Descriptive characteristics of inpatients with tardive dyskinesia as distinguished from inpatients without tardive dyskinesia

The purpose of this study was to investigate the relationship of the presence or absence of tardive dyskinesia (TD) to drug and behavioral history variables. The author hoped to determine if there were descriptive characteristics, unique to patients with TD, which could merit further investigation as precursors of TD. Two samples, with 26 subjects each, were drawn from patients identified at Eastern State Hospital and screened by a psychiatrist. The TD and No-TD groups were matched on age, sex, and diagnosis. Entire drug histories were recorded and entire behavioral (hospitalization) histories were rated. Data collection was discontinued, for both subjects, with the emergence of TD symptoms in the TD subject. This was an ex post facto design.;It was hypothesized that significant differences would be found between the two groups on history of antipsychotic and antiparkinson medications, history of polypharmacy, history of drug-free days and periods, history of extrapyramidal symptoms (EPS), history of psychiatric behavior patterns, race, eye color, and dental status. A trend was noted for the No-TD group to have consistently higher means on all of the drug variables. Significantly higher means for the No-TD group were found for mean cumulative and mean daily dose of antipsychotics, mean length of antiparkinson agent administration, and in the number of EPS incidences. The TD group had significantly more edentulous subjects than the No-TD groups.;Although TD is clearly related to antipsychotic ingestion, apparently it is not related to the quantity of antipsychotics ingested. Future study should, therefore, focus on the relationship of individual vulnerability to the development of TD rather than on drug variables such as those investigated in this study. Further investigation of the behavioral precursors is indicated. A prospective design is recommended in order to clarify relationships, such as EPS history and the development of TD, that remain unclear in retrospective investigations

Microhomology-mediated deletion and gene conversion in African trypanosomes.

Antigenic variation in African trypanosomes is induced by DNA double-strand breaks (DSBs). In these protozoan parasites, DSB repair (DSBR) is dominated by homologous recombination (HR) and microhomology-mediated end joining (MMEJ), while non-homologous end joining (NHEJ) has not been reported. To facilitate the analysis of chromosomal end-joining, we established a system whereby inter-allelic repair by HR is lethal due to loss of an essential gene. Analysis of intrachromosomal end joining in individual DSBR survivors exclusively revealed MMEJ-based deletions but no NHEJ. A survey of microhomologies typically revealed sequences of between 5 and 20 bp in length with several mismatches tolerated in longer stretches. Mean deletions were of 54 bp on the side closest to the break and 284 bp in total. Break proximity, microhomology length and GC-content all favored repair and the pattern of MMEJ described above was similar at several different loci across the genome. We also identified interchromosomal gene conversion involving HR and MMEJ at different ends of a duplicated sequence. While MMEJ-based deletions were RAD51-independent, one-sided MMEJ was RAD51 dependent. Thus, we describe the features of MMEJ in Trypanosoma brucei, which is analogous to micro single-strand annealing; and RAD51 dependent, one-sided MMEJ. We discuss the contribution of MMEJ pathways to genome evolution, subtelomere recombination and antigenic variation

Genome-wide RNAi selection identifies a regulator of transmission stage-enriched gene families and cell-type differentiation in <i>Trypanosoma brucei</i>

<div><p><i>Trypanosoma brucei</i>, causing African sleeping-sickness, exploits quorum-sensing (QS) to generate the ‘stumpy forms’ necessary for the parasite’s transmission to tsetse-flies. These quiescent cells are generated by differentiation in the bloodstream from proliferative slender forms. Using genome-wide RNAi selection we screened for repressors of transmission stage-enriched mRNAs in slender forms, using the stumpy-elevated ESAG9 transcript as a model. This identified <i>REG9</i>.<i>1</i>, whose RNAi-silencing alleviated <i>ESAG9</i> repression in slender forms and tsetse-midgut procyclic forms. Interestingly, trypanosome surface protein Family 5 and Family 7 mRNAs were also elevated, which, like <i>ESAG9</i>, are <i>T</i>. <i>brucei</i> specific and stumpy-enriched. We suggest these contribute to the distinct transmission biology and vector tropism of <i>T</i>. <i>brucei</i> from other African trypanosome species. As well as surface family regulation, <i>REG9</i>.<i>1</i>-depletion generated QS-independent development to stumpy forms <i>in vivo</i>, whereas <i>REG9</i>.<i>1</i> overexpression in bloodstream forms potentiated spontaneous differentiation to procyclic forms in the absence of an external signal. Combined, this identifies <i>REG9</i>.<i>1</i> as a regulator of developmental cell fate, controlling the expression of <i>Trypanosoma brucei</i>-specific molecules elevated during transmission.</p></div

VEX1 controls the allelic exclusion required for antigenic variation in trypanosomes

Allelic exclusion underpins antigenic variation and immune evasion in African trypanosomes. These bloodstream parasites use RNA polymerase-I (pol-I) to transcribe just one telomeric variant surface glycoprotein (VSG) gene at a time, producing superabundant and switchable VSG coats. We identified trypanosome VSG exclusion-1 (VEX1) using a genetic screen for defects in telomere-exclusive expression. VEX1 was sequestered by the active VSG and silencing of other VSGs failed when VEX1 was either ectopically expressed or depleted, indicating positive and negative regulation, respectively. Positive regulation affected VSGs and nontelomeric pol-I-transcribed genes, whereas negative regulation primarily affected VSGs. Negative regulation by VEX1 also affected telomeric pol-I-transcribed reporter constructs, but only when they contained blocks of sequence sharing homology with a pol-I-transcribed locus. We conclude that restricted positive regulation due to VEX1 sequestration, combined with VEX1-dependent, possibly homology-dependent silencing, drives a "winner-takes-all" mechanism of allelic exclusion

Who’s Milking It? Scripted Stories of Food Labour

This article explores representations of food labour at different stages in the supply chain through a labour process theory perspective. Employing multi-modal critical discourse analysis it analyses visual data collected from three television programmes focused on dairy production and consumption. The research sheds light on the power relations inherent to food production and the devaluing of manual food labour in supply chains, which are shaped by the current capitalist socio-political environment. The findings expose ways in which media can reinforce dominant understandings of food supply chains, while making aspects of food labour invisible

Antigenic variation in African trypanosomes: the importance of chromosomal and nuclear context in VSG expression control.

African trypanosomes are lethal human and animal parasites that use antigenic variation for evasion of host adaptive immunity. To facilitate antigenic variation, trypanosomes dedicate approximately one third of their nuclear genome, including many minichromosomes, and possibly all sub-telomeres, to variant surface glycoprotein (VSG) genes and associated sequences. Antigenic variation requires transcription of a single VSG by RNA polymerase I (Pol-I), with silencing of other VSGs, and periodic switching of the expressed gene, typically via DNA recombination with duplicative translocation of a new VSG to the active site. Thus, telomeric location, epigenetic controls and monoallelic transcription by Pol-I at an extranucleolar site are prominent features of VSGs and their expression, with telomeres, chromatin structure and nuclear organization all making vitally important contributions to monoallelic VSG expression control and switching. We discuss VSG transcription, recombination and replication control within this chromosomal and sub-nuclear context

Tagging a T. brucei RRNA locus improves stable transfection efficiency and circumvents inducible expression position effects.

In Trypanosoma brucei, RNA interference (RNAi) and recombinant protein expression are established as powerful approaches for functional genomics, particularly when combined with inducible expression. The favoured methods involve exploiting homologous recombination to target expression cassettes to a chromosome sub-set to establish stable cell lines. Unfortunately, bloodstream-form cells, those that cause disease in mammals, exhibit low efficiency stable transfection. Current expression systems can also exhibit other undesirable features, including variable position effects and leaky, inducible expression. We have developed systems in bloodstream-form cells that alleviate these problems. Using constructs for RNAi and expression of (GFP) tagged proteins, we target a (hyg) tagged ribosomal RNA (RRNA) locus which circumvents position effects and allows increased targeting efficiency. We also report a compatible double-inducible system for tight regulation of highly toxic products. This system exploits a new inducible RRNA promoter to drive T7 RNA polymerase (T7RNAP) transcription which then drives expression from inducible T7 promoters. The developments described should facilitate functional analysis and increased throughput

Insights into antitrypanosomal drug mode-of-action from cytology-based profiling

Chemotherapy continues to have a major impact on reducing the burden of disease caused by trypanosomatids. Unfortunately though, the mode-of-action (MoA) of antitrypanosomal drugs typically remains unclear or only partially characterised. This is the case for four of five current drugs used to treat Human African Trypanosomiasis (HAT); eflornithine is a specific inhibitor of ornithine decarboxylase. Here, we used a panel of T. brucei cellular assays to probe the MoA of the current HAT drugs. The assays included DNA-staining followed by microscopy and quantitative image analysis, or flow cytometry; terminal dUTP nick end labelling to monitor mitochondrial (kinetoplast) DNA replication; antibody-based detection of sites of nuclear DNA damage; and fluorescent dye-staining of mitochondria or lysosomes. We found that melarsoprol inhibited mitosis; nifurtimox reduced mitochondrial protein abundance; pentamidine triggered progressive loss of kinetoplast DNA and disruption of mitochondrial membrane potential; and suramin inhibited cytokinesis. Thus, current antitrypanosomal drugs perturb distinct and specific cellular compartments, structures or cell cycle phases. Further exploiting the findings, we show that putative mitogen-activated protein-kinases contribute to the melarsoprol-induced mitotic defect, reminiscent of the mitotic arrest associated signalling cascade triggered by arsenicals in mammalian cells, used to treat leukaemia. Thus, cytology-based profiling can rapidly yield novel insight into antitrypanosomal drug MoA

Preventable Asthma Episodes Among Urban/Rural Children and Adolescents: A Comparative Study

Context: Asthma is a chronic respiratory illness that is increasing in prevalence among children in the United States. A limited number of studies have examined the relationship between rurality and the prevalence of asthma in minority children, and those studies found mixed results. The aim of this study is to examine urban/rural locality and its impact on asthma episodes and preventable emergency department visits, and to provide quantitative evidence concerning the relationship between patient characteristics and geographic location. Methods: This is a retrospective study and secondary data analysis of the 2000 National Health Interview Survey. Parametric testing using Univariate/Bivariate/Multivariate analysis was performed to examine emergency department utilization for asthma episodes among urban/rural children and adolescents in the United States. Findings: Regardless of the geographic location, Black children were more likely to visit the emergency room within the past twelve months (urban area (OR=1.59; 95% CI 0.87, 2.33) – rural area (OR=2.68; 95% CI 1.39, 4.05)). Additionally, children who experienced an asthma episode in the past twelve months were more likely to report not visiting the emergency department (OR=1.93; 95% CI 1.53, 2.44). Conclusions: Racial and urban/rural differences exist among children with asthma visits to the emergency department. Asthma prevalence and disparities continue to be a burden in the United States and its deficiencies across geographic locations reflect the health of the US population as a whole