A high-performance instrumentation system to measure the fluorescence kinetics of plants for in vivo photosynthesis research

2001 ◽  
Vol 50 (3) ◽  
pp. 679-689 ◽  
Author(s):  
G. Bulgarea ◽  
M. Boukadoum
Keyword(s):  
High Performance ◽  
Fluorescence Kinetics ◽  
Photosynthesis Research ◽  
Kinetics Of

scholarly journals In Vivo Two-Photon Fluorescence Kinetics of Primate Rods and Cones

2016 ◽  
Vol 57 (2) ◽  
pp. 647 ◽  
Author(s):  
Robin Sharma ◽  
Christina Schwarz ◽  
David R. Williams ◽  
Grazyna Palczewska ◽  
Krzysztof Palczewski ◽  
...  
Keyword(s):  
Fluorescence Kinetics ◽  
Rods And Cones ◽  
Two Photon ◽  
Two Photon Fluorescence ◽  
Photon Fluorescence ◽  
Kinetics Of

scholarly journals A Novel Pet Tracer 18f-labeled Thiamine: Synthesis, Metabolic Kinetics, and Evaluation on Cerebral Thiamine Metabolism Status

2020 ◽  
Author(s):  
Changpeng Wang ◽  
Siwei Zhang ◽  
Yuefei Zou ◽  
Hongzhao Ma ◽  
Donglang Jiang ◽  
...  
Keyword(s):  
High Performance ◽  
Metabolic Kinetics ◽  
Thiamine Metabolism ◽  
Pet Tracer ◽  
Positron Emission ◽  
Computer Tomography Imaging ◽  
The Status ◽  
Kinetics Of

Abstract Background:Someneuropsychological diseases are associated with abnormal thiamine metabolism, including Korsakoff-Wernicke syndrome and Alzheimer’s disease. However, in vivo detection of brain thiamine metabolism status isstill unavailable and needs to be developed.Methods:A novel PET tracer 18F-labeled thiaminewasautomatically radio-synthesized via a two-step route. The main parameters of characterization were proved by high performance liquid chromatography (HPLC). Metabolic kinetics of 18F-labeled thiamine and the status of cerebral thiamine uptakein mice and marmosets were studied by micro-positron emission tomography (PET)/computer tomography imaging. Also, in vivo stability, renal excretion rate, biodistribution, and the correlation between cerebral 18F-labeled thiamine retention and blood thiamine levels were investigated.Results: The 18F-labeled thiamine was stableboth in vitro and in vivoand manifested fast uptake and clearance in vivo. The biodistribution of 18F-labeled thiamine were consistent with previously reports on thiamine distribution in mice. The retention of cerebral 18F-labeled thiamine was higher in mice with thiamine deficiency than that in control mice, and negatively correlated with blood thiaminediphosphate levels in marmosets.Conclusion:The 18F-labeled thiamine met the requirements for ideal PET tracer to in vivoevaluate the status of cerebral thiamine metabolism. This study laid the foundation for further studies on the relevant diseases.

Effect of pH and inhibitors on beta-amyloid fibril assembly

1996 ◽  
Vol 54 ◽  
pp. 752-753
Author(s):  
Beverly E. Maleeff ◽  
Timothy K. Hart ◽  
Stephen J. Wood ◽  
Ronald Wetzel
Keyword(s):  
Amyloid Fibril ◽  
Peptide Fragment ◽  
Hydrophobic Peptides ◽  
Amyloid Fibril Formation ◽  
Effects Of Ph ◽  
Severity Of The Disease ◽  
Kinetics Of ◽  
The Brain

Alzheimer's disease is characterized post-mortem in part by abnormal extracellular neuritic plaques found in brain tissue. There appears to be a correlation between the severity of Alzheimer's dementia in vivo and the number of plaques found in particular areas of the brain. These plaques are known to be the deposition sites of fibrils of the protein β-amyloid. It is thought that if the assembly of these plaques could be inhibited, the severity of the disease would be decreased. The peptide fragment Aβ, a precursor of the p-amyloid protein, has a 40 amino acid sequence, and has been shown to be toxic to neuronal cells in culture after an aging process of several days. This toxicity corresponds to the kinetics of in vitro amyloid fibril formation. In this study, we report the biochemical and ultrastructural effects of pH and the inhibitory agent hexadecyl-N-methylpiperidinium (HMP) bromide, one of a class of ionic micellar detergents known to be capable of solubilizing hydrophobic peptides, on the in vitro assembly of the peptide fragment Aβ.

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.

Hepatobiliary Kinetics of 113mIn-Phenolphthalexon

1981 ◽  
Vol 20 (02) ◽  
pp. 90-93
Author(s):  
P.B. Parab ◽  
U.R. Raikar ◽  
R.D. Ganatra ◽  
M. C. Patel
Keyword(s):  
Biliary Excretion ◽  
Iminodiacetic Acid ◽  
Organ Distribution ◽  
Liver Uptake ◽  
On Line ◽  
Rapid Clearance ◽  
Chemical Purity ◽  
Kinetics Of ◽  
High Liver

Phenolphthalexon, a compound with iminodiacetic acid as a functional group, has been labelled with 113mIn to high chemical purity and its usefulness in studies of biliary excretion patency has been studied. Organ distribution of 113mIn-phenolphthalexon in mice was characterized by high liver uptake (50.8% of the administered dose after 5 min) and rapid clearance through the gall bladder. An animal model for studying obstruction of biliary excretion has been developed. Data on the kinetics of the radiopharmaceutical were obtained by collecting in-vivo data through an on-line computer.

Continuous Quantitative Monitoring of Mural, Platelet-Dependent, Thrombus Kinetics in the Crushed Rat Femoral Vein

1991 ◽  
Vol 65 (04) ◽  
pp. 425-431 ◽  
Author(s):  
F Stockmans ◽  
H Deckmyn ◽  
J Gruwez ◽  
J Vermylen ◽  
R Acland
Keyword(s):  
Thrombus Formation ◽  
Femoral Vein ◽  
Maximum Size ◽  
Digital Analysis ◽  
Video Recordings ◽  
Quantitative Monitoring ◽  
Set Up ◽  
Kinetics Of ◽  
Quantitative Nature

SummaryA new in vivo method to study the size and dynamics of a growing mural thrombus was set up in the rat femoral vein. The method uses a standardized crush injury to induce a thrombus, and a newly developed transilluminator combined with digital analysis of video recordings. Thrombi in this model formed rapidly, reaching a maximum size 391 ± 35 sec following injury, after which they degraded with a half-life of 197 ± 31 sec. Histological examination indicated that the thrombi consisted mainly of platelets. The quantitative nature of the transillumination technique was demonstrated by simultaneous measurement of the incorporation of 111In labeled platelets into the thrombus. Thrombus formation, studied at 30 min interval in both femoral veins, showed satisfactory reproducibility overall and within a given animalWith this method we were able to induce a thrombus using a clinically relevant injury and to monitor continuously and reproducibly the kinetics of thrombus formation in a vessel of clinically and surgically relevant size

Acquired Haemophilia: Functional Study of Antibodies to Factor VIII

1981 ◽  
Vol 45 (03) ◽  
pp. 285-289 ◽  
Author(s):  
J P Allain ◽  
A Gaillandre ◽  
D Frommel
Keyword(s):  
Factor Viii ◽  
Functional Study ◽  
Factor Viii Inhibitor ◽  
Acquired Haemophilia ◽  
Viii Inhibitor ◽  
Kinetics Of ◽  
Antibody Function ◽  
Native Plasma

SummaryFactor VIII complex and its interaction with antibodies to factor VIII have been studied in 17 non-haemophilic patients with factor VIII inhibitor. Low VIII:C and high VIIIR.Ag levels were found in all patients. VIII:WF levels were 50% of those of VTIIRrAg, possibly related to an increase of poorly aggregated and electrophoretically fast moving VIIIR:Ag oligomers.Antibody function has been characterized by kinetics of VIII :C inactivation, saturability by normal plasma and the slope of the affinity curve. Two major patterns were observed:1) Antibodies from 6 patients behaved similarly to those from haemophiliacs by showing second order inhibition kinetics, easy saturability and steep affinity slope (> 1).2) Antibodies from other patients, usually with lower titres, inactivated VIII :C according to complex order kinetics, were not saturable, and had a less steep affinity slope (< 0.7). In native plasma, or after mixing with factor VIII concentrate, antibodies of the second group did not form immune complexes with the whole factor VIII molecular complex. However, dissociation procedures did release some antibodies from apparently low molecular weight complexes formed in vivo or in vitro. For appropriate management of non-haemophilic patients with factor VIII inhibitor, it is important to determine the functional properties of their antibodies to factor VIII.

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