The role of p53 in suppression of KSHV cyclin-induced lymphomagenesis

Kaposi's sarcoma-associated herpesvirus (KSHV) encodes a cyclin D homolog, K cyclin, that is thought to promote viral oncogenesis. However, expression of K cyclin in cultured cells not only triggers cell cycle progression but also engages the p53 tumor suppressor pathway, which probably restricts the oncogenic potential of K cyclin. Therefore, to assess the tumorigenic properties of K cyclin in vivo, we transgenically targeted expression of K cyclin to the B and T lymphocyte compartments via the E micro promoter/enhancer. Around 17% of E micro -K cyclin animals develop lymphoma by 9 months of age, and all such lymphomas exhibit loss of p53. A critical role of p53 in suppressing K cyclin-induced lymphomagenesis was confirmed by the greatly accelerated onset of B and T lymphomagenesis in all E micro -K cyclin/p53(-/-) mice. However, absence of p53 did not appear to accelerate K cyclin-induced lymphomagenesis by averting apoptosis: E micro -K cyclin/p53(-/-) end-stage lymphomas contained abundant apoptotic cells, and transgenic E micro -K cyclin/p53(-/-) lymphocytes in vitro were not measurably protected from DNA damage-induced apoptosis compared with E micro -K cyclin/p53(wt) cells. Notably, whereas aneuploidy was frequently evident in pre-lymphomatous tissues, end-stage E micro -K cyclin/p53(-/-) tumors showed a near-diploid DNA content with no aberrant centrosome numbers. Nonetheless, such tumor cells did harbor more restricted genomic alterations, such as single-copy chromosome losses or gains or high-level amplifications. Together, our data support a model in which K cyclin-induced genome instability arises early in the pre-tumorigenic lymphocyte population and that loss of p53 licenses subsequent expansion of tumorigenic clones.     

WIPI-1alpha (WIPI49), a member of the novel 7-bladed WIPI protein family, is aberrantly expressed in human cancer and is linked to starvation-induced autophagy

WD-repeat proteins are regulatory beta-propeller platforms that enable the assembly of multiprotein complexes. Here, we report the functional and bioinformatic analysis of human WD-repeat protein Interacting with PhosphoInosides (WIPI)-1alpha (WIPI49/Atg18), a member of a novel WD-repeat protein family with autophagic capacity in Saccharomyces cerevisiae and Caenorhabditis elegans, recently identified as phospholipid-binding effectors. Our phylogenetic analysis divides the WIPI protein family into two paralogous groups that fold into 7-bladed beta-propellers. Structural modeling identified two evolutionary conserved interaction sites in WIPI propellers, one of which may bind phospholipids. Human WIPI-1alpha has LXXLL signature motifs for nuclear receptor interactions and binds androgen and estrogen receptors in vitro. Strikingly, human WIPI genes were found aberrantly expressed in a variety of matched tumor tissues including kidney, pancreatic and skin cancer. We found that endogenous hWIPI-1 protein colocalizes in part with the autophagosomal marker LC3 at punctate cytoplasmic structures in human melanoma cells. In addition, hWIPI-1 accumulated in large vesicular and cup-shaped structures in the cytoplasm when autophagy was induced by amino-acid deprivation. These cytoplasmic formations were blocked by wortmannin, a classic inhibitor of PI-3 kinase-mediated autophagy. Our data suggest that WIPI proteins share an evolutionary conserved function in autophagy and that autophagic capacity may be compromised in human cancers.     

A double-blind switch study of paroxetine and venlafaxine in obsessive-compulsive disorder

BACKGROUND: The treatment guidelines for obsessive-compulsive disorder (OCD) propose to switch serotonin reuptake inhibitors (SRIs) in case of refractoriness. However, no controlled research has been published yet that prospectively examined the effects of changing SRIs. This article describes the first double-blind switch study of 2 SRIs in patients with OCD. METHOD: 150 patients with primary OCD, according to DSM-IV criteria, were randomly assigned in a 12-week, double-blind trial to receive dosages titrated upward to 300 mg/day of venlafaxine (N = 75) or 60 mg/day of paroxetine (N = 75). Primary efficacy was assessed by the change from baseline on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), and nonresponse was defined as less than 25% reduction on the Y-BOCS. After a 4-week tapering phase, 43 nonresponders were switched to 12 additional weeks of the alternate antidepressant, of which 16 patients received venlafaxine and 27 received paroxetine. RESULTS: Eighteen of 43 patients benefited from a switch to the alternate SRI with a mean +/- SD decrease of at least 25% on the Y-BOCS. At the end of 12 weeks, responder rates were 56% for paroxetine (15/27) and 19% for venlafaxine (3/16). An intent-to-treat, last-observation-carried-forward analysis demonstrated a mean decrease on the Y-BOCS of 1.8 +/- 3.5 in the venlafaxine group and 6.5 +/- 7.1 in the paroxetine group. After 2 consecutive SRI trials, 109 of 150 patients (73%) achieved a Y-BOCS decrease of at least 25%. CONCLUSION: The results of the current study show that 42% of the nonresponders benefited from a crossover to the other SRI, and that paroxetine was more efficacious than venlafaxine in the treatment of nonresponders to a previous SRI trial. Switching SRIs in case of refractoriness may be considered a useful strategy for patients with OCD.     

C57BL/6J and DBA/2J mice differ in extinction and renewal of extinguished conditioned fear

While a number of studies have examined the acquisition and expression of conditioned fear in inbred mice, very few have examined extinction of conditioned fear in inbred mice and few attempts have been made to compare extinction learning between inbred strains. Because inbred strains differ in a number of physiological and biochemical variables, differences in extinction learning may provide insight into the genetic influence of extinction learning. The purpose of this study was to examine extinction and renewal of conditioned fear in two common inbred strains of mice. C57BL/6J and DBA/2J mice were conditioned with pairings of either a tone or light and foot shock in a single session. On the following 4 days, mice were given extinction training, consisting of tone or light alone trials (Experiment 1A). C57 mice exhibited robust spontaneous recovery between sessions, but did extinguish both within and between sessions. DBA mice extinguished more quickly relative to C57 mice, and this extinction was stable between sessions (i.e., DBA mice did not exhibit spontaneous recovery). The rapid loss of fear in DBA relative to C57 mice was extinction-dependent and not merely due to poor long-term memory (Experiment 1B). Renewal testing (Experiment 2) replicated the strain difference in extinction and also showed that DBA mice have a deficit in the context specificity of extinction. C57 mice, but not DBA mice showed renewal of extinguished fear when tested in a context different from the one in which extinction training took place. These data suggest that the nature of extinction learning is influenced by characteristics of the inbred mouse strain.     

A hematology surveillance study of petrochemical workers exposed to benzene

Historically, complete blood counts (CBCs) have been recognized as an easy and readily available screen for hematotoxicity following occupational exposure to benzene. The purpose of this study is to evaluate hematology data from employees who have ever participated in the Shell Benzene Medical Surveillance Program (BMSP) compared to employees who have not participated and to examine the sensitivity of CBCs to detect hematological changes in a low-exposure occupational setting. This large study included 1200 employees who participated in the BMSP, with mean benzene exposure (TWA-8) of 0.60 ppm from 1977 to 1988 and 0.14 ppm since 1988, and 3227 comparison employees. The comparison group included employees not enrolled in either the benzene or butadiene surveillance programs. Abnormality of six CBC parameters and the adjusted mean values of these parameters in the exposed group were compared with that of the comparison group. We found no increased abnormality for any hematology parameter among exposed employees. The adjusted mean values (adjusted for age, sex, race, length of time between first and last exam, and current smoking status) of the exposed employees were similar to those in the comparison group. At current occupational exposure levels for benzene, no evidence of adverse hematological effects was observed in this study. These results raise the question of whether annual CBC surveillance for benzene-exposed workers has adequate sensitivity to detect meaningful hematological changes due to low-level exposures.     

A comparison of anterior and posterior chamber lenses after cataract extraction in rural Africa: a within patient randomised trial

BACKGROUND: Extracapsular cataract extraction (ECCE) with a posterior chamber intraocular lens (PC IOL) is the preferred method of cataract surgery in developed countries. However, intracapsular cataract extraction (ICCE) with an anterior chamber lens (AC IOL) may be appropriate in rural Africa. A randomised controlled trial was carried out to compare these surgical strategies. METHODS: Participants over 50 years requiring bilateral cataract surgery were recruited from outreach clinics in rural north and east Uganda. One eye was randomly allocated to AC IOL or PC IOL, the other eye being allocated to the second strategy. The main outcome measure was WHO distance visual acuity (VA) category after a minimum of 1 year. Secondary outcomes were numbers and causes of complications and refractive corrections. RESULTS: Of the 110 participants recruited, 98 (89%) were assessed at least 1 year after the operation (median follow up 17.5 months). Nine eyes randomised to PC IOL were converted to AC IOL; one eye randomised to AC IOL inadvertently received PC IOL. There was no difference in VA between 95 pairs of eyes for which data for both eyes were available (uncorrected VA, p = 0.26; corrected VA, p = 0.59). 80 (82%, 95% CI 73 to 89) and 82 (84%, 95% CI 75 to 90) eyes randomised to AC IOL and PC IOL respectively had corrected VA of 6/18 or better. 16 (16%, 95% CI 10 to 25) and eight (8%, 95% CI 4 to 15) eyes respectively had secondary procedures or other complications. CONCLUSIONS: Where both strategies are available, ECCE with PC IOL should be first choice because of fewer complications. Where ECCE with PC IOL is not immediately feasible, ICCE with AC IOL is an acceptable interim technique.     

The effect of nitrostyrene on cell proliferation and macrophage immune responses

The use of mood enhancing drugs such as amphetamine and ecstasy are now prevalent in society. These compounds are known to produce serious psychological and physiological problems in users, which can, in some circumstances result in death. While there has been much research into the effects of these drugs on the body, little if any research has investigated the effect of the side products and synthetic reaction by-products which are a consequence of there illegal production. In the study the effects of nitrostyrene, a reaction by-product in one of the routes to synthesis of amphetamine sulphate, on cell viability and macrophage function was determined. Treatment with nitrostyrene at doses >0.75 microg/mL had a significant suppressive effect on the proliferation of stomach cancer lines. Treatment of macrophages with doses as high as 10 microg/mL did not effect cell viability. Nitrostyrene treatment of macrophages, stimulated with IFN gamma and LPS, resulted in a dose dependent differential inhibition in IL12, IL6 and nitrite production, even using doses < 0.5 microg/mL. Thus ranking of the three, on the basis of the suppressive effect obtained, is IL12 > nitrite > IL6. Thus ingestion of nitrostyrene contaminated ecstasy is likely to have a adverse effect on the immune responses of the recreational user.     

A double blind comparison of venlafaxine and paroxetine in obsessive-compulsive disorder

SUMMARY: While the usefulness of clomipramine and selective serotonin reuptake inhibitors (SSRIs) in obsessive-compulsive disorder (OCD) has been established, the efficacy of serotonin-norepinephrine reuptake inhibitors remains to be determined. This report describes the first randomized double-blind comparison study of an SNRI in patients with obsessive-compulsive disorder. The current study compares the efficacy and tolerability of venlafaxine with paroxetine. One hundred and fifty patients with primary OCD according to DSM-IV criteria were randomly assigned in a 12-week double-blind trial to receive dosages titrated upward to 300 mg/d of venlafaxine (n = 75) or 60 mg/d of paroxetine (n = 75). Primary efficacy was assessed by the change from baseline on the Yale-Brown obsessive-compulsive scale (Y-BOCS). Other assessments throughout the trial included the Hamilton depression rating scale, and the Hamilton anxiety rating scale. An intent-to-treat, last-observation-carried-forward analysis demonstrated a mean decrease on the Y-BOCS of 7.2 +/- 7.5 in the venlafaxine group and of 7.8 +/- 5.4 in the paroxetine group. In both treatment groups, a responder rate (decrease > 35% on the Y-BOCS) of approximately 40% was found. There were no significant differences between venlafaxine and paroxetine with regard to response or responder rates. The incidence of adverse events for venlafaxine and paroxetine was comparable. The most common side effects for venlafaxine were somnolence, insomnia, a dry mouth, and sweating; and for paroxetine somnolence, sweating, nausea, and headache. These results show that venlafaxine was equally effective to paroxetine in treating patients with OCD. Venlafaxine may be a useful therapy for obsessive-compulsive patients, but is not superior to SSRIs.