Epidemic Enteropathogenic Escherichia Coli,Newfoundland, 1963: Autopsy Study of 16 Cases

The autopsy findings and certain other features are described in 16 fatal cases of infantile diarrhea associated with enteropathogenic Escherichia coli infection during the 1963 epidemic in Newfoundland which resulted in 100 deaths. Age is an important factor in the severity of the infection and in the outcome. Almost one-half the patients were under 4 months and a third under 2 months. Pathological changes in the gastrointestinal tract were meagre and were not pathognomonic. Other pathological findings and their possible role in the severity and fatal outcome in enteropathogenic Escherichia coli gastroenteritis are discussed. Such conditions as prematurity, congenital anomaly, trauma, neoplasm and metabolic disorders were, no doubt, also important factors in the outcome. Severe respiratory tract infection was the leading terminal cause of death. No sex, seasonal or geographic variation was found. Enteropathogenic Escherichia coli serotype 0111:B4 was the prevalent infecting organism.     

Specific-sized Hyaluronan Fragments Promote Expression of Human β-Defensin 2 in Intestinal Epithelium

Hyaluronan (HA) is a glycosaminoglycan polymer found in the extracellular matrix of virtually all mammalian tissues. Recent work has suggested a role for small, fragmented HA polymers in initiating innate defense responses in immune cells, endothelium, and epidermis through interaction with innate molecular pattern recognition receptors, such as TLR4. Despite these advances, little is known regarding the effect of fragmented HA at the intestinal epithelium, where numerous pattern recognition receptors act as sentinels of an innate defense response that maintains epithelial barrier integrity in the presence of abundant and diverse microbial challenges. Here we report that HA fragments promote expression of the innate antimicrobial peptide human β-defensin 2 (HβD2) in intestinal epithelial cells. Treatment of HT-29 colonic epithelial cells with HA fragment preparations resulted in time- and dose-dependent up-regulated expression of HβD2 protein in a fragment size-specific manner, with 35-kDa HA fragment preparations emerging as the most potent inducers of intracellular HβD2. Furthermore, oral administration of specific-sized HA fragments promotes the expression of an HβD2 ortholog in the colonic epithelium of both wild-type and CD44-deficient mice but not in TLR4-deficient mice. Together, our observations suggest that a highly size-specific, TLR4-dependent, innate defense response to fragmented HA contributes to intestinal epithelium barrier defense through the induction of intracellular HβD2 protein.     

Adamantyl N-benzylbenzamide: new series of depigmentation agents with tyrosinase inhibitory activity

A new series of polyhydroxylated N-benzylbenzamide derivatives containing an adamantyl moiety has been synthesized, and the depigmenting and tyrosinase inhibitory activities of the molecules were evaluated. The lipophilic character of the adamantyl moiety appeared to confer greater depigmentation power on the benzamide derivatives as compared to those lacking adamantyl substitution. Molecular modeling was applied in order to elucidate the interactions between ligands and tyrosinase that led to inhibition.     

Chitooligosaccharides induce apoptosis in human myeloid leukemia HL-60 cells

In this study we propose a novel anticancer agent using hetero-chitooligosaccharide (hetero-COS). To examine the possibility of the hetero-COS as a anticancer agent, we prepared nine kinds of hetero-COS with relatively higher molecular weights (90, 75 and 50-COS I, 5-10kDa), medium molecular weights (90, 75 and 50-COS II, 1-5kDa), and lower molecular weights (90, 75 and 50-III, below 1kDa), and their anticancer properties were investigated on HL-60 cells using flow cytometry and morphological analysis. The results obtained indicate that 90-COS III, which is relatively higher degree of deacetylation and lower molecular weights, showed the highest anticancer activity, and the data showed the anticancer property of the hetero-COSs depended on their degree of deacetylation values and molecular weight.     

Ethanol extract of paeonia suffruticosa Andrews (PSE) induced AGS human gastric cancer cell apoptosis via fas-dependent apoptosis and MDM2-p53 pathways

ABSTRACT: BACKGROUND: The root bark of Paeonia suffruticosa Andrews (PSE), also known as Moutan Cortex, has been widely used in Asia to treat various diseases. The molecular mechanisms by which PSE exerts its anti-oxidant and anti-inflammatory activities are well known, but its anti-cancer activity is not yet well understood. Here, we present evidence demonstrating that PSE can be used as a potent anti-cancer agent to treat gastric cancer. METHODS: The effects of the ethanol extract of PSE on cell proliferation were determined using an MTT (1-(4,5-dimethylthiazol-2-yl)-3,5-diphenylformazan) assay. Cell cytotoxicity induced by the PSE extact is measured using an LDH leakage assay. Flow cytometry was used to analyze the cell cycle and to measure the subG0/G1 apoptotic cell fraction. Apoptosis induced by the PSE extact is also examined using a DNA fragmentation assay. Western blot analysis is used to measure the levels of apoptotic proteins such as Fas receptor, caspase-8, caspase-3, PARP, Bax, Bcl-2, MDM2, and p53. RESULTS: This study demonstrated that treating AGS cells with the PSE extact significantly inhibited cell proliferation and induced cytotoxicity in a dose- and time-dependent manner. The PSE extract also induced apoptosis in AGS cells, as measured by flow cytometry and a DNA fragmentation assay. We found that the PSE extract induced apoptosis via the extrinsic Fas-mediated apoptosis pathway, which was concurrent with the activation of caspases, including caspase-8 and caspase-3, and cleavage of PARP. The MDM2-p53 pathway also played a role in the apoptosis of AGS cells that was induced by the PSE extract. CONCLUSIONS: These results clearly demonstrate that the PSE extact displays growth-suppressive activity and induces apoptosis in AGS cells. Our data suggest that the PSE extact might be a potential anti-cancer agent for gastric cancer.     

Hydrophobic interface between two regulators of K+ conductance domains critical for calcium-dependent activation of large conductance Ca2+-activated K+ channels

It has been suggested that the large conductance Ca(2)+-activated K(+) channel contains one or more domains known as regulators of K(+) conductance (RCK) in its cytosolic C terminus. Here, we show that the second RCK domain (RCK2) is functionally important and that it forms a heterodimer with RCK1 via a hydrophobic interface. Mutant channels lacking RCK2 are nonfunctional despite their tetramerization and surface expression. The hydrophobic residues that are expected to form an interface between RCK1 and RCK2, based on the crystal structure of the bacterial MthK channel, are well conserved, and the interactions of these residues were confirmed by mutant cycle analysis. The hydrophobic interaction appears to be critical for the Ca(2+)-dependent gating of the large conductance Ca(2+)-activated K(+) channel.     

Antihypertensive activity of chitin derivatives

To develop angiotensin I converting enzyme (ACE) inhibitory chitin derivatives based on the properties of ACE inhibitors, chitins with different degree of deacetylation were chemically modified by grafting 2-chloroethylamino hydrochloride onto chitin at the C-6 position. Three kinds of chitin derivatives were prepared and designated as aminoethyl-chitin (AEC) with 10% degree of deacetylation, aminoethyl-chitin with 50% degree of deacetylation (AEC50), and aminoethyl-chitin with 90% degree of deacetylation (AEC90). IC50 values of three chitin derivatives on ACE were 0.064 microM (AEC), 0.038 microM (AEC50), and 0.103 microM (AEC90). The results of Dixon plots revealed that AEC50 was a competitive inhibitor, and the inhibition constant (Ki) value was 0.021 microM. In addition, the antihypertensive effect of AEC50 on spontaneously hypertensive rats (SHR) was evaluated, and the result showed that it effectively decreased systolic blood pressure (SBP) in a dose-dependent manner.     

DNA methylation levels in porcine fetal fibroblasts induced by an inhibitor of methylation, 5-azacytidine

Removal of the somatic DNA methylation pattern from donor cells and remodeling of embryonic status have been suggested as integral processes for successful nuclear transfer (NT) reprogramming. This study has investigated the effects of 5-azacytidine (5-azaC), a DNA methylation inhibitor, on global methylation changes in porcine fetal fibroblasts (PFF); this may improve NT attributable to the potential reprogramming of the methyl groups. PFF in 5th passage cultures were treated with 0, 0.5, 1.0, 2.0, and 3.0 μM 5-azaC for 96 h; 5-azaC inhibited the growth at all tested concentrations. At the higher concentrations of 5-azaC used, cells appeared to exhibit morphological changes and to become apoptotic as observed by TUNEL assay. Thus, cells were negatively affected by 5-azaC. Differences in cellular ploidy were also observed at higher concentrations. Analysis showed no considerable changes in the proportion of cells at the G₁-phase of the cell cycle with 5-azaC concentrations. The fractional part of the methylated DNA of these cells was significantly reduced by 5-azaC treatment. Confocal microscopy confirmed the inhibition of methylation levels in PFF with increased concentrations of 5-azaC. Exposure to 5-azaC altered the expression of genes involved in imprinting (IGF2) or pro-apoptosis (BAX), whereas there was a reduction in the expression of the main enzyme responsible for replicating the DNA methylation pattern (DNMT1) and anti-apoptosis (BCL2L1). Therefore, 5-azaC induces a relative reduction in methylation in PFF, and cells treated with 0.5 μM 5-azaC may have enhanced potential for porcine NT.The financial support of BioGreen 21 (grant no. 100052004002000) and KOSEF (grant no. R05-2004-000-10702-0) in Korea is gratefully acknowledged.