Coordination and management of TNP from acute to primary care: overcoming the issues.
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Continuity of Patient Care↗
Biomedical subjects
A Barker
Publications and source records attributed to A Barker.
Formation of an alphaCP1-KH3 complex with UC-rich RNA.
The alphaCP family of proteins [also known as poly(C)-binding or heterogeneous nuclear ribonucleoprotein E proteins] are involved in the regulation of messenger RNA (mRNA) stability and translational efficiency. They bind via their triple heterologous nuclear ribonucleoprotein K homology (KH) domain structures to C-rich mRNA, and are thought to interact with other mRNA-binding proteins as well as provide direct nuclease protection. In particular, alphaCP1 and alphaCP2 have been shown to bind to a specific region of androgen receptor (AR) mRNA, resulting in its increased stability. The roles of each of the KH motifs in the binding affinity and the specificity is not yet understood. We report the beginning of a systematic study of each of the alphaCP KH domains, with the cloning and expression of alphaCP1-KH2 and alphaCP1-KH3. We report the ability of alphaCP1-KH3, but not alphaCP1-KH2, to bind the target AR mRNA sequence using an RNA electrophoretic mobility gel shift assay. We also report the preparation of an alphaCP1-KH3/AR mRNA complex for structural studies. (1)H-(15)N heteronuclear single quantum correlation NMR spectra of (15)N-labelled alphaCP1-KH3 verified the integrity and good solution behaviour of the purified domain. The titration of the 11-nucleotide RNA target sequence from AR mRNA resulted in a rearrangement of the (1)H-(15)N correlations, demonstrating the complete binding of the protein to form a homogeneous protein/RNA complex suitable for future structural studies.
Amino Acid Motifs↗
Structure and RNA binding of the third KH domain of poly(C)-binding protein 1.
Poly(C)-binding proteins (CPs) are important regulators of mRNA stability and translational regulation. They recognize C-rich RNA through their triple KH (hn RNP K homology) domain structures and are thought to carry out their function though direct protection of mRNA sites as well as through interactions with other RNA-binding proteins. We report the crystallographically derived structure of the third domain of alphaCP1 to 2.1 A resolution. alphaCP1-KH3 assumes a classical type I KH domain fold with a triple-stranded beta-sheet held against a three-helix cluster in a betaalphaalphabetabetaalpha configuration. Its binding affinity to an RNA sequence from the 3'-untranslated region (3'-UTR) of androgen receptor mRNA was determined using surface plasmon resonance, giving a K(d) of 4.37 microM, which is indicative of intermediate binding. A model of alphaCP1-KH3 with poly(C)-RNA was generated by homology to a recently reported RNA-bound KH domain structure and suggests the molecular basis for oligonucleotide binding and poly(C)-RNA specificity.
3' Untranslated Regions↗
Chronic cognitive effects of bilateral subdural haematomas in the rat.
Humans suffering from subdural haematomas often show long-term cognitive dysfunctions. For identifying putative, recovery-enhancing therapeutics, animal models need to be developed in which recovery of function can be measured. For investigating whether and which type of recovery, i.e. spontaneous or training-induced recovery, or continuous partial retardation, is present in the rat model for bilateral subdural haematomas, spatial navigation abilities were assessed in the Morris water escape task in independent groups of rats at 1, 2, 4, 8, or 18 weeks after surgery. Complete spontaneous recovery seemed to occur at 8 weeks after injury. However, at 18 weeks after injury, the subdural haematoma caused a renewed deterioration of water maze performance, which was of a lesser degree than the impairments observed immediately after injury. This second phase performance deterioration was accompanied by an increase in generalised astrocyte reactivity. The rat subdural haematoma model provides an interesting tool for investigating spontaneous recovery processes of spatial navigation (8 weeks after injury), but also for progressive brain dysfunctions, considering the second phase of behavioural impairments seen at 18 weeks after injury.
Animals↗
The direction of mental health care for the elderly.
The way that mental health care for older people is developing in the UK is being shaped by a number of factors. These include demographic shifts, changes in the general population's attitudes to health, alterations in professional practice, governmental policy, and medical and technological advances. This article summarises some key aspects of these changes and predicts the likely direction of growth of mental health services in response.
Aged↗
Composting under controlled conditions.
Three cylindrical reactors, each with a working capacity of approximately 200 litres, were used to investigate composting. The process was optimised and conditions were controlled so that composting on a laboratory-scale thermally resembled that occurring in the core of large open heaps. A baseline flow of humidified air aerated the reactors in five-minute bursts. The reactors operated as closed systems with facilities to analyse the composition of the off-gas for ammonia, oxygen and carbon dioxide. Temperature was used to monitor the progress of the process. Heat loss from the reactor surface was compensated for with an external heat source. A basic model of radial conductive heat losses showed that 53 watts per square-metre would be the maximum heat flux needed to keep the temperature difference across the reactor to within a degree when running at 60 degrees C. A heating cable was used, which could supply 150 watts per square-metre, and the radial temperature difference was reduced to within a degree in more than 60% of the recorded temperatures in the case studies presented. The temperature of the composting material was held at 60 degrees C using a high flow rate 'cooling' aeration with temperature feedback. This, however, led to a mean vertical temperature difference of at least 10 degrees C. The aeration strategy resulted in a well-aerated material, which favoured aerobic microbial activity and the temperature increased as a result of the internally generated heat associated with composting. Three-quarters of the ammonia was emitted in the first week.
Bacteria, Aerobic↗
Anticholinesterase drugs for alcoholic Korsakoff syndrome.
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Cholinesterase Inhibitors↗
Synthetic mannosides act as acceptors for mycobacterial alpha1-6 mannosyltransferase.
A series of synthetic mannosides was screened in a cell-free system for their ability to act as acceptor substrates for mycobacterial mannosyltransferases. Evaluation of these compounds demonstrated the incorporation of [14C]Man from GDP-[14C]Man into a radiolabeled organic-soluble fraction and analysis by thin layer chromatography and autoradiography revealed the formation of two radiolabeled products. Each synthetic acceptor was capable of accepting one or two mannose residues, resulting in a major and a minor mannosylated product. Both products from each acceptor were isolated and their mass was confirmed by fast-atom bombardment-mass spectrometry (FABMS). Characterization of each mannosylated product by exo-glycosidase digestion. acetolysis and linkage analysis by gas chromatography mass spectrometry of partially per-O-methylated alditols, revealed only alpha1-6-linked products. In addition. the antibiotic amphomycin selectively inhibited the formation of mannosylated products suggesting polyprenolmonophosphate-mannose (C15 50-P-Man) was the immediate mannose donor in all mannosylation reactions observed. The ability of synthetic disaccharides to act as acceptor substrates in this system, is most likely due to the action of a mycobacterial polyprenol-P-Man:mannan alpha1-6 mannosyltransferase involved in the biosynthesis of linear alpha1-6-linked lipomannan.
Carbohydrate Sequence↗
A comparison of the effect of new and established insecticides on nontarget invertebrates of winter wheat fields.
Six insecticides, a carbamate (pirimicarb), four pyrethroid/mixtures (tao-fluvalinate, zeta-cypermethrin, deltamethrin, and pirimcarb+deltamethrin), and an organophosphate (dimethoate), registered for use within cereals, were field-tested for toxicity to beneficial nontarget invertebrate groups important as food for farmland birds. Compared to the control and the other compounds, pirimicarb was the least toxic for most invertebrate groups examined. The pyrethroids and pyrethroid mixture significantly reduced numbers of many of the nontarget groups compared to the control and pirimicarb. Tao-fluvalinate was the least toxic pyrethroid tested when compared to the other compounds. Toxicity was further tested on larvae of graminivorous sawflies, an important chick- food group, using field-sprayed plants in laboratory and semifield trials. None of the pyrethroid and carbamate compounds and mixtures was as toxic as the organophosphate, but all were more toxic than the control. The semifield experiments provided a useful way of determining potential insecticide impact on this nontarget group where field populations are often too low for field trials to have statistically conclusive results.
Agriculture↗
Obesity and approaches to weight in an urban African-American community.
OBJECTIVES: To describe the prevalence of obesity, associated factors, and current approaches to weight in an inner city African-American community. DESIGN: In-home survey by community health interviewers. SETTING: Baltimore, Maryland. PARTICIPANTS: 2196 community residents identified in a probability sample of census blocks. MAIN OUTCOME MEASURES: Self-reported height and weight and calculated Body Mass Index (BMI), category of BMI, and stated weight goals. RESULTS: Sixty percent of participants were overweight (BMI> or =25 kg/m2), and 31% were obese (BMI> or =30 kg/m2). In multivariate analysis, women, those earning $15,000-30,000, and those aged 45-60 were more likely to be obese; less likely to be obese were smokers, daily drinkers, and those with "good" or "excellent" health. Sixty-one percent of obese participants reported trying to lose weight, while 36% of normal weight participants were trying to gain weight. Of those trying to lose weight, 35% were using recommended approaches, and 26% received "the professional help they needed to control their weight." CONCLUSIONS: Although obesity was prevalent, few were using recommended weight loss strategies and a significant minority of normal weight participants were trying to gain weight, indicating a need for improved weight management and obesity prevention in the African-American community.
Adolescent↗
Churg-Strauss syndrome in patients receiving montelukast as treatment for asthma.
STUDY OBJECTIVES: We previously reported eight patients who developed Churg-Strauss syndrome in association with zafirlukast treatment for asthma and postulated that the syndrome resulted from unmasking of a previously existing condition due to corticosteroid withdrawal and not from a direct drug effect. The availability of montelukast, a new leukotriene receptor antagonist with a different molecular structure, permitted us to test this hypothesis. Our goals were to ascertain whether the Churg-Strauss syndrome developed in patients taking montelukast and other novel asthma medications, and to describe potential mechanisms for the syndrome. DESIGN: Case series. SETTING: Outpatient and hospital practices of pulmonologists in the United States and Belgium. PATIENTS: Four adults (one man, three women) who received montelukast as treatment for asthma; two women who received salmeterol/fluticasone therapy, but not montelukast. RESULTS: Churg-Strauss syndrome developed in the four asthmatic patients who received montelukast. In each case, there was a long history of difficult-to-control asthma characterized by multiple exacerbations that had required frequent courses of oral systemic corticosteroids or high doses of inhaled corticosteroids for control. Two other asthmatics who received fluticasone and salmeterol but not montelukast therapy developed the same syndrome with tapering doses of oral or high doses of inhaled corticosteroids. CONCLUSIONS: The occurrence of Churg-Strauss syndrome in asthmatic patients receiving leukotriene modifiers appears to be related to unmasking of an underlying vasculitic syndrome that is initially clinically recognized as moderate to severe asthma and treated with corticosteroids. Montelukast does not appear to directly cause the syndrome in these patients.
Acetates↗
Community health survey in an urban African-American neighborhood: distribution and correlates of elevated blood pressure.
While considerable improvements have been made over the last 30 years in hypertension (HTN) awareness, treatment, and control, a recent reversal of these trends has been documented with African-American adults, particularly among those continuing to suffer from uncontrolled hypertension and its adverse consequences. This paper presents data from a cross-sectional representative survey of the health status of an urban African-American community. The study was designed in partnership with community leadership to improve HTN care and control. The baseline survey was a face-to-face interview (including blood pressure [BP] measurements) of 2,196 adults residing in randomly selected blocks in the Sandtown-Winchester neighborhood in Baltimore City. These sample data were compared with national data from the NHANES III survey, and demonstrated similar awareness of hypertension. However, hypertension control rates among treated hypertensives were significantly lower in the study community (28%) than in the national survey (44%). Compared with normotensive individuals, those with HTN were significantly older, had less education, were less likely to be employed, and had lower annual incomes. Individuals with HTN were also significantly more likely to rate their health as poor/fair, to report a history of heart disease, stroke, diabetes, kidney disease, obesity, high cholesterol, and lack of exercise, as well as to be at greater risk of alcoholism or alcohol problems. Hypertensive individuals (88% with reported prior history, 12% newly detected) were significantly more likely to have a usual source of care, have seen a health professional in the last 12 months, and to be extremely satisfied with the provider; however, 20% of individuals with hypertension reported no health insurance. These data indicate the need for focused interventions to enhance hypertension maintenance of care and adherence to treatment.
Adult↗
Dimerisation mutants of Lac repressor. I. A monomeric mutant, L251A, that binds Lac operator DNA as a dimer.
Dimer formation between monomers of the Escherichia coli Lac repressor is substantially specificed by the interactions between three alpha-helices in each monomer which form a hydrophobic interface. As a first step in analysing the specificity of this interaction, we examined the mutant L251A. LacR bearing this mutation in a background lacking the C-terminal heptad repeats is completely incapable of forming dimers in solution, with a dimer-monomer equilibrium dissociation constant, or Kd, higher than 10(-5)M. This correlates with a 200-fold decrease in its ability to repress the lac operon in vivo compared to dimeric LacR. Surprisingly, the mutant is still capable of forming dimers upon binding to short operator DNA in vitro. Analysis of the kinetic parameters of binding of the mutant to operator DNA reveals a 2000 to 3000-fold increase in the equilibrium dissociation constant (Kd) of the mutant-DNA complex in comparison to dimeric LacR-operator complexes, with the change almost entirely due to a greater than 1000-fold decrease in association rate. The dissociation rate varies only by a factor of about two, in comparison to dimeric LacR. This change reflects a kinetic pathway in which dimer formation, in solution or on DNA, is the rate-limiting step. These findings have implications for the specificity and stability of the protein-protein interface in question.
Bacterial Proteins↗
Altered expression profile of the surface glycopeptidolipids in drug-resistant clinical isolates of Mycobacterium avium complex.
Members of the Mycobacterium avium complex are the most frequently encountered opportunistic bacterial pathogens among patients in the advanced stage of AIDS. Two clinical isolates of the same strain, numbers 397 and 417, were obtained from an AIDS patient with disseminated M. avium complex infection before and after treatment with a regimen of clarithromycin and ethambutol. To identify the biochemical consequence of drug treatment, the expression and chemical composition of their major cell wall constituents, the arabinogalactan, lipoarabinomannan, and the surface glycopeptidolipids (GPL), were critically examined. Through thin layer chromatography, mass spectrometry, and chemical analysis, it was found that the GPL expression profiles differ significantly in that several apolar GPLs were overexpressed in the clinically resistant 417 isolate at the expense of the serotype 1 polar GPL, which was the single predominant band in the ethambutol-susceptible 397 isolate. Thus, instead of additional rhamnosylation on the 6-deoxytalose (6-dTal) appendage to give the serotype 1-specific disaccharide hapten, the accumulation of this nonextended apolar GPL probably provided more precursor substrate available for further nonsaccharide substitutions including a higher degree of O-methylation to give 3-O-Me-6-dTal and the unusual 4-O-sulfation on 6-dTal. Further data showed that this alteration effectively neutralized ethambutol, which is known to inhibit arabinan synthesis. Thus, in contrast with derived Emb-resistant mutants of Mycobacterium smegmatis or Mycobacterium tuberculosis, which are devoid of a surface GPL layer, the lipoarabinomannan from resistant 417 isolate grown in the presence of this drug was not apparently truncated.
AIDS-Related Opportunistic Infections↗
Is nitrocellulose filter binding really a universal assay for protein-DNA interactions?
The ability to bind to nitrocellulose is commonly accepted as being a universal property of proteins and has been widely used in many different fields of study. This property was first exploited in the study of DNA-binding proteins 30 years ago, in studies involving DNA binding by the lactose repressor (LacR) of Escherichia coli. Termed the filter-binding assay, it remains the quickest and easiest assay available for the study of protein-DNA interactions. However, the exact mechanism by which proteins bind to nitrocellulose remains uncertain. Given the supposedly universal nature of the interaction, we were surprised to notice that certain LacR variants were completely unable to bind simultaneously to DNA containing a single lac operator and nitrocellulose. Investigation of this loss of binding suggests that LacR requires a protein region that is both hydrophobic in nature and more or less unstructured, in order to bind to both nitrocellulose and DNA. In the case of wild-type, tetrameric LacR, the DNA-recognition domain that is not bound to DNA suffices. Dimeric LacR variants will only bind if they have certain C-terminal extensions. These experiments sound a cautionary note for the use of filter binding as an assay of choice, particularly in applications involving screening for the DNA-binding site of putative DNA-binding proteins.
Amino Acid Sequence↗
Four dimers of lambda repressor bound to two suitably spaced pairs of lambda operators form octamers and DNA loops over large distances.
Transcription factors that are bound specifically to DNA often interact with each other over thousands of base pairs [1] [2]. Large DNA loops resulting from such interactions have been observed in Escherichia coli with the transcription factors deoR [3] and NtrC [4], but such interactions are not, as yet, well understood. We propose that unique protein complexes, that are not present in solution, may form specifically on DNA. Their uniqueness would make it possible for them to interact tightly and specifically with each other. We used the repressor and operators of coliphage lambda to construct a model system in which to test our proposition. lambda repressor is a dimer at physiological concentrations, but forms tetramers and octamers at a hundredfold higher concentration. We predict that two lambda repressor dimers form a tetramer in vitro when bound to two lambda operators spaced 24 bp apart and that two such tetramers interact to form an octamer. We examined, in vitro, relaxed circular plasmid DNA in which such operator pairs were separated by 2,850 bp and 2,470 bp. Of these molecules, 29% formed loops as seen by electron microscopy (EM). The loop increased the tightness of binding of lambda repressor to lambda operator. Consequently, repression of the lambda PR promoter in vivo was increased fourfold by the presence of a second pair of lambda operators, separated by a distance of 3,600 bp.
DNA, Viral↗
Training astronauts using three-dimensional visualisations of the International Space Station.
Recent advances in personal computer technology have led to the development of relatively low-cost software to generate high-resolution three-dimensional images. The capability both to rotate and zoom in on these images superposed on appropriate background images enables high-quality movies to be created. These developments have been used to produce realistic simulations of the International Space Station on CD-ROM. This product is described and its potentialities demonstrated. With successive launches, the ISS is gradually built up, and visualised over a rotating Earth against the star background. It is anticipated that this product's capability will be useful when training astronauts to carry out EVAs around the ISS. Simulations inside the ISS are also very realistic. These should prove invaluable when familiarising the ISS crew with their future workplace and home. Operating procedures can be taught and perfected. "What if" scenario models can be explored and this facility should be useful when training the crew to deal with emergency situations which might arise. This CD-ROM product will also be used to make the general public more aware of, and hence enthusiastic about, the International Space Station programme.
Astronauts↗
Schizophrenia and diabetes mellitus.
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Adult↗