Evaluation of a novel bis-naphthalimide anticancer agent,DMP 840, against human xenografts derived from adult,juvenile, and pediatric cancers

The new bis-naphthalimide antitumor agent (R,R)2,2-[1,2-ethanediylbis[imino(1-methyl-2.1-ethanediyl)]-bis {5-nitro-1H-benz[de]-isoquinoline-1,3-2H) dione} dimethanesulfonate (DMP 840) was evaluated against parental and multidrug-resistant human KB cell lines in vitro and against these lines growing as xenografts in immunedeprived mice. In vitro, KB8-5 cells were 50-fold resistant to vincristine but only 16-fold resistant to DMP 840 as measured by clonogenic survival. For in vivo evaluation, DMP 840 was given by i. v. injection daily for 9 days or for 5 days/week for 2 consecutive weeks [(dx5)2]. In contrast to the cross-resistance of KB cell lines in vitro, both KB3-1 and KB8-5 tumors were highly and equally sensitive to DMP 840; only KB3-1 xenografts demonstrated sensitivity to vincristine, which was consistent with the in vitro results. DMP 840 was also evaluated against a panel of human tumors comprising colon adenocarcinoma and rhabdomyosarcoma xenografts. Against eight lines of colon adenocarcinoma, DMP 840 caused a high frequency of partial and complete regressions in two lines and significant inhibition of growth in two lines. DMP 840 caused complete regressions in five of six lines of advanced rhabomyosarcomas, demonstrating a broad range of effective dose levels. The pattern of activity against this tumor panel was similar but not identical to that of two inhibitors of topoisomerase I. There was no cross-resistance to DMP 840 in xenografts selected for resistance to vincristine or in a rhabdomyosarcoma selected for resistance to the topoisomerase I inhibitor topotecan. In contrast, a colon tumor selected for topotecan resistance was completely resistant to DMP 840. Slight cross-resistance to DMP 840 was demonstrated in a rhabdomyosarcoma xenograft that was selected for primary resistance to melphalan and was cross-resistant to topoisomerase I inhibitors. The pattern of activity and cross-resistance in these tumors was compared with that shown by two agents that inhibit topoisomerase I: topotecan and CPT-11.This work was supported in part by CA23099, Cancer Center Support (CORE) grant CA21675, The Du Pont Merck Pharmaceutical Company, and by American Lebanese Syrian Associated Charities (ALSAC)     

Original article: Effects of Raised Extracellular Magnesium on Platelet Reactivity

The inhibitory effects on platelet reactivity of increased extracellular magnesium were investigated. Wherever possible, experiments were performed in hirudinized whole blood. Concentration dependent inhibition of platelet aggregation and dense granule release were observed with MgSO(4). Antiaggregatory effects were identical with MgCl(2), indicating that the effects are due to the Mg(2+) ion. Antiaggregatory effects of CaCl(2), differed from those of MgCl(2), indicating that this is not a non-specific divalent cation effect. MgSO(4) also caused concentration-dependent inhibition of platelet thromboxane production. Experiments in the presence of apyrase and indomethacin showed that complex formation with ADP and inhibition of cyclo-oxygenase do not entirely account for the inhibitory effect of magnesium on platelet activation. Studies with an anti-GPIIb/IIIa antibody showed that the inhibitory effects on the release reaction and thromboxane synthesis are independent of those on aggregation. The results are consistent with magnesium modifying an intracellular signal transduction pathway common to several agonists, rather than the effects of magnesium being specific for one agonist. This study also shows that MgSO(4) inhibits agonist-induced increases in intracellular free calcium. Increasing the extracellular concentration of magnesium up to 10 mM had no effect on agonist-induced increments in intraplatelet free Mg(2+) concentration.     

Practice effects with the NIMH AIDS abbreviated neuropsychological battery.

The degree of practice effects with the Brief NIMH Neuropsychological Battery for HIV Infection and AIDS is reported using a 7-10 day test-retest interval. The patient groups were asymptomatic and symptomatic of HIV while the control group was made up of "at risk" volunteers. Statistically significant practice effects were obtained on the California Verbal Learning Test, the Paced Auditory Serial Addition Task and the Visual Search Test among the infected individuals. The controls subjects demonstrated statistically significant practice effects on all of the neuropsychological tests. The implications of these findings in prospective studies are discussed.     

Chain transfer by addition-fragmentation mechanism, 5 Investigation of the chain transfer activity of several ethyl 2-(substituted)cinnamates

A variety of ethyl 2-(substituted)cinnamates

1 Systematic name: ethyl 3-phenyl-2-(substituted)propenoate.

were synthesized and added to vinylic monomer polymerizations. These olefins are activated towards free radical addition and contain a homolytic leaving group in the allylic position. Thus, they exhibit chemical transfer properties in free radical polymerization. The compounds studied include bromide, iodide, sulfone, mercaptan and peroxide derivatives. Cinnamic iodide, however, exhibits degradative chain transfer activity. These compounds have an advantage over simple thiols in that they permit a good control of molar mass by an addition-fragmentation mechanism involving difunctionalization of the resulting telomers. The methods of synthesis of ethyl 2-(substituted)cinnamates are discussed through the nucleophilic substitution of various anions toward the allylic bromo derivative prepared from ethyl 2-(α-hydroxybenzyl)propenoate.     

Ischemic stress induces deposition of amyloid β immunoreactivity in human brain

The histoblot immunostaining technique for locating and characterizing amyloidogenic proteins was used to obtain information about the relationship of cerebral ischemia/hypoxia to the accumulation of amyloid protein (Aß). We investigated brains of 131 subjects (ages 25–94 years, mean 72 years). Three distribution patterns of A immunoreactivity were identified: (1) colocalization with diffuse and neuritic plaques of Alzheimer's disease (AD) and aging; (2) diffuse punctate deposits in the cerebral cortex in association with small vessel cerebral vascular disease; and (3) cerebral cortical accumulation localized to arterial boundary zones and other regions susceptible to ischemic/hypoxic injury designated stress-induced deposits (SID). SID were not identified in tissue sections by immunohistochemical, Congo red or Bielschowsky silver techniques; no histological abnormalities were present in adjacent formalin-fixed tissue sections. SID occurred in subjects with histories of cerebral ischemia, and severe orthostatic hypotension. There was also an association with aging in general and with the incidence of neuritic plaques specifically. These latter findings are consistent with the hypothesis that brain ischemia/hypoxia plays a role in the pathogenesis of AD.     

Anterior segment findings in AIDS patients with cytomegalovirus retinitis

Background: Anterior segment findings in AIDS patients presenting with cytomegalovirus (CMV) retinitis have not been specifically addressed in the American literature. Methods: Our study evaluated 21 AIDS patients with CMV retinitis. Results: Nineteen (90%) of these patients exhibited corneal endothelial deposits concurrent with CMV retinitis. The endothelial deposits were microscopic, opaque, linear flecks arranged in a reticular-like fashion. Of 42 eyes evaluated, 32 (76%) demonstrated active CMV retinitis. Corneal endothelial deposits were noted in 26 (81%) of the 32 eyes with retinitis. These corneal endothelial deposits were absent in the eyes which did not have CMV retinitis. Conclusion: Meticulous examination of the retina of an HIV-positive or AIDS patient who presents with reticularly arranged, linear, flecked corneal endothelial deposits should be performed to ensure that the diagnosis of CMV retinitis can be ruled out.     

Oxidative reactions in the tear fluid of patients suffering from dry eyes

Purpose: To evaluate whether products of oxidative and inflammatory reactions are detectable in the tear fluid of patients suffering from dry eyes. Methods: The tear fluid of 217 patients (397 eyes) was sampled. Criteria for grouping of the patients were (1) basic secretion test (sicca l: BST = 0–5 mm, n = 78 eyes; sicca 2: BST = 6–10 mm, n = 109 eyes) and (2) subjective symptoms (normal BST, burning, foreign body sensations, tearing, dryness of the eyes: n = 78 eyes). One group of healthy patients (normal BST, n = 132 eyes) served as controls. Lipid peroxide levels and myeloperoxidase activity, as parameters for oxidative tissue damage and inflammatory activity, were determined in the tear fluid. Those patients whose consent could be obtained were subjected to the rose bengal test (sicca 1: 56 eyes; sicca 2: 97 eyes; subjective symptoms: 44 eyes; controls: 49 eyes). The correlation between BST and rose bengal test results was calculated. Results: Lipid peroxides were significantly (P < 0.05) higher in the groups sicca 1 and subjective symptoms than in healthy controls, as was the inflammatory activity in groups sicca 1, sicca 2 and subjective symptoms. Additionally, the inflammatory activity in the group sicca 1 was significantly (P < 0.05) higher than in the groups sicca 2 and subjective symptoms. No evidence of a significant correlation between BST and rose bengal test results was observed. Conclusions: Both oxidative tissue damage and polymorphonuclear leukocytes indicating an oxidative potential occur in the tear film of patients suffering from dry eyes. These reactions lead to severe damage of the involved tissue. Free radicals and inflammation may be involved in the pathogenesis or in the self-propagation of the disease.     

Activity of the morpholino anthracycline 3′-deamino-3′-morpholino-13-deoxo-10-hydroxycarminomycin (MX2) against human tumor colony-forming unitsin vitro

Summary In several preclinical systems, the morpholino anthracycline MX2 has greater antitumor activity than doxorubicin, is less cardiotoxic, and is effective against multidrug resistant cancer cells. We used a human tumor soft-agar cloning assay to test the cytotoxicity of MX2 against single cell suspensions from freshly obtained human tumors. Tumor cells were exposed to MX2 at 0.05 and 0.5 g/ml either for 1 hour (201 specimens; 77 [38%] assessable) or continuously (231 specimens; 91 [39%] assessable). Superior antitumor activity was observed with continuous exposure (19%in vitro response at 0.05 g/ml and 69% at 0.5 g/ml) than with 1-hour exposure (1.3% at 0.05 g/ml and 12% at 0.5 g/ml). Activity was seen against all types of cancer tested including renal (91%), melanoma (88%), ovarian (73%), breast (71%) and non-small-cell lung (67%) cancer at a MX2 concentration of 0.5 g/ml after continuous exposure. If appropriate plasma levels can be achieved in patients, MX2 could have significant clinical activity in patients with those tumors.