Experiments on a spontaneously orginated visceral tumor in the newt, Triturus pyrrhogaster

Is cancer just an incurable infectious disease?

The word 'cancer' is of Latin derivation and means crab. By the turn of the 20th Century organized medicine had come to the conclusion that it was not a matter of whether infectious disease caused cancer, but which one. For over two hundred years a cancer germ had been discovered and rediscovered, named and renamed, each scientist adding to the knowledge, but to no avail. Then, in 1910, certain American medical powers did a 180-degree rotation, deciding that cancer was not caused by a microbe, and that anyone who thought otherwise was a heretic, a charlatan or a quack. But Dr. Virginia Livingston and her network were none of the above, their meticulous peer-reviewed research and publications, done at the height of US post World War II technology. And Dean Burk, Head of Cell Chemistry at the NCI went so far as to say that Livingston's cancer germ was as real and certain as anything known about cancer. Researcher, MD Alan Cantwell Jr. grew up thinking that all germs responsible for the important diseases were supposed to have already been discovered. But much to his dismay, he found one that was left out: the cancer germ. Cantwell already knew that for finding this, Livingston had already been branded by traditional medicine, leaving what he thought to be perhaps the major discovery of the 20th century largely discredited. The striking analogy between cancer and tuberculosis was noticed long before the tubercle bacillus was discovered. In 1877, Sir John Simon clearly pointed out the similarity and in fact argued very strongly in favor of a microbial origin for cancer. But Simon's vindication would have to wait for Livingston's germ, which although tuberculosis-like, was not tuberculosis but an atypical form of this mycobacterium, melded from the mycobacterium and other related Actinomycetales. Had medical science and the powers that be spent as much time in investigating and destroying Livingston's germ as they did in attacking her and those around her, cancer might be curable today.

Gastric leiomyomas in the Japanese newt, Cynops pyrrhogaster; ultrastructural observations

Nineteen of 700 outwardly healthy captive adult Japanese newts, Cynops pyrrhogaster, had nodular neoplasms protruding on the gastric serosal surface. These tumours were characterized as sharply circumscribed leiomyomas of the muscularis externa with occasional submucosal involvement. Ultrastructural analysis of tumour myocytes revealed irregular-shaped, well-differentiated cells with cytoplasmic processes, and reduced quantities of intracellular myofibrils. They were surrounded by enlarged intercellular spaces filled with disorganized and increased amounts of collagen. Vacuolation was seen both in tumour myocytes and in mucous epithelial cells. Virus-like particles were observed in nuclei of some tumour myocytes. Interstitial cells with laminated-type granules were seen amongst tumour cells. These relatively benign leiomyomas shared some morphologic features with human gastric leiomyomas. Their cause and prognosis remain unknown.

Development of the heartbeat during normal ontogeny and during long-term organ culture of hearts of the newt, Cynops pyrrhogaster

Development of cardiac contraction was investigated in the newt, Cynops pyrrhogaster, during normal development and in hearts maintained in long-term organ culture. In the embryos the heart began beating as early as stage 33. The heart rate increased up to stage 52 and then gradually decreased to the adult rate by stage 60. The heart rate showed a logarithmic temperature dependence. In organ-cultured hearts the pattern of heart rate depended on the stage at which the heart was explanted; cultured embryonic hearts showed a pattern of increase and decline similar to that seen in vivo, and hearts explanted near metamorphosis showed only a slow decline.

Teratogenic effects of carcinogenic agents on limb regeneration in the Japanese newt Cynops pyrrhogaster

Normal regeneration of the amputated forelimb of the Japanese newt Cynops pyrrhogaster and regeneration after a single intraperitoneal injection of three potent mutagenic/carcinogenic agents was investigated. Three dose levels of each agent and controls were tested for teratogenicity in this newt model with the following chemicals: N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 4-nitro-quinoline-1-oxide, and 2-(2-furyl)-3-(5-nitrofuryl)acrylamide. These chemicals were administered at 10 days (late dedifferentiation stage), 20 days (late bud stage), and 30 days (early digits stage) after amputation at the midforelimb. A total of 628 newts, with 16-20 animals per group, were used. Normal forelimb regeneration in Cynops pyrrhogaster closely paralleled that reported for other species. A variety of deformities, including syndactyly, polydactyly, oligodactyly, brachydactyly, and digital branching, were occasionally observed in control regenerating forelimbs, with syndactyly occurring at highest incidence (17.5%). All three mutagens at all tested dose levels enhanced the incidence of teratogenic changes, though increases were not always statistically significant. MNNG, particularly when administered at the time of initial chondrogenesis (20 days, late bud stage), was especially teratogenic. The type of forelimb deformity was not mutagen-specific in this experiment. As Cynops pyrrhogaster is easily and inexpensively maintained and tolerates surgery well, this model with the regenerating forelimb should prove useful for further studies on teratogen screening. Also, studies directed toward mutagenic and epigenetic effects of exogenous agents on rapidly proliferating and differentiating tissues can be investigated with this model, which obviates transplacental excursion and metabolism of test compounds.