170 research outputs found
Time to discontinuation of atypical versus typical antipsychotics in the naturalistic treatment of schizophrenia
BACKGROUND: There is an ongoing debate over whether atypical antipsychotics are more effective than typical antipsychotics in the treatment of schizophrenia. This naturalistic study compares atypical and typical antipsychotics on time to all-cause medication discontinuation, a recognized index of medication effectiveness in the treatment of schizophrenia. METHODS: We used data from a large, 3-year, observational, non-randomized, multisite study of schizophrenia, conducted in the U.S. between 7/1997 and 9/2003. Patients who were initiated on oral atypical antipsychotics (clozapine, olanzapine, risperidone, quetiapine, or ziprasidone) or oral typical antipsychotics (low, medium, or high potency) were compared on time to all-cause medication discontinuation for 1 year following initiation. Treatment group comparisons were based on treatment episodes using 3 statistical approaches (Kaplan-Meier survival analysis, Cox Proportional Hazards regression model, and propensity score-adjusted bootstrap resampling methods). To further assess the robustness of the findings, sensitivity analyses were performed, including the use of (a) only 1 medication episode for each patient, the one with which the patient was treated first, and (b) all medication episodes, including those simultaneously initiated on more than 1 antipsychotic. RESULTS: Mean time to all-cause medication discontinuation was longer on atypical (N = 1132, 256.3 days) compared to typical antipsychotics (N = 534, 197.2 days; p < .01), and longer on atypicals compared to typicals of high potency (N = 320, 187.5 days; p < .01), medium potency (N = 140, 213.5 days; p < .01), and low potency (N = 74, 208.7 days; p < .01). Among the atypicals, only clozapine, olanzapine, and risperidone had significantly longer time to all-cause medication discontinuation compared to typicals, regardless of potency level, and compared to haloperidol with prophylactic anticholinergic treatment. When compared to perphenazine, a medium-potency typical antipsychotic, only clozapine and olanzapine had a consistently and significantly longer time to all-cause medication discontinuation. Results were confirmed by sensitivity analyses. CONCLUSION: In the usual care of schizophrenia patients, time to medication discontinuation for any cause appears significantly longer for atypical than typical antipsychotics regardless of the typical antipsychotic potency level. Findings were primarily driven by clozapine and olanzapine, and to a lesser extent by risperidone. Furthermore, only clozapine and olanzapine therapy showed consistently and significantly longer treatment duration compared to perphenazine, a medium-potency typical antipsychotic
Association and interaction of PPAR-complex gene variants with latent traits of left ventricular diastolic function
<p>Abstract</p> <p>Background</p> <p>Abnormalities in myocardial metabolism and/or regulatory genes have been implicated in left ventricular systolic dysfunction. However, the extent to which these modulate left ventricular diastolic function (LVDF) is uncertain.</p> <p>Methods</p> <p>Independent component analysis was applied to extract latent LVDF traits from 14 measured echocardiography-derived endophenotypes of LVDF in 403 Caucasians. Genetic association was assessed between measured and latent LVDF traits and 64 single nucleotide polymorphisms (SNPs) in three peroxisome proliferator-activated receptor <it>(PPAR)</it>-complex genes involved in the transcriptional regulation of fatty acid metabolism.</p> <p>Results</p> <p>By linear regression analysis, 7 SNPs (4 in <it>PPARA</it>, 2 in <it>PPARGC1A</it>, 1 in <it>PPARG</it>) were significantly associated with the latent LVDF trait, whereas a range of 0-4 SNPs were associated with each of the 14 measured echocardiography-derived endophenotypes. Frequency distribution of <it>P </it>values showed a greater proportion of significant associations with the latent LVDF trait than for the measured endophenotypes, suggesting that analyses of the latent trait improved detection of the genetic underpinnings of LVDF. Ridge regression was applied to investigate within-gene and gene-gene interactions. In the within-gene analysis, there were five significant pair-wise interactions in <it>PPARGC1A </it>and none in <it>PPARA </it>or <it>PPARG</it>. In the gene-gene analysis, significant interactions were found between rs4253655 in <it>PPARA </it>and rs1873532 (p = 0.02) and rs7672915 (p = 0.02), both in <it>PPARGC1A</it>, and between rs1151996 in <it>PPARG </it>and rs4697046 in <it>PPARGC1A </it>(p = 0.01).</p> <p>Conclusions</p> <p>Myocardial metabolism <it>PPAR</it>-complex genes, including within and between genes interactions, may play an important role modulating left ventricular diastolic function.</p
Comparative Analysis of mRNA Isoform Expression in Cardiac Hypertrophy and Development Reveals Multiple Post-Transcriptional Regulatory Modules
Cardiac hypertrophy is enlargement of the heart in response to physiological or pathological stimuli, chiefly involving growth of myocytes in size rather than in number. Previous studies have shown that the expression pattern of a group of genes in hypertrophied heart induced by pressure overload resembles that at the embryonic stage of heart development, a phenomenon known as activation of the âfetal gene programâ. Here, using a genome-wide approach we systematically defined genes and pathways regulated in short- and long-term cardiac hypertrophy conditions using mice with transverse aortic constriction (TAC), and compared them with those regulated at different stages of embryonic and postnatal development. In addition, exon-level analysis revealed widespread mRNA isoform changes during cardiac hypertrophy resulting from alternative usage of terminal or internal exons, some of which are also developmentally regulated and may be attributable to decreased expression of Fox-1 protein in cardiac hypertrophy. Genes with functions in certain pathways, such as cell adhesion and cell morphology, are more likely to be regulated by alternative splicing. Moreover, we found 3âČUTRs of mRNAs were generally shortened through alternative cleavage and polyadenylation in hypertrophy, and microRNA target genes were generally de-repressed, suggesting coordinated mechanisms to increase mRNA stability and protein production during hypertrophy. Taken together, our results comprehensively delineated gene and mRNA isoform regulation events in cardiac hypertrophy and revealed their relations to those in development, and suggested that modulation of mRNA isoform expression plays an importance role in heart remodeling under pressure overload
Bacterial Communities of Diverse Drosophila Species: Ecological Context of a HostâMicrobe Model System
Drosophila melanogaster is emerging as an important model of non-pathogenic hostâmicrobe interactions. The genetic and experimental tractability of Drosophila has led to significant gains in our understanding of animalâmicrobial symbiosis. However, the full implications of these results cannot be appreciated without the knowledge of the microbial communities associated with natural Drosophila populations. In particular, it is not clear whether laboratory cultures can serve as an accurate model of hostâmicrobe interactions that occur in the wild, or those that have occurred over evolutionary time. To fill this gap, we characterized natural bacterial communities associated with 14 species of Drosophila and related genera collected from distant geographic locations. To represent the ecological diversity of Drosophilids, examined species included fruit-, flower-, mushroom-, and cactus-feeders. In parallel, wild host populations were compared to laboratory strains, and controlled experiments were performed to assess the importance of host species and diet in shaping bacterial microbiome composition. We find that Drosophilid flies have taxonomically restricted bacterial communities, with 85% of the natural bacterial microbiome composed of only four bacterial families. The dominant bacterial taxa are widespread and found in many different host species despite the taxonomic, ecological, and geographic diversity of their hosts. Both natural surveys and laboratory experiments indicate that host diet plays a major role in shaping the Drosophila bacterial microbiome. Despite this, the internal bacterial microbiome represents only a highly reduced subset of the external bacterial communities, suggesting that the host exercises some level of control over the bacteria that inhabit its digestive tract. Finally, we show that laboratory strains provide only a limited model of natural hostâmicrobe interactions. Bacterial taxa used in experimental studies are rare or absent in wild Drosophila populations, while the most abundant associates of natural Drosophila populations are rare in the lab
The neurobiology of mouse models syntenic to human chromosome 15q
Autism is a neurodevelopmental disorder that manifests in childhood as social behavioral abnormalities, such as abnormal social interaction, impaired communication, and restricted interest or behavior. Of the known causes of autism, duplication of human chromosome 15q11âq13 is the most frequently associated cytogenetic abnormality. Chromosome 15q11âq13 is also known to include imprinting genes. In terms of neuroscience, it contains interesting genes such as Necdin, Ube3a, and a cluster of GABAA subunits as well as huge clusters of non-coding RNAs (small nucleolar RNAs, snoRNAs). Phenotypic analyses of mice genetically or chromosomally engineered for each gene or their clusters on a region of mouse chromosome seven syntenic to human 15q11âq13 indicate that this region may be involved in social behavior, serotonin metabolism, and weight control. Further studies using these models will provide important clues to the pathophysiology of autism. This review overviews phenotypes of mouse models of genes in 15q11âq13 and their relationships to autism
Responses of phytoplankton to experimental fertilization with ammonium and phosphate in an African soda lake
Phytoplankton abundance in tropical lakes is more often judged to be limited by nitrogen than phosphorus, but seldom does the evidence include controlled enrichments of natural populations. In January 1980 we performed the first experimental fertilization in an equatorial African soda lake, Lake Sonachi, a small, meromictic volcanic crater lake in Kenya. During our study the natural phytoplankton abundance was ca. 80 ÎŒg chl a /l, and the euphotic zone PO 4 and NH 4 concentrations were less than 0.5 ÎŒM. In the monimolimnion PO 4 reached 180 ÎŒM and NH 4 reached 4,600 ÎŒM. Replicate polyethylene cylinders (5 m long, 1.2 m 3 ) were enriched to attain 10 ÎŒM PO 4 and 100 ÎŒM NH 4 . Phytoplankton responses were measured as chlorophyll, cell counts and particulate N, P and C. After two days, the chlorophyll increase in the P treatment was significantly higher than the control ( P <0.01) while the N treatment was not. After five days the molar N/P ratio of seston was the same in the N treatment and control (23) but only 6 in the P treatment. The molar N/P ratio of seston in an unenriched Lake Sonachi sample was 21 and in samples from Lakes Bogoria and Elmenteita, two shallow soda lakes in Kenya, the ratios were 12 and 70 respectively. We conclude that limitation of phytoplankton abundance by phosphorus can occur even in some tropical African soda lakes.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47742/1/442_2004_Article_BF00367954.pd
Systematic Review of Potential Health Risks Posed by Pharmaceutical, Occupational and Consumer Exposures to Metallic and Nanoscale Aluminum, Aluminum Oxides, Aluminum Hydroxide and Its Soluble Salts
Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007).
Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of âtotal Alâassumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold.
The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+ 3 to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+ 2 and Al(H2O)6 + 3] that after complexation with O2âąâ, generate Al superoxides [Al(O2âą)](H2O5)]+ 2. Semireduced AlO2âą radicals deplete mitochondrial Fe and promote generation of H2O2, O2 âą â and OHâą. Thus, it is the Al+ 3-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates.
Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer\u27s disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants.
The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances
Current Data on and Clinical Insights into the Treatment of First Episode Nonaffective Psychosis: A Comprehensive Review
Implementing the most suitable treatment strategies and making appropriate clinical decisions about individuals with a first episode of psychosis (FEP) is a complex and crucial task, with relevant impact in illness outcome. Treatment approaches in the early stages should go beyond choosing the right antipsychotic drug and should also address tractable factors influencing the risk of relapse. Effectiveness and likely metabolic and endocrine disturbances differ among second-generation antipsychotics (SGAs) and should guide the choice of the first-line treatment. Clinicians should be aware of the high risk of cardiovascular morbidity and mortality in schizophrenia patients, and therefore monitoring weight and metabolic changes across time is mandatory. Behavioral and counseling interventions might be partly effective in reducing weight gain and metabolic disturbances. Ziprasidone and aripiprazole have been described to be least commonly associated with weight gain or metabolic changes. In addition, some of the SGAs (risperidone, amisulpride, and paliperidone) have been associated with a significant increase of plasma prolactin levels. Overall, in cases of FEP, there should be a clear recommendation of using lower doses of the antipsychotic medication. If no or minimal clinical improvement is found after 2 weeks of treatment, such patients may benefit from a change or augmentation of treatment. Clinicians should provide accurate information to patients and relatives about the high risk of relapse if antipsychotics are discontinued, even if patients have been symptom free and functionally recovered on antipsychotic treatment for a lengthy period of time.This review was carried out at the Hospital MarqueÂŽs de Valdecilla, University of Cantabria, Santander, Spain, with the following Grant support: Instituto de Salud Carlos III PI020499, PI050427, PI060507, Plan Nacional de Drugs Research Grant 2005-Orden sco/3246/2004, SENY FundacioÂŽ Research Grant CI 2005-0308007, FundacioÂŽn MarqueÂŽs de Valdecilla API07/011 and CIBERSAM
- âŠ