Are interventions to increase the uptake of screening for cardiovascular disease risk factors effective? A systematic review and meta-analysis.

BACKGROUND: Cardiovascular disease (CVD) is the leading cause of death globally. However, many individuals are unaware of their CVD risk factors. The objective of this systematic review is to determine the effectiveness of existing intervention strategies to increase uptake of CVD risk factors screening. METHODS: A systematic search was conducted through Pubmed, CINAHL, EMBASE and Cochrane Central Register of Controlled Trials. Additional articles were located through cross-checking of the references list and bibliography citations of the included studies and previous review papers. We included intervention studies with controlled or baseline comparison groups that were conducted in primary care practices or the community, targeted at adult populations (randomized controlled trials, non-randomized trials with controlled groups and pre- and post-intervention studies). The interventions were targeted either at individuals, communities, health care professionals or the health-care system. The main outcome of interest was the relative risk (RR) of screening uptake rates due to the intervention. RESULTS: We included 21 studies in the meta-analysis. The risk of bias for randomization was low to medium in the randomized controlled trials, except for one, and high in the non-randomized trials. Two analyses were performed; optimistic (using the highest effect sizes) and pessimistic (using the lowest effect sizes). Overall, interventions were shown to increase the uptake of screening for CVD risk factors (RR 1.443; 95% CI 1.264 to 1.648 for pessimistic analysis and RR 1.680; 95% CI 1.420 to 1.988 for optimistic analysis). Effective interventions that increased screening participation included: use of physician reminders (RR ranged between 1.392; 95% CI 1.192 to 1.625, and 1.471; 95% CI 1.304 to 1.660), use of dedicated personnel (RR ranged between 1.510; 95% CI 1.014 to 2.247, and 2.536; 95% CI 1.297 to 4.960) and provision of financial incentives for screening (RR 1.462; 95% CI 1.068 to 2.000). Meta-regression analysis showed that the effect of CVD risk factors screening uptake was not associated with study design, types of population nor types of interventions. CONCLUSIONS: Interventions using physician reminders, using dedicated personnel to deliver screening, and provision of financial incentives were found to be effective in increasing CVD risk factors screening uptake.

Phosphorylation of calsenilin at Ser63 regulates its cleavage by caspase-3.

Calsenilin is a member of the neuronal calcium sensor (NCS) family of proteins that interacts with the presenilins. Calsenilin has been found to act as a Kv4alpha channel interactor and as a transcriptional repressor. We have recently shown that calsenilin can be cleaved by caspase-3 and that its cleavage separates the conserved calcium-binding domain from the variable N-terminal domain. Here, we demonstrate that calsenilin can be phosphorylated by casein kinase I and that its phosphorylation can be regulated by intracellular calcium. In addition, phosphorylated calsenilin is a substrate for serine/threonine protein phosphatase (PP) 1 and/or 2A. Phosphorylation within the N-terminal domain at Ser63, the major phosphorylation site of calsenilin, inhibits cleavage of the molecule by caspase-3. Given that the N-terminal domain of calsenilin is not conserved in the larger NCS family including other KChIP/CALP proteins, phosphorylation of calsenilin may regulate a functional role that is unique to this member of the superfamily.

Biochemical and immunocytochemical characterization of calsenilin in mouse brain.

Mutations in the presenilin 1 and 2 genes cause the majority of early onset familial forms of Alzheimer's disease. Here we describe the biochemical and immunohistochemical characterization of calsenilin, a novel calcium binding protein that we have previously shown to interact with presenilins 1 and 2, in mouse brain. The co-immunoprecipitation of endogenous calsenilin and presenilin 1 demonstrates that these proteins are physiologic binding partners. Although calsenilin has been predicted to be a soluble protein, we have found that the majority of it is tightly associated with the cytoplasmic face of intracellular membranes and that it can only be dissociated using harsh treatments such as urea. In addition, we have demonstrated that calsenilin is a developmentally regulated protein that is mainly present in the brain, where it localizes to both the hippocampus and cerebellum. Calsenilin staining co-localized with the somatodendritic marker microtubule-associated protein-2 primarily in the granular cell layer of the cerebellum, indicating that calsenilin expression is primarily neuronal. In primary cultured neurons, calsenilin immunoreactivity was observed in cell bodies as well as in some neuronal processes. Co-localization experiments using specific axonal and dendritic markers indicate that these processes were mainly axonal in nature, although a smaller subset of dendrites also appears to contain calsenilin. In summary, we have established that calsenilin and presenilin 1 can interact at physiologic levels, and that calsenilin is a developmentally regulated protein that is expressed primarily in the cerebellum and hippocampus. Although calsenilin is a soluble protein, it is tightly associated with the membrane. Finally, the expression pattern of calsenilin, which is similar to that of the presenilin(s), suggests that the common locations of these two proteins provide an opportunity for physical interaction in vivo.

Calsenilin enhances apoptosis by altering endoplasmic reticulum calcium signaling.

Calsenilin (also called DREAM and KChIP3), a member of the neuronal calcium sensor family, was isolated in a yeast two-hybrid screen using an apoptotic domain of presenilin 2 as bait. Calsenilin is a cytoplasmic protein, but interacts with the COOH-termini of both presenilin 1 and presenilin 2 at the endoplasmic reticulum and the Golgi apparatus. In this study, we have investigated calsenilin's effect on apoptosis. In stable neuroglioma cell lines, we observed that calsenilin enhances apoptosis in response to serum withdrawal or thapsigargin. Consistent with these observations, caspase and apparently calpain activities were increased during apoptosis in calsenilin-overexpressing cells. Moreover, using calcium imaging we were able to show that cells treated with thapsigargin released more calcium from intracellular stores when calsenilin was overexpressed. Taken together, these data suggest that calsenilin causes cells to be more susceptible to apoptotic triggers, possibly by altering calcium dynamics.

Calsenilin is a substrate for caspase-3 that preferentially interacts with the familial Alzheimer's disease-associated C-terminal fragment of presenilin 2.

Calsenilin is a member of the recoverin family of neuronal calcium-binding proteins that we have previously shown to interact with presenilin 1 (PS1) and presenilin 2 (PS2) holoproteins. The expression of calsenilin can regulate the levels of a proteolytic product of PS2 (Buxbaum, J. D., Choi, E. K., Luo, Y., Lilliehook, C., Crowley, A. C., Merriam, D. E., and Wasco, W. (1998) Nat. Med. 4, 1177-1181) and reverse the presenilin-mediated enhancement of calcium signaling (Leissring, M. A., Yamasaki, T. R., Wasco, W., Buxbaum, J. D., Parker, I., and LaFerla, F. M. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 8590-8593). Here, we have used cultured mammalian cells that transiently or stably express calsenilin to extend the characterization of calsenilin and of the calsenilin-PS2 interaction. We have found that calsenilin has the ability to interact with endogenous 25-kDa C-terminal fragment (CTF) that is a product of regulated endoproteolytic cleavage of PS2 and that the presence of the N141I PS2 mutation does not significantly alter the interaction of calsenilin with PS2. Interestingly, when the 25-kDa PS2 CTF and the 20-kDa PS2 CTF are both present, calsenilin preferentially interacts with the 20-kDa CTF. Increases in the 20-kDa fragment are associated with the presence of familial Alzheimer's disease-associated mutations (Kim, T., Pettingell, W. H., Jung, Y., Kovacs, D. M., and Tanzi, R. E. (1997) Science 277, 373-376). However, the finding that the production of the 20-kDa fragment is regulated by the phosphorylation of PS2 (Walter, J., Schindzielorz, A., Grunberg, J., and Haass, C. (1999) Proc. Natl. Acad. Sci. U. S. A. 96, 1391-1396) suggests that it is a regulated physiological event that also occurs in the absence of the familial Alzheimer's disease-associated mutations in PS2. Finally, we have demonstrated that calsenilin is a substrate for caspase-3, and we have used site-directed mutagenesis to map the caspase-3 cleavage site to a region that is proximal to the calcium binding domain of calsenilin.

Ryanodine-affinity chromatography purifies 106 kD Ca2+ release channels from skeletal and cardiac sarcoplasmic reticulum.

A 106 kD protein was isolated from skeletal sarcoplasmic reticulum (SR) vesicles and shown to have the properties of SR Ca2+ release channels, including blockade by 5 nM ryanodine. In view of extensive reports that the ryanodine-receptor complex consists of four 565 kD junctional feet proteins (JFPs) and is the 'physiological' Ca2+ release channel, we prepared ryanodine-affinity columns to isolate its receptor site(s). Conditions known to maximize the association and dissociation of ryanodine to SR proteins were respectively used to link, then elute, the receptor(s) from ryanodine-affinity columns. The method purified a protein at about 100 kD from both rabbit skeletal and canine cardiac SR vesicles. The skeletal and cardiac proteins isolated by ryanodine-affinity chromatography were identified as the low molecular weight Ca2+ release channel through their antigenic reaction with an anti-106 kD monoclonal antibody. Upon reconstitution in planar bilayers, both skeletal and cardiac proteins revealed the presence of functional SR Ca2+ release channels. Surprisingly, ryanodine-affinity columns did not retain JFPs but purified 106 kD Ca2+ release channels which are a minor component (0.1-0.3%) of SR proteins.

Reactive disulfides trigger Ca2+ release from sarcoplasmic reticulum via an oxidation reaction.

Reactive disulfide compounds (RDSs) with a pyridyl ring adjacent to the S-S bond such as 2,2'-dithiodipyridine (2,2'-DTDP), 4,4'-dithiodipyridine, and N-succinimidyl 3(2-pyridyldithio)propionate (SPDP) trigger Ca2+ release from sarcoplasmic reticulum (SR) vesicles. They are known to specifically oxidize free SH sites via a thiol-disulfide exchange reaction with the stoichiometric production of thiopyridone. Thus, the formation of a mixed S-S bond between an accessible SH site on an SR protein and a RDS causes large increases in SR Ca2+ permeability. Reducing agents, glutathione (GSH) or dithiothreitol reverse the effect of RDSs and permit rapid re-uptake of Ca2+ by the Ca2+, Mg2+-ATPase. The RDSs, 2,2'-DTDP, 4,4'-dithiodipyridine and SPDP displaced [3H]ryanodine binding to the Ca2+-receptor complex at IC50 values of 7.5 +/- 0.2, 1.5 +/- 0.1, and 15.4 +/- 0.1 microM, respectively. RDSs did not alter the rapid initial phase of Ca2+ uptake by the pump, stimulated ATPase activity, and induced release from passively loaded vesicles with nonactivated pumps; thus they act at a Ca2+ release channel and not at the Ca2+, Mg2+-ATPase. Efflux rates increased in 0.25-1.0 mM [Mg2+]free then decreased in 2-5 mM [Mg2+]free. Adenine nucleotides inhibited the oxidation of SHs on SR protein by RDSs and thus reduced Ca2+ efflux rates. However, once RDSs oxidized these SH sites and opened the Ca2+ release pathway, subsequent additions of nucleotides stimulated Ca2+ efflux. In skinned fibers, 2,2'-dithiodipyridine elicited rapid twitches which were blocked by ruthenium red. These results indicate that RDSs trigger Ca2+ release from SR by oxidizing a critical SH group, and thus provide a method to covalently label the protein(s) involved in causing these changes in Ca2+ permeability.

Disulfide linkage of biotin identifies a 106-kDa Ca2+ release channel in sarcoplasmic reticulum.

Reactive disulfide reagents (RDSs) with a biotin moiety have been synthesized and found to cause Ca2+ release from sarcoplasmic reticulum (SR) vesicles. The RDSs oxidize SH sites on SR proteins via a thiol-disulfide exchange, with the formation of mixed disulfide bonds between SR proteins and biotin. Biotinylated RDSs identified a 106-kDa protein which was purified by biotin-avidin chromatography. Disulfide reducing agents, like dithiothreitol, reverse the effect of RDSs and thus promoted active re-uptake of Ca2+ and dissociated biotin from the labeled protein indicating that biotin was covalently linked to the 106-kDa protein via a disulfide bond. Several lines of evidence indicate that this protein is not Ca2+, Mg2+-ATPase and is not a proteolytic fragment or a subunit of the 400-kDa Ca2+-ryanodine receptor complex (RRC). Monoclonal antibodies against the ATPase did not cross-react with the 106-kDa protein, and polyclonal antibodies against the 106-kDa did not cross-react with either the ATPase or the 400-kDa RRC. RDSs did not label the 400-kDa RRC with biotin. Linear sucrose gradients used to purify the RRC show that the 106-kDa protein migrated throughout 5-20% linear sucrose gradients, including the high sucrose density protein fractions containing 400-kDa RRC. Protease inhibitors diisopropylfluorophosphate used to prevent proteolysis of 400-kDa proteins did not alter the migration of 106-kDa in sucrose gradients nor the patterns of biotin labeling of the 106-kDa protein. Incorporation of highly purified 106-kDa protein (free of RRC) in planar bilayers revealed cationic channels with large Na+ (gNa+ = 375 +/- 15 pS) and Ca2+ (gCa2+ = 107.7 +/- 12 pS) conductances which were activated by micromolar [Ca2+]free or millimolar [ATP] and blocked by micromolar ruthenium red or millimolar [Mg2+]. Thus, the SR contains a sulfhydryl-activated 106-kDa Ca2+ channel with apparently similar characteristics to the 400-kDa "feet" proteins.

Neonatal endosulfan neurotoxicity: behavioral and biochemical changes in rat pups.

Repeated administration of 0.5 mg/kg endosulfan (for 5 days a week) for 3 and 5 weeks of age, produced no significant alteration either in the binding of 3H-5HT to frontal cortical membranes or in foot-shock induced fighting behavior. However, administration of 1 mg/kg endosulfan for 5 weeks caused a significant increase in 3H-5HT binding as well as in foot shock induced aggressive behavior. The endosulfan-induced increase in aggressive behavior and increased binding of 3H-5HT were detectable even 8 days after the cessation of endosulfan treatment. Scatchard analysis revealed that exposure to endosulfan altered the affinity (KD) of the receptors without causing any significant change in maximum number of high affinity binding sites (Bmax). The endosulfan-induced fighting behavior was blocked by the pretreatment of animals with methysergide, a 5-HT blocker. These results suggest an involvement of serotonergic systems in the neonatal neurotoxicity of endosulfan.

Effect of gestational and neonatal styrene exposure on dopamine receptors.

The effect of styrene (200 mg/kg, orally) on dopamine receptor binding using 3H-spiroperidol as a specific ligand was studied in developing rats. Gestational exposure caused no significant change in the binding of 3H-spiroperidol to striatal membranes of pups at 2 and 3 weeks of age. However, styrene exposure during lactation and the gestation-lactation period caused a significant increase in binding of 3H-spiroperidol. Scatchard analysis revealed that styrene exposure caused an increase in the number of receptor sites without affecting their affinity. Results of behavioral studies (amphetamine-induced locomotor activity and apomorphine-induced stereotypy) showed that styrene exposure during the gestation-lactation period caused a significant increase in motor activity and stereotypy of the rat pups. These behavioral and biochemical studies suggest that early postnatal exposure to styrene affects dopaminergic function.

Involvement of serotonergic receptors in endosulfan neurotoxicity.

Single dose of 1 and 3 mg/kg endosulfan did not show any significant effect on binding of 3H-serotonin to frontal cortical membranes as well as on foot-shock-induced fighting behaviour in rats, where as repeated exposure of endosulfan (3 mg/kg for 30 days) caused a significant increase in 3H-serotonin binding. Scatchard analysis showed an increase in the affinity of the receptor (KD) in the treated animals while number of receptor sites (Bmax) remained unaltered. Long term endosulfan exposure caused aggressive behaviour (foot-shock-induced fighting behaviour) which was blocked by methysergide, a 5-HT blocker. These results indicate the involvement of serotonergic receptors in endosulfan neurobehavioral toxicity.