Tumour cell uptake of lactosaminated and intact N-succinyl-chitosans and antitumour effects of conjugates with mitomycin C

BACKGROUND: The relationship between the uptake of lactosaminated and intact N-succinyl-chitosans into hepatoma cells (MH134 and AH130) and liver metastatic tumour model cells (M5076) and the antitumour effects of their conjugates with mitomycin C (MMC) were investigated. MATERIALS AND METHODS: Fluorescently-labelled carriers were administered to tumour-bearing mice. The fluorescence intensity and microscopic examinations were performed at 1 hour post-injection. The antitumour effects were examined according to several schedules: one of them was the administration of each conjugate at a dose of 4 mg eq. MMC/kg x 4 days at 3 days post-inoculation. RESULTS: A difference in uptake was found by measurement of fluorescence intensity between both carriers only in MH134 cells, but was not recognized by fluorescence microscopy. Among these cell lines, the uptake of carriers into M5076 cells tended to be the most extensive. The difference in antitumour effects of the conjugates against MH134 and M5076 was reflected by the biodistribution study. CONCLUSION: The pattern of antitumour effects was markedly different among cell lines of different origins.     

A topographic analysis of the proliferating tumor cells in an autopsied brain with infiltrative thalamic glioma

Deep-seated gliomas, including thalamic gliomas, have a poor prognosis because of difficulty of accessibility for surgery. In addition, an infiltrative pattern of the tumor is related to a poor prognosis. In this study, the infiltrative/invasive profile of the proliferating tumor cells of a right thalamic glioma was evaluated in an autopsied brain. A 71-year-old man died from extensive infiltration of a right thalamic glioma. The distribution of the proliferating tumor cells at the right thalamic tumor level was represented by the topographic map of MIB-1 labeling indices (LI) on the whole-brain coronal slice, and this map was analyzed with pathological findings and postmortem T2-weighted magnetic resonance imaging (MRI). The highest MIB-1 LI was 24% for the whole autopsy brain at the thalamic tumor level, whereas the MIB-1 LI was 21% for the biopsy sample of the right thalamic glioma. Because this patient survived only 9 months after diagnosis of the tumor as anaplastic astrocytoma, it was confirmed that 21% MIB-1 LI of the biopsy sample was relevant to his prognosis. The topographic map of MIB-1 LI showed that the proliferating tumor cells of the right thalamic glioma invaded the ventricular walls and the contralateral thalamus by the periventricular route, but there was no exophytic extension to the cortex. In conclusion, topographic analysis of the proliferative potential detected by MIB-1 immunostaining provides information on the growth pattern of human glioma.     

A clinical study of resected bronchopulmonary carcinoids

19 surgically treated cases with bronchopulmonary carcinoid in our hospital were studied clinically, and we discussed the criteria of limited operation for typical carcinoid. 11 cases had typical carcinoid and 8 had atypical. All patients of typical type were alive with no recurrence. No lymph node metastasis was revealed in all cases of typical type. On the contrary, in cases of atypical type, 1 had n 2 disease and 1 had distant metastasis. The five survival rates of patients with typical carcinoid was 100%, and significantly better than that of patients with atypical, 27%. Therefore, patients with typical carcinoid can be cured by limited operation, but radical operation should be indicated for atypical carcinoid.     

The effects of sulfhydryl blockers and metal ions on nickel accumulation by rat primary hepatocyte cultures

Previously, we found that nickel (Ni) accumulation by rat hepatocytes involves Ca channel transport processes. However, other mechanisms responsible for Ni accumulation are still unclear. Therefore, in the present study we examined the effects of sulfhydryl (SH) blockers on Ni accumulation by hepatocytes. Hepatocytes were exposed to various concentrations of N-ethylmaleimide (NEM) (0.5, 1 or 2 mM) or monoiodoacetic acid (MIA) (0.1, 0.25 or 0.5 mM), potent blockers of SH ligands, for 30 min and subsequently exposed to 10 microM NiCl(2) for an additional 60 min. Pretreatment with NEM and MIA enhanced the Ni accumulation by hepatocytes to maximum of 156 and 73%, respectively. The effects of essential and nonessential metal ions on Ni accumulation were also investigated. Pretreatment with 10 microM of Cu, Zn, Co, Cd and Mn, decreased Ni accumulation by 46, 30, 20, 18 and 11%, respectively. In contrast, pretreatment with Hg (10 and 20 microM) enhanced the Ni accumulation by almost 81 and 140%, respectively. Furthermore, significant decrease in SH concentration in the hepatocyte membrane was observed by the treatment with NEM, MIA and Hg, but not with Cu, Zn and Cd. These results suggest that Ni accumulation by hepatocytes does not appear to be dependent on the SH carrier-mediated transport processes, and that to block the SH ligands in the plasma membrane may facilitate the Ni crossing of the cell membrane.     

Polygraphic study on the clinical seizures induced during nocturnal sleep.

The subjects of this study consisted of 17 epileptic patients with clinical seizures during all-night sleep recording (the seizure group) and another 17 epileptic patients without clinical seizures (the control group). The results obtained were as follows: 1) The 50-90% out of total clinical seizures were induced in non-REM sleep, while a few clinical seizures were induced in REM sleep. The number of clinical seizures in sleep stage of higher activity level increased as the incidence of clinical seizure during all-night grew. 2) In the seizure group REM sleep could not be detectable during all-night in five cases out of 17 cases, while we could not find cases lacking REM sleep in the control group. This difference between two subject groups was statistically significant (P less than 0.025). 3) As to focal spike group, the spike discharge incidence of total sleeping time and of each sleep stage was higher respectively in the seizure group than that in the control group, and particularly in St.1, St.2 and REM sleep the figure of the discharge incidence was found significantly higher in the seizure group than that in the control group (P less than 0.05). We discussed on above-mentioned results, and we emphasized particularly that REM-sleep suppresses clinical seizures, although non-REM sleep induces clinical seizures.     

Role of organic anion transporting polypeptide 2 in pharmacokinetics of digoxin and beta-methyldigoxin in rats

Recently, we found that potent P-glycoprotein (P-gp) inhibitors, such as verapamil and cyclosporin A, markedly modulated the pharmacokinetics of digoxin in rats, whereas they did not affect beta-methyldigoxin pharmacokinetics significantly. Digoxin is also a substrate of rat organic anion transporting polypeptide 2 (Oatp2). Here, we compared the magnitude of Oatp2-mediated drug interaction of digoxin and beta-methyldigoxin using amiodarone as an Oatp2 inhibitor in rats. Amiodarone (20 mg/kg) given intravenously significantly increased plasma levels and decreased biliary excretion, liver distribution, and intestinal distribution of digoxin administered intravenously at a dose of 10 mug/kg. Amiodarone also significantly decreased biliary excretion and liver distribution of beta-methyldigoxin, but the change in plasma levels of beta-methyldigoxin was quite small. These findings may give a clue in selecting these cardiac glycosides in clinical pharmacotherapy for patients receiving multiple drugs towards escape from Oatp2-mediated drug interactions.     

Oxidative DNA damage in relation to neurotoxicity in the brain of mice exposed to arsenic at environmentally relevant levels

To clarify the association between oxidative DNA damage and the neurotoxicity of arsenic, the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) as an index of oxidative DNA damage in the brain was examined in mice fed with drinking water containing 1 or 2 ppm arsenic, using an HPLC-electrochemical detector and immunohistochemical method. 8-OHdG levels were significantly increased in the brain of mice given arsenic and its immunoreactivity was distributed in the cerebral and cerebellar cortexes. Cerebral cortex neurons and Purkinje cells in the cerebellar cortex showed degenerative changes in accordance with the distribution of 8-OHdG immunoreactivity. The levels of arsenic in this study were lower than those reported in epidemiological studies. Thus, we conclude that environmentally relevant levels of arsenic induce pathological changes through oxidative DNA damage in the brain tissues in vivo and that cerebral and cerebellar cortex neurons seem to be the major targets of arsenic neurotoxicity.