylation. The method can also be used for the synthesis of [gamma-32P]ATP of the desired specific radioactivity. It can easily be applied to the synthesis of unlabeled ThTP or ribo- and deoxyribonucleoside 5(')-triphosphates. In the latter case, inexpensive 5(')-monophosphate precursors can be used as reactants in a 20-fold excess of phosphoric acid. Deoxyribonucleoside 5(')-triphosphates were obtained in 6h with a yield of at least 70%. After purification, the nucleotides were found to be suitable substrates for Taq polymerase during polymerase chain reaction cycling. Our method can easily be scaled up for industrial synthesis of a variety of labeled and unlabeled triphosphoric derivatives from their mono- or diphosphate precursors.

Topics: Adenosine Triphosphate; Biochemistry; Deoxyribonucleotides; Dicyclohexylcarbodiimide; Isotope Labeling; Nucleosides; Phosphoric Acids; Phosphorus Radioisotopes; Phosphorylation; Proteins; Receptors, Nicotinic; Thiamine Triphosphate

Recent data indicate that intravascular betaa-irradiation from centrally located sources at the time of balloon angioplasty or stenting reduces proliferation of smooth muscle cells, neointima formation, and restenosis. In an effort to simplify radiation delivery, a novel beta-radiation source was developed based on the adsorption of 32P (phosphoric acid) by pH-sensitive chitosan hydrogel on a poly(ethylene terephthalate) balloon surface. To prevent the 32P-isotope desorption in the patient's blood, the adsorbed phosphoric acid was precipitated as CaHPO4 on the surface by a saturated Ca(OH)2/5% CaCl2 solution. Various polyurethanes were applied to seal the radioactive surface by the dip-coating method. The isotope off-rate results were determined. Optimal results were obtained by serially coating with two polyurethane solutions. This approach holds promise for simplifying and improving the safety, and minimizing the cost of intravascular brachytherapy.

Topics: Adsorption; Angioplasty, Balloon; Beta Particles; Chitin; Chitosan; Humans; Hydrogels; Indolizines; Microscopy, Electron; Phosphoric Acids; Phosphorus Radioisotopes; Polyethylene Terephthalates; Spectroscopy, Fourier Transform Infrared; Thiophenes

Restenosis after percutaneous interventions in coronary and peripheral arteries leads to repeat procedures and surgery in a significant number of patients. We have previously demonstrated that irradiation of an arterial site using an endovascular source (brachytherapy) is highly effective in preventing the restenotic process. To this end, a novel beta radiation delivery system was developed, based on the adsorption of (32)P (o-phosphoric acid) by pH-sensitive chitosan hydrogel on a poly(ethylene terephthalate) (PET) balloon surface. The PET balloon surface was treated with oxygen plasma and coated with chitosan hydrogel. Covalent bonds, ionic bonds, and hydrogen bonds all contribute to the adhesion between chitosan hydrogel and PET. In the aqueous phosphoric acid (PA) solution, the -NH(2) groups of chitosan were protonated by PA and the adsorption of PA occurred at the same time. The effect of PA concentration and temperature on adsorption efficiency and kinetics were studied. More than 70% PA was adsorbed on the sample surface in 0.2 mM PA solution. The surface of samples was also investigated by attenuated total reflection-Fourier transform infrared spectroscopy and scanning electron microscopy. PET surface may be modified to carry high activity beta emitters; such materials may be useful in a therapeutic setting

Topics: Adsorption; Angioplasty, Balloon, Coronary; Chitin; Chitosan; Coated Materials, Biocompatible; Dose-Response Relationship, Drug; Hydrogels; Microscopy, Electron, Scanning; Oxygen; Phosphoric Acids; Phosphorus Radioisotopes; Polyethylene Terephthalates; Spectroscopy, Fourier Transform Infrared; Surface Properties; Temperature

The phosphoenolpyruvate:sugar phosphotransferase system (PTS) plays a key role in sugar uptake and metabolic regulation in bacteria. PTS proteins form a divergent phosphorylation cascade. Enzyme I (EI) is at the top of the cascade and mediates phosphoryl-transfer from phosphoenolpyruvate to the phosphoryl-carrier protein HPr, which then distributes the phosphoryl-groups to the different carbohydrate transporters. In addition, some PTS proteins have a regulatory function in catabolite repression, inducer exclusion and chemotaxis which is modulated by their degree of phosphorylation in response to the availability of substrates. Using as a reporter the IacZ gene under control of the bgl t2 transcriptional terminator and as an effector the transcriptional antiterminator LicT from B. subtilis, a two-plasmid reporter gene system was constructed in order to monitor PTS activity. LicT, when present at low concentration in E. coli, is inactivated by EI/HPr-dependent phosphorylation and conversely is active in a ptsl- mutant lacking El. Active LicT allows for transcriptional readthrough at bgl t2, resulting in a full-length lacZ transcript. Beta-galactosidase activities are increased 4-8-fold in a ptsl+ strain growing on PTS substrates relative to growth on non-PTS substrates and approximately 30-fold in a ptsl- mutant. This gain-of-function in response to dephosphorylation of El or lack of active El can be used to monitor changes of El activity caused by mutations and environmental factors and for screening and validation of inhibitors of the PTS as potentially novel antibacterial compounds.

Topics: Bacterial Proteins; beta-Galactosidase; Genes, Bacterial; Genes, Reporter; Phosphoenolpyruvate Sugar Phosphotransferase System; Phosphoric Acids; Phosphorus Radioisotopes; Phosphorylation; Phosphotransferases (Nitrogenous Group Acceptor); Plasmids; RNA-Binding Proteins; Terminator Regions, Genetic; Transcription Factors

In order to examine the role of protein kinase A (PKA) in the regulation of arachidonic acid availability, the interaction between cAMP agonists and the G protein activator AIF4- in their effects on phospholipid metabolism were measured in MC3T3-E1 osteoblasts. We show that forskolin and 8-brcAMP, activators of PKA, amplify the AIF4(-)-induced stimulation of phosphatidylinositol-specific phospholipase C (phosphatidylinositol inositolphosphohydrolase; EC 3.1.4.3), measured by the formation of [3H]inositol phosphates in prelabeled cells. However, the AIF4(-)-stimulated production of 1,2-diacylglycerols and the release of [3H]arachidonic acid ([3H]AA) were inhibited 50-75% by forskolin and 8-bromocAMP. Furthermore, pretreatment with PKA activators prevented much of the AIF4(-)-induced loss of [3H]AA from phosphatidylcholine and phosphatidylethanolamine in prelabeled osteoblasts. In addition, in the absence of AIF4-, forskolin was found to stimulate the incorporation of [3H]AA and [32P]orthophosphoric acid selectively into these two major phospholipids and selectively increased their mass. The effects of forskolin and 8-BrcAMP on the levels of free [3H]AA were completely reversed by pretreatment with the PKA inhibitor H-89. Therefore, our findings suggest that the activation of cAMP-dependent protein kinase can reduce the availability of free arachidonic acid for prostaglandin synthesis in osteoblast cells by stimulating its reesterification via phospholipid resynthesis.

Topics: Aluminum Compounds; Animals; Arachidonic Acid; Cell Line; Cyclic AMP-Dependent Protein Kinases; Diglycerides; Enzyme Activation; Fatty Acids; Fluorides; Osteoblasts; Phosphatidylcholines; Phosphatidylethanolamines; Phospholipids; Phosphoric Acids; Phosphorus Radioisotopes; Tritium

A single intraperitoneal injection of the human therapeutic drug bleomycin (BL) was administered to three groups of male Fischer 344 rats at time 0, and the incorporation of [35S]methionine ("synthesis") and phosphorylation patterns of stress proteins (sps/hsps) from bone marrow cells were analyzed over time by two-dimensional electrophoresis and fluorography. Two groups of rats, young ad libitum (Y/AL--3 months) and old ad libitum (O/AL--28 months), had free access to rat chow, and a third group of old rats (O/CR--28 months) were maintained on a caloric restricted intake (60% of the AL diet). The administration of BL in Y/AL, O/AL and O/CR animals activated the 35S-labeling of sp 90 which reached a peak at 4 hours. Labeling of sp 90 was significantly greater in Y/AL compared to O/AL, and the incorporation pattern of O/CR was intermediate to Y/AL and O/AL animals. All labeling of sp 90 in each group had disappeared by 10 hours after BL administration. Stress protein 70x (inducible form) in these three animal groups displayed a similar pattern of 35S-incorporation, but the amount of labeling was less than that of sp 90. No labeling of sp 70x remained by 13 hours after BL administration. Phosphorylation ([32P] phosphate incorporation) of sp 90 reached a maximum level at 2 hours in all animals, and 32P-labeling in Y/AL was significantly increased over O/AL and O/CR with an intermediate level found in O/CR animals. The turnover rate (phosphorylation/dephosphorylation) of sp 90 induced by BL was significantly suppressed and temporarily extended in O/AL as compared with O/CR, which implied that CR not only increased incorporation of sp 90, but also enhanced a utilization of the phosphate pool very similar to that seen in Y/AL animals.

Topics: Aging; Animals; Bleomycin; Energy Intake; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Male; Methionine; Phosphoric Acids; Phosphorus Radioisotopes; Phosphorylation; Rats; Rats, Inbred F344; Sulfur Radioisotopes; Time Factors

An in situ (explant tissue culture) model has been developed to study the effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), hormones, and growth factors either alone or in combination. In our model system, the effect of TCDD on protein phosphorylation was greatly affected by the presence or the absence of externally added D-glucose. In the presence of a physiologically relevant level of glucose (13.3 mM), TCDD clearly stimulated protein phosphorylation as in the case of in vivo data. However, in the absence of D-glucose, TCDD clearly inhibited protein phosphorylation. On the other hand, TCDD reduced the glucose uptake activity in isolated adipose tissue either in the presence or absence of D-glucose (13.3 mM). Therefore, the TCDD-induced reduction of glucose transport does not appear to be related directly to the simultaneous rise in protein phosphorylation. For comparison, several agents which are known to affect protein phosphorylation were tested. These hormonal agents generally affected the TCDD-untreated adipose tissues in the manner expected from their known actions, indicating that this in situ model is an adequate system to study their independent actions. The TCDD-treated adipose tissue samples showed only mild or insignificant response to these hormonal stimuli. In terms of the changes in the pattern of protein phosphorylation activities, the action of TCDD appeared to resemble that of EGF and T3. Since under in situ conditions no agents such as EGF or T3 can be expected to be present, the observed TCDD-induced changes are suggestive of the basic intracellular changes in cellular activities. The types of TCDD-induced protein kinases appear to be protein tyrosine kinases and protein kinase C.

Topics: Adipose Tissue; Animals; Blotting, Western; Down-Regulation; Glucose; Growth Substances; Guinea Pigs; Hormones; Male; Monosaccharide Transport Proteins; Phosphoric Acids; Phosphoric Monoester Hydrolases; Phosphorus Radioisotopes; Phosphorylation; Polychlorinated Dibenzodioxins; Protein Kinases; Proteins; Receptors, Cell Surface; Signal Transduction; Tyrosine; Up-Regulation

The chemical form of gaseous 35S species produced during the production of H3(32)PO4 was characterized in order to reduce 35S discharge by understanding its production mechanism and chemical reactivity. An air sample was evacuated from the cell in which the H3(32)PO4 production was being carried out and collected in a sample gas reservoir. Gaseous sulfur species contained in the sample were condensed in a cold trap maintained at -180 degrees C and analyzed by means of gas chromatography using a flame photometric detector. Sulfur dioxide (SO2) was the only sulfur species detected. Equilibrium constant calculations showed that SO2 would be expected to be the predominant species produced by reactions of sulfur molecules (Sn:n = 2-8) with oxygen in air and that the quantity of SO2 produced would be reduced by heating the irradiated sulfur target under vacuum or in atmospheres of inert gases.

Topics: Chromatography, Gas; Gases; Isotope Labeling; Phosphoric Acids; Phosphorus Radioisotopes; Sulfur Radioisotopes

The rates of total protein, actin and tubulin synthesis were studied for monolayer (L-929) and suspension (LS) cultures of mouse L cell. Data on pulse 34S-label incorporation into the cellular protein pool show that LS characterized by a short cell cycle have, comparatively to L-929, higher rates of protein synthesis and phosphorylation. According to PAGE data, the level of actin and tubulin synthesis in suspension line exceeds that in monolayer one. The correlation between growth conditions, biosynthetic parameters and dynamics of cytoskeleton is discussed.

Topics: Actins; Animals; L Cells; Methionine; Mice; Phosphoric Acids; Phosphorus Radioisotopes; Phosphorylation; Sulfur Radioisotopes; Tubulin

Glutamine synthetase from Rhodospirillum rubrum was purified and characterized with respect to its pH optimum and the effect of Mg2+ on its active and inactive forms. Both adenine and phosphorus were incorporated into the inactive form of the enzyme, indicating covalent modification by AMP. The modification could not be removed by phosphodiesterase. Evidence for regulation of the enzyme by oxidation was obtained. Extracts from oxygen-treated cells had lower specific activities than did extracts from cells treated anaerobically. Glutamine synthetase activity was found to decrease in the dark in phototrophically grown cells; activity was recovered on re-illumination.

Topics: Adenine; Enzyme Activation; Glutamate-Ammonia Ligase; Hydrogen-Ion Concentration; Light; Magnesium; Magnesium Chloride; Oxygen; Phosphoric Acids; Phosphorus Radioisotopes; Rhodospirillum rubrum