Fasting protects against the side effects of irinotecan but preserves its anti-tumor effect in Apc15lox mutant mice

Irinotecan is a widely used topoisomerase-I-inhibitor with a very narrow therapeutic window because of its severe toxicity. In the current study we have examined the effects of fasting prior to irinotecan treatment on toxicity and anti-tumor activity. FabplCre;Apc^15lox/+ mice, which spontaneously develop intestinal tumors, of 27 weeks of age were randomized into 3-day fasted and ad libitum fed groups, followed by treatment with a flat-fixed high dose of irinotecan or vehicle. Side-effects were recorded until 11 days after the start of the experiment. Tumor size, and markers for cell-cycle activity, proliferation, angiogenesis, and senescence were measured. Fasted mice were protected against the side-effects of irinotecan treatment. Ad libitum fed mice developed visible signs of discomfort including weight loss, lower activity, ruffled coat, hunched-back posture, diarrhea, and leukopenia. Irinotecan reduced tumor size in fasted and ad libitum fed groups similarly compared to untreated controls (2.4 ± 0.67 mm and 2.4 ± 0.82 mm versus 3.0 ± 1.05 mm and 2.8 ± 1.08 mm respectively, P < 0.001). Immunohistochemical analysis showed reduced proliferation, a reduced number of vascular endothelial cells, and increased levels of senescence in tumors of both irinotecan treated groups. In conclusion, 3 days of fasting protects against the toxic side-effects of irinotecan in a clinically relevant mouse model of spontaneously developing colorectal cancer without affecting its anti-tumor activity. These results support fasting as a powerful way to improve treatment of colorectal carcinoma patients.     

SRY sequence in maternal plasma: Implications for non-invasive prenatal diagnosis: First report from India

AIM:

The presence of circulatory cell-free fetal DNA in maternal plasma has found new applications in non-invasive risk-free prenatal diagnosis.

MATERIALS AND METHODS:

We made use of a size separation approach along with real time polymerase chain reaction (PCR) to evaluate the use of fetal DNA in the detection of the sex of the fetus. Cell-free fetal DNA was isolated from the plasma of 30 women (10–20 weeks gestation) using a size separation approach. We made use of Taq Man Chemistry and real time PCR using primers and probes for GAPDH and SRY.

RESULTS:

Only 24 cases could be studied as there was no amplification in six cases. Fetal sex was accurately determined in all of the 24 cases wherein 19 women were carrying male fetuses and five women were carrying female fetuses. An increase in the amount of fetal DNA was observed with an increase in the gestational age.

CONCLUSIONS:

Real time PCR analysis is a highly sensitive and accurate tool for non-invasive prenatal diagnosis, allowing detection of the sex of the fetus as early as 10 weeks of gestation. Non-invasive prenatal diagnosis eliminates the risk of fetal loss associated with the invasive procedure.     

MIDAS: software for analysis and visualisation of interallelic disequilibrium between multiallelic markers

Background  

Various software tools are available for the display of pairwise linkage disequilibrium across multiple single nucleotide polymorphisms. The HapMap project also presents these graphics within their website. However, these approaches are limited in their use of data from multiallelic markers and provide limited information in a graphical form.     

Phosphatidylinositol 3-phosphate indirectly activates KCa3.1 via 14 amino acids in the carboxy terminus of KCa3.1

KCa3.1 is an intermediate conductance Ca2+-activated K+ channel that is expressed predominantly in hematopoietic cells, smooth muscle cells, and epithelia where it functions to regulate membrane potential, Ca2+ influx, cell volume, and chloride secretion. We recently found that the KCa3.1 channel also specifically requires phosphatidylinositol-3 phosphate [PI(3)P] for channel activity and is inhibited by myotubularin-related protein 6 (MTMR6), a PI(3)P phosphatase. We now show that PI(3)P indirectly activates KCa3.1. Unlike KCa3.1 channels, the related KCa2.1, KCa2.2, or KCa2.3 channels do not require PI(3)P for activity, suggesting that the KCa3.1 channel has evolved a unique means of regulation that is critical for its biological function. By making chimeric channels between KCa3.1 and KCa2.3, we identified a stretch of 14 amino acids in the carboxy-terminal calmodulin binding domain of KCa3.1 that is sufficient to confer regulation of KCa2.3 by PI(3)P. However, mutation of a single potential phosphorylation site in these 14 amino acids did not affect channel activity. These data together suggest that PI(3)P and these 14 amino acids regulate KCa3.1 channel activity by recruiting an as yet to be defined regulatory subunit that is required for Ca2+ gating of KCa3.1.     

Evaluation of immunomodulatory activity of Suvarnamalini vasant, a generic Ayurvedic herbomineral formulation

Suvarnamalini vasant-a generic Ayurvedic herbomineral preparation was studied for its immunomodulatory activity by 1) evaluating it's effect on phagocytic function of polymorphonuclear white blood cells of rats and 2) it's effect in E.coli-induced peritonitis in albino mice. Pretreatment of rats with Suvarnamalini vasant improved the phagocytic function of polymorphonuclear white blood cells and also protected mice against E.coli-induced peritonitis. The results indicate the potential of Suvarnamalini vasant as an immunomodulator.     

Changes in lipid peroxidation and free radical scavengers in kidney of hypothyroid and hyperthyroid rats

Kidney weight was significantly decreased in hypothyroidism (induced by Na131I administration) and increased in hyperthyroidism (induced by thyroxine treatment) as compared to control in female Wistar rats. The tissue lipid peroxidation level remained unchanged in hyperthyroid rats but significantly increased in hypothyroid rats. Superoxide dismutase was decreased in both experimental groups but more so in hyperthyroid rats. Catalase was reduced significantly in hyperthyroid rats but remained unaffected in hypothyroid rats. Tissue glutathione peroxidase (GPx) activity was increased while reduced glutathione levels remained unaltered in both hypothyroid and hyperthyroid rats. Plasma GPx activity was significantly low in both the hypothyroid and hyperthyroid rats. The results suggest alterations in the oxidative stress in hypothyroid and hyperthyroid rat kidneys with concomitant changes of free radical scavengers.