Successful administration of mitotane (O, p'-DDD) in pediatric oncology.

INTRODUCTION: Mitotane (o, p'-DDD) is a molecule that was developed many years ago for adrenal cortical carcinoma, but no suitable pediatric dosage form is available for administration to young children. Mitotane requires therapeutic drug monitoring because of its long half-life and difficulty in stabilizing plasma concentrations. Furthermore, Mitotane is a highly lipophilic drug that requires concurrent lipid administration. CASE REPORT: We present the case of a 3-year-old girl who was diagnosed with metastatic adrenal cortical carcinoma. Due to the difficulty in administering the tablets and the non-stabilized mitotane dosages, a nasogastric tube was inserted. An administration protocol based on dispersing the tablets in whole milk was established by the pharmacy team. This led to the stabilization of the disease for at least 1.5 years. MANAGEMENT AND OUTCOME: Mitotanemia is difficult to stabilize even when treatment is administered orally. To maintain biological efficacy, we propose an easily reproducible protocol. The efficacy was stabilized at a dosage of 1500 mg per day. Mitotanemia fluctuated between 14 mg/mL, and 20 mg/mL. The implementation of this protocol prevented treatment discontinuation. DISCUSSION: The administration of narrow therapeutic range drugs via a nasogastric tube is a challenge for healthcare teams, particularly in pediatric patients. Based on the findings of this clinical case, clinicians should consider future use of this protocol. The use of whole milk as a vehicle for mitotane is a simple, effective, and reproducible method to administer the drug to pediatric patients and can be used for other similar cases.

Arsenic exposure in utero and nonepidermal proliferative response in adulthood in Tg.AC mice.

To expand our knowledge on the transplacental carcinogenic potential of inorganic arsenic, pregnant Tg.AC mice received drinking water with 0, 42.5, or 85 ppm arsenite from gestation day 8 to 18. After birth, groups (n = 25) of offspring received topical 12-O-tetradecanoyl phorbol-13-acetate (TPA) (2 microg twice a week) for 36 weeks and were killed; nonskin tumors were assessed. Arsenic increased adrenal cortical adenomas (ACAs; 25%-29%) compared with control (0%) independent of TPA in all male groups. Arsenic increased urinary bladder (UB) hyperplasia in males, but only with TPA. Arsenic induced ACAs in all female groups (control 0%; arsenic 17%-26%). Arsenic-treated females had UB hyperplasia in most groups (control 0%; arsenic 26%-32%), with 2 UB papillomas. All arsenic-treated females had uterine hyperplasia (26%-40%; control 4%) independent of TPA, and 3 had uterine tumors. Thus, arsenic in utero rapidly induces ACAs and uterine and UB preneoplasias in Tg.AC mice, showing transplacental carcinogenic potential in yet another strain of mice.

Inhalation carcinogenicity study with nickel metal powder in Wistar rats.

Epidemiological studies of nickel refinery workers have demonstrated an association between increased respiratory cancer risk and exposure to certain nickel compounds (later confirmed in animal studies). However, the lack of an association found in epidemiological analyses for nickel metal remained unconfirmed for lack of robust animal inhalation studies. In the present study, Wistar rats were exposed by whole-body inhalation to 0, 0.1, 0.4, and 1.0 mg Ni/m(3) nickel metal powder (MMAD=1.8 microm, GSD=2.4 microm) for 6 h/day, 5 days/week for up to 24 months. A subsequent six-month period without exposures preceded the final euthanasia. High mortality among rats exposed to 1.0 mg Ni/m(3) nickel metal resulted in the earlier termination of exposures in this group. The exposure level of 0.4 mg Ni/m(3) was established as the MTD for the study. Lung alterations associated with nickel metal exposure included alveolar proteinosis, alveolar histiocytosis, chronic inflammation, and bronchiolar-alveolar hyperplasia. No increased incidence of neoplasm of the respiratory tract was observed. Adrenal gland pheochromocytomas (benign and malignant) in males and combined cortical adenomas/carcinomas in females were induced in a dose-dependent manner by the nickel metal exposure. The incidence of pheochromocytomas was statistically increased in the 0.4 mg Ni/m(3) male group. Pheochromocytomas appear to be secondary to the lung toxicity associated with the exposure rather than being related to a direct nickel effect on the adrenal glands. The incidence of cortical tumors among 0.4 mg Ni/m(3) females, although statistically higher compared to the concurrent controls, falls within the historical control range; therefore, in the present study, this tumor is of uncertain relationship to nickel metal exposure. The lack of respiratory tumors in the present animal study is consistent with the findings of the epidemiological studies.

Nude mice as a model for gonadotropin-induced adrenocortical neoplasia.

Certain inbred mice (e.g., DBA/2J, CE) develop sex steroid producing adrenocortical tumors following gonadectomy. This adrenal response is thought to result from an unopposed increase in circulating gonadotropins and/or a decrease in factor(s) of gonadal origin. To differentiate between these two possibilities, we utilized the NU/J strain of nude mice, which are immunologically compromised and therefore permissive to xenografts. One group of female nude mice was gonadectomized, while another group of females received xenografts of CHO cells stably transfected with human chorionic gonadotropin (hCG). After 1-2 months, subcapsular adrenocortical neoplasms containing sex steroid-producing cells were observed in both groups. We conclude that high levels of circulating gonadotropins are sufficient to induce adrenocortical tumorigenesis, even in the presence of intact gonads.

Dual effects of prolonged ACTH stimulation on 4-hydroxyaminoquinoline 1-oxide-induced adrenocortical lesions in rats.

The effects of a long-acting synthetic ACTH on 4-hydroxyaminoquinoline 1-oxide (4HAQO)-induced adrenocortical lesions were investigated in female rats. A total of 140 6-week-old rats were divided into 4 equal groups, given a single s.c. injection of 7 mg/kg 4HAQO or vehicle, followed by repeated sc administration of the synthetic ACTH or no further treatment. Subgroups of 10 rats in each group were sequentially sacrificed at weeks 20, 30, and 40. Adenomas and adenomatous nodules developed in the adrenal cortex of animals receiving 4HAQO and the chronic ACTH stimulation. Both lesions were located in the deeper zones of the adrenal cortex adjacent to the medulla and were composed of large-sized, clear-type cells. From week 20, middle zone, cortical cystic degeneration, which mimics the age-associated degenerative change named adrenal peliosis, was frequently observed in the adrenal glands of animals treated with 4HAQO alone. Its development was inhibited by ACTH. In the control animals, peliotic changes occurred at low incidence and only at the termination of experiment. These results indicate that long-term stimulation of ACTH promotes the development of adrenocortical tumors but suppresses the occurrence of adrenal peliosis in rats treated with 4HAQO.

D-glucose combined chronic toxicity and carcinogenicity studies in Sprague-Dawley rats and Syrian golden hamsters.

After an initial period of 16 weeks with increasing concentrations, D-glucose was administered at 30% in the diet to 50 male and 50 female Sprague-Dawley rats from the 17th to the 112th study week. Additional 10 male and 10 female animals were treated for 14 months and then sacrificed for interim examination. Groups of 60 male and 60 female Syrian golden hamsters received D-glucose in the form of 20% solution in tap water for a period of 80 weeks. In each case, groups consisting of an equal number of untreated animals served as controls. General behavior and mortality were not affected by the treatment. The rats and hamsters treated with glucose showed significantly higher body weights of up to a maximum of 16% in male and 26% in female rats, or 15% in male and female hamsters. In rats, the increase was evident by week 14, and in the hamsters by week 10. Glucose-dosed rats displayed a slightly increased feed intake and a reduced water intake. Both parameters, however, were not influenced in hamsters. Hematological and histopathological examination showed no pertinent changes in hematopoetic tissue. Sharply increased blood glucose and renal glucose excretion values were present in rats beginning with 18 months and were indicative of the development of non-insulin-dependent diabetes mellitus (NIDDM). The insulin concentrations in peripheral blood were not appreciably affected, although there was a trend to higher values in males at all evaluation times and in females only at 3 months. Pathological evaluation did not show any compound related non-neoplastic lesions. The incidences of islet cell adenomas in the pancreas of male rats were significantly increased and the cortical adenomas in the adrenals of females were decreased. In addition, the mammary gland adenomas (in females) and the Leydig cell tumors of the testes were decreased. In hamsters, the incidence of adrenocortical adenomas were increased in the females. No other pertinent neoplastic changes were observed. In conclusion, the increases and decreases in benign neoplasms of hormone-sensitive tissues, appear to be the result of nutritionally/metabolism-induced modulation of the homeostasis in these 4 tissues in both species, and not the result of chronic glucose administration.

Data analysis: statistical analysis and use of historical control data.

Survival-adjusted methods for the statistical analysis of tumor data from long-term rodent carcinogenicity studies are described. Although most of these methods require knowledge of whether individual tumors are "fatal" or "incidental," such determinations may be difficult. Several methods for dealing with this and with other data analysis issues are discussed. Historical control tumor data may be useful in the interpretation of rodent carcinogenicity studies, particularly for rare tumors and for borderline effects. Although statistical methods are available for using historical control data in a formal testing framework, the primary difficulty is establishing a database that is truly comparable to the study under evaluation with respect to those factors known to influence tumor occurrence. Major sources of variability in tumor incidence include the animal room environment, dietary factors/body weight, gross necropsy and slide preparation procedures, and histopathology diagnosis. The National Toxicology Program's use of historical control data is briefly described and illustrated.

Chronic toxicity and carcinogenicity of bis(tri-n-butyltin)oxide (TBTO) in the rat.

In a 106-wk toxicity and carcinogenicity study, groups of 60 male and 60 female weanling Wistar rats were fed 0, 0.5, or 50 mg bis(tri-n-butyltin)oxide (TBTO)/kg diet. In males, feed consumption was increased in all treated groups and increased water consumption occurred at 5 and 50 mg/kg. During the second year, body weight decreased in the 50-mg/kg males, while the females in that group showed no weight gain. Excess mortality was confined to the 50-mg/kg group towards the end of the study. Haematological changes, comprising anaemia, lymphocytopenia and thrombocytosis were noted mainly at the high-dose level. Also, signs of decreased kidney function and increased plasma enzyme activities (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) were noted. No effects on serum hormone concentrations (thyrotropin, follicle stimulating hormone, luteinizing hormone or insulin) were observed, except for a decrease in the free thyroxin:thyroxin ratio in both sexes at the high-dose level. Higher serum IgM and IgA levels were present at 50 mg/kg, while, in females, IgG was decreased. At 50 mg/kg, the ovaries, adrenals, spleen (females), heart (males), pituitary, liver and kidneys were increased in weight, but the thyroid weight was decreased in females. The total tin concentrations in liver and kidneys showed a dose relationship and, in general, the concentrations were similar after 1 and 2 yr. Non-neoplastic histological alterations after 1 yr consisted of a decrease in the cell height of the thyroid follicles in all dose groups, with a reduced number of psammoma bodies at 50 mg/kg, a decrease in splenic iron content at 5 (females only) and 50 mg/kg, and a slight bile-duct activation. After 2 yr, only the thyroid changes were still present. In addition, at 2 yr, vacuolation and pigmentation of the proximal tubular epithelium and nephrosis were enhanced at 50 mg/kg. The incidence of benign tumours of the pituitary was significantly elevated and enhanced at 0.5 and 50 mg/kg. At 50 mg/kg increases in pheochromocytomas in the adrenal medulla and in parathyroid adenomas (males) were noted, while adrenal cortical tumours were decreased (males). There was a low, non-dose-related incidence of pancreatic carcinoma. Other tumour rates were in line with control data. It is concluded that lifetime feeding of 50 mg TBTO/kg diet induces toxicity in various organ systems. An increase in some common tumours was found at the high dose, probably due to hormonal or immunological changes.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal cortical foci and nodules in Sprague-Dawley rats treated with N-nitrosomorpholine. Light and electron microscopic findings.

Treatment of male Sprague-Dawley rats with N-nitrosomorpholine (NNM) in the drinking water at a dose of 120 mg/l for 7 weeks resulted in a subsequent enhanced development of focal and nodular lesions in the adrenal cortex. Sequential observation revealed that focal lesions in the zona reticularis/fasciculata or the zona glomerulosa developed both earlier and at a significantly higher incidence in animals treated with carcinogen than in untreated controls. Foci observed within or adjacent to the zona glomerulosa were all of pale cell appearance and contained large numbers of electron-dense cytoplasmic granules similar to those observed in normal granulosa cells. The foci and nodules which arose in the zona reticularis/fasciculata were, in contrast, characterized by a reduction or loss of the dense osmiophilic droplets normally seen in the cells of this region of the adrenal cortex, a pronounced increase in pleomorphic mitochondria of atypical appearance and the development of vacuoles.

Chronic carcinogenesis studies of acrolein and related compounds.

Acrolein and two of its more stable derivatives, the oxime and the diethylacetal, and the related allyl alcohol were given in drinking water to groups of 20 male and 20 female F344 rats at doses close to the maximum that could be tolerated by the animals, for most of their lifetime. Acetaldoxime served as a control for the hydroxylamine derivative of acrolein. Most of the tumors were common in untreated rats of this strain. Only adenomas of the adrenal cortex in females were more numerous than in untreated controls. Acrolein itself was too toxic to hamsters to conduct a carcinogenesis study. Acrolein oxime, acrolein diethylacetal and allyl alcohol were all quite toxic to hamsters, but 2 mg per week by gavage was tolerated by groups of 20 male Syrian hamsters. There was a small number of tumors of the pancreatic ducts and of the forestomach in the treated hamsters, but the incidence was not statistically significant.

Iron exclusion by proliferative foci and neoplastic lesions induced by 7,12-dimethylbenz(a)anthracene in the rat adrenal cortex.

Proliferative and neoplastic adrenal cortical lesions were produced in female Sprague-Dawley rats by 7,12-dimethylbenz(a)anthracene. These lesions were studied for their ability to store histochemically demonstrable cellular iron compared with normal adrenocortical cells following iron loading by subcutaneous injection of iron-dextran. Stainable iron was excluded, under conditions in which normal cortical cells were heavily loaded with iron, in three histological types of adrenal cortical lesions; eosinophilic and basophilic proliferative foci; adenomas and lesions transitional between foci and tumours. The property of iron exclusion may be useful in studying neoplastic development in the adrenal gland.

Comparative carcinogenicity of two isomers of nitroso-2,6-dimethylmorpholine in guinea pigs.

The cis and trans isomers of nitroso-2,6-dimethylmorpholine (Me2NMOR) were administered by gavage to male Strain-2 guinea pigs as solutions in oil twice weekly for 30 weeks. Those animals treated with the cis isomer developed almost 100% incidence of liver tumors, together with tumors of the lung and adrenal cortex. In contrast, almost none of the animals treated with the trans isomer died with tumors. In rats, the trans isomer was considerably more potent than the cis, whereas this is not the result in guinea pigs, in which the cis is possibly more potent than the trans. This suggests that the mechanisms of activation in the 2 species might be different.

Spontaneous and estrogen-produced tumors in Nb rats and their behavior after transplantation.

Tumors in rats of the Nb strain, arising either spontaneously or after prolonged treatment with s.c. pellets of estrogen, were transplanted to establish whether hormone conditioning was required for their growth. Whereas all spontaneous tumors arising in males and many of those in females were autonomous on transplant, most of those arising in estrogenized rats continued to require hormones for growth after transplantation. The latter included carcinomas of the adrenal cortex, breast, pituitary ectopic tissue, ovary (thecomas), Leydig cells of testis, thymus, pancreas,salivary glands, oribital gland (fibroadenoma), liposarcoma, and lymphoma. Many of the tissues of origin of the tumors have not been considered to be under theinfluence of estrogens. A type of hormone-responsive tumor that was inhibited by estrogen and that grew only in normal rats is described. Ali estrogens tested, including estriol , were interchangeable in action. The incidence of the more common tumors of the adrenal, breast, and pituitary was very low in normal rats, but higher in females. All tumors were more common after estrogenization in both sexes, particularyly in older animals. The secretion of steroids and pitiutary hormones by many tumors led to obvious biological effects. Pituitary secretion led to severe lesions frequently associated with diseases in humans, but the signs of such diseases in the rat apparently were hormone dependent and disappeared if the tumor was removed. The overall results raised the possiblity that estrogens were not carcinogenic per se but stimulated the growth of previously altered cells and that, following their transplantation, this hormone requirement was retained. Irrespective of the mechanism of carcinogenesis, hormone-dependent tumor growth was not irreversible but was controlled in an unexpectedly wide spectrum of organs by exogenous estrogen. Host factors may play a major role in controlling the growth of many tumors and the ultimate course of the disease.