Preparation of doxorubicin-containing chitosan microspheres for transcatheter arterial chemoembolization of hepatocellular carcinoma.

A new form of doxorubicin hydrochloride (DRH)-containing chitosan microspheres (CMs) was prepared by employing an expanding-loading-shrinking (E-L-S) process. One hundred mg of pre-formed CMs were soaked in absolute ethanol and then placed in reduced pressure (the expanding process). Ten mg of DRH (2 mg ml(-1)) were added into the expanded CMs (the loading process). Next the microspheres were freeze-dried (the shrinking process). As a result of this E-L-S process, 10% (w/w) DRH-containing CMs (DRH-CM) were made. During 7 days, 22.6% of the DRH was observed to be released on the in vitro drug release study. In addition, these new DRH-CMs could be used for transcatheter arterial chemoembolization (TACE) procedure in VX2 hepatic tumour models of rabbit and the anti-tumour effects of DRH-CMs were investigated. On the post-CT scan 7 days after the TACE, total infarctions of the VX2 tumour were observed in 5 rabbits among the 6 total rabbits.

Effects of folate supplementation on two provisional molecular markers of colon cancer: a prospective, randomized trial.

OBJECTIVES: Dietary folate intake is inversely associated with the risk of colorectal cancer. This study investigated the effect of folate supplementation on genomic DNA methylation and DNA strand breaks in exons 5-8 of the p53 gene of the colonic mucosa, two provisional biomarkers of colon cancer. METHODS: Twenty subjects with adenomas were randomized to receive either folate (5 mg/day) or placebo for 1 yr after polypectomy. At baseline, 6 months and 1 yr, systemic and colonic measures of folate status were determined, as were the biomarkers mentioned earlier. RESULTS: Folate supplementation increased serum, red blood cell and colonic mucosal folate concentrations (p < 0.02). Folate supplementation also increased the extent of genomic DNA methylation at 6 months and 1 yr (p = 0.001), whereas placebo administration was associated with an increase in the extent of genomic DNA methylation only at 1 yr. Similarly, folate supplementation decreased the extent of p53 strand breaks in exons 5-8 at 6 months and 1 yr (p < 0.02), whereas placebo administration was associated with a decrease in the extent of p53 strand breaks only at 1 yr. CONCLUSIONS: Both of these provisional biomarkers of colon cancer underwent accelerated improvement at 6 months with folate supplementation. However, these markers also improved with placebo at 1 yr. Therefore, potential confounding factors that seem to modulate these biomarkers need to be identified and corrected in order for these markers to serve as suitable surrogate endpoints in folate chemoprevention trials.

Chronic alcohol consumption induces genomic but not p53-specific DNA hypomethylation in rat colon.

Alcohol consumption has been implicated as an etiologic agent in colorectal carcinogenesis, but the mechanism by which alcohol enhances the development of colorectal cancer is not yet known. Recent reports indicate that alcohol consumption can diminish cellular S-adenosylmethionine levels, thus possibly altering normal patterns of DNA methylation, a phenomenon that is mediated by S-adenosylmethionine and whose abnormalities are observed in colonic neoplasia. This study investigated the effect of chronic alcohol consumption on genomic DNA methylation of rat colonic epithelium and methylation of the p53 tumor suppressor gene, abnormalities of which have been implicated in colonic carcinogenesis. Two groups of rats (n = 10/group) were pair-fed either an alcohol-containing or an isocaloric control Lieber-DeCarli diet for 4 wk. The extent of genomic DNA methylation was assessed by incubating the extracted DNA with [(3)H]S-adenosylmethionine and Sss1 methyltransferase. Gene-specific methylation was assessed by using semiquantitative polymerase chain reaction (PCR). Tritiated methyl uptake by colonic DNA (which is inversely correlated with genomic methylation) from alcohol-fed rats was 57% less than that in control DNA (P < 0.05). However, gene-specific DNA methylation, both in the p53 gene (exons 5-8) and in the beta-actin gene, a control gene, did not differ between the two groups. In conclusion, this study indicates that chronic alcohol consumption produces genomic DNA hypomethylation in the colonic mucosa. This may constitute a means by which carcinogenesis is enhanced, although further studies are required to establish causality.

Vitamin B12 deficiency in the elderly.

Vitamin B12 deficiency is estimated to affect 10%-15% of people over the age of 60, and the laboratory diagnosis is usually based on low serum vitamin B12 levels or elevated serum methylmalonic acid and homocysteine levels. Although elderly people with low vitamin B12 status frequently lack the classical signs and symptoms of vitamin B12 deficiency, e.g. megaloblastic anemia, precise evaluation and treatment in this population is important. Absorption of crystalline vitamin B12 does not decline with advancing age. However, compared with the younger population, absorption of protein-bound vitamin B12 is decreased in the elderly, owing to a high prevalence of atrophic gastritis in this age group. Atrophic gastritis results in a low acid-pepsin secretion by the gastric mucosa, which in turn results in a reduced release of free vitamin B12 from food proteins. Furthermore, hypochlorhydria in atrophic gastritis results in bacterial overgrowth of the stomach and small intestine, and these bacteria may bind vitamin B12 for their own use. The ability to absorb crystalline vitamin B12 remains intact in older people with atrophic gastritis. The 1998 recommended daily allowance for vitamin B12 is 2.4 micrograms, but elderly people should try to obtain their vitamin B12 from either supplements or fortified foods (e.g. fortified ready-to-eat breakfast cereals) to ensure adequate absorption from the gastrointestinal tract. Because the American food supply is now being fortified with folic acid, concern is increasing about neurologic exacerbation in individuals with marginal vitamin B12 status and high-dose folate intake.

Melatonin protects nigral dopaminergic neurons from 1-methyl-4-phenylpyridinium (MPP+) neurotoxicity in rats.

In the present study, the in vivo neuroprotective effects of melatonin, as an antioxidant, were assessed in Sprague-Dawley rats with a unilateral lesion of substantia nigra (SN) caused by a stereotaxic injection of neurotoxin, 1-methyl-4-phenylpyridinium (MPP+). When expressed as a percentage ratio of lesioned to intact side, increased lipid peroxidation product (malondialdehyde, MDA, 117% of control) and decreased tyrosine hydroxylase (TH) enzyme activity (60% of control) in SN were observed 4 h after MPP+ lesion. In contrast, however, melatonin treatment prevented MPP+ neurotoxicity by the almost complete recovery of MDA (99% of control) and TH levels (96% of control), indicating the potent antioxidative effects of melatonin. In addition, further reduction of TH enzyme activity (52% of control) was seen 1 week after MPP+ infusion. Continuous (twice a day for 5 days), not acute (4 h) treatment with melatonin produced the partial, but not statistically significant, recovery of TH enzyme activity (71% of control), when sacrificed 1 week after MPP+ lesion. Taken together, the present results support the hypothesis that melatonin may provide the useful therapeutic strategies for the treatment of oxidative stress-induced neurodegenerative disease such as Parkinson's disease (PD).