1081 



Li, C. P., N. M. Tauraso, B. Eddy, B. Prescott,and E. C. Martino. 1972. 



Studies on inhibition of viral oncogenesis. III. Effect of clam extracts 

 and methotrexate on tumor formation in male and female hamsters induced by 

 virulent and attenuated adenovirus-12 . Arch. Ges. Virusforsch. 36(3-4): 

 284-295. 



Newborn hamsters were inoculated subcutaneously at birth with adenovirus-12, 

 Hollinshead strain. Four to 5 days later they were treated with Mercenaria 

 mercenaria liver extracts (CLE). Tumor incidence in males, treated and 

 control, was statistically lower than in females. Treated hamsters of both 

 sexes had significantly fewer tumors than controls. During the study the 

 virus lost much of its oncogenicity, but all animals inoculated with virulent 

 or attenuated virus responded to treatment. A total dose of 100-350 meg/ 

 hamster in 2 to 3 injections within 12 days after birth prevented some 

 hamsters from developing tumors in later life. Eleven assay experiments, 

 using 663 hamsters over several years, showed that treatment with clam 

 extracts reduced tumor incidence by 50% or more as compared to controls. 

 - modified authors' summary - J.L.M. 



1082 



Li, C. P., B. Prescott, B. Eddy, G. Caldes, W. P,. Green, E. C. Martino, and 

 A. M. Young. 1965. 



Antiviral activity of paolins from clams. Ann. N.Y. Acad. Sci. 130, Art. 

 1: 374-382. 



Certain substances present in abalone, oyster, queen conch, squid, sea snail, 

 and Mercenaria mercenaria possess significant antibacterial and antiviral 

 activity in vitro and in vivo. Antitumor activity also has been reported. 

 Ammonium sulphate extracts were prepared from Mercenaria mercenaria taken in 

 Aug and Sept (because clams have been reported to possess greater antitumor 

 activity in summer) and separated by Sephadex G-25 into fractions. The major 

 fractions had molecular weights of 9,000 to 10,000, 1,400 to 6,400, and 700 to 

 1,300. They inhibited herpes simplex virus and adenovirus type 12 in tissue 

 cultures. A mixture of fractions 1 and 2 (highest molecular weights) had no 

 effect on herpes simplex virus keratitis in rabbits, but either the ammonium 

 sulphate extract or fractions 1 and 2 reduced tumor formation in hamsters 

 induced by adenovirus type 12. - amended authors' summary - J.L.M. 



1083 



Li, C. P., N. M. Tauraso, B. Prescott, B. E. Eddy, R. C. Hoye , E. C. Martino, 

 G. Caldes, and C. Gorschboth. 1972. 



Intratumor therapy in rodents with aqueous clam extracts. Cancer Res. 32(6): 

 1201-1205. 



Aqueous extract of Mercenaria mercenaria was injected directly into and around 

 small, superficial, slowly growing solid s.c. adenovirus 12 and SV40 virus- 

 induced tumors in hamsters. Treatment was daily or at selected intervals. 

 Half of 74 treated hamsters showed complete tumor regression within 4 weeks 

 of the first injection. No systemic toxicity was observed. Hamsters 

 apparently were normal 4 to 9 months after tumor regression. The remaining 

 treated tumors grew after partial regression and killed the hosts. Controls 

 were 75 tumor-bearing hamsters, which were untreated or treated with placebos, 

 including 8.5% NaCl and heated clam extract. All control tumors grew and 

 killed the hamsters. One-third of melanomas in CDFi mice, similarly treated, 

 showed complete regression. (Abstracter's note: this paper cites some 

 problems of cancer chemotherapy. The drug may be deactivated by the liver or 

 removed by binding to plasma proteins or by rapid excretion. In general, 

 tumors have a relatively poor blood supply and drugs can reach the inner area 

 of the tumor only by diffusion. Thus, although a drug may be a highly 

 selective tumor inhibitor, it may not reach all tumor cells in high con- 

 centration. These facts are important in interpretation of effectiveness of 

 mercenene in cancer therapy, especially when experimental studies that 

 demonstrate high antitumor specificity are based on injection into tumors.) 

 - modified authors' summary - J.L.M. 



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