scholarly journals Porphyrins and Metalloporphyrins: Potential Hypoxic Agents

1996 ◽  
Vol 3 (2) ◽  
pp. 85-89 ◽  
Author(s):  
B. R. James ◽  
G. G. Meng ◽  
J. J. Posakony ◽  
J. A. Ravensbergen ◽  
C. J. Ware ◽  
...  
Keyword(s):  
Copper Complex ◽  
Chinese Hamster Ovary ◽  
Chinese Hamster ◽  
Cobalt Complexes ◽  
Water Soluble ◽  
The Other ◽  
Enhancement Ratio ◽  
Selective Toxicity ◽  
Further Development ◽  
Positively Charged

Synthetic water-soluble porphyrins and their metalloporphyrin derivatives with Co(III), Cu(II), Ru(II) and Pt(II), containing various functional groups within the meso-positions of the porphyrin, were synthesised and evaluated as hypoxic agents, especially as cytotoxins and radiosensitisers. Cobalt complexes of the porphyrins containing positively charged methylpyridinium groups showed selective toxicity toward hypoxic Chinese Hamster Ovary (CHO) cells. The Co(III) complexes of the cationic and the anionic porphyrins are all weak radiosensitisers toward hypoxic cells, the highest sensitisation enhancement ratio (SER = 1.22, at 50 μM) being with a porphyrin complex containing a cis-arrangement of two nitro and two methylpyridinium meso-substituents. A copper complex of a tetracationic porphyrin showed slight radiosensitisation activity with an SER value of about 1.1. The other metalloporphyrins showed no hypoxic selectivity or radiosensitisation activity. In total, over 50 porphyrin free bases have been synthesised, of which half are water-soluble and have been metallated; thus, the chemistry is now in place for further development of water-soluble hypoxic agents.

Review of the current methods of Chinese Hamster Ovary (CHO) cells cultivation for production of therapeutic protein

2020 ◽  
Vol 17 ◽  
Author(s):  
Shazid Md. Sharker ◽  
Md. Atiqur Rahman
Keyword(s):  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Mass Production ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Therapeutic Protein ◽  
Specific Productivity ◽  
Ovary Cells ◽  
Further Development ◽  
Interesting Area

Most of clinical approved protein-based drugs or under in clinical trial have a profound impact in the treatment of critical diseases. The mammalian eukaryotic cells culture approaches, particularly the CHO (Chinese Hamster Ovary) cells are mainly used in the biopharmaceutical industry for the mass-production of therapeutic protein. Recent advances in CHO cell bioprocessing to yield recombinant proteins and monoclonal antibodies have enabled the expression of quality protein. The developments of cell lines are possible to upgrade specific productivity. As a result, it holds an interesting area for academic as well as industrial researchers around the world. This review will concentrate on the recent progress of the mammalian CHO cells culture technology and the future scope of further development for the mass-production of protein therapeutics.

Properties of Latex-Insulated Wire

1935 ◽  
Vol 8 (4) ◽  
pp. 635-640
Author(s):  
J. McGavack
Keyword(s):  
Nineteenth Century ◽  
Patent Protection ◽  
Water Soluble ◽  
The Other ◽  
Insulation Material ◽  
Further Development

Abstract In 1863 latex was proposed and actually used to insulate wire. Siemens had the happy thought of employing this material to cover conductors and actually went so far as to obtain patent protection for his idea. From that time until recently, there has been practically nothing accomplished in the manner directed by Siemens. In fact, no commercial insulation material resulted from the idea proposed in the middle of the nineteenth century. It is not hard to see why such a plausible idea was abandoned. The insulation obtained in the manner disclosed by Siemens was not nearly as good as the other known methods for insulating wire. Conductors covered by the method then proposed could not be used in water or where any moisture was present. There were too many water-soluble materials in the latex; and as no method was known at that time to remove these materials from latex without coagulating the latex itself, no further development was accomplished.

Characteristics of nonpathogenic strains of Listeria monocytogenes

1991 ◽  
Vol 37 (8) ◽  
pp. 647-650 ◽  
Author(s):  
J. M. Farber ◽  
J. I. Speirs ◽  
R. Pontefract ◽  
D. E. Conner
Keyword(s):  
Listeria Monocytogenes ◽  
Key Words ◽  
Chinese Hamster Ovary ◽  
Cho Cells ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
The Other ◽  
Ovary Cells

Five strains of nonpathogenic Listeria monocytogenes were characterized for (i) hemolysin production, (ii) cytolysis of Chinese hamster ovary (CHO) cells, and (iii) ability to attach and enter intestine 407 cells. Four of the five strains produced variable hemolysis and were weakly cytolytic for Chinese hamster ovary cells, whereas the other isolate was consistently hemolytic and strongly cytolytic for CHO cells. None of the strains was able to penetrate intestine 407 cells. In addition, two of the five strains were found to be nonmotile. Key words: Listeria monocytogenes, nonpathogenic, attachment, motility, hemolysis.

Malignancy-related characteristics of wild type and drug-resistant chinese hamster ovary cells

Pathology ◽  
1993 ◽  
Vol 25 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Wanda B. Mackinnon ◽  
Marlen Dyne ◽  
Rebecca Hancock ◽  
Carolyn E. Mountford ◽  
Adrienne J. Grant ◽  
...  
Keyword(s):  
Chinese Hamster Ovary ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Drug Resistant ◽  
Wild Type ◽  
Ovary Cells

The effect of cation concentration on the nitrogen splitting constant of nitroxide free radicals

1990 ◽  
Vol 55 (10) ◽  
pp. 2377-2380
Author(s):  
Hamza A. Hussain
Keyword(s):  
Hydrogen Peroxide ◽  
Hydrogen Bonding ◽  
Free Radicals ◽  
Esr Spectroscopy ◽  
The Other ◽  
Tetraethylammonium Bromide ◽  
Splitting Constant ◽  
The One ◽  
Positively Charged ◽  
Two Equilibria

Nitroxide free radicals prepared from diethylamine, piperidine and pyrrolidine by oxidation with hydrogen peroxide were studied by ESR spectroscopy. The changes in the 14N splitting constant (aN) caused by the addition of KBr or tetraethylammonium bromide were measured in dependence on the concentration of the ions. For diethylamine nitroxide and piperidine nitroxide, the results are discussed in terms of two equilibria: the one, involving the anion, is associated with a gain or loss of hydrogen bonds to the nitroxide oxygen atom, the other is associated with the formation of solvent shared units involving the cation, which results in changes in the hydrogen bonding strenght. The large increase in the aN value in the case of pyrrolidine nitroxide is explained in terms of an interaction from one side of the positively charged N atom; the increase in aN in the case of diethylamine and piperidine nitroxides is explained in terms of interactions with both sides of the positively charged N atom.

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