Physician perspectives on resuscitation status and DNR order in elderly cancer patients

Aim

To evaluate the process of placing DNR order in elderly cancer patients in practice and analysis of physician perspectives on the issue.

Background

Decision not to resuscitate (DNR/DNAR) is part of practice in elderly cancer care. Physicians issue such orders when a patient is suffering from irreversible disease and the patient''s life is coming to an end. Modern practice emphasises the need of communication with the patients and their relatives while issuing a DNR. The decision making process of placing DNR can be quite daunting. The moral and ethical dimensions surrounding such a decision make it a contentious topic.

Materials and methods

We searched the literature to find relevant works that would help physicians and especially the junior health care staff in dealing with the complexities. In this article, we discuss the issues that physicians encounter whilst dealing with a DNR order in elderly cancer patients.

Results

There are no objective adjuncts or guidelines directed towards the approach of placing a DNR in elderly cancer patients. Better communication with the patients and relatives when making such decision remains a very important aspect of a DNR decision. Most health care staff find themselves ill equipped to deal with such situation. Active training and briefing of junior staff would help them deal better with the stresses involved in this process.

Conclusion

There are complex psychosocial, medical, ethical and emotive aspects associated with placing a DNR order. Patients and their loved ones and the junior staff involved in the care of patient need early communication and briefing for better acceptance of DNR. Studies that could devise or identify tools or recommendations would be welcome.     

Cardiovascular Changes in Atherosclerotic ApoE-Deficient Mice Exposed to Co60 (γ) Radiation

Background

There is evidence for a role of ionizing radiation in cardiovascular diseases. The goal of this work was to identify changes in oxidative and nitrative stress pathways and the status of the endothelinergic system during progression of atherosclerosis in ApoE-deficient mice after single and repeated exposure to ionizing radiation.

Methods and Results

B6.129P2-ApoE tmlUnc mice on a low-fat diet were acutely exposed (whole body) to Co60 (γ) (single dose 0, 0.5, and 2 Gy) at a dose rate of 36.32 cGy/min, or repeatedly (cumulative dose 0 and 2 Gy) at a dose-rate of 0.1 cGy/min for 5 d/wk, over a period of 4 weeks. Biological endpoints were investigated after 3–6 months of recovery post-radiation. The nitrative stress marker 3-nitrotyrosine and the vasoregulator peptides endothelin-1 and endothelin-3 in plasma were increased (p<0.05) in a dose-dependent manner 3–6 months after acute or chronic exposure to radiation. The oxidative stress marker 8-isoprostane was not affected by radiation, while plasma 8-hydroxydeoxyguanosine and L-3,4-dihydroxyphenylalanine decreased (p<0.05) after treatment. At 2Gy radiation dose, serum cholesterol was increased (p = 0.008) relative to controls. Percent lesion area increased (p = 0.005) with age of animal, but not with radiation treatment.

Conclusions

Our observations are consistent with persistent nitrative stress and activation of the endothelinergic system in ApoE−/− mice after low-level ionizing radiation exposures. These mechanisms are known factors in the progression of atherosclerosis and other cardiovascular diseases.     

RdgB proteins: functions in lipid homeostasis and signal transduction

The RdgBs are a group of evolutionarily conserved molecules that contain a phosphatidylinositol transfer protein (PITP) domain. However in contrast to classical PITPs (PITPalpha) with whom they share the conserved PITP domain, these proteins also contain several additional sequence elements whose functional significance remains unknown. The founding member of the family DrdgB alpha (Drosophila rdgB) appears to be essential for sensory transduction and maintenance of ultra structure in photoreceptors (retinal sensory neurons). Although proposed to support the maintenance of phosphatidylinositol 4, 5 bisphosphate [PI (4, 5) P(2)] levels during G-protein coupled phospholipase C activity in these cells, the biochemical mechanism of DrdgB alpha function remains unresolved. More recently, a mammalian RdgB protein has been implicated in the maintenance of diacylglycerol (DAG) levels and secretory function at Golgi membranes. In this review we discuss existing work on the function of RdgB proteins and set out future challenges in understanding this group of lipid transfer proteins.     

Molecular alterations in oral carcinogenesis: significant risk predictors in malignant transformation and tumor progression

In this study an attempt was made to establish the significance of a battery of molecular alterations and thereby identify risk predictors in oral carcinogenesis. For this purpose, EGFR, Stat3, H-ras, c-myc, p53, cyclin D1, p16, Rb, Ki-67 and Bcl-2 were localized immunohistochemically in normal mucosa (n=12), hyperplasia (n=35), dysplasia (n=25), early stage carcinoma (n=65) and advanced stage carcinoma (n=70). Deregulation occurred at an early stage and the number of alterations increased with disease progression. Using multivariate logistic regression analysis, the significant risk predictor for hyperplasia from normal mucosa was Ki-67 (OR=5.75, p=0.021); the significant risk predictors for dysplasia from hyperplasia were EGFR (OR=12.96, p=0.002), Stat3 (OR=17.16, p=0.0001), p16 (OR=5.50, p=0.039) and c-myc (OR=5.99, p=0.052); the significant risk predictors for early stage carcinoma from dysplasia were p53 (OR=6.63, p=0.0001) and Rb (OR=3.81, p=0.056); and the significant risk predictors for further progression were EGFR (OR=5.50, p=0.0001), Stat3 (OR=4.49, p=0.0001), H-ras (OR=4.05, p=0.001) and c-myc (OR=2.99, p=0.015). Cyclin D1 holds a key position linking upstream signaling pathways to cell cycle regulation. Gene products of the mitogenic signaling pathway play an equally significant role as cell cycle regulatory proteins in the hyperplasia-dysplasia-early-advanced-carcinoma sequence and together may provide a reference panel of markers for use in defining premalignant lesions and predicting the risk of malignant transformation and tumor progression.     

Genetic transformation of <Emphasis Type="Italic">Gentiana macrophylla</Emphasis> with <Emphasis Type="Italic">Agrobacterium rhizogenes</Emphasis>: growth and production of secoiridoid glucoside gentiopicroside in transformed hairy root cultures

Hairy root cultures of Gentiana macrophylla were established by infecting the different explants four Agrobacterium rhizogenes strains namely A₄GUS, R1000, LBA 9402 and ATCC11325, and hairy root lines were established with A. rhizogenes strain R1000 in 1/2 MS + B₅ medium. Initially, 42 independent hairy root clones were maintained and seven clones belongs to different category were evaluated for growth, morphology, integration and expression of Ri T-DNA genes, and alkaloid contents in dry root samples. On the basis of total root elongation, lateral root density and biomass accumulation on solid media, hairy root clones were separated into three categories. PCR and Southern hybridization analysis revealed both left and right T-DNA integration in the root clones and RT-PCR analysis confirmed the expression of hairy root inducible gene. GUS assay was also performed to confirm the integration of left T-DNA. The accumulation of considerable amounts of the root-specific secoiridoid glucosides gentiopicroside was observed in GM1 ( and ) and the GM2 ( and DNA) type clones in considerably higher amount whether as two but callus-type clones (GM3) accumulated much less or only very negligible amounts of gentiopicroside. Out of four media composition the 1/2 MS + B₅ vitamin media was found most suitable. We found that initial establishment of root cultures largely depends on root:media ratio. Maximum growth rate was recorded in 1:50 root:media ratio. The maximum biomass in terms of fresh weight (33-fold) was achieved in 1/2 MS + B₅ media composition after 35 days in comparison to sixfold increase in control. The biomass increase was most abundant maximum from 15 to 30 days. Influence of A. rhizogenes strains and Ri plasmid of hairy root induction, the possible role of the T_L-DNA and T_R-DNA genes on growth pattern of hairy root, initial root inoculum:media ratio and effect of media composition is discussed.     

Medicarpin,a legume phytoalexin sensitizes myeloid leukemia cells to TRAIL-induced apoptosis through the induction of DR5 and activation of the ROS-JNK-CHOP pathway

Tumor necrosis factor α-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent with cancer cell-selective cell death inducing effect. However, the major limitation in the usage of TRAIL as a chemotherapeutic agent is the development of TRAIL resistance in many cancer types including myeloid leukemia. In this study, we report for the first time that Medicarpin (Med), a naturally occurring phytoalexin sensitizes myeloid leukemia cells to TRAIL-induced apoptosis. Combination of Med and TRAIL induced significantly higher apoptosis compared with that of the individual treatments of either agent alone through activation of both the extrinsic and the intrinsic cell death pathways characterized by the activation of caspases 8, 9, 3, and 7. Med treatment downregulated antiapoptotic proteins (Survivin, Bcl2, Bcl-xL, XIAP, and c-FLIP), upregulated pro-apoptotic proteins (Bax, Cytochrome C, Smac/Diablo, Bid, truncated Bid (tBid), p-eIF2α, Bip, and CHOP (CCAAT-enhancer binding protein homologous protein)), induced G2/M cell-cycle arrest, and increased the expression of the functional TRAIL receptor DR5 through activation of the ROS-JNK-CHOP pathway. Gain and loss of function studies clearly indicated that DR5 expression was critical for Med-induced TRAIL sensitization. The Med-induced TRAIL sensitization did not involve the NFkB signaling pathway or redistribution of DR5 in lipid rafts. The concomitant treatment with Med and TRAIL showed robust apoptotic effects in primary myeloid leukemia cells but had no toxic effects in primary human peripheral blood mononuclear cells (PBMCs). In conclusion, our results suggest that Med sensitizes myeloid leukemia cells to TRAIL-induced apoptosis through the upregulation of DR5 through activation of the ROS-JNK-CHOP pathway.Myeloid leukemia is a hematologic malignancy characterized by aberrant hematopoiesis with rapid proliferation of the undifferentiated and immature blood cells of the myeloid lineage.¹ The conventional therapeutic strategies for myeloid leukemia are limited by systemic side effects, development of chemoresistance, and poor survival outcomes.² Therefore, it is necessary to look for novel therapeutic agents and strategies for this dreadful disease.Therapy failure and chemo-resistance in myeloid leukemia cells are attributed to several mechanisms including resistance to the death receptor (DR)-mediated apoptosis.³ The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent characterized by its cancer cell-specific pro-apoptotic action mediated through the DRs.⁴ However, its therapeutic potential is severely compromised by acquired TRAIL resistance through the downregulation of DRs and adaptor proteins or the increased expression of antiapoptotic proteins in myeloid leukemia cells.⁵ Therefore, it is important to identify novel agents that can sensitize these TRAIL-resistant cells and could be combined therapeutically with TRAIL to amplify its pro-apoptotic effects.⁵In search of novel yet non-toxic TRAIL sensitizing agents, numerous studies have focused their attention on natural agents that could potentiate TRAIL-mediated apoptotic effects at physiologically attainable concentrations.⁶ The plant phytoalexins are a class of low molecular weight compounds with potent anticancer activities exerted through inhibition of cancer cell proliferation, invasion, and metastasis.⁷ Medicarpin (Med), a legume phytoalexin has excellent oral bioavailability and potent antiproliferative activity against breast cancer and acute myeloid leukemia (AML) cells.^8,9 Med also inhibits the oncogenic NFkB signaling by attenuating the TNF-α-induced nuclear translocation of p65.⁸In this study, we hypothesized that Med does not only inhibit cancer cell proliferation but also sensitizes cells to undergo DR-mediated apoptosis and explored whether it would sensitize the myeloid leukemia cell lines to TRAIL-induced apoptosis. We further attempted to elucidate the molecular mechanism associated with this effect.     

Kinetic and Thermodynamic Characterization of Glucoamylase from Colletotrichum sp. KCP1

Extracellular glucoamylase of Colletotrichum sp. KCP1 produced through solid state fermentation was purified by two steps purification process comprising ammonium sulphate precipitation followed by gel permeation chromatography (GPC). The Recovery of glucoamylase after GPC was 50.40 % with 19.3-fold increase in specific activity. The molecular weight of enzyme was found to be 162.18 kDa by native-PAGE and was dimeric protein of two sub-units with molecular weight of 94.62 and 67.60 kDa as determined by SDS-PAGE. Activation energy for starch hydrolysis was 26.45 kJ mol⁻¹ while temperature quotient (Q₁₀) was found to be 1.9. The enzyme was found to be stable over wide pH range and thermally stable at 40–50 °C up to 120 min while exhibited maximum activity at 50 °C with pH 5.0. The pKa₁ and pKa₂ of ionisable groups of active site controlling V_max were 3.5 and 6.8, respectively. V_max, K_m and K_cat for starch hydrolysis were found to be 58.82 U ml⁻¹, 1.17 mg (starch) ml⁻¹ and 449 s⁻¹, respectively. Activation energy for irreversible inactivation (E_a(d)) of glucoamylase was 74.85 kJ mol⁻¹. Thermodynamic parameters of irreversible inactivation of glucoamylase and starch hydrolysis were also determined.     

Using Liquid Crystals to Reveal How Mechanical Anisotropy Changes Interfacial Behaviors of Motile Bacteria

Bacteria often inhabit and exhibit distinct dynamical behaviors at interfaces, but the physical mechanisms by which interfaces cue bacteria are still poorly understood. In this work, we use interfaces formed between coexisting isotropic and liquid crystal (LC) phases to provide insight into how mechanical anisotropy and defects in LC ordering influence fundamental bacterial behaviors. Specifically, we measure the anisotropic elasticity of the LC to change fundamental behaviors of motile, rod-shaped Proteus mirabilis cells (3 μm in length) adsorbed to the LC interface, including the orientation, speed, and direction of motion of the cells (the cells follow the director of the LC at the interface), transient multicellular self-association, and dynamical escape from the interface. In this latter context, we measure motile bacteria to escape from the interfaces preferentially into the isotropic phase, consistent with the predicted effects of an elastic penalty associated with strain of the LC about the bacteria when escape occurs into the nematic phase. We also observe boojums (surface topological defects) present at the interfaces of droplets of nematic LC (tactoids) to play a central role in mediating the escape of motile bacteria from the LC interface. Whereas the bacteria escape the interface of nematic droplets via a mechanism that involved nematic director-guided motion through one of the two boojums, for isotropic droplets in a continuous nematic phase, the elasticity of the LC generally prevented single bacteria from escaping. Instead, assemblies of bacteria piled up at boojums and escape occurred through a cooperative, multicellular phenomenon. Overall, our studies show that the dynamical behaviors of motile bacteria at anisotropic LC interfaces can be understood within a conceptual framework that reflects the interplay of LC elasticity, surface-induced order, and topological defects.     

Magnesium Modulates Actin Binding and ADP Release in Myosin Motors

We examined the magnesium dependence of five class II myosins, including fast skeletal muscle myosin, smooth muscle myosin, β-cardiac myosin (CMIIB), Dictyostelium myosin II (DdMII), and nonmuscle myosin IIA, as well as myosin V. We found that the myosins examined are inhibited in a Mg²⁺-dependent manner (0.3–9.0 mm free Mg²⁺) in both ATPase and motility assays, under conditions in which the ionic strength was held constant. We found that the ADP release rate constant is reduced by Mg²⁺ in myosin V, smooth muscle myosin, nonmuscle myosin IIA, CMIIB, and DdMII, although the ADP affinity is fairly insensitive to Mg²⁺ in fast skeletal muscle myosin, CMIIB, and DdMII. Single tryptophan probes in the switch I (Trp-239) and switch II (Trp-501) region of DdMII demonstrate these conserved regions of the active site are sensitive to Mg²⁺ coordination. Cardiac muscle fiber mechanic studies demonstrate cross-bridge attachment time is increased at higher Mg²⁺ concentrations, demonstrating that the ADP release rate constant is slowed by Mg²⁺ in the context of an activated muscle fiber. Direct measurements of phosphate release in myosin V demonstrate that Mg²⁺ reduces actin affinity in the M·ADP·P_i state, although it does not change the rate of phosphate release. Therefore, the Mg²⁺ inhibition of the actin-activated ATPase activity observed in class II myosins is likely the result of Mg²⁺-dependent alterations in actin binding. Overall, our results suggest that Mg²⁺ reduces the ADP release rate constant and rate of attachment to actin in both high and low duty ratio myosins.     

Pyrazolopyridines as potent PDE4B inhibitors: 5-Heterocycle SAR

Following the discovery of 4-(substituted amino)-1-alkyl-pyrazolo[3,4-b]pyridine-5-carboxamides as potent and selective phosphodiesterase 4B inhibitors, [Hamblin, J. N.; Angell, T.; Ballentine, S., et al. Bioorg. Med. Chem. Lett. 2008, 18, 4237] the SAR of the 5-position was investigated further. A range of substituted heterocycles showed good potencies against PDE4. Optimisation using X-ray crystallography and computational modelling led to the discovery of 16, with sub-nM inhibition of LPS-induced TNF-α production from isolated human peripheral blood mononuclear cells.