scholarly journals Acceleration of Dark Reversion of Phytochrome in Vitro by Calcium and Magnesium

1975 ◽  
Vol 56 (1) ◽  
pp. 157-159 ◽  
Author(s):  
Moshé Negbi ◽  
David W. Hopkins ◽  
Winslow R. Briggs
Keyword(s):  
Dark Reversion ◽  
Calcium And Magnesium

The Effect of Calcium and Magnesium on Rabbit Blood Platelet Aggregation in Vitro

1964 ◽  
Vol 12 (01) ◽  
pp. 179-200 ◽  
Author(s):  
Torstein Hovig
Keyword(s):  
Platelet Aggregation ◽  
Cation Exchange ◽  
Calcium Concentration ◽  
Blood Platelets ◽  
Blood Platelet ◽  
Rabbit Blood ◽  
Calcium And Magnesium ◽  
Induced Aggregation ◽  
Blood Platelet Aggregation

SummaryThe effect of calcium and magnesium on the aggregation of rabbit blood platelets in vitro was studied, with the following results:1. Platelet aggregation induced by ADP or collagen could be prevented by EGTA or EDTA. The aggregating effect was restored by recalcification. The effect was also restored by addition of magnesium in EDTA-PRP, but not in EGTA-PRP unless a surplus of calcium was present.2. Calcium remained in concentrations of the order of 0.15–0.25 mM after dialysis or cation exchange of plasma. Aggregation of washed platelets resuspended in such plasma could not be produced with ADP or collagen, unless the calcium concentration was increased or that magnesium was added.3. The adhesiveness of blood platelets to collagen was reduced in EGTA-PRP and EDTA-PRP. Release of ADP from platelets influenced by collagen could not be demonstrated either in EGTA-PRP (presence of magnesium) or in EDTA-PRP.4. It is concluded that calcium is a necessary factor both for the reaction leading to release of ADP and for the the aggregation produced by ADP.5. Thrombin induced aggregation of washed platelets suspended in tris-buffered saline in the presence of calcium. No effect of magnesium could be observed unless small quantities of calcium were present.

scholarly journals In vitro activity of omadacycline and levofloxacin against Escherichia coli, Klebsiella pneumoniae and Staphylococcus saprophyticus in human urine supplemented with calcium and magnesium

2020 ◽  
Author(s):  
Paul Pagano ◽  
Andrea Marra ◽  
Dean Shinabarger ◽  
Chris Pillar
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Human Urine ◽  
Vitro Activity ◽  
In Vitro Activity ◽  
Standard Medium ◽  
Staphylococcus Saprophyticus ◽  
Normal Human ◽  
Calcium And Magnesium

Abstract Background Omadacycline, an aminomethylcycline, was approved in 2018 for the treatment of acute bacterial skin and skin structure infections and community-acquired bacterial pneumonia. In a Phase Ib study, around 34% of the absorbed dose of omadacycline was shown to be excreted in urine—an important property for urinary tract infection (UTI) treatment. Therefore, omadacycline has been studied in two Phase II trials for the treatment of uncomplicated UTIs and acute pyelonephritis. The activity of omadacycline against UTI pathogens in human urine is important to understand in this context. Objectives To study the in vitro activity of omadacycline against UTI pathogens in human urine supplemented with calcium and magnesium. Methods Omadacycline activity was compared with that of levofloxacin against the urinary pathogens Escherichia coli, Klebsiella pneumoniae and Staphylococcus saprophyticus in standard medium, pooled normal human urine and neutral pH-adjusted pooled normal human urine spiked with calcium or magnesium at concentrations consistent with hypercalcaemia and hypermagnesaemia. Results The activities of omadacycline and levofloxacin against these urinary pathogens were lower in urine relative to standard medium; addition of Mg2+ to broth and urine had a further negative impact on omadacycline activity, whereas the addition of Ca2+ had less of an impact. Levofloxacin activity was not substantially reduced in either broth or urine by the addition of divalent cations. Conclusions The activity of omadacycline against UTI organisms was lower in urine relative to standard medium and was negatively impacted by magnesium. Omadacycline displayed slightly reduced activity when excess calcium was present, but, overall, the differences were ≤2-fold. These observations should be considered along with the pharmacokinetics of the agent for clinical context.

scholarly journals Extracellular Calcium and Magnesium, but Not Iron, Are Needed for Optimal Growth of Blastomyces dermatitidis Yeast Form Cells In Vitro

2004 ◽  
Vol 11 (2) ◽  
pp. 426-429 ◽  
Author(s):  
Steven S. Giles ◽  
Charles J. Czuprynski
Keyword(s):  
Chelating Agents ◽  
Ferric Iron ◽  
Optimal Growth ◽  
Binding Activity ◽  
Blastomyces Dermatitidis ◽  
Serum Transferrin ◽  
Yeast Form ◽  
Calcium And Magnesium ◽  
Shed Light

ABSTRACT In the present study, we demonstrate that the yeast form of Blastomyces dermatitidis can proliferate for short periods of time in the absence of ferric iron but not in the absence of calcium or magnesium. The results of this study shed light on the resistance of B. dermatitidis to chelating agents, such as deferoxamine, and may explain how B. dermatitidis resists the iron-binding activity of serum transferrin.

Parathyroid Hormone Secretion in vitro: Regulation by Calcium and Magnesium Ions

Nature ◽  
1970 ◽  
Vol 225 (5237) ◽  
pp. 1056-1058 ◽  
Author(s):  
LOUIS M. SHERWOOD ◽  
INGEBORG HERRMAN ◽  
C. ANDREW BASSETT
Keyword(s):  
Parathyroid Hormone ◽  
Hormone Secretion ◽  
Magnesium Ions ◽  
Calcium And Magnesium ◽  
Calcium And Magnesium Ions

In Vitro Evaluation of Highly Absorptive Ceramics Materials Needs Consideration of Calcium and Magnesium Ions Adsorbed to the Materials

2001 ◽  
Vol 218-220 ◽  
pp. 153-156 ◽  
Author(s):  
Shinichi Sotome ◽  
Toshimasa Uemura ◽  
Masanori Kikuchi ◽  
Shigeru Itoh ◽  
M. Tanaka ◽  
...  
Keyword(s):  
Magnesium Ions ◽  
In Vitro Evaluation ◽  
Calcium And Magnesium ◽  
Calcium And Magnesium Ions

scholarly journals Trans-Aconitate Utilization by Sheep

1968 ◽  
Vol 21 (3) ◽  
pp. 529 ◽  
Author(s):  
GS Kennady
Keyword(s):  
Fatty Acids ◽  
Volatile Fatty Acids ◽  
Dry Weight ◽  
Weight Basis ◽  
Rumen Microorganisms ◽  
Calcium And Magnesium ◽  
Urinary Citrate ◽  
Cis And Trans

Sheep fed diets containing 3�5 and 7� 0% trans�aconitate on a dry weight basis for 5 days appeared normal and maintained normal levels of blood citrate, ketones, and aconitate, but showed large increases in urinary citrate. Calcium and magnesium levels in plasma and urine were not substantially modified. When trans-aconitate was placed in the rumen it disappeared rapidly but did not increase the concentration of rumen volatile fatty acids; blood and urinary aconitate values remained low. trans-Aconitate did not inhibit the fermentation of soluble substrates by rumen microorganisms in vitro. Both cis- and trans-aconitate were fermented slowly.

Sign in / Sign up

Export Citation Format

Share Document