The preparation of 3H-labeled acyclic nucleoside phosphonates and study of their stability

2010 ◽  
Vol 75 (7) ◽  
pp. 757-766 ◽  
Author(s):  
Tomáš Elbert ◽  
Petra Břehová ◽  
Antonín Holý
Keyword(s):  
Liquid Nitrogen ◽  
Radiochemical Purity ◽  
Labeled Compounds ◽  
H Nmr ◽  
Catalytic Dehalogenation ◽  
Acyclic Nucleoside Phosphonates ◽  
Specific Activities ◽  
Acyclic Nucleoside ◽  
Purine Ring ◽  
Better Than

9-(2-Phosphonomethoxyethyl)-2,6-diamino-[8-3H]purine (4), 9-(2-phosphonomethoxyethyl)-[8-3H]guanine (6) and (R)-9-(2-phosphonomethoxypropyl)-[8-3H]adenine (11) with specific activities of 10.9, 7.9 and 16 Ci/mmol, respectively, were prepared by a catalytic dehalogenation of the corresponding 8-bromo derivatives 1, 2 and 9. The rate of the exchange of the tritium label on C-8 of the purine ring in title compounds with the hydrogen of water under physiological pH at 20 °C was studied using 3H NMR. The loss of 3H-label attained 7% in [8-3H]tenofovir (11), 10% in [8-3H]PMEDAP (4) and 12% in [8-3H]PMEG (6) after the period of 3 weeks. Storage at a temperature of –196 °C in liquid nitrogen ensured a better than 97% radiochemical purity of the prepared labeled compounds even after a six-month period.

Water accumulation as a function of temperature on specimens in an electron microscope cold stage

1986 ◽  
Vol 44 ◽  
pp. 114-115 ◽  
Author(s):  
M.K. Lamvik ◽  
D.A. Kopf ◽  
S.D. Davilla ◽  
J.D. Robertson
Keyword(s):  
Electron Microscope ◽  
Mass Loss ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Liquid Nitrogen Temperature ◽  
Liquid Helium Temperature ◽  
Helium Temperature ◽  
Cold Stage ◽  
Water Accumulation ◽  
Better Than

Last year we reported1 that there is a striking reduction in the rate of mass loss when a specimen is observed at liquid helium temperature. It is important to determine whether liquid helium temperature is significantly better than liquid nitrogen temperature. This requires a good understanding of mass loss effects in cold stages around 100K.

Acyclic nucleoside phosphonates and human telomerase inhibition

2005 ◽  
Author(s):  
Miroslav Hájek ◽  
Naděžda Matulová ◽  
Ivan Votruba ◽  
Antonín Holý ◽  
Eva Tloušťová
Keyword(s):  
Telomerase Inhibition ◽  
Acyclic Nucleoside Phosphonates ◽  
Acyclic Nucleoside ◽  
Human Telomerase

Tyrosine-based prodrugs of acyclic nucleoside phosphonates

2014 ◽  
Author(s):  
Tomáš Tichý ◽  
Karel Pomeisl ◽  
Marcela Krečmerová ◽  
Charles E. McKenna
Keyword(s):  
Acyclic Nucleoside Phosphonates ◽  
Acyclic Nucleoside

scholarly journals In-silico designing of acyclic nucleoside phosphonates and their anti-HIV potential

2012 ◽  
Vol 12 (Suppl 1) ◽  
pp. P3
Author(s):  
Dipti Yadav ◽  
Anuradha Singh ◽  
Madhu Yadav ◽  
Ramendra K Singh
Keyword(s):  
In Silico ◽  
Acyclic Nucleoside Phosphonates ◽  
Acyclic Nucleoside ◽  
Anti Hiv

scholarly journals Synthesis of fluorinated acyclic nucleoside phosphonates with 5-azacytosine base moiety

Tetrahedron ◽  
2019 ◽  
Vol 75 (39) ◽  
pp. 130529 ◽  
Author(s):  
Karel Pomeisl ◽  
Marcela Krečmerová ◽  
Radek Pohl ◽  
Robert Snoeck ◽  
Graciela Andrei
Keyword(s):  
Acyclic Nucleoside Phosphonates ◽  
Acyclic Nucleoside ◽  
Base Moiety

scholarly journals A Comparison of 940 nm Diode Laser and Cryosurgery With Liquid Nitrogen in the Treatment of Gingival Physiologic Hyperpigmentation Using Split Mouth Technique: 12 Months Follow Up

2019 ◽  
Vol 10 (2) ◽  
pp. 131-138
Author(s):  
Leila Jokar ◽  
Mojtaba Bayani ◽  
Hamid Hamidi ◽  
Mohammad Keivan ◽  
Saranaz Azari-Marhabi
Keyword(s):  
Liquid Nitrogen ◽  
Diode Laser ◽  
Randomized Study ◽  
Facial Esthetics ◽  
Surgical Methods ◽  
Significant Difference ◽  
Treatment Procedures ◽  
Gingival Depigmentation ◽  
Better Than

Introduction: Gingival hyperpigmentation is excessive deposition of melanin pigments in the epithelium of gingiva which affects facial esthetics. Various surgical methods for gingival depigmentation have been used to treat the darkened color of pigmented gingiva. This study compared the use of 940 nm diode laser and liquid nitrogen cryosurgery in the treatment of gingival physiologic hyperpigmentation in terms of gingival depigmentation, postoperative pain, healing duration, pigmentation recurrence, and patients’ satisfaction. Methods: Fifteen systemically healthy patients (11 females and 4 males; 17-35 years of age) with bilateral gingival physiologic hyperpigmentation were enrolled in this split-mouth randomized study. Maxillary anterior labial gingiva of each patient was divided into left and right halves, and each half was randomly depigmented by either laser or cryosurgery. Patients were given questionnaires to evaluate the procedures and were followed up in 3, 7, 10, 17 and 21 days postoperatively for the assessment of gingival healing and 1, 3, 6 and 12 months after the treatments to detect any sign of pigmentation recurrence. Results: The severity of post-op pain measured by visual analogue scale (VAS) was mild to average and showed no significant difference between the 2 modalities (P>0.05). There was no considerable swelling or hemorrhage after the treatment procedures and the healing duration was significantly shorter in laser (P<0.05). The degree of pigmentation in all gingival sites treated by laser reached and remained at zero until the last follow up (1 year) and reached zero in 9 out of 15 cryosurgerytreated sites. All patients were completely satisfied with the laser, and 9 out of 15 were completely satisfied with cryosurgery. No pigmentation recurrence was observed during any follow-up periods. Conclusion: Removal of gingival physiologic hyperpigmentation by laser therapy and cryotherapy was effective and safe. The efficiency of the laser was better than cryotherapy.

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