scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1941 ◽  
Vol 141 (3) ◽  
pp. 775-787 ◽  
Author(s):  
V.R. Potter
Keyword(s):  
Hydrogen Transport ◽  
Animal Tissues

scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1942 ◽  
Vol 142 (2) ◽  
pp. 543-555 ◽  
Author(s):  
V.R. Potter ◽  
W.C. Schneider
Keyword(s):  
Hydrogen Transport ◽  
Animal Tissues

THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

Medicine ◽  
1940 ◽  
Vol 19 (4) ◽  
pp. 441-474 ◽  
Author(s):  
VAN R. POTTER
Keyword(s):  
Hydrogen Transport ◽  
Animal Tissues

scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1943 ◽  
Vol 26 (5) ◽  
pp. 443-455 ◽  
Author(s):  
V. R. Potter ◽  
H. G. Albaum
Keyword(s):  
Alkaline Phosphatase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Cytochrome Oxidase ◽  
Adenosine Triphosphatase ◽  
Succinic Dehydrogenase ◽  
Hydrogen Transport ◽  
Animal Tissues ◽  
Cytochrome C Reductase ◽  
Enzyme Systems

1. The effect of ribonuclease on various enzyme systems was studied as one approach to the problem of whether or not these enzymes are contained in macromolecules of ribonucleoprotein nature in protoplasm. 2. Ribonuclease inhibited CoI-cytochrome c reductase, succinic dehydrogenase, and cytochrome oxidase, all of which require cytochrome c in order to function. Ribonuclease did not act on cytochrome c. 3. Ribonuclease did not inhibit urease, xanthine oxidase, catalase, alkaline phosphatase, or adenosine triphosphatase under the conditions employed. 4. It was suggested that ribonuclease acted sterically by preventing contact between cytochrome c and its activating centers. 5. It was suggested that the enzymes inhibited may be contained in a ribonucleoprotein of macromolecular dimensions but that the enzymes not inhibited are not necessarily excluded from such a complex by the data presented. 6. Further evidence against the Szent-Györgyi theory of hydrogen transport was presented and discussed.

scholarly journals STUDIES ON THE MECHANISM OF HYDROGEN TRANSPORT IN ANIMAL TISSUES

1943 ◽  
Vol 26 (4) ◽  
pp. 391-404 ◽  
Author(s):  
V. R. Potter ◽  
K. P. DuBois
Keyword(s):  
Succinic Dehydrogenase ◽  
Sulfhydryl Group ◽  
Carboxyl Groups ◽  
Common Denominator ◽  
Hydrogen Transport ◽  
Animal Tissues ◽  
Sulfhydryl Reagents ◽  
Sh Groups ◽  
Copper Zinc ◽  
Sulfhydryl Compounds

1. The mechanism of succinic dehydrogenase action was studied by means of inhibitors. 2. The enzyme is inhibited by a large number of diverse compounds whose only common denominator appears to be their ability to react with SH groups. These compounds include quinonoid structures, sulfhydryl reagents, sulfhydryl compounds, copper, zinc, selenite, and arsenite. 3. In contrast to the above inhibitors, the action of malonate does not appear to involve sulfhydryl groups and is explained on the basis of its affinity for the enzyme groups which react with the carboxyl groups of succinate. 4. The action of malonate and the sulfhydryl reactants is mutually exclusive, and this fact suggests the conclusion that the sulfhydryl group of the enzyme is located between the carboxyl affinity points. 5. On the basis of the deduced structure of the succinate-activating center of the enzyme, it is suggested that the enzyme may function by oscillating between the EnSH and EnS· forms, rather than by a thiol-disulfide equilibrium.

A Brief Introduction to Porphyrin Compounds Used in Tumor Imaging and Therapies

2020 ◽  
Vol 20 ◽  
Author(s):  
Lili Pan ◽  
Yu Ma ◽  
Xiaoai Wu ◽  
Huawei Cai ◽  
Feng Qin ◽  
...  
Keyword(s):  
Tumor Imaging ◽  
Photoacoustic Imaging ◽  
Therapeutic Agents ◽  
Biochemical Properties ◽  
Therapeutic Effects ◽  
Future Prospects ◽  
Animal Tissues ◽  
Sonodynamic Therapy ◽  
Porphyrin Derivatives ◽  
Porphyrin Analogues

Abstract:: As a group of heterocyclic macrocycle organic natural compounds occurring universally in animal tissues and plants, porphyrins are composed of four modified pyrrole subunits. Porphyrin analogues/derivatives possess multiple biochemical properties because of their unique structures and have been extensively investigated in cancer treatment. Studies have shown that porphyrins and their derivatives have the ability to locate in tumor cells in a variety of human cancers, and these compounds not only exhibit potent therapeutic effects as photodynamic agents but also show promising properties in medicinal imaging, such as MRI, photoacoustic imaging, fluorescence imaging and PET/SPECT imaging. This paper reviews the recent reports of porphyrin derivatives as therapeutic agents used in tumor therapies, such as sonodynamic therapy, photodynamic therapy and radiotherapy, as well as imaging agents for multimodality tumor imaging. The limitations of porphyrin-based compounds in tumor treatments and future prospects are also summarized.

When animals are not quite what they eat: diet digestibility influences 13C-incorporation rates and apparent discrimination in a mixed-feeding herbivore

2011 ◽  
Vol 89 (6) ◽  
pp. 453-465 ◽  
Author(s):  
Daryl Codron ◽  
Jacqui Codron ◽  
Matt Sponheimer ◽  
Stefano M. Bernasconi ◽  
Marcus Clauss
Keyword(s):  
Isotope Composition ◽  
Stable Carbon Isotope ◽  
Food Sources ◽  
Capra Hircus ◽  
Stable Carbon ◽  
Animal Tissues ◽  
Themeda Triandra ◽  
Low Protein ◽  
Medicago Sativa L ◽  
Discrimination Factors

The stable carbon isotope composition of animal tissues represents the weighted sum of the variety of food sources eaten. If sources differ in digestibility, tissues may overrepresent intake of more digestible items and faeces may overrepresent less digestible items. We tested this idea using whole blood and faeces of goats ( Capra hircus L., 1758) fed different food mixtures of C3 lucerne ( Medicago sativa L.) and C4 grass ( Themeda triandra Forssk.). Although blood and faecal δ13C values were broadly consistent with diet, results indicate mismatch between consumer and diet isotope compositions: both materials overrepresented the C3 (lucerne) component of diets. Lucerne had lower fibre digestibility than T. triandra, which explains the results for faeces, whereas underrepresentation of dietary C4 in blood is consistent with low protein content of the grass hay. A diet switch experiment revealed an important difference in 13C-incorporation rates across diets, which were slower for grass than lucerne diets, and in fact equilibrium states were not reached for all diets. Although more research is needed to link digestive kinetics with isotope incorporation, these results provide evidence for nonlinear relationships between consumers and their diets, invoking concerns about the conceptual value of “discrimination factors” as the prime currency for contemporary isotope ecology.

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