Urinary Bladder Neoplasms Induced by Feeding Bracken Fern (Pteris Aquilina) to Cows1

[CANCER RESEARCH 27 Part 1, 917-924, May 1967]

Urinary Bladder Neoplasms Induced by Feeding Bracken Fern (Pteris aquilina) to Cows1

A. M. PAMUKCU [1], S. K. GOKSOY [1], AND J. M. PRICE [2]

[/] Department of Pathological Anatomy, College of Veterinary Medicine, University of Ankara, Ankara, Turkey, and Division of Clinical Oncology, University of Wisconsin Medical School, Madison, Wisconsin 53706

SUMMARY recovered from tumors of the bovine urinary bladder (16). The behavior of the infectious agent in test calves resembles that The chronic toxicity of bracken fern (Pteris aquilina) har of the bovine cutaneous papilloma virus. It may be a passenger vested near Bolu, Turkey, where bovine bladder tumors occur virus and not related to the etiology of the bladder tumors. The in a high incidence, was tested by feeding the plant to 18 cows bladder tumors produced with this agent (16) and with the of native stock ranging from 1.5 to 4 years of age. The cows bovine cutaneous papilloma virus (2) were self-limiting. weighed from 100 to 150 kg and were fed from 300 to 600 gm Bracken fern (Pteris aquilina) has often been associated with of dried or 400 to 1000 gm of fresh plant daily in an attempt to the occurrence of chronic hematuria (3, 19, 20, 23). Fatal poison simulate natural exposure in the field. Of 18 animals fed bracken ing of cattle with bracken fern has been reproduced by many fern, 10 developed neoplasms of the urinary bladder and 3 of investigators by feeding either fresh fronds, sun-dried bracken, these lesions were carcinomas. The 2 carcinomas which invaded or powdered rhizomes mixed with an otherwise adequate diet the muscular wall of the urinary bladder were found 2.6 and 3.3 (5, 20, 23) and with a fraction extracted from the bracken plant years after the initiation of feeding. The 8 animals which died of with boiling ethanol (9). The bracken plant is known to contain toxicity without evidence of bladder neoplasms after a mean substances with radiomimetic activity. A high level of bracken feeding time of 163 days included 5 of the 7 animals fed the in the diet of cattle caused a hemorrhagic syndrome in which highest dosage of bracken. Most of the animals which develojied there was panmyeloid bone marrow damage. Widespread pete- bladder lesions were fed bracken at a lower dietary level for a chial hemorrhages (6-8) were also seen in these animals. mean period of 550 days (range, 276 to 1192 days). Ten control Recently it has been found that, following the continuous animals not exiiosed to bracken fern did not manifest any clini feeding of a low level of bracken in the ration over a period of cal symptoms during the experiment. The histologie appearance many months, polypoid bladder lesions (23) and tumors have of the neoplasms and other parameters of the study suggest been observed in cattle (20). Georgiev et al. (12) obtained an that this experiment has resulted in the production of lesions extract from the urine of cattle fed hay from hematuria areas that are indistinguishable from the naturally occurring bovine which, when introduced into the urinary bladder of dogs, bladder tumors which are a common feature of bovine enzootic produced changes similar to hemangiomas in a dog. When the hematuria. These results provide further evidence for the pres same extract was applied to the skin of white mice, papillo- ence of a carcinogenic substance in bracken fern. mas were produced. An extract of urine from cattle in the hematuria region of INTRODUCTION Bulgaria produced hematuria, capillary proliferations, and Although urinary bladder tumors were once common in the adenomatous proliferations in the bladder walls of calves, dogs, Pacific Northwest of North America, they are now rarely seen and rate, respectively, when surgically introduced into the in the United States (1). Bladder tumors are frequently found bladders of these animals (11). When an acetone solution of in cattle in various parts of the world such as Turkey, Yugo this extract was applied to the skin of mice, papillomas devel slavia, Bulgaria, Panama, and Brazil (3, 20). The tumors are oped. Some papillomas changed into epidermoid carcinoma and commonly associated with a syndrome known as chronic enzootic carcinosarcoma (11). Similar resulte were obtained with an hematuria (17, 18). The pathologic features and clinical course extract of urine from a healthy cow fed hay from the hematuria of these neoplasms (19) resemble human industrial and non- area in Bulgaria. When this extract was applied to the skin of industrial bladder tumors (14). mice, it produced papillomas and carcinomas (10). By biologic The etiology of the naturally occurring bovine urinary bladder teste, we were able to demonstrate that the acidic fraction of tumors remains obscure. Recently, a papilloma-like virus was urine from bracken-fed cattle contained one or more carcin ogenic substances which induced a relatively high incidence of carcinoma (33%) in the transitional epithelium of the mouse 1This investigation was supported by Grant FG-TU-102 of the bladder (21). United States Department of Agriculture, Agricultural Research Service, and by USPHS Research Grant No. CA-08254 from the Evans and Mason (4) reported the development of intestinal National Cancer Institute. adenocarcinoma in rate fed bracken fern. A survey by Parker Received June 24, 1966; accepted December 29, 1966. and McCrea (22) for bracken poisoning of sheep on the North

MAY 1967 917

TABLE 1 each animal after it died or was killed. The urinary bladders The Amount of Bracken Fern Supplement Fed to the Four Groups of were distended postmortem with 10% formalin solution injected Animals into the urethra. After the fixation of the bladder, a specimen was taken for histologie examination. The paraffin sections were supplement ofanimals7443Bracken(gm/animal/day)Dried600500400300Fresh1000600500400stained with hematoxylin and eosin. Special staining methods GroupininIVNo. were used when necessary, but all photomicrographs (Figs. 2- 12) were from sections stained with hematoxylin and eosin. The urinary bladders of all but 4 of the control animals were obtained and examined for comparison with those of the test animals.

RESULTS The development of manifestations of toxicity apj>eared to be Yorkshire Moors revealed that a number of older animals from dÃ©tendentupon the amount of bracken fern fed to each animal. areas infested with bracken died of the same type of tumor as Signs typical of poisoning api>eared in 3 animals (Cows 2, 3, and that produced in rats fed a bracken diet [cited by Evans and 4) out of 7 in the 1st group in a j^eriod of 46 to 67 days after the Mason (4)]. administration of 600 gm of dried or 1000 gm of fresh bracken These results suggest that bracken fern may be one of the per day. The animals in the 4th group, which received 300 gm factors responsible for the high incidence of bladder tumors in of dried or 400 gm of fresh bracken daily, survived longer than bovine species in those parts of the world where cattle receive a did the animals in the other 3 groups. However, the animals in continuous low level of bracken by eating the fresh plant or the each group showed considerable individual variation in reac dried plant which may be mixed with hay. It was felt worth tions to the toxic effects of bracken. For example, Cow 1, fed a while to investigate the possible carcinogenic activity of bracken high level of bracken fern, survived longer than did most of the directly by feeding the plant to cattle. The results of the bracken animals which received a smaller amount of bracken (Table 2). fern feeding experiment are the subject of this report. Three hundred gm of dried bracken per day appeared to be most suitable for the production of chronic toxicity and bladder neo MATERIALS AND METHODS plasms. Clinical Findings. An early sign of chronic toxicity con Eighteen cows of native stock ranging from 1.5 to 4 years of sisted of hematuria which began as microhematuria and then age and weighing from 100 to 150 kg were fed bracken fern develo[)ed into macrohematuria, causing discoloration of the (Pteris aquilina) obtained from the vicinity of Bolu, Turkey. urine in a few cases. However, in 1 animal (Cow 8), macrohema The experimental animals were obtained from herds near Ankara turia became apparent without previous observation of micro where bovine bladder tumors do not occur. The animals were hematuria. In 8 cases (Cows 1, 5, 7, 11, 13, 14, 15, and 21), only kept in a barn at Bolu near the source of the bracken. Although microhematuria was observed. Microhematuria associated with the syndrome of acute bracken poisoning has not been observed macrohematuria was observed in 3 animals (Cows 6, 9, and 954). in the region of Bolu, bladder tumors occur very frequently. The The duration of feeding had a great influence on the develop bracken was harvested in July and was spread out to dry first in ment and continuation of hematuria. The minimal period of the sun for a day and then in the shade. It was chopped in a time required for producing microhematuria was 67 days of hay cutter before being introduced into the diet. In the summer, bracken feeding. Hematuria was insidious in development and chopped fresh green bracken was administered to the animals. was characterized by a slow and progressive increase with fre The amounts of bracken fern supplement fed to the animals in quent intermissions of variable duration lasting from a few days each of 4 experimental groups are shown in Table 1. to several months. In the early stages of feeding of bracken, no Fourteen additional cows of the same age and breed but not systemic disturbance of any kind was observed. There was no exposed to bracken fern were used as control animals. Twelve rise in body temara ture or loss of weight. of the animals were fed hay and straw, collected from nonhema- Bracken poisoning was associated with hÃ©matologiechanges turic areas, for a period of 4 years. Eight of these 12 controls in 11 of the 18 animals. The main feature was a progressive were autopsied at the end of the study. The other 4 animals in diminution in the number of white cells and platelets in the this group are still under observation. All of the test animals peripheral blood. The changes reached maximum proportions a and the other 2 control animals received the same basic diet of few days before the death of the animal (Table 2). The fall in timothy and alfalfa hay and a standard dairy feed supplement the total number of leukocytes was associated with a drastic (1% salt, 27% corn, 27% bran, 27% oats, and 18% linseed oil diminution in the number of polymorphs. The inversion of the meal). The calculated amount of chopiied bracken, either dried numbers of polymorphs and lymphocytes suggested that bracken or fresh, was mixed with the basic diet given individually to feeding severely damaged the bone marrow. These changes were each test animal once a day. The feeding experiment was started coincident with a fall in the numbers of the platelets in most on June 1, 1961, and continued for more than 4 years. cases (Table 2). The blood changes apjieared not to be affected The clinical signs and symptoms displayed by the test and by the duration of feeding. Cows 5, 6, 15, and 16 received bracken control animals were closely observed and recorded. Urine was for 302, 978, 327, and 276 days, respectively, and these 4 ani examined for blood periodically. Blood cell counts and differen mals did not develo]) significant blood changes. In contrast with tial leukocyte counts were made. Necropsy was ijerformed on the marked fall in the number of platelets and white cells, the

918 CANCER RESEARCH VOL. 27

TABLE 2 Leukocyte and Platelet Counts and Differential Leukocyte Counts of the Animals at a Late Stage of the Toxic Keaction io Bracken Feeding

countsWBC(lO'/cumm)10.07.17.37.88.03.05.02.93.07.210.01.71.31.51.00.03.54.9Platelets (%)Poly- Group time No.IIIIIIIVAnimalNo.1234578131415169111218621954Cell (days)3956752403021133602803503272769363743782189781541192Hematuria+â€”â€”â€”++++++-+++++++

(lO'/cumm)5.56.86.35.96.52.03.01.01.55.55.01.70.82.00.52.53.14.5Differentialleukocytecountsmo rnho- nuclear26111024120000182600002885Lymphocyte5278806376100941001006806100100100100568590Mono-cyte666770600850000243Eosino-phil6546500005300001435Baso-phil000000000100000000Survival

number of red blood cells per cu mm remained within normal weight, the animals were not very emaciated since subcutaneous limits until severe macrohematuria and terminal hemorrhages and omental fat was present. occurred. Hemorrhages were also noted in the alimentary tract, heart, Toward the end of the experiment, a few animals exhibited a gall bladder, nasal mucosa, tongue, larynx, trachea, lungs, and loss of condition and their hair became rough and staring. Flesh pancreas; in the capsule of the spleen but not in its substance; was lost particularly from the hind quarters. Some cows did not under the capsules and in the hili of lymph nodes; under the show any marked loss of condition. Body temperature rose to capsules of the adrenal glands and thyroid; in the mammary about 107 to 108Â°Fin 9 of the 18 animals (Cows 7, 9, 11, 12, gland, ovaries, uterus, cervix, and kidneys; in the aorta; external 13, 14,15,18, and 954) up to 12 days prior to death. Hemorrhages to and in the dura mater and under the pia mater. No hemor from the nose and blood in the feces were observed in 6 of these rhages were observed in the brain itself, and there were no hem animals with high body temperature (Cows 7, 11, 14, 15, 18, orrhages into the joint cavities. and 954). Diarrhea followed constipation in 2 animals (Cows 12 By gross inspection, small white necrotic areas from pin-point and 18). size up to 5 cm in diameter were noted in the liver of 11 animals All the animals in the 4 groups fed bracken died with some (Cows 1, 4, 5, 7, 11, 12, 13, 14, 15, 18, and 21). The subcapsular signs of bracken poisoning. Death was due to extensive internal lesions tended to be triangular in section. In Cows 9 and 16, the hemorrhage or other manifestations of bracken poisoning. lesions were yellow in color and were often near a portal vein. The 14 animals not exposed to bracken fern did not manifest In every cow fed bracken, there were multiple submucosal any clinical symptoms during the experiment. There were no hemorrhages extending throughout the urinary tract from the blood changes or blood in the urine of these animals. calyces of the kidneys to the urethra. The degree of hemorrhage Postmortem Findings. The primary feature of bracken varied from pin-point lesions to confluent hemorrhages showing poisoning was multiple hemorrhages throughout the carcass, but almost complete infiltration of the submucosa. There was no their degree and location varied. Hemorrhages were observed in obvious gross ulcÃ©ration.Pieris cuÂ¿uÃ¼inaalsocaused hyperplastic the subcutaneous tissues, in the fasciai planes, in the muscles, and neoplastia changes in the epithelial and stromal layers of serosae, subserosae, mucosae, and submucosae. The subcutane ous tissue of the neck and the lumbar region of 3 animals (Cases the urinary bladder in 10 of the 18 animals. 1, 5, and 7) was grossly edematous and gelatinous in appearance. Tumors were observed macroscopically in only 3 animals The mediastinum and subpleural tissue of the right lung of 1 (Cows 6, 9, and 954), and in 7 animals (Cows 1, 8, 11, 12, 13, animal had a similar gelatinous appearance. Although they lost 15, and 16) more clearly microscopically (Table 3). The macro-

MAY 1967 919

TABLE 3 Salient Features of Urinary Bladder Tumors Induced by Bracken Feeding and Survival Time of Animals

consumed tumorsEpithelialPapillomaPapillomaPapillomaPapillomaclassification of Group (kg/animal)Fresh6000183(>189030304872Dried192180125134123285120114249292Survival No.IIIIIIIVAnimalNo.18131516911126954Bracken time (days)3953602803272769363743789781192Histologie stromalPapillomaand

and capil laryhemangiomaTransitional

cell car heman-gioendotheliomaCapillarycinoma and

andtransitional cellcarcinomaPapillomaEpithelial

hemangiomaSquamous cell car cinoma and heman giomaStromalFibroma scopic api>earance of tumors in these 3 cases (Cows 6, 9, and with small round cells and mononuclear cells in the portal triad, 954) is described below. particularly in relation to infarcts. No fibrosis was found (Fig. Case 6. Hemangiomas were situated at various sites in the 2). The wedge-shaped hemorrhagic areas seen under the capsule mucosa of the urinary bladder as dark-red patches varying from of kidneys were infarcts. a pinhead up to a few cm in diameter. They were of rather firm The histologie changes in the urinary bladders showed great consistency. The tumors were capillary hemangiomas (Fig. 12). variations (Figs. 3-6), including hy|x>rplastic, metaplastic, and Case 9. Lesions in the bladder consisted of a vascular growth neoplastic changes. The histology of the lesions (Figs. 7-9, 12) and multiple sessile nodules. The vascular tumor was located at was similar to that described by others (17, 18) for the spon the trigone region of the bladder. It presented as a dark-red, taneous Ijovine bladder cancers. The tumors of epithelial or sharply defined patch 1 by 3 cm in size. The tumor was of soft mesenchymal origin developed in the urinary bladder of 10 of consistency, and blood could be expressed from it by pressure. the 18 cows which survived for a prolonged jxriod of bracken Histologie examination revealed that the tumor was a hemangio- feeding. Of these tumors, 7 were benign, including transitional endothelioma. The multiple sessile nodules which were firm and cell papillomas, a fibroma, and capillary hemangiomas. The grayish white in color were distributed throughout the bladder remaining 3 tumors were found to be malignant neoplasms con mucosa. The surface epithelium was smooth. The nodules were sisting of transitional or squamous cell carcinomas and a hemangi- firmly attached to the mucosa and were histologically diagnosed oendothelioma (Table 3). A relatively high incidence of tumors as transitional cell carcinoma. The tumors were contiguous and a high degree of malignancy followed bracken feeding lasting and infiltrated the submucosa. No metastasis was detected. longer than 1 year. Two of the 3 carcinomas (Cases 9 and 954) Case 954. The bladder contained a large blood clot. Lesions in developed in animals that survived more than 936 days and the bladder consisted of small congested patches of mucous penetrated the muscle wall (Figs. 9, 10), whereas the other membrane, punctate hemorrhagic foci, papillomas, and domelike carcinoma (Case 11) developed in only 374 days and was confined nodules distributed throughout the bladder (Fig. 1). The wall to the submucosa (Fig. 11). No gross or microscopic metastasis of the bladder was greatly thickened. The tumors infiltrated into was found in any of the animals. the muscular coat and reached the subserosa. The serosal surface The urinary bladders of the 10 control animals did not show of the bladder was nodular. No metastasis to the iliac lymph any gross or microscopic changes. These 10 controls and the 4 nodes or to distant organs was detected (Figs. 7-10). living controls did not have hematuria, blood changes, or other Histologie findings. Microscopically, the main lesions were signs or symptoms. hemorrhages scattered throughout the various organs. The pathologic changes in the livers consisted of centrilobular DISCUSSION necrosis, fatty degeneration, hemorrhagic or ischemie infarcts The hypothesis that bracken fern may be related to the etiology associated with bacteria or fibrin, and occasionally infiltration of bovine urinary bladder tumors obtained its first experimental

920 CANCER RESEARCH VOL. 27

support in the relatively long-term feeding trials by Rosenberger 5. Evans, W. C. Bracken Poisoning of Farm Animals. Vet. and Heeschen (23) and Pamukcu (20). Recently, Evans and Record, 76: 365-369, 1964. Mason (4) produced intestinal adenocarcinoma in rats with 6. Evans, W. C., Evans, E. T. R., and Hughes, L. E. Studies on bracken feeding. The effect of ingestion of bracken on the Bracken Poisoning in Cattle. I. Brit. Vet. J., 110: 295-306, constituents in the urine of cattle was studied by Doebereiner 1954. (3), who found no detectable differences with respect to content 7. Evans, W. C., Evans, E. T. R., and Hughes, L. E. Studies on of diazotizable aromatic amines or phenols. Biologic tests (10-12, Bracken Poisoning in Cattle. II. 1950 Bracken Poisoning Experiments (Lluest Farm). Brit. Vet. J., 110: 365-380, 1954. 21), however, have demonstrated that urine from cattle in the 8. Evans, W. C., Evans, E. T. R., and Hughes, L. E. Studies on hematuria regions, from cows fed hay from the hematuria Bracken Poisoning in Cattle. III. Field Outbreaks of Bovine districts, or from cattle fed bracken fern contained some carcino Bracken Poisoning. Brit. Vet. J., 110: 426-442, 1954. genic agent which induced tumors in the bladders of the calf, 9. Evans, W. C., Evans, I. A., Thomas, A. J., Watkins, J. E., dog, rat, or mouse and tumors in the skin of mice. The present and Chamberlain, A. G. Studies on Bracken Poisoning in studies demonstrated that bracken contained one or more sub Cattle. IV. Brit. Vet. J., 114: 180-198, 1958. stances which induced a relatively high incidence of benign 10. Georgiev, R., and Antonov, S. Ãœberdie Ã„tiologie der chroni tumors and carcinomas in the bladders of 18 cows (Table 3). schen vesikalen HÃ¤maturie der Rinder. II. Mitteilung. Ver The development of malignant tumors in the transitional epi suche zur Feststellung der Anwesenheit kanzerogener Metaboliten im Harn gesunder KÃ¼heaus einem HÃ¤maturie- thelium of the bovine bladder required a long period of feeding of freien Gebiet bei FÃ¼ttsrung mit Heu aus HÃ¤maturiegebieten. a low level of bracken. The carcinomas (Grade II) developed in Wien. Tieraerztl. Monatsschr., 6%:90-94, 1965. 2 cases (Cows 9 and 954) about 3 years after the initiation of 11. Georgiev, R., Antonov, S., Vrigasov, A., Dimitrov, A., and feeding. The animals in each feeding group at different levels of Goranov, C. Ãœber die Ã„tiologie der chronischen vesikalen bracken in the diet showed considerable individual variation in HÃ¤maturie der Rinder. I. Mitteilung. Zur Frage des karzino- their reaction to the toxic effects of bracken. Ingestion of 300 matÃ¶sen Charakters der chronischen vesikalen HÃ¤maturie der gm of dried bracken per day appeared to be relatively nontoxic Rinder. Wien. Tieraerztl. Monatsschr., 51: 641-657, 1964. and most suitable for producing chronic toxicity and neoplasms 12. Georgiev, R., Vrigasov, A., Antonov, S., and Dimitrov, A. in cows weighing from 100 to 150 kg. Toxicity in the animals was Versuche zur Feststellung der Anwesenheit kanzerogener Stoffe im Harn der mit Heu aus HÃ¤maturiegebieten gefÃ¼tterten associated with an inversion of the numbers of polymorphs and KÃ¼he.Wien. Tieraerztl. Monatsschr., 50: 589-595, 1963. lymphocytes. This inversion was coincident with the fall in the 13. Kwasniewski, V. Die Inhaltstoffe der Rhizome des Adlerfarns, numbers of thrombocytes in most cases. Platelet and differential Pteridium aquilinum (L.) KÃ¼hn. Arch. Pharm., 888: 307-311, leukocyte counts might be used as a guide to monitor Â¡mending 1955. serious acute toxicity. 14. Mostofi, F. K. Pathology of Cancer of Bladder. Acta UniÃ³ The nature of the carcinogenic substance in bracken and in Intern. Contra Cancrum, 18: 611-615, 1962. the urine of cows fed bracken has not been determined. A variety 15. Nakabayashi, T. Isolation of Astragalin and Isoquercitrin of chemicals, suchasastragalin, isoquercitrin, rutin (15), catechol- from Bracken, Pteridium aquilinum. Bull. Agr. Chem. Soc. tannins, pteraquilin, sugar, starch, aliphatic nondrying oil, and Japan, 19: 104-109, 1955. much pectose mucin (13), have been identified in bracken; yet 16. Olson, C., Pamukcu, A. M., and Brobst, D. F. Papilloma-like Virus from Bovine Urinary Bladder Tumors. Cancer Res., there is no indication that these chemicals or their metabolites 25: 840-849, 1965. may be bladder carcinogens. 17. Pamukcu, A. M. Investigations on the Pathology of Enzootic The results obtained in this study are in agreement with the Bovine Haematuria in Turkey. Zentr. Veterinaermed., 2: findings of others (10-12, 20, 21) who have presented evidence 409-429, 1955. for the carcinogenic activity of bracken fern. Although the num 18. Pamukcu, A. M. Tumors of the Urinary Bladder in Cattle and ber of animals in the present study was small, the histologie Water Buffalo Affected with Enzootic Bovine Hematuria. spectrum of the lesions resembles that found naturally occurring Zentr. Veterinaermed., 4: 185-197, 1957. in cattle in the disease areas. Accordingly, it appears that the 19. Pamukcu, A. M. Tumors of the Urinary Bladder in Cattle, results obtained in this study represent the first successful with Special Reference to Etiology and Histogenesis. Acta UniÃ³ Intern. Contra Cancrum, 18: 625-638, 1962. attempt to produce the natural disease under laboratory 20. Pamukcu, A. M. Epidemiologie Studies on Urinary Bladder conditions. Tumors in Turkish Cattle. Ann. N. Y. Acad. Sci., 108:938-947, 1963. REFERENCES 21. Pamukcu, A. M., Olson, C., and Price, J. M. Assay of Fractions 1. Brobst. D. F., and Olson, C. Neoplastic and Proliferative of Bovine Urine for Carcinogenic Activity after Feeding Lesions of the Bovine Urinary Bladder. Am. J. Vet. Res., Bracken Fern (Pteris aquilina). Cancer Res., 26: 1745-1753, 84: 105-111, 1963. 1966. 2. Brobst, D. F., and Olson, C. Histopathology of Urinary 22. Parker, W. H., and McCrea, C. T. Bracken (Pteris aquilina) Bladder Tumors Induced by Bovine Cutaneous Papilloma Agent. Cancer Res., 25: 12-19, 1965. Poisoning of Sheep in the North York Moors. Vet. Ree., 77: 861-865, 1965. Cited by Evans and Mason (4). 3. Doebereiner, J. Chromatography of Urine from Cattle Fed Bracken Fern (Pteridium aquilinum (L.) KÃ¼hn).M.S. Thesis, 23. Rosenberger, G., and Heeschan, W. Adlerfarn (Pteris University of Wisconsin, 1963. aquilina)â€”die Ursache des sog. Stallrotes der Rinder (Haema 4. Evans, I. A., and Mason, J. Carcinogenic Activity of Bracken. turia vesicalis bovis chronica). Deut. Tieraerztl. Wochschr., Nature, S08: 913-914, 1965. 67: 201-208, 19GO.

MAY 1967 921

FIG. 1. Case 954. Multiple hemangiomas and round tumor masses in the mucosa of the opened urinary bladder of a cow fed bracken for 1192days. FIG. 2. Case 954. Widespread centrilobular necrosis in the liver. X 115. FIG. 3. Case 6. Bladder showing solid ingrowths of epithelium into subepithelial tissue (Brunn's nest) and chronic inflammation of the bladder wall. X 250. FIG. 4. Case 11. Moderate hyperplasia of transitional epithelium with some cells showing hydropic degeneration. Branched crypts lined with transitional epithelium (cystitis glandularis). X 140. FIG. 5. Case 6. Marked hyperplasia of transitional epithelium wit h many cells showing hydropic degeneration and deep-seated branched crypts lined with transitional epithelium. The distinction between hyperplasia and benign neoplasia is difficult with this type of lesion. X 140. FIG. 6. Case 11. Transitional cell papilloma. X 95. FIG. 7. Case 954. Glandular metaplasia of enteric type and chronic inflammatory infiltration of the bladder wall. X 115. FIG. 8. Case 954. Squamous cell carcinoma. X 115. FIG. 9. Case 954. Squamous cell carcinoma infiltrating into the submucosa. X 115. FIG. 10. Case 954. From same section as Fig. 9. Note infiltration of cells of Squamous cell carcinoma into the bladder wall. X 115. FIG. 11. Case 11. Transitional cell carcinoma infiltrating into the wall of the bladder. X 250. FIG. 12. Case 0. Capillary hemangioma. X 250.

922 CANCER RESEARCH VOL. 27

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MAY 1967 923

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CANCER RESEARCH VOL. 27

A. M. Pamukcu, S. K. Göksoy and J. M. Price

Cancer Res 1967;27:917-924.

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