scholarly journals The Hantzsch reaction for nitrogen-13 PET: preparation of [13N]nifedipine and derivatives

2021 ◽  
Author(s):  
Julia Blower ◽  
Michelle Ma ◽  
Fahad Al salemee ◽  
Antony Gee
Keyword(s):  
Half Life ◽  
Hantzsch Reaction ◽  
Short Half Life

Nitrogen-13 is an attractive but under-used PET radionuclide for labelling molecules of biological and pharmaceutical interest, complementing other PET radionuclides. Its short half-life (t1/2 = 9.97 min) imposes synthetic challenges,...

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

scholarly journals Tafazzins from Drosophila and mammalian cells assemble in large protein complexes with a short half-life

Mitochondrion ◽  
2015 ◽  
Vol 21 ◽  
pp. 27-32 ◽  
Author(s):  
Yang Xu ◽  
Ashim Malhotra ◽  
Steven M. Claypool ◽  
Mindong Ren ◽  
Michael Schlame
Keyword(s):  
Half Life ◽  
Mammalian Cells ◽  
Protein Complexes ◽  
Large Protein ◽  
Short Half Life

scholarly journals The tumor suppressor OVCA1 is a short half‑life protein degraded by the ubiquitin‑proteasome pathway

2018 ◽  
Author(s):  
Yingwei Lin ◽  
Fandou Kong ◽  
Yan Li ◽  
Yinghui Wang ◽  
Ling Song ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Half Life ◽  
Ubiquitin Proteasome Pathway ◽  
Short Half Life ◽  
Ubiquitin Proteasome ◽  
Proteasome Pathway

Pulmonary vasodilation by nitric oxide gas and prodrug aerosols in acute pulmonary hypertension

1998 ◽  
Vol 84 (2) ◽  
pp. 435-441 ◽  
Author(s):  
Christophe Adrie ◽  
Fumito Ichinose ◽  
Alexandra Holzmann ◽  
Larry Keefer ◽  
William E. Hurford ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pulmonary Hypertension ◽  
Vascular Resistance ◽  
Pulmonary Circulation ◽  
Half Life ◽  
Hemodynamic Effects ◽  
Pulmonary Vasodilation ◽  
Short Half Life ◽  
Acute Pulmonary Hypertension ◽  
Inhaled No

Adrie, Christophe, Fumito Ichinose, Alexandra Holzmann, Larry Keefer, William E. Hurford, and Warren M. Zapol. Pulmonary vasodilation by nitric oxide gas and prodrug aerosols in acute pulmonary hypertension. J. Appl. Physiol. 84(2): 435–441, 1998.—Sodium 1-( N, N-diethylamino)diazen-1-ium-1,2-diolate {DEA/NO; Et2N[N(O)NO]Na} is a compound that spontaneously generates nitric oxide (NO). Because of its short half-life (2.1 min), we hypothesized that inhaling DEA/NO aerosol would selectively dilate the pulmonary circulation without decreasing systemic arterial pressure. We compared the pulmonary selectivity of this new NO donor with two other reference drugs: inhaled NO and inhaled sodium nitroprusside (SNP). In seven awake sheep with pulmonary hypertension induced by the infusion of U-46619, we compared the hemodynamic effects of DEA/NO with those of incremental doses of inhaled NO gas. In seven additional awake sheep, we examined the hemodynamic effects of incremental doses of inhaled nitroprusside (i.e., SNP). Inhaled NO gas selectively dilated the pulmonary vasculature. Inhaled DEA/NO produced nonselective vasodilation; both systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were reduced. Inhaled SNP selectively dilated the pulmonary circulation at low concentrations (≤10−2 M), inducing a decrease of PVR of up to 42% without any significant decrease of SVR (−5%), but nonselectively dilated the systemic circulation at larger doses (>10−2 M). In conclusion, despite its short half-life, DEA/NO is not a selective pulmonary vasodilator compared with inhaled NO. Inhaled SNP appears to be selective to the pulmonary circulation at low doses but not at higher levels.

Identification of absorption lines of short half-life actinides in the spectrum of Przybylski’s star (HD 101065)

2008 ◽  
Vol 24 (2) ◽  
pp. 89-98 ◽  
Author(s):  
V. F. Gopka ◽  
A. V. Yushchenko ◽  
V. A. Yushchenko ◽  
I. V. Panov ◽  
Ch. Kim
Keyword(s):  
Half Life ◽  
Absorption Lines ◽  
Short Half Life

Long Live β-Blockers in Takotsubo Outflow Obstruction! Rather With a Short Half-Life?

2015 ◽  
Vol 31 (8) ◽  
pp. 1074.e7 ◽  
Author(s):  
Francesco Santoro ◽  
Riccardo Ieva ◽  
Matteo Di Biase ◽  
Natale Daniele Brunetti
Keyword(s):  
Half Life ◽  
Outflow Obstruction ◽  
Short Half Life ◽  
Β Blockers

Which NSAID? (19 Oct, p.81): a postscript and a correction

1987 ◽  
Vol 25 (26) ◽  
pp. 103.1-103
Keyword(s):  
Half Life ◽  
Adverse Reactions ◽  
Morning Stiffness ◽  
Rank Order ◽  
The Elderly ◽  
Active Metabolites ◽  
Short Half Life ◽  
Elimination Half ◽  
Inhibition Of Prostaglandin Synthesis ◽  
High Concentrations

A letter to the Lancet (S S Adams, 21 Nov 1987, 1204–5) points out that when the CSM adverse reactions data for the 11 NSAIDs cited in our table are ranked in descending order of toxicity, nearly all those with a long plasma elimination half-life of about 10 hours or more (for the drug + active metabolites) come at the top of the list. The other compounds have a short half-life, 4 hours or less. The table below shows the relevant CSM data rearranged in rank order, and the approximate half-lives of the drugs. Half-lives vary widely between patients and tend to be longer in the elderly. Toxicity is obviously not determined by slow elimination alone, but prolonged high concentrations of a drug in the tissues are likely to exacerbate any toxic effects. Short-acting drugs may allow some recovery between doses from the potentially damaging inhibition of prostaglandin synthesis at vulnerable sites, such as the gut and kidney. NSAIDs with a short half-life should therefore be preferred unless a somewhat longer action is needed to alleviate morning stiffness. Sustained-release forms of NSAIDs with an otherwise short half-life should also be used cautiously.

scholarly journals Radiocarbon in Dinosaur Fossils: Compatibility with an Age of Millions of Years

2020 ◽  
Vol 82 (2) ◽  
pp. 72-79
Author(s):  
Philip J. Senter
Keyword(s):  
Bone Mineral ◽  
Half Life ◽  
Biological Evolution ◽  
Bacterial Activity ◽  
Radiocarbon Date ◽  
Fossil Bone ◽  
Short Half Life ◽  
Science Educators

The recent discovery of radiocarbon in dinosaur bones at first seems incompatible with an age of millions of years, due to the short half-life of radiocarbon. However, evidence from isotopes other than radiocarbon shows that dinosaur fossils are indeed millions of years old. Fossil bone incorporates new radiocarbon by means of recrystallization and, in some cases, bacterial activity and uranium decay. Because of this, bone mineral – fossil or otherwise – is a material that cannot yield an accurate radiocarbon date except under extraordinary circumstances. Mesozoic bone consistently yields a falsely young radiocarbon “date” of a few thousand to a few tens of thousands of years, despite the fact that it is millions of years old. Science educators need to be aware of the details of these phenomena, to be able to advise students whose acceptance of biological evolution has been challenged by young-Earth creationist arguments that are based on radiocarbon in dinosaur fossils.

Implications of designing clarithromycin loaded solid lipid nanoparticles on their pharmacokinetics, antibacterial activity and safety

RSC Advances ◽  
2016 ◽  
Vol 6 (80) ◽  
pp. 76621-76631 ◽  
Author(s):  
Manu Sharma ◽  
Namita Gupta ◽  
Sumeet Gupta
Keyword(s):  
Antibacterial Activity ◽  
Solid Lipid Nanoparticles ◽  
Oral Bioavailability ◽  
Half Life ◽  
Lipid Nanoparticles ◽  
Solid Lipid ◽  
Short Half Life ◽  
Intracellular Infections

The major obstacles for treatment of intracellular infections with clarithromycin are poor gastrointestinal solubility, short half-life (3–4 h), low oral bioavailability and hepatotoxicity.

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