In vitro chemosensitivity of freshly explanted tumor cells to pemetrexed is correlated with target gene expression

AIM OF THE STUDY

mRNA expression of genes involved in the mechanism of action of pemetrexed was correlated with in vitro chemosensitivity of freshly explanted human tumor specimens.

EXPERIMENTAL DESIGN

Chemosensitivity to pemetrexed was studied in soft-agar. Multiplex rtPCR experiments for reduced folate carrier (RFC), folate receptor-alpha (FR-alpha), folylpolyglutamate synthetase (FPGS), thymidylate synthase (TS), dihydrofolate reductase (DHFR), glycinamide ribonucleotide formyl transferase (GARFT), mrp4, and mrp5 were performed in parallel. Correlations, threshold optimization, sensitivity, specificity, and efficiency were analyzed using the appropriate statistical methodologies.

RESULTS

In 61 samples, low levels of TS, GARFT, DHFR, and mrp4 gene expression significantly correlated with chemosensitivity to pemetrexed. Optimization analyses demonstrated threshold values of 144 copies for TS and six copies for mrp4 relative to 10(4) copies of beta-actin.

CONCLUSIONS

These results form a rational basis for the design of clinical trials to evaluate the expression of these enzymes as predictors for treatment outcome.

Coronary interventional devices: balloon, atherectomy, thrombectomy and distal protection devices

With increased operator experience and improved device technology, there has been a constant growth in the number of complex lesions (ie, thrombotic lesions, diffuse lesions,calcified lesions, nondilatable rigid lesions, ostial lesions, bifurcations, and chronic total occlusions) attempted by interventionalists with the use of drug-eluting stents. Although coronary stent implantation remains the mainstay and ultimate step for the treatment of most coronary lesions, adjunctive devices may be essential for lesion preparation in some cases (5%-10%) to allow stent deployment and expansion and prevent distal embolization. Thrombectomy and distal protection devices have shown to be effective in the interventions of saphenous vein graft lesions, although their use remains unproven in acute myocardial infarctions.

Enzastaurin a protein kinase Cbeta-selective inhibitor, inhibits the growth of SCLC and NSCLC cell lines

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Background: PKCβ is a member of the PKC family of serine-threonine protein kinases involved in tumor cell proliferation and apoptosis. Inhibition of PKCs induced differentiation and enhanced chemotherapy. PKCβ activation is required for tumor-induced angiogenesis. The PKCβ-selective inhibitor enzastaurin, originally developed as an antiangiogenic agent, inhibited tumor cell proliferation in prostate, colon and glioblastoma cell lines in vitro. In NSCLC lines, enhanced phosphorylation and altered PKC expression was demonstrated. In SCLC lines specific PKC isoforms were associated with cisplatin resistance. Methods: The growth inhibitory effects of enzastaruin were evaluated by 6-day MTT assays; the cell cycle effects by FACS analysis; the effects on downstream phophorylated signaling molecules by western blotting. Results: Enzastaurin inhibited the growth of 11 SCLC lines (IC50s 3–10 μM) and 4 NSCLC cell lines (IC50s 3–10 μM). An increase of 7–31% of cells in the G2/M phase of the cell cycle compared to untreated control was observed following 48 hour exposure to the IC50 dose of enzastaurin in both SCLC and NSCLC cell lines. PKCβ has been shown to phosphorylate both GSK3β and Akt. A 24-hour IC50 enzastaurin exposure significantly reduced phosphorylation of GSK3β (Ser9) in both SCLC and NSCLC lines. No changes were observed in phospho-AKT (Thr308) in either SCLC or NSCLC cell lines. Phospho-ribosomal protein S6 (Ser240/244) was also reduced in both SCLC and NSCLC cell lines. Potential synergy was studied between enzastaurin and pemetrexed in SCLC and NSCLC lines and the results were analyzed using the Calcusyn Program by Chou and Talalay. Synergistic (CI <1) to additive interactions were observed between pemetrexed (IC20–70) and enzastaurin (≤ IC50) in both SCLC lines (N = 3) and NSCLC lines (N = 2). Conclusions: We conclude that enzastaruin produces in vitro growth inhibition of SCLC and NSCLC cell lines through inhibition of GSK3β ser9 phosphorylation and has synergistic growth inhibition with pemetrexed.

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Mail and phone interventions for weight loss in a managed-care setting: weigh-to-be 2-year outcomes

OBJECTIVE

Evaluate effectiveness of weight-loss interventions in a managed care setting.

METHODS

Three-arm randomized clinical trial: usual care, mail, and phone intervention. Participants were 1801 overweight managed care organization (MCO) members. Measures included baseline height, weight at baseline and 24 months, self-reported weight at 18 months. Intervention and participation in other weight-related programs was monitored across 24 months.

RESULTS

Weight losses were 2.2, 2.4, and 1.9 kg at 18 months in the mail, phone, and usual care groups, respectively. Mail and phone group weight changes were not significantly different from usual care (P<0.35). Weight losses at 24 months did not differ by condition (0.7 kg mail, 1.0 kg phone, and 0.6 kg usual care, P=0.55). Despite treatment availability over 24 months, participation diminished after 6 months. Participation was a significant predictor of outcomes in the mail and phone groups at 18 months and the mail group at 24 months. Cost-effectiveness of phone counseling was $132 per 1 kg of weight loss with mail and usual care achieving similar cost-efficiency of $72 per 1 kg of weight loss.

CONCLUSION

Although mail- and phone-based weight-loss programs are a reasonably efficient way to deliver weight-loss services, additional work is needed to enhance their short- and long-term efficacy.

Kinetic validation of the use of carboxydichlorofluorescein as a drug surrogate for MRP5-mediated transport

Multidrug resistance protein-5 (MRP5, ABCC5) is a member of the ATP-binding cassette transporter superfamily that effluxes a broad range of natural and xenobiotic compounds such as cyclic GMP, antiviral compounds, and cancer chemotherapeutic agents including nucleoside-based drugs, antifolate agents and platinum compounds. In cellular assays, MRP5 transfectants are less fluorescent after incubation with 5-chloromethylfluorescein diacetate (CMFDA). The present study examines the uptake of a close fluorescent analog, carboxydichlorofluorescein (CDCF), and drug substrates into inside-out membrane vesicles prepared from MRP transfected cells. MRP5-mediated uptake of CDCF was ATP-dependent and GSH-independent and possessed a Km of 12 microM and a Vmax of 56 pmol/min/mg prot. Comparison of kinetic parameters with drug substrates such as methotrexate (MTX), pemetrexed (Alimta), and the metabolite of 5-fluorouracil, 5-fluorodeoxyuridine monophosphate (5-FdUMP) (Km values of 0.3-1.3 mM) indicated that MRP5 has a 25-100-fold higher affinity for CDCF than for these drugs and that they share a common transport binding site. In addition, the potency of MRP5 inhibitors such as probenecid, MK571, and the phosphodiesterase 5 inhibitors correlated well between the uptake of CDCF and MTX. A survey of CDCF uptake by other MRPs revealed that MRP2 (ABCC2) also demonstrated ATP-dependent uptake with a Km of 19 microM and Vmax of 95.5 pmol/min/mg prot, while MRP1 (ABCC1) and MRP4 (ABCC4) had little to no uptake. Taken together, these data indicate that CDCF is a useful fluorescent drug surrogate with which to measure ATP-dependent MRP5-mediated transport.

The relationship between critical flux and fibre movement induced by bubbling in a submerged hollow fibre system

Bubbling has been used to enhance various processes. In this paper we deal with the effect of bubbling on submerged hollow fibre membranes, where bubbling is applied to prevent severe membrane fouling. Previous work with submerged hollow fibres has observed that significant fibre movement can be induced by bubbling and that there is a qualitative relationship between fibre movement and filtration performance. Therefore, the aim of the present research has been to analyse the link between bubbling, fibre movement and critical flux, identified as the flux at which the transmembrane pressure (TMP) starts to rise. Tests were performed on vertical isolated fibres with a model feed of yeast suspension. The fibres were subject to steady bubbling from below. The parameters of interest were the fibre characteristics, such as tightness, diameter and length, as well as feed concentration. The results confirmed that the critical fluxes are affected by the fibre characteristics and feed concentration. Higher critical flux values can be achieved by using loose fibres, smaller diameters and longer fibres. The enhancement is partially linked to fibre movement and this is confirmed by improved performance when fibres are subject to mechanical movement in the absence of bubbling.

The photocatalytic degradation of reactive black 5 using TiO2/UV in an annular photoreactor

The textile effluent is a major industrial polluter because it is highly colored, containing about 15% unfixed dyes as well as high levels of salts that can potentially be discharged into the environment. Photocatalytic oxidation using an thin gap annular UV reactor with TiO2 was used to break down the colour of a synthetic effluent ranging up to 400 ppm in dye concentration of Reactive Black 5 and up to 80 g/L in NaCl. Results show that the reaction kinetics was dominated by the TiO2 loading, the initial dye concentration, and the dissolved oxygen concentration; with the other parameters showing less significant effects. High rates of decolorization were found, with a linear fit to the Langmuir-Hinshelwood equation yielding a reaction rate constant (k) of 2.45 ppm/min, and an adsorption equilibrium constant (K) of 0.048 ppm(-1) based on color removal. The presence of the combination of high dissolved oxygen (15 ppm) and sodium chloride (up to 80 g/L) was found to enhance the decolorization and mineralization rates of the reactive dye. However, pH was found to not significantly affect the degradation rate. Since textile effluent is strongly alkaline, this result is significant, as no solution neutralisation is required and direct treatment of the effluent is possible.

Cholinergic interneurons of the nucleus accumbens and dorsal striatum are activated by the self-administration of cocaine

The nucleus accumbens, a major component of the ventral striatum, and the dorsal striatum are primary targets of the mesolimbic dopamine pathway, which is a pathway that plays a critical role in reward and addiction. The shell compartment of the nucleus accumbens and the ventromedial striatum, in particular, receive extensive afferent projections from the ventral tegmental area, which is the major afferent source of the mesolimbic pathway [Prog Brain Res 99 (1993) 209; J Neurosci 7 (1987) 3915]. The present study focused on striatal cholinergic interneurons as potential key neurons involved in the neural basis of drug reinforcement. The main finding of this study is that cholinergic interneurons located in the shell compartment of the nucleus accumbens and the ventromedial striatum were activated, as measured by Fos labeling, following a 1 h session of the self-administration of cocaine in rats. A direct correlation existed between the percent of cholinergic interneurons that were activated and the amount of cocaine that was self-administered. The greatest amount of administered cocaine (approximately 10 mg/kg) resulted in the activation of approximately 80% of the cholinergic neurons. No such correlation existed in the group of animals that self-administered saline. In addition, activation was not found in the core compartment of the nucleus accumbens or the dorsolateral striatum, which receive extensive innervation from the substantia nigra and thus are more closely tied to the motor effects of the drug. In conclusion, cocaine-driven neuronal activation was specific to the shell compartment of the nucleus accumbens (R(2)=0.9365) and the ventromedial striatum (R(2)=0.9059). These findings demonstrate that cholinergic interneurons are involved in the initial stage of cocaine intake and that these neurons are located in areas of the nucleus accumbens and dorsal striatum that are more closely tied to the rewarding and hedonic effects rather than the motor effects of cocaine intake.

Concentric intermediate filament lattice links to specialized Z-band junctional complexes in sonic muscle fibers of the type I male midshipman fish

Type I male midshipman fish produce high-frequency hums for prolonged durations using sonic muscle fibers, each of which contains a hollow tube of radially oriented thin and flat myofibrils that display extraordinarily wide ( approximately 1.2 microm) Z bands. We have revealed an elaborate cytoskeletal network of desmin filaments associated with the contractile cylinder that form interconnected concentric ring structures in the core and periphery at the level of the Z bands. Stretch and release of single fibers revealed reversible length changes in the elastic desmin lattice. This lattice is linked to Z bands via novel intracellular desmosome-like junctional complexes that collectively form a ring, termed the "Z corset," around the periphery and within the core of the cylinder. The junctional complex consists of regularly spaced parallel approximately 900-nm-long cytoskeletal rods, or "Z bars," interconnected with slender (3-4 nm) plectin-positive filaments. Z bars are linked to the Z band by plectin filaments and on the opposite side to a dense mesh of desmin filaments. Adjacent Z bands are linked by slender filaments that appear to suspend sarcotubules. We propose that the highly reinforced elastic desmin cytoskeleton and the unique Z band junctions are structural adaptations that enable the muscles' high-frequency and high-endurance activity.

Social exchange of cigarettes by youth

OBJECTIVE

This study seeks to determine the magnitude, nature, and correlates of social exchange of cigarettes among youth who smoke.

DESIGN

Cross sectional survey.

SETTING

Schools in 29 Minnesota communities.

PARTICIPANTS

All students in grades 8, 9, and 10 (ages 13-16 years) in each participating school. The parent/child response rate for the survey was 90%. Analyses included 4124 respondents who smoked at least one cigarette in the month before the survey.

OUTCOME MEASURES

Social exchange scale, consisting of 16 items assessing aspects of social provision and acquisition of cigarettes.

RESULTS

Almost 90% of youth in this study had obtained a cigarette from, and about 75% of them had provided cigarettes to, another teen in the prior month. Daily smokers provided to more teens and provided more often than those who smoked less than daily. Daily smokers also reported having more social sources, both teens and adults, than lighter smokers, and were more likely to have both bought from and sold cigarettes to other teens (p < 0.0001 for all comparisons between daily and less than daily smokers). In a multivariate analysis, social exchange was associated with grade, whether siblings and friends smoke, level of smoking, age of smoking initiation, parental influences and community norms about teen smoking, and buying cigarettes.

CONCLUSIONS

Social provision and acquisition of cigarettes among teens are widespread, reciprocal behaviours. Parental and community expectations about smoking influence social exchange, possibly by providing opportunities or barriers for social smoking. Commercial and social availability are not mutually exclusive; rather social exchange extends the reach of commercial sources.

Limits of detection of regional differences in vasodilated flow in viable myocardium by first-pass magnetic resonance perfusion imaging

BACKGROUND

Perfusion imaging techniques intended to identify regional limitations in coronary flow reserve in viable myocardium need to identify 2-fold differences in regional flow during coronary vasodilation consistently. This study evaluated the suitability of current first-pass magnetic resonance approaches for evaluating such differences, which are 1 to 2 orders of magnitude less than in myocardial infarction.

METHODS AND RESULTS

Graded regional differences in vasodilated flow were produced in chronically instrumented dogs with either left circumflex (LCx) infusion of adenosine or partial LCx occlusion during global coronary vasodilation. First-pass myocardial signal intensity-time curves were obtained after right atrial injection of gadoteridol (0.025 mmol/kg) with an MRI inversion recovery true-FISP sequence. The area under the initial portion of the LCx curve was compared with that of a curve from a remote area of the ventricle. Relative LCx and remote flows were assessed simultaneously with microspheres. The ratio of LCx and remote MRI curve areas and the ratio of LCx and remote microsphere concentrations were highly correlated and linearly related over a 5-fold range of flow differences (y=0.96 x+/-0.07, P<0.0001, r(2)=0.87). The 95% confidence limits for individual MRI measurements were +/-35%. Regional differences of >/=2-fold were consistently apparent in unprocessed MR images.

CONCLUSIONS

Clinically relevant regional reductions in vasodilated flow in viable myocardium can be detected with 95% confidence over the range of 1 to 5 times resting flow. This suggests that MRI can identify and quantify limitations in perfusion reserve that are expected to be produced by stenoses of >/=70%.

Occult mucosal injuries with radiofrequency ablation of the palate

OBJECTIVE

To determine the true incidence of mucosal injury after radiofrequency ablation of the palate (RFAP) for snoring and mild obstructive sleep apnea, and to evaluate the consequences of this injury.

STUDY DESIGN AND SETTING

A prospective, nonrandomized analysis of RFAP was undertaken at Stanford University Hospital. Endoscopic examinations of the nasal surface of the palate and of the posterior pharyngeal wall were performed to supplement the routine oral cavity examinations in the postoperative period. Visual analog scales of pain were completed by the patients. Twenty-three patients underwent a total of 54 RFAP procedures using the Somnus system at the recommended level of energy (600 J in the midline palate, and 300 J to each lateral palate).

RESULTS

Fourteen of the 23 first stage procedures were associated with a total of 16 mucosal injuries representing an incidence of 60.9%. Mucosal injury at the 1st stage prompted a reduction in energy at the 2nd stage to 500 J in the midline and 250 J laterally; there were 4 injuries among 19 2nd stage procedures (21.1%). The overall incidence of mucosal injury, including stage 3 and 4 procedures, was therefore 42.6%; 37% of these were "occult" (only visualized endoscopically).

CONCLUSIONS AND SIGNIFICANCE

RFAP, although intended to be mucosa-sparing, is nevertheless associated with a high incidence of mucosal injuries, many of which are occult. The occurrence of these mucosal ulcers is usually associated with only a trivial degree of increased pain postoperatively.

Pemetrexed disodium: a novel antifolate clinically active against multiple solid tumors

Pemetrexed disodium (ALIMTA), "pemetrexed") is a novel, multi-targeted antifolate that has demonstrated promising clinical activity in a wide variety of solid tumors, including non-small cell lung, breast, mesothelioma, colorectal, pancreatic, gastric, bladder, cervix, and head and neck. Pemetrexed inhibits multiple folate-dependent enzymes involved in both purine and pyrimidine synthesis including thymidylate synthase, dihydrofolate reductase, glycinamide ribonucleotide formyltransferase, and aminoimidazole carboxamide ribonucleotide formyltransferase. As a single agent, pemetrexed exhibits a moderate toxicity profile at a dose of 500 mg/m(2) by 10-minute infusion once every 21 days with myelosuppression being the dose-limiting toxicity. Folic acid added to the diet in preclinical studies reduced toxicities while maintaining antitumor activity. Based on this observation and clinical toxicities, folic acid and vitamin B(12) dietary supplementation has been recently introduced into all ongoing trials. Studies combining pemetrexed with other active chemotherapeutic agents demonstrate that these combination therapies may become important treatment regimens in a variety of cancer types. Currently, pemetrexed phase III trials are ongoing in mesothelioma and non-small cell lung cancer with future trials planned to explore this unique multitargeted antifolate.

Direct evidence for the existence of Miltenberger antigen

The Miltenberger (Mi) subsystem, which originally consisted of four phenotypes, now has 11 phenotypes. The antigens of this subsystem belong to the MNS blood group system. The Mia antigen has been reported to be present on red blood cells with several Miltenberger phenotypes, namely: Mi.I, Mi.II, Mi.III, Mi.IV, Mi.VI and Mi.X. However, the existence of the Mia antigen as a separate entity has been in question and difficult to prove with polyclonal reagents. We report the first monoclonal anti-Mia (GAMA210), whose epitope is TNDKHKRD or QTNDMHKR, and thereby confirm the existence of the Mia antigen.

Novel roles of kallistatin, a specific tissue kallikrein inhibitor, in vascular remodeling

We have purified, cloned and characterized kallistatin, a tissue kallikrein-binding protein (KBP) in humans and rodents. Kallistatin is a unique serine proteinase inhibitor (serpin) with Phe-Phe residues at the P2 and P1 positions. Structural and functional analysis of kallistatin by site-directed mutagenesis and protein engineering indicate that wild-type kallistatin is selective for tissue kallikrein. Kallistatin is expressed and localized in endothelial and smooth muscle cells of blood vessels and has multiple roles in vascular function independent of the tissue kallikrein-kinin system. First, kallistatin induces vasorelaxation of isolated aortic rings and reduces renal perfusion pressure in isolated rat kidneys. Transgenic mice overexpressing rat kallistatin are hypotensive, and adenovirus-mediated gene delivery of human kallistatin attenuates blood pressure rise in spontaneously hypertensive rats. Second, kallistatin stimulates the proliferation and migration of vascular smooth muscle cells in vitro and neointima formation in balloon-injured rat arteries. Third, kallistatin inhibits the proliferation, migration and adhesion of endothelial cells in vitro and angiogenesis in the rat model of hindlimb ischemia. These results demonstrate novel roles of kallistatin in blood pressure regulation and vascular remodeling.