Molecular signaling mechanisms of apoptosis in hereditary non-polyposis colorectal cancer

Colorectal cancer is the second most leading cause of cancer related deaths in the western countries. One of the forms of colorectal cancer is hereditary non-polyposis colorectal cancer (HNPCC), also known as “Lynch syndrome”. It is the most common hereditary form of cancer accounting for 5%-10% of all colon cancers. HNPCC is a dominant autosomal genetic disorder caused by germ line mutations in mismatch repair genes. Human mismatch repair genes play a crucial role in genetic stability of DNA, the inactivation of which results in an increased rate of mutation and often a loss of mismatch repair function. Recent studies have shown that certain mismatch repair genes are involved in the regulation of key cellular processes including apoptosis. Thus, differential expression of mismatch repair genes particularly the contributions of MLH1 and MSH2 play important roles in therapeutic resistance to certain cytotoxic drugs such as cisplatin that is used normally as chemoprevention. An understanding of the role of mismatch repair genes in molecular signaling mechanism of apoptosis and its involvement in HNPCC needs attention for further work into this important area of cancer research, and this review article is intended to accomplish that goal of linkage of apoptosis with HNPCC. The current review was not intended to provide a comprehensive enumeration of the entire body of literature in the area of HNPCC or mismatch repair system or apoptosis; it is rather intended to focus primarily on the current state of knowledge of the role of mismatch repair proteins in molecular signaling mechanism of apoptosis as it relates to understanding of HNPCC.

Gamma-ray emission probabilities in the decay of (177m)Lu

γ-Ray emission probabilities from the decay of the long-lived (T(1/2)=160.44d) isomeric state in (177m)Lu were measured with planar (LEPS) and coaxial Ge detectors. The isomer γ-ray and β(-)-decay branching intensities were also determined. Measurements were carried out at low absolute efficiencies in order to minimize coincidence summing losses. The results are compared with the previous measurements.

Attenuation of tissue oxidative stress by dietary restriction in rats on simulated microgravity

INTRODUCTION

Physiologic alterations caused by oxidative stress can be assessed by measuring tissue malondialdehyde (MDA) levels, a biomarker for oxidative stress. The goal of this study is to determine the consequences of a twenty percent caloric restriction on the increased oxidative stress documented in tissues from rats exposed to simulated microgravity.

MATERIALS/METHODS

Three groups of male SD rats (N=6 in each group) were used: Group 1, control; Group 2, food restricted (20% less food than control); and Group 3, food restricted with HLS. Group 3 was suspended after one week on the HLS-restricted diet and maintained for 14 days. Tissues harvested on day 14 were measured for MDA levels.

RESULTS

The body weight gain of Group 2 and Group 3 was reduced as compared to that of Group 1 ( p <0.05) with no significant changes in water intakes. MDA levels in Group 2 were not different from those of the control group and were elevated only in liver tissues (p<0.05). In Group 3, MDA levels in the heart, liver, brain, and testes were significantly elevated (p<0.05) compared to the levels of Groups 1 and 2.

CONCLUSIONS

Food restriction alleviated tissue oxidative response in all tissues except for the liver. Excessive stress resulting from HLS appeared to have been minimized by dietary restriction in all tissues except for the heart, liver, brain, and testes.

Parimal Chowdhury’s work on smoking related pancreatic disorders

Cigarette smoking is a known risk factor for the development of numerous diseases. The role of nicotine in the induction of pancreatic inflammation and pancreatic cancer as a result of cigarette smoking has been recognized and reported in the literature. The mechanism by which nicotine induces such pathologies is as yet unknown. An understanding of the proliferative potential of nicotine in primary and tumor cells of the pancreas will allow us to develop measures that will ultimately lead to intervention, prevention and treatment of these diseases. Studies show that nicotine can increase the cell numbers of cer-tain cancer cell lines, suggesting that exposure to nicotine can lead to the disruption of the dynamic balance between cell death and proliferation, which is required for normal functioning of cells. We hypothesize that nicotine induces oxidative stress in pancreatic acinar cells and thus contributes to this disruption. We have used the AR42J cell line in our study because of its stability as an immortal tumor cell line and its known physiological similarity to primary acinar cells. Our studies show that mitogen activated protein kinase signaling is induced by nicotine in AR42J cells, causing an increase in lipid peroxidation and a subsequent decrease in cell function. Our data suggest that exposure to nicotine induces oxidative stress, leading to cell injury and compromised function, thus implicating cigarette smoking as a plausible mechanism.

First evidence of chikungunya virus infection in Assam, Northeast India

During June-September 2008, an illness characterized by fever, headache and joint pain was reported in Assam state, northeast India. It presented characteristic features resembling chikungunya or dengue virus infection based on clinical symptoms. Dengue and chikungunya IgM antibody was detected in 10.0% (28/280) and 3.6% (10/280) patients respectively. The chikungunya positive patients did not travel to and from any endemic region confirming indigenous transmission. Persistent arthralgia and hearing loss has been observed in a recovered patient. Entomological surveys revealed the presence of vectors viz. Aedes aegypti and Aedes albopictus. This is the maiden report of chikungunya occurrence in Northeast India.

Effects of aminoguanidine on tissue oxidative stress induced by hindlimb unloading in rats

We investigated the effects of hindlimb unloading (HLU) on malondialdehyde (MDA), a biomarker for oxidative stress, and glutathione (GSH) levels in tissues of rats. Aminoguanidine (AG), a nucleophilic hydralazine compound and an in vivo antioxidant against reactive oxygen species (ROS) and lipid peroxidation, was used to confirm the HLU-induced oxidative response. Three groups of rats were used: Group 1 was a loaded control group that was maintained on drinking water only; Groups 2 and 3 were hindlimb unloaded (HLU) groups that were maintained on drinking water and on AG in drinking water, respectively. The hindlimb unloaded rats maintained on tap water had significantly elevated MDA levels in 7 tissues (brain, lung, pancreas, kidney, intestine, heart, liver) when compared to the paired hindlimb loaded controls (p <0.05). In contrast, the hindlimb unloaded rats maintained on AG in drinking water had no increase in tissue MDA levels when compared to the loaded controls; moreover, their tissue MDA levels were significantly reduced from the HLU group on tap water (p <0.05). In HLU rats maintained on AG, there were no changes in tissue GSH levels with the exception of brain, where GSH levels were significantly reduced when compared to the other groups (p <0.05). In summary, HLU induced an oxidative response in rats and this response was reduced significantly by ingestion of AG. These results suggest the potential application of AG in the diet of astronauts living in a stressful environment.

A report of the Sixth Annual Meeting of the International Society for the Prevention of Tobacco Induced Diseases (ISPTID)

The Sixth meeting of the International Society for the Prevention of Tobacco Induced Diseases (ISPTiD) was held in Little Rock, Arkansas on November 2–4, 2007 and has brought together 140 participants, scientists and experts in this specialized field from 30 countries across the World. The central theme of the conference was the "Translational Approaches to the Prevention of Tobacco Induced Diseases". Discussions held during the three days meeting's sessions (including poster session and platform discussion) promoted a better understanding of the connection between tobacco use and associated medical and health consequences. The Sixth Annual meeting of ISPTiD served as another successful step toward decrease in the huge sociological and economical burden that the entire World is facing with this addiction. The proceedings of the meeting were published in the conference booklet, the ISPTiD global web site and Cancer Database abstract web site. Funds generated from this meeting helped in part to establish the society's Journal "Tobacco Induced Diseases "into the major scientific journal index PubMed database and BioMed Central. The meeting set the tone for next the Annual meeting in Kyoto, Japan for the year 2008 with the theme "Tobacco free future".

Collective oblate rotation at high spins in neutron-rich 180Hf

We report on experimental evidence for collective oblate rotation becoming favored at high spins in a rigid, well-deformed, axially symmetric nucleus. Excited states established up to spin 20variant Planck's over 2pi in 180Hf are consistent with predictions that nucleon alignments would favor oblate over prolate shapes at high spins in neutron-rich Hf isotopes. The results highlight the influence of valence orbitals on the interplay between nucleon alignments and nuclear shapes and provide a rare example of independent particle dynamics in competing potential wells.