Inhibitory effect of 4,4'-diaminodiphenylmethane on liver, kidney and bladder carcinogenesis in rats ingesting N-ethyl-N-hydroxyethylnitrosamine or N-butyl-N-(4-hydroxybutyl) nitros-amine

The effects of 4,4' -diaminodiphenylmethane (DDPM) administration in the "post-initiation" stage of liver, kidney and bladder carcinogenesis were examined in male F344 rats. In experiment 1, rats were given drinking water containing 0.1% N-ethyl-N-hydroxyethyl-nitrosamine for 2 weeks than diet containing 0.1% DDPM for 32 weeks. In week 3, the right kidney was removed. The incidence of hepatocellular carcinoma was significantly less in rats given DDPM than in controls. DDPM decreased the incidence and average number/cm2 of neoplastic nodules and renal cell tumors of the kidney. In experiment II, rats were given 0.01% N-butyl-N-(4-hydroxybutyl)nitrosamine for 4 weeks and then 0.1% DDPM for 34 weeks kin their drinking water. DDPM inhibited the induction of papillomas in the bladder. These results indicate that DDPM administration in the "post-initiation" stage inhibited liver, kidney and bladder carcinogenesis in rats.

Dose response of saccharin in induction of urinary bladder hyperplasias in Fischer 344 rats pretreated with N-butyl-N-(4-hydroxybutyl)nitrosamine

Studies were made on the dose response of saccharin in the induction of bladder lesions. Inbred F344 rats of both sexes were pretreated with 100 ppm N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in the drinking water for 4 weeks. Sodium saccharin was given at 50,000, 10,000, 2,000, and 400 ppm in the diet for 32 weeks after BBN administration, and surviving rats were killed at the end of week 36 of the experiment. No increase in incidence of papilloma or cancer was noted in either sex at any dose of saccharin after BBN as compared to levels induced by BBN alone. The incidences of two types of hyperplasia and average number of papillary or nodular hyperplasias per 10 cm of basement membrane were significantly increased in the group receiving 50,000 ppm saccharin as compared to the group given BBN only. None of the incidences or numbers of these lesions were significantly different in any of the other saccharin-treated groups when compared to the group treated with BBN alone except for the incidences of two types of hyperplasias in the female rats dosed with 10,000 ppm saccharin. Dose-response curves showed enhanced hyperplastic responses in both sexes given 2,000--50,000 ppm saccharin. Administration of various doses of saccharin without BBN did not cause any changes in the urinary bladders of rats of either sex. These results show that saccharin enhances the induction of early-stage bladder lesions and that the biologic response demonstrates a dose-response effect.

Chronic effects of norharman in rats treated with aniline

The carcinogenic effects of aniline and norharman given alone or in combination were examined in rats. Neoplastic changes including hyperplastic changes of the urinary bladder were not found in all groups. Papillomas of forestomach were observed in 5 rats out of 110 rats. However, this was not significantly different among the groups. Pyelonephritis or chronic nephritis were also seen in all groups. Hematological and blood biochemical analysis did not show any notable difference in the animals treated with aniline and/or norharman.

Effects of caffeine and saccharin on DNA in the bladder epithelium of rats treated with N-butyl-N-(3-carboxy-propyl)-nitrosamine

The damage to DNA caused by N-butyl-N-(3-carboxypropyl)-nitrosamine (BCPN), saccharin and caffeine in the urinary bladder epithelium of female rats and its subsequent repair was investigated using alkaline sucrose density gradient analysis with a fluorimetric procedure for DNA determination and light and electron microscopy. Exposure of the bladder epithelium to 50 mg/kg body wt. of BCPN solution for 5 min resulted in serious damage of DNA within 2 h. Subsequent repair of most of the DNA damage, as indicated by reconversion of low molecular weight DNA fragments to larger ones, began after 6 h, and appeared to be complete after 48 h. Caffeine and saccharin induced no remarkable changes in the sedimentation profiles of DNA of the epithelial cells, with or without pretreatment of the cells with BCPN (administered to rats as 0.05% BCPN in the drinking water for 4 weeks). These results were confirmed by light and electron microscopy.

Structural proteins of hand, foot and mouth disease viruses

Coxsackievirus A16 (CA16) and enterovirus 71 (E71), which cause hand, foot and mouth disease, were compared with respect to their polypeptide composition by PAGE. Only three proteins were resolved for CA16, whereas the four characteristic structural proteins of E71, (VP1, VP2, VP3 and VP4) were separated. The distribution of labeled proteins suggested that the molecular weights of VP2 and VP3 of CA16 were very similar. The smallest protein, VP4, of CA16 and E71 had the same molecular weight, but the other proteins of the two serotypes were different in their molecular weights.

Neurovirulence in cynomolgus monkeys of enterovirus 71 isolated from a patient with hand, foot and mouth disease

Six cynomolgus monkeys were inoculated subcutaneously with enteroviurs 71 (E71), isolated from the stools of a patient with hand, foot and mouth disease (HFMD). Clinical symptoms were observed in three of the six monkeys. One monkey showed complete paralysis of the lower extremities and two animals showed weakness in the hind limbs 4 to 7 days after inoculation. Lesions were found in the central nervous system (CNS) of all monkeys. Mild to moderate vascular lesions, perivascular cuffings, degeneration and disappearance of the neurons and meningial lymphocytic infiltration were observed in the grey and/or white matter of the spinal cord, medulla oblongata, cerebral cortex and brain stem. No virus was recovered from the CNS or liver of any of the six monkeys. However, serum neutralizing antibody titers had risen in monkeys inoculated with E71.

Common antigen between coxsackievirus A 16 and enterovirus 71

Cross immunofluorescence revealed that coxsackievirus A 16 (CA 16) shared a common antigen with enterovirus 71 (E 71). The cross reactivity of these two serotypes was also examined by complement fixation test with purified virus preparations fractionated by sucrose density gradient centrifugation and two peaks of antigenicity were detected, one being type-specific and the other cross-reacting. The common antigen was heat-stable and attributable to empty capsids. Immuno-diffusion also revealed the common antigen. Infants without antibody to E 71 developed complement fixing and precipitin antibody to E 71 after recovery from hand, foot and mouth disease caused by CA 16.

Epidemic of hand, foot and mouth disease associated with enterovirus 71 infection

Viruses isolated from patients with hand, foot and mouth disease in widespread outbreaks in Japan in 1973 were identified as enterovirus 71. Although cases with aseptic meningitis were observed concurrently, the main clinical symptom associated with enterovirus 71 infection was hand, foot and mouth disease.

Damage and repair of DNA in urinary bladder epithelium of rats treated with N-butyl-N-(4-hydroxybutyl) nitrosamine

N-Butyl-N-(4-hydroxybutyl) nitrosamine (BBN), which selectively induced urinary bladder tumors in several experimental animal species, was found to cause damage of DNA in the bladder epithelium. Wistar strain rats were given 100 mg/kg of BBN intravesically and killed after 2, 6, 12, 24, or 48 hr. DNA damage was examined by measuring the change in sedimentation pattern in an alkaline sucrose gradient. Amount of DNA in each fraction was determined by fluorescence spectrophotometry. At 2 hr, the sedimentation profile shifted from heavier (No 15, control peak) to lighter (Nos. 2 approximately 4) fractions, and the maximum effect appeared at 6 hr as a single peak in the lighter fractions. At 12 hr, damaged DNA was in the process of repair as two peaks were present, one light and one heavy. At 48 hr, the sedimentation profile showed a single peak identical with that of controls indicating complete repair of DNA.