In order to increase the retention of drug activity, regiospecific coupling has been used to synthesize conjugates of methotrexate (MTX, 1) with normal rabbit IgG (NRG) and a mouse anti-human renal cancer monoclonal IgG (Dal K-20). MTX gamma-methyl ester (4) was produced either by selective esterification of MTX or by coupling of 4-amino-4-deoxy-N10-methylpteroic acid (2) with suitable glutamic acid derivatives. The MTX gamma-methyl ester (4) was then converted to the corresponding hydrazide 6. An amide-linked conjugate was formed when the MTX gamma-hydrazide (6) was converted to reactive acylating species 7 by using tert-butyl nitrite or trifluoroacetaldehyde, which were reacted with nucleophilic centers, presumably epsilon-amino groups, in native IgG. A hydrazone-linked conjugate was formed when MTX gamma-hydrazide (6) was reacted directly with IgG that had first been oxidized with periodate to form polyaldehyde IgG. The regiospecifically synthesized conjugates were somewhat more effective inhibitors in vitro of dihydrofolate reductase and of colony formation by human renal cancer (Caki-1) cells than were control nonregiospecific conjugates.
An "optimum acidity" range for fruit jelly-making by the hot method has been reported by different workers. Tarr1 has attached pectin-acid compound significance to this and supports his hypothesis by a series of experiments in which the number of cc. of different acids required to give a definite
The spectrogram of apple pectin ash with which we worked gave the lines of the following elements: Na, K, Ca, Mg, Fe, Al, Mn, Si, and P. Chemical analysis shows the presence of chlorides, sulphates, carbonates and organic acid anions. According to Wiley, 56y0 of the ash of apples, expressed as oxides, is potassium, 9% is phosphorus; Mg, Ca, S, are each present in the neighborhood of 3 7 0 ; the other elements are present in quantities less than one per cent.There are three recognized methods for removing electrolyte impurities from colloid sols: electrodialysis ; reprecipitation; washing by decantation with a non-peptizing solvent.
Methods of PurificationReprecipitatzon by Alcohol: Taking ash content as criterion of efficiency, reprecipitation by alcohol is, in our opinion, the least satisfactory of the three
would be a valuable aid to anybody-having occasion to make use of a reference library,-and the aboveproposed small portable machines carried by investigators and translators may very well be used as "feeders" for the large machine in the home plant. The cost of the bromide paper is about $1.75 per 100 ft., and a 100-ft. roll of paper measures only 4.375 in. wide by 4 in. diameter and has a capacity of about 300 exposures. The entire apparatus weighs but a few pounds and does not occupy more than the table space allotted to any one reader or the space occupied by a large dictionary or several volumes of some periodical, and no reasonable objection to its use can be interposed by any librarian, the argument, if any, being on the side of the reader, inasmuch as the book to be copied may be released for issue to another reader in an incredibly short time after "pushing the button." CONCLUSION There is apparently a need for a portable and cheaply operated photographic device for copying illustrations and articles on file in reference librariesfor the purpose of compiling the technical data needed in an investigation. The experiments described indicate that the use and manufacture of such a device are both within the range of commercial possibility. It is believed that a device combining the operating principles of the existing bromide paper copying machines and the self-illuminated meter-reading cameras would prove to be a valuable aid in data compilation, and simple enough in operation for use by nontechnical clerical assistants. There appears to be no reason why it should not be possible to simply "push the button--and read the book at home." POTASH FROM KELP. II-THE EXPERIMENTAL DIS-TILLATION OF KELP AT LOW TEMPERATURES1
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