Chromaffin cell catecholamine secretion: bisindolylmaleimide compounds exhibit novel and potent antagonist effects at the nicotinic cholinergic receptor in pheochromocytoma cells

Activation of protein kinase C (PKC) stimulates nicotine-induced catecholamine secretion. PKC down-regulation by prolonged pretreatment with phorbol 12-myristate 13-acetate diminished nicotine-induced catecholamine secretion only slightly (approximately 16%), suggesting substantial PKC independence of nicotinic receptor activation. However, we found that bisindolylmaleimide compounds (which are also putative PKC chemical inhibitors) dramatically inhibited nicotine-induced catecholamine secretion (IC(50) values of approximately 24-37 nM). This inhibition was specific for the nicotinic cholinergic receptor. Catecholamine secretion induced by other nicotinic agonists (such as epibatidine, anatoxin, or cytisine) was also powerfully antagonized by bisindolylmaleimide II (IC(50) values of approximately 60-90 nM). Even high-dose nicotinic agonists failed to overcome the inhibition by bisindolylmaleimide II, suggesting noncompetitive nicotinic antagonism by this class of compounds. Nicotinic inhibition by bisindolylmaleimide seemed not to be readily reversible. Structure-activity studies of bisindolylmaleimide compounds revealed that bisindolylmaleimides I through III are the most potent nicotinic antagonists at the nicotinic cholinergic receptor in PC-12 cells (IC(50) < or =37 nM), whereas bisindolylmaleimide IV and V have far less nicotinic antagonist activity (IC(50) >1 microM); the active compounds I through III have cationic tails at an indole nitrogen, whereas the least potent compounds IV and V do not. By contrast, a free NH within the maleimide ring is crucial for PKC inhibition by this class of compounds. We conclude that bisindolylmaleimides I through III are some of the most potent noncompetitive neuronal nicotinic antagonists, indeed the most potent such antagonists we have observed in PC-12 cells. Nicotinic antagonism of these compounds seems to be independent of PKC inhibition.     

Monitoring changes in gene expression in renal ischemia-reperfusion in the rat

BACKGROUND: Although acute renal failure (ARF) is a relatively common disorder with major morbidity and mortality, its molecular basis remains incompletely defined. The present study examined global gene expression in the well-characterized ischemia-reperfusion model of ARF using DNA microarray technology. METHODS: Male Wistar rats underwent bilateral renal ischemia (30 min) or sham operation, followed by reperfusion for 1, 2, 3 or 4 days. Plasma creatinine increased approximately fivefold over baseline, peaking on day 1. Renal total RNA was used to probe cDNA microarrays. RESULTS: Alterations in expression of 18 genes were identified by microarray analysis. Nine genes were up-regulated (ADAM2, HO-1, UCP-2, and thymosin beta4 in the early phase and clusterin, vanin1, fibronectin, heat-responsive protein 12 and FK506 binding protein in the established phase), whereas another nine were down-regulated (glutamine synthetase, cytochrome p450 IId6, and cyp 2d9 in the early phase and cyp 4a14, Xist gene, PPARgamma, alpha-albumin, uromodulin, and ADH B2 in the established phase). The identities of these 18 genes were sequence-verified. Changes in gene expression of ADAM2, cyp2d6, fibronectin, HO-1 and PPARgamma were confirmed by quantitative real-time polymerase chain reaction (PCR). ADAM2, cyp2d6, and PPARgamma have not previously been known to be involved in ARF. CONCLUSION: Using DNA microarray technology, we identified changes in expression of 18 genes during renal ischemia-reperfusion injury in the rat. We confirmed changes in five genes (fibronectin, ADAM2, cyp 2d6, HO-1 and PPARgamma) by quantitative real-time PCR. Several genes, not previously been identified as playing a role in ischemic ARF, may have importance in this disease.     

Dialysis session length ("t") as a determinant of the adequacy of dialysis

Several studies have shown an association between the hemodialysis session length (the t of Kt or Kt/V) and favorable outcomes for patients on maintenance hemodialysis. In a single randomized controlled trial that systematically varied hemodialysis session length, shorter session length was associated with an increased risk for morbidity and mortality, independent of the time-averaged concentration of urea. Observational studies of dialysis session length have yielded conflicting results, although virtually all studies have confounded hemodialysis session length with hemodialysis efficiency or dose. Limited observational data from nocturnal hemodialysis programs more strongly suggest an independent beneficial effect of longer session length. In aggregate, data on the effects of hemodialysis session length are inconclusive. Future studies should evaluate hemodialysis session length independent of efficiency, and should consider the evaluation of dose by using other clearance parameters and the adequacy of ultrafiltration in addition to solute kinetics.     

Infectivity enhanced adenoviral-mediated mda-7/IL-24 gene therapy for ovarian carcinoma

OBJECTIVE: Melanoma differentiation associated gene-7 [mda-7/Interleukin (IL)-24] has been identified as a novel anti-cancer agent, which specifically induces apoptosis in cancer cells but not in normal epithelial, endothelial and fibroblast cells. The objective of this study was to evaluate the anti-tumor effect of adenovirus-mediated mda-7/IL-24 (Ad.mda-7) gene therapy in ovarian carcinoma and further improve anti-tumor effect by enhancing infectivity of Ad.mda-7. METHODS: A panel of human ovarian carcinoma cells, OV-4, HEY, SKOV3, SKOV3.ip1 and control normal human mesothelial cells, were infected by a replication deficient recombinant adenovirus encoding mda-7/IL-24 and control virus Ad.CMV.Luc. After 72 h, apoptosis was evaluated by TUNEL and Hoechst staining and further quantified by fluorescent activated cell sorter (FACS) analysis. Infectivity of Ad.mda-7 was enhanced by retargeting it to CD40 or EGF receptors overexpressed on ovarian cancer cells. Subsequently, enhancement in apoptosis of CD40- or epidermal growth factor receptor (EGFR)-retargeted Ad.mda-7 was evaluated. RESULTS: Adenoviral-mediated delivery of mda-7 induces apoptosis ranging from 10-23% in human ovarian cancer cells tested with the highest percentage of apoptosis noted in SKOV3 cells. Minimal apoptosis was noted in normal mesothelial cells. CD40- or EGFR-retargeted Ad.mda-7 increased apoptosis by 10-32% when compared to that achieved with untargeted Ad.mda-7. CONCLUSION: Ad.mda-7 exhibits ovarian cancer-specific apoptosis, but does not affect normal human mesothelial cells. Infectivity enhanced CD40- and EGFR-retargeted Ad.mda-7 augments apoptosis induction, thus increasing the therapeutic index and translational potential of Ad.mda-7 gene therapy.     

Tacrolimus therapy in pediatric patients with treatment-resistant nephrotic syndrome

This is a retrospective analysis of 16 children started on tacrolimus with various types of treatment-resistant nephrotic syndrome. There are 13 patients with focal glomerulosclerosis, 1 minimal change disease, and 2 IgA nephropathy with nephrosis. The mean age of the children was 11.4 years (range 3.5–18.1 years) with a mean age at diagnosis of 5.6 years (range 1.6–13.3 years). All patients initially received prednisone 2 mg/kg per day. Other therapies for 15 of 16 included cyclosporine (n=15), chlorambucil (n=5), mycophenolate mofetil (n=5), levamisole (n=3), i.v. methylprednisolone (n=3), and cyclophosphamide (n=2). The major indication for the initiation of tacrolimus included treatment resistance/dependence (n=15) and intolerable side effects from other therapies (n=1). The average time from the diagnosis to initiation of tacrolimus was 5.3 years (range 0.3–13.3 years, median 6 years). The initial dosage of tacrolimus utilized was 0.1 mg/kg per day divided into two doses. The mean follow-up period was 6.5 months (range 2.5–18 months). Thirteen patients (81%) went into a complete remission within an average of 2 months (range 0.5–5.5 months), with 3 patients relapsing while on treatment. Three patients did not respond. Of these, 2 had partial remissions (13%) and 1 failed to respond. Adverse events included anemia (n=1), seizure (n=1), worsening or new-onset hypertension (n=5), and sepsis (n=1). All patients remain on tacrolimus. Tacrolimus is an effective, well-tolerated medication for treatment-resistant forms of nephrotic syndrome in children, with a complete remission rate of 81% and a partial remission rate of 13% (totaling 94%).     

Design of semicarbazones and their bio-isosteric analogues as potential anticonvulsants

A series of semicarbazones and hydrazones were prepared and evaluated for anticonvulsant activity. Some compounds provided significant protection against maximal electroshock (MES) and subcutaneous strychnine induced seizures (ScSty). Compound 2a emerged as the most active compound at a dose of 30 mg/kg in ScSty test. The compounds 1a, 1g and 2a-e showed significant potentiation of sedative and hypnotic activity of pentobarbitone sodium. Thus compound 2a could serve as a prototype for future developments.     

Community-Based Colorectal Cancer Screening Trials with Multi-Ethnic Groups: A Systematic Review

The objective of this review was to summarize the current literature of community-based colorectal cancer screening randomized controlled trials with multi-ethnic groups. The CDC reports 40% of adults do not receive time-appropriate colorectal cancer screening. Although overall screening rates have improved since 2000, disparities remain. Studies examining community characteristics may offer insight into improving screening rates and eliminating disparities. We identified community-based colorectal cancer screening studies using PubMed and Ovid Medline database searches. Inclusion criteria were: community-based, randomized controlled trials; English language; published from 1/2001 to 8/2009; all colorectal cancer screening test interventions recommended in the 2008 “Joint Consensus” report; and study participants from at least two racial/ethnic groups, with not more than 90% representation from one group. There were 29 relevant articles published during 2001–2009; with 15 meeting inclusion criteria. We categorized the final studies (n = 15) into the four categories of Patient mailings (n = 3), Telephone outreach (n = 3), Electronic/multimedia (n = 4), and Counseling/community education (n = 5). Of 15 studies, 11 (73%) demonstrated increased screening rates for the intervention group compared to controls, including all studies (100%) from the Patient mailings and Telephone outreach groups, 4 of 5 (80%) Counseling/community education studies, and 1 of 4 (25%) Electronic/multimedia interventions. Patient choice and tailoring of information were common features of trials that increased screening rates across study categories. Including community-level factors and social context may be useful in future design and evaluation of colorectal cancer interventions to reduce or prevent new cases of colorectal cancer.