Enhanced anticancer efficacy by use of mitomycin C adsorbed on small activated carbon particles in mice

A new dosage form of mitomycin C (MMC-CH) was tested for toxicity and therapeutic efficacy against intraperitoneally inoculated cancer cells in mice. MMC-CH is a suspension comprising 7.16 mg/ml of activated carbon particles, 1 mg/ml of mitomycin C (MMC) and 20 mg/ml of polyvinylpyrrolidone in saline. The LD50 value determined by means of the Litchfield-Wilcoxon method after intraperitoneal administration was 2.29 times higher for MMC-CH than for MMC aqueous solution. Mice were inoculated intraperitoneally with 2 X 10(5) P388 leukemia cells and given an intraperitoneal injection of 10 to 1.25 mg/kg of MMC in the form of MMC-CH or MMC aqueous solution 24 hr after the inoculation. The median survival time was prolonged to 270.5%, 223.0% or 168.3% by MMC-CH at the dose equivalent to 10, 5 or 2.5 mg/kg of MMC, respectively, while it was prolonged to 182.7%, 139.6% or 155.4% by MMC aqueous solution at the dose of 5, 2.5 or 1.25 mg/kg of MMC, respectively, as compared with the median survival time in the non-treated group. MMC-CH prolonged the survival time to more than 120% as compared with the same dose of MMC given as MMC aqueous solution, and was less toxic.

Antigenic and biochemical characterization of poliovirus type 1 isolates

By the introduction of Sabin oral poliovirus vaccine, the circulation of wild type polioviruses has virtually disappeared in Japan. However, an outbreak of poliomyelitis associated with sporadic transmission of type 1 wild strain occurred in Nagano in 1980. Furthermore, we found that some type 1 wild strains were introduced into Japan from abroad in 1981. In recent surveys, the two poliovirus type 1 isolates which have non-vaccine-like antigenic character were detected in Aichi. Then, an investigation to trace the origin of these strains was performed, by using intratypic serodifferentiation and biochemical techniques. Electrophoretic migration patterns of their structural polypeptides were quite different from the vaccine virus. In the oligonucleotide mapping, however, one of them gave patterns very similar to those of the vaccine virus. We could conclude that one originated most probably from wild strains, and the other was an antigenic variant derived from the vaccine virus. It showed that oligonucleotide mapping was a very useful method for identification of antigenic modified Sabin type 1 derivatives.

Activated carbon particles as anti-cancer drug carrier into regional lymph nodes

The effect of a new dosage form for anti-cancer agents was studied on tissue distribution and compared with the aqueous solution form. The new dosage form, developed in order to distribute a greater amount of the agent to regional lymph nodes, comprises polyvinylpyrrolidone and small activated carbon particles adsorbing pepleomycin (PEP-CH) or mitomycin C (MMC-CH) in saline. Pepleomycin at 500 micrograms/kg or mitomycin C at 250 micrograms/kg were injected into the gastric wall of dogs in the new dosage form or the aqueous solution form. The activity level of the agents in tissues was bioassayed within 24 h after injection by the thin agar plate method. Statistically, the new dosage form maintained an activity level in lymph nodes that was significantly higher than the aqueous solution form (ratio of PEP-CH to solution form, 6-32 times in 24 h; MMC-CH, 100-1000 times in 6 h; p less than 0.05-0.01), and a concentration in blood that was significantly lower (PEP-CH, about 1/2 times in 2 h; MMC-CH, 1/10-1/5 times in 1 h; p less than 0.05).

Enhanced chemotherapeutic efficacy on carcinomatous peritonitis using a new dosage form in animal experiments

A new dosage form, comprising Mitomycin C adsorbed on activated carbon particles (MMC-CH) was studied for its local therapeutic effects on carcinomatous peritonitis. After intraperitoneal transplantation of 10(7) cells of Yoshida sarcoma, drug treatment was given on day 2. The ED50 value on ascites was determined with Litchfield-Wilcoxon's method on day 6. The therapeutic index (LD50/ED50) on ascites in MMC-CH treatment was 3.09 times higher than that in Mitomycin C solution treatment.

[Fundamental studies on the properties of a new adriamycin delivery system involving adsorption to activated carbon particles]

Adriamycin (ADM) was absorbed onto fine particles of activated charcoal. The characteristics of this newly developed drug delivery system were then examined in vitro. Eighty micrograms of ADM was released from the charcoal reversibly, and the biological activity of ADM released from the charcoal was retained perfectly. The ADM was released so slowly and continuously that the concentration of ADM around the charcoal particles remained high for a long time. Such characteristics suggested that ADM-CH may be available for the treatment of peritonitis carcinomatosa and lymph node metastases.

Metabolism of 2- and 3-tert-butyl-4-hydroxyanisole (2- and 3-BHA) in the rat (I): Excretion of BHA in urine, feces and expired air and distribution of BHA in the main organs

The mechanism of the carcinogenic or toxic action of BHA on rat forestomach was examined by studies on the excretion and tissue distribution of radioactivity in F344 male rats given tert-butyl- or methoxy-labelled 3-BHA orally. Within 2 days after a single oral dose of labelled BHA at 1 g/kg body wt, 87-96% of the 14C was excreted, mainly in the urine with smaller amounts in the feces and expired air. More 14C was found in the tissues of rats given the methoxy-labelled compounds. The distributions of 14C in the forestomach and the glandular stomach were similar. At 168 h after treatment, more 14C was found in the forestomach of rats given 2-BHA than in that of rats given 3-BHA. These results indicate that excretion of BHA is rapid, that 4-O-methyl demethylation may take place readily and that demethylated methyl group may become distributed non-specifically in tissues. The carcinogenic or toxic action of BHA on the forestomach does not seem to be due accumulation of BHA in the forestomach.

Chemotherapy for carcinomatous peritonitis and pleuritis with MMC-CH, mitomycin C adsorbed on activated carbon particles. Clinical trials

A new drug dosage form comprising activated carbon particles adsorbing mitomycin C (MMC-CH) is designed to slowly release its components, and has affinity for the tumor surface and lymph nodes and a tendency to stay long in the local portion. The therapeutic index of MMC-CH in experimental carcinomatous peritonitis is 3.1 times as high as that of MMC-solution. In clinical experiments 81 patients with carcinomatous effusions were administered with MMC-CH (2.0-2.4 mg/kg in terms of MMC) in bolus intracavitarily. Fifty-one patients responded well to the MMC-CH therapy. Nineteen patients were alive for more than 6 months. The responders showed marked improvement in subjective symptoms, and 26 patients became dischargeable from hospital. Bone marrow suppression and peritoneal irritation were main adverse effects, but the symptoms were temporary and not so serious in spite of a high dose of MMC.

[Studies on para-aortic metastatic lymph nodes in gastric cancer after endoscopic injection of activated carbon particles]

When activated carbon particles are injected into the tissues, they are absorbed into the lymphatic capillary and reach to the regional lymph nodes. Utilising this property of the activated carbon, we injected small sized carbon particles (CH-44) around the gastric cancer using endoscope to examine para-aortic lymph node metastasis. Sixty eight patients with gastric cancer existing serosal invasion were subjected to extended radical gastrectomy dissecting para-aortic lymph nodes as well as regional lymph nodes. Twenty patients (29.4%) had para-aortic lymph node metastasis. Cumulative 5-year survival rate of these patients after surgery was 20.0 per cent. High incidence of metastasis in para-aortic lymph nodes was found in the lymph nodes larger than 4mm in diameter, but 15.9 per cent of lymph nodes less than 2mm in diameter had metastasis. Large lymph nodes occupied almost wholly by cancer cells were stained scarcely by activated carbon particles, but lymph nodes with moderate or slight metastasis were stained black well and this method was very useful for lymph node dissection, even for micro-lymph nodes which seemed to escape from naked eye at surgery.

Toxicity and pathological effects of a new dosage form of mitomycin C for carcinomatous peritonitis

A new dosage form (MMC-CH) of mitomycin C (in a suspension of activated carbon adsorbing mitomycin C in saline), designed for intracavitary use in carcinomatous peritonitis, was studied for its toxicity and pathological effects in rats. The LD50 values determined with the Litchfield-Wilcoxon's method in three types of MMC-CH were 7.6 (100 micrograms/ml MMC and 0.5 mg/ml activated carbon in saline), 16.5 (100 micrograms/ml MMC and 0.75 mg/ml activated carbon in saline), and more than 25 mg/kg (100 micrograms/ml MMC and 1 mg/ml activated carbon in saline), while in mitomycin C solution the value was 3.05 mg/kg. The lethal toxicity decreased with the change of dosage form. Studies on survival, symptoms of intoxication and macroscopic and microscopic examinations of autopsied animals revealed that there was no evidence of any additional side effects produced by the change of dosage form.

Dose response in butylated hydroxyanisole induction of forestomach carcinogenesis in F344 rats

Groups of 50 6-week-old male F344 rats were given a powdered diet containing 0, 0.125, 0.25, 0.5, 1, or 2% butylated hydroxyanisole [(BHA) CAS: 25013-16-5] for 104 weeks. The highest dose--2% BHA--induced significant increase in the incidence of squamous cell carcinoma of the forestomach. Papillomas of the forestomach developed in 20 and 100% of the rats given diets containing 1 and 2% BHA, respectively. The incidence of epithelial hyperplasia of the forestomach increased with the increased BHA doses, to 100% incidence at the highest dose. Thus the incidences of proliferative and neoplastic lesions of the forestomach were dose dependent.

Modifying effects of butylated hydroxyanisole, di(2-ethylhexyl)phthalate or indomethacin on mouse hepatocarcinogenesis initiated by N-nitrosodiethylamine

Preneoplastic and neoplastic liver and lung lesions were studied in male B6C3F1 mice given a single injection (80 mg/kg) of N-nitrosodiethylamine (DEN) intraperitoneally at 4 weeks of age, followed 1 week later by oral exposure to di(2-ethylhexyl)-phthalate (DEHP; at 6000 ppm in the diet), butylated hydroxyanisole (BHA; 7500 ppm in the diet) or indomethacin (10 ppm in the drinking water) alone or in combination (DEHP and BHA or DEHP and indomethacin), and continued for 29 weeks. DEHP or BHA alone and the combination of DEHP and BHA increased the incidence of DEN-initiated focal hepatocellular proliferative lesions (FHPL), including both microscopic hyperplastic foci and hepatocellular adenomas. Mice that received BHA alone or DEHP plus BHA had FHPL that were composed predominantly of eosinophilic hepatocytes, while FHPL in DEHP-exposed mice were basophilic. Indomethacin showed neither promotional or antipromotional effects, except for lung tumors. Mice receiving DEHP and indomethacin after DEN had significantly fewer lung lesions. A high incidence of renal papillary necrosis and nephropathy was observed in the indomethacin-DEHP exposed mice, while these lesions were not found in mice treated with indomethacin alone or DEHP alone. These findings suggest that BHA, an antioxidant, promoted pre-neoplastic liver lesions while indomethacin, a known inhibitor of prostaglandin synthesis and a chemopreventive agent for colon and mammary tumors in other studies, had no effect on liver tumor promotion by DEHP.

Tissue levels and biological effects of N-nitrosodimethylamine in mice during chronic low or high dose exposure with or without ethanol

In a study of the metabolism, disposition, and hepatotoxicity of the environmental carcinogen N-nitrosodimethylamine (NDMA), as a function of dose in the drinking water and of concomitant administration of ethanol, outbred Swiss mice were given NDMA for 1-4 weeks at levels of 50-0.5 ppm, with or without 10, 20, or 30% ethanol. NDMA, assayed in blood, liver, kidney, lung, and brain by thermal energy analysis after methylene chloride extraction, was detectable (greater than 0.5 ppb) in tissues of the mice after all doses of NDMA. The 0.5-ppm dose yielded tissue levels of NDMA (1-4 ppb) near the detection limit of 0.5 ppb; this was also found to be the minimal concentration causing significant numbers of lung tumors in strain A mice after treatment for 16-18 weeks. Co-administration of ethanol caused an increase in blood and tissue levels of NDMA at all levels of both chemicals, often by a factor of 10 or more. Ethanol also partially alleviated the morphological hepatotoxic effects of NDMA at 50 ppm (centrilobular hemorrhage and necrosis). These results are consistent with competitive inhibition of metabolic activation of NDMA by ethanol. Ten per cent ethanol did not induce liver NDMA demethylase activity significantly and did not prevent loss of this activity from the livers of mice receiving 5-50 ppm NDMA. Thus, inhibition, rather than induction, of NDMA metabolism was the predominant effect of ethanol, with increased levels of NDMA in blood and other tissues as a consequence.

Lack of effect of phenobarbital on hepatocellular carcinogenesis initiated by N-nitrosodiethylamine or methylazoxymethanol acetate in male Syrian golden hamsters

Subchronic toxicity and long-term tumor-promoting effects of phenobarbital (PB) were investigated in male Syrian golden hamsters. In subchronic studies, PB was administered in drinking water to 5-week-old male hamsters for periods of 8 or 16 weeks at dosage levels of 250, 500, or 1000 ppm. No significant change in the ratio of liver weight to body weight was observed at 8 weeks; however, at 16 weeks there was a dose-dependent increase in the ratio of liver weight to body weight and a significant decrease in body weight gain among animals that received PB at 1000 ppm. The effect of PB on hepatic cytochrome P-450 and P-450-dependent aminopyrine N-demethylase activity was compared in male Syrian golden hamsters, F-344/NCr rats, and B6C3F1 mice. PB enhanced cytochrome P-450 activity in all three species; however, a significant increase (p less than 0.05) in aminopyrine N-demethylase activity was observed only in rats and mice. Potentially preneoplastic hepatocellular hyperplastic foci and hepatocellular neoplasms were studied in weanling male Syrian golden hamsters that received a single ip injection of either 100 mg N-nitrosodiethylamine (DEN)/kg body wt or 20 mg methylazoxymethanol acetate (MAM)/kg body wt at 5 weeks of age, followed by administration of 500 ppm PB in drinking water that began 2 weeks after the carcinogen injection and continued to 69 weeks of age. Groups of hamsters were killed at 25, 52, and 69 weeks of age; portions of liver and other organs with gross lesions were fixed in Formalin and examined histologically. MAM was a more potent hepatocarcinogen than DEN in male Syrian golden hamsters. PB failed to promote the development of either preneoplastic hepatocellular foci or hepatocellular neoplasms (adenomas or carcinomas) in either DEN- or MAM-initiated hamsters. Also, PB had no effect on the development of nonhepatic lesions occurring either spontaneously or induced by DEN or MAM in these animals.

The chronic hepatotoxic, tumor-promoting, and carcinogenic effects of acetaminophen in male B6C3F1 mice

Acetaminophen (ACT), the most commonly used analgesic and antipyretic in the United States, was previously demonstrated to be a hepatocarcinogen in one mouse study but not in rats. In order to help elucidate the potential mechanisms of carcinogenesis by this nongenotoxic chemical and its relationship to hepatotoxicity, ACT was fed to groups of 60-120 male B6C3F1 mice at dietary concentrations of 5000 or 10,000 ppm from 6 weeks of age for periods of up to 70 weeks to study the hepatotoxic effects of ACT. To test for potential liver tumor-promoting effects of ACT, N-nitrosodiethylamine (DEN) was injected intraperitoneally at 40 mg/kg into additional groups of 30-60 male B6C3F1 mice at 4 weeks of age. Two weeks later some mice received ACT at dietary concentrations of 5000 or 10,000 ppm. Mice were sacrificed either at 24 weeks after DEN injection or after 22 or 70 weeks of ACT exposure. The livers were weighed and prepared for qualitative and quantitative histological evaluation of focal hepatocellular proliferative lesions (FHPL) including microscopic hyperplastic foci and neoplasms by automated image analysis. At 24 weeks the incidence and number of FHPL per square centimeter were significantly increased only in DEN-treated mice receiving 10,000 ppm ACT. Chronic hepatotoxicity was mild at this time. At 72 weeks ACT alone had no effect on the incidence or number of naturally occurring liver tumors despite severe chronic hepatotoxicity and suppression of body weight gain in mice receiving 10,000 ppm and only mild toxicity at 5000 ppm. There were histological findings suggesting that the chronic hepatotoxicity had, in part, a vascular pathogenesis. This study provided evidence against the hypothesis that chronic hepatotoxicity, in and of itself, results in an increased incidence of naturally occurring liver tumors in mice.

Anticancer agents adsorbed by activated carbon particles, a new form of dosage enhancing efficacy on lymphnodal metastases

A new dosage form consisting of small activated carbon particles which adsorb Aclacinomycin A, Adriamycin, Mitomycin C or Pepleomycin was prepared in order to deliver larger amounts of anticancer agents to the lymph nodes through the high ability of lymphatics to adsorb particles. Animal experiments showed that: The LD50 values of the new dosage form were higher than those of the dosage in solution. The concentration of agents in lymph nodes was maintained at a higher level in the new dosage form than in solution form. Clinically 33% of lymphnodal metastatic lesions became degenerative or inflammatory after a single administration.

Selective delivery of high levels of mitomycin C to peritoneal carcinomatosis using a new dosage form

Selective delivery of a high level of Mitomycin C (MMC) in intraperitoneal disseminated lesions was studied using a new dosage form of MMC, called MMC-CH. Intracavitary MMC-CH delivered a much higher level of MMC selectively to intraperitoneal tissues, with a much lower level of MMC in the whole body, in comparison with MMC solution. The index [MMC level in the intraperitoneal organs]: [MMC level in blood] was much higher and increased with time in the MMC-CH group, but not in the MMC solution group.

Promoting effects of various agents in rat urinary bladder carcinogenesis initiated by N-butyl-N-(4-hydroxybutyl)nitrosamine

The effects of various chemicals on the development of neoplastic lesions in the urinary bladder were investigated in male F344 rats given 0.05% N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) as an initiator in their drinking water for 4 weeks. The compounds tested, indomethacin, acemetacin, epsilon-aminocaproic acid (EACA), diphenyl, allopurinol and acetaminophen (AAP), were added to the diet or drinking water for 32 weeks, and all animals were killed at the end of week 36. Of the chemicals tested, only diphenyl significantly increased the incidences and average numbers (per 10 cm basement membrane) of papillary or nodular hyperplasias (PN hyperplasia), papillomas and carcinomas of the urinary bladder over those in animals treated with BBN alone. These findings show that diphenyl is a promoter of urinary bladder carcinogenesis in male F344 rats.

Studies on the pathogenesis of atrial myocarditis in mice infected with Coxsackie virus B3

Coxsackie virus B3 (CB3) was inoculated intraperitoneally into BALB/c mice to determine whether atrial myocarditis is due primarily to virus multiplication in the atrial myocardium or is secondary to the effects of virus multiplication in the ventricular myocarditis. Ventricular changes were observed in 15 (71%) out of 21 mice. The lesions consisted of hyaline or granular degeneration and necrosis with or without calcium deposits of the muscle fibres and inflammatory mononuclear cell infiltration. Histopathological changes in the atrial myocardium were found in 14 (67%) out of 21 mice. The lesions in the atrial myocardium were oedema or thickening of the endocardium, degeneration and necrosis of the muscle fibres and inflammatory mononuclear cell infiltration. The incidence and degrees of intensity of the histopathological changes in the atrial myocardium were less than those of the ventricular myocardium in mice inoculated with CB3, but no difference in the nature of the histopathological changes between the atrial and ventricular myocardium were observed. A high virus titer was found in the atrial myocardium as well as in the ventricular myocardium, and virus antigen was detected in the degenerating or necrotizing muscle fibres in the atrial myocardium by immunofluorescent technique. It is clear that CB3 could produce not only ventricular myocarditis, but also atrial myocarditis. We conclude, therefore, that damage of the atrial myocardium is due to direct action of the virus.

Combined effects of butylated hydroxyanisole and other antioxidants in induction of forestomach lesions in rats

The possibility that changes in the forestomach of rats induced by butylated hydroxyanisole (BHA) are caused by inductions of free radicals and their reactions with macromolecules was examined. Groups of five male F344 rats were pretreated with 1% alpha-tocopherol, 1% ellagic acid, 1% propyl gallate, 0.25% ethoxyquin, 0.5% glutathione, 1% sodium L-ascorbate or 1% 3,3'-thiodipropionic acid for 1 week, then treated with the same antioxidant plus 1% BHA for 1 week, and then killed. Histological examination showed that BHA induced epithelial hyperplasia of the forestomach. This induction of hyperplasia was not inhibited, but increased by the antioxidants, particularly propyl gallate and ethoxyquin. Thus the induction of hyperplasia by BHA may not be related to a free radical reaction.

Diagnosis of the depth of cancer invasion by submucosography

A new method was developed to diagnose the depth of cancer invasion using submucosography combined with special charcoal suspension containing mitomycin C, and applied to 8 cases of gastric cancer. Correct diagnosis of the depth of the cancer invasion was obtained in 7 of the 8 cases. As some cases of early gastric cancer can be treated endoscopically, it is important to know the condition of the invasion before any treatment is performed.

Subchronic toxicity study of sodium o-phenylphenate in mice

A 13-week subchronic oral toxicity study of sodium o-phenylphenate (SOPP) was conducted in B6C3F1 mice. Body weight gain was significantly depressed in 1.0 and 2.0% SOPP-treated males and in both sexes treated with 4.0%. Urinalysis showed an increase in pH and a decrease of specific gravity in the 4.0% group of both sexes. Relative liver weights of both sexes receiving 1.0, 2.0 and 4.0% SOPP were significantly greater than those of the controls. No treatment-related histopathologic findings were noted. On scanning electron microscopic (SEM) examination, the bladder epithelium of mice given 2.0% SOPP appeared normal at any time periods investigated. This study showed that while 4.0% SOPP was very toxic to both sexes, 2.0% SOPP did not cause statistically significant changes in organ weights.

Ultrastructural changes of motoneurons in monkeys infected with enterovirus 71. Brief report

Tissues of the central nervous system (CNS) of cynomolgus monkeys were examined by electron microscopy after intraspinal inoculation of enterovirus 71 (E71). A characteristic finding was the appearance of numerous membrane-bound vesicles (Mbvs) in affected motoneurons. Similar Mbvs were also present in E71-infected cynomolgus monkey kidney (CMK) cells in culture. Virus-like particles were found within or around Mbvs in motoneurons as well as in infected CMK cells in culture. Neither Mbvs nor E71 antigens as detected by immunofluorescence were found in supporting tissues, vascular endothelium, or inflammatory cells. Quite similar findings had been seen in poliovirus infections. It was suggested that the appearance of Mbvs in the cytoplasm of motoneuron is the direct results of virus multiplication in E71 infection as in poliovirus infection.