A characterisation of patient drop outs in a cohort of HIV positive homosexual/bisexual men and intravenous drug users.
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Adolescent↗
Biomedical subjects
J Turner
Publications and source records attributed to J Turner.
Homologous upregulation of sst2 somatostatin receptor expression in the rat arcuate nucleus in vivo.
In vitro studies using various cell systems have provided conflicting results regarding homologous regulation of somatostatin (SRIH) receptors, and information on whether SRIH regulates the expression of its own receptors in vivo is lacking. In the present study we examined, by in situ hybridization, the effects of pretreatment with the sst2-preferring SRIH analog, octreotide, in vivo, on mRNA levels of two SRIH receptor subtypes, sst1 and sst2, in rat brain and pituitary. (125)I-[DTrp(8)]-SRIH binding was also measured in these regions. Three hours after the iv injection of 50 microg octreotide to conscious adult male rats, there was a 46% increase (p < 0.01) in the labeling density of sst2 mRNA-expressing cells in the hypothalamic arcuate nucleus compared to normal saline-pretreated controls, but not in any of the other brain regions examined. Computer-assisted image analysis revealed that 3 h exposure to octreotide significantly (p < 0.01) augmented both the number and labeling density of sst2 mRNA-expressing cells in the arcuate nucleus, compared to those in saline-treated controls. By contrast, within the anterior pituitary gland, in vivo exposure to octreotide did not affect the expression of sst2 mRNA. No changes in sst1 mRNA-expressing cells were observed after octreotide treatment in any of the regions measured, indicating that the observed effects were homologous, i.e. specific of the receptor subtype stimulated. Octreotide pretreatment was also without effect on the density of (125)I-[DTrp(8)]-SRIH binding in either the arcuate nucleus or pituitary. These results demonstrate, for the first time, that SRIH preexposure in vivo upregulates the expression of a subtype of its own receptors, sst2, within the central nervous system. They further suggest that pretreatment with SRIH in vivo does not cause sst2 receptor desensitization in arcuate nucleus and pituitary. Such homologous regulatory mechanisms may play an important role in the neuroendocrine control of growth hormone (GH) secretion by the arcuate nucleus.
Animals↗
CD8- and CD95/95L-dependent mechanisms of resistance in mice with chronic pulmonary tuberculosis.
The role of CD8 T lymphocytes in the immune response to Mycobacterium tuberculosis infection remains enigmatic, with persuasive reports of both cytolytic and noncytolytic (cytokine-mediated) responses to infection. To address the importance of the cytolytic mechanisms, mice with targeted disruptions for CD8 and perforin or with gene mutations in the CD95/ CD95L signaling pathway were exposed to pulmonary infection. All mice tested showed no differences in their ability to contain the growth of infection during the early phase of disease. As the chronic phase of the disease ensued, however, both CD8- and CD95/CD95L-deficient mice gradually lost their ability to limit bacterial growth. This was associated with a tendency toward pyogenic inflammation in the lung. This tendency was not seen in the perforin gene-disrupted mice. In CD8 gene-disrupted mice, the ability to generate interferon-gamma secreting T cells was unimpaired. Although these cells were capable of entering the lung they were unable to influence the increasing bacterial load in this organ.
Animals↗
Postnatal expression in hyaline cartilage of constitutively active human collagenase-3 (MMP-13) induces osteoarthritis in mice.
It has been suggested that increased collagenase-3 (MMP-13) activity plays a pivotal role in the pathogenesis of osteoarthritis (OA). We have used tetracycline-regulated transcription in conjunction with a cartilage-specific promoter to target a constitutively active human MMP-13 to the hyaline cartilages and joints of transgenic mice. Postnatal expression of this transgene resulted in pathological changes in articular cartilage of the mouse joints similar to those observed in human OA. These included characteristic erosion of the articular cartilage associated with loss of proteoglycan and excessive cleavage of type II collagen by collagenase, as well as synovial hyperplasia. These results demonstrate that excessive MMP-13 activity can result in articular cartilage degradation and joint pathology of the kind observed in OA, suggesting that excessive activity of this proteinase can lead to this disease.
Animals↗
Determining the optimal dose of haloperidol in first-episode psychosis.
Uncertainty exists as to the most appropriate dose of haloperidol in first-episode psychosis. This study set out to determine whether ultra-low doses of haloperidol could successfully treat patients with first-episode psychosis. Thirty-five patients with a first episode of psychosis were treated with haloperidol in an open label, fixed protocol over a 12-week period with doses restricted to 1 mg per day for the first 4 weeks. Twenty-nine (83%) remained on haloperidol after 12 weeks at a mean dose of 1.78 mg per day, 16 (55%) had stabilized on 1 mg/day or less. The mean percentage reduction in Positive and Negative Symptom Scale score between baseline and 6 and 12 weeks was 30.3% (SD 20.9%) and 41.4% (SD 16.6%), respectively. There were no significant differences in mean extrapyramidal symptom ratings between baseline and 12 weeks. Ultra-low doses of haloperidol are effective and well tolerated in first-episode psychosis. Initial doses should be maintained for a sufficient period of time to allow for the medication to take full effect.
Adolescent↗
Conversations with parents of medically ill children: a study of interactions between medical students and parents and pediatric residents and parents in the clinical setting.
BACKGROUND: The traditional remedies applied by medical schools to the perennial problem of teaching "caring competence" have been unsuccessful. PURPOSE: Our purpose was to design and evaluate a simple and effective method for helping students maintain affective contact with their patients. METHODS: Third-year medical students and pediatric residents were given the opportunity to talk informally with parents of medically ill children and reflect on the value of this experience for their learning. Trainees' opinions of the experience were measured with focus groups and a questionnaire. RESULTS: Trainees were delighted with the experience, particularly with the following aspects: the opportunity to hear a personally relevant story told in a sincere manner, the realization that they could have an authentic interaction "even" in a medical setting, and the usefulness of the information they derived from the conversation. CONCLUSIONS: We concluded that something unique to the conversational experience has educational value.
Adolescent↗
The assessment of poorly performing doctors: the development of the assessment programmes for the General Medical Council's Performance Procedures.
BACKGROUND: Modernization of medical regulation has included the introduction of the Professional Performance Procedures by the UK General Medical Council in 1995. The Council now has the power to assess any registered practitioner whose performance may be seriously deficient, thus calling registration (licensure) into question. Problems arising from ill health or conduct are dealt with under separate programmes. METHODS: This paper describes the development of the assessment programmes within the overall policy framework determined by the Council. Peer review of performance in the workplace (Phase 1) is followed by tests of competence (Phase 2) to reflect the relationship between clinical competence and performance. The theoretical and research basis for the approach are presented, and the relationship between the qualitative methods in Phase 1 and the quantitative methods in Phase 2 explored. CONCLUSIONS: The approach is feasible, has been implemented and has stood legal challenge. The assessors judge and report all the evidence they collect and may not select from it. All their judgements are included and the voice of the lay assessor is preserved. Taken together, the output from both phases forms an important basis for remediation and training should it be required.
Clinical Competence↗
Health receives scant attention in budget speech.
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Budgets↗
The delta subunit of DNA polymerase III holoenzyme serves as a sliding clamp unloader in Escherichia coli.
In Escherichia coli, the circular beta sliding clamp facilitates processive DNA replication by tethering the polymerase to primer-template DNA. When synthesis is complete, polymerase dissociates from beta and DNA and cycles to a new start site, a primed template loaded with beta. DNA polymerase cycles frequently during lagging strand replication while synthesizing 1-2-kilobase Okazaki fragments. The clamps left behind remain stable on DNA (t(12) approximately 115 min) and must be removed rapidly for reuse at numerous primed sites on the lagging strand. Here we show that delta, a single subunit of DNA polymerase III holoenzyme, opens beta and slips it off DNA (k(unloading) = 0.011 s(-)(1)) at a rate similar to that of the multisubunit gamma complex clamp loader by itself (0.015 s(-)(1)) or within polymerase (pol) III* (0.0065 s(-)(1)). Moreover, unlike gamma complex and pol III*, delta does not require ATP to catalyze clamp unloading. Quantitation of gamma complex subunits (gamma, delta, delta', chi, psi) in E. coli cells reveals an excess of delta, free from gamma complex and pol III*. Since pol III* and gamma complex occur in much lower quantities and perform several DNA metabolic functions in replication and repair, the delta subunit probably aids beta clamp recycling during DNA replication.
Blotting, Western↗
The impact of domestic violence on individuals.
There is extensive evidence of the adverse effects of domestic violence across all age groups and cultural backgrounds. The impact of domestic violence may be long-term, affecting emotional adjustment, physical health and subsequent relationships. Health professionals should be aware of the confounding effect of youth, age and cultural diversity on presentation. Shame and isolation militate against disclosure. Specific, sensitive questioning that incorporates awareness of cultural and social issues is essential to detect domestic violence and initiate appropriate assistance.
Aged↗
Human Krüppel-like factor 8: a CACCC-box binding protein that associates with CtBP and represses transcription.
CACCC-boxes are recognised by transcription factors of the Sp/Krüppel-like Factor (Sp1/KLF) family. Here we describe one member of this family, KLF8/ZNF741/BKLF3 (KLF8). KLF8 contains a characteristic C-terminal DNA-binding domain comprised of three Krüppel-like zinc fingers, but also has limited homology to another family member, KLF3/Basic Krüppel-like Factor (KLF3/BKLF), in its N-terminus. Most significantly, it shares with KLF3/BKLF a Pro-Val-Asp-Leu-Ser/Thr motif. In KLF3/BKLF this motif mediates contact with the co-repressor protein C-terminal Binding Protein (CtBP). We demonstrate that the KLF8 Pro-Val-Asp-Leu-Ser motif also contacts CtBP. We show that the N-terminus of KLF8 functions as a repression domain and that its activity relies on the integrity of the CtBP recognition motif. We demonstrate that the zinc fingers of KLF8 recognize CACCC elements in DNA and that full-length KLF8 can repress a CACCC-dependent promoter. Finally we determine that KLF8 is broadly expressed in human tissues. These results establish KLF8 as a CACCC-box binding protein that associates with CtBP and represses transcription.
3T3 Cells↗
DNA structure requirements for the Escherichia coli gamma complex clamp loader and DNA polymerase III holoenzyme.
The Escherichia coli chromosomal replicase, DNA polymerase III holoenzyme, is highly processive during DNA synthesis. Underlying high processivity is a ring-shaped protein, the beta clamp, that encircles DNA and slides along it, thereby tethering the enzyme to the template. The beta clamp is assembled onto DNA by the multiprotein gamma complex clamp loader that opens and closes the beta ring around DNA in an ATP-dependent manner. This study examines the DNA structure required for clamp loading action. We found that the gamma complex assembles beta onto supercoiled DNA (replicative form I), but only at very low ionic strength, where regions of unwound DNA may exist in the duplex. Consistent with this, the gamma complex does not assemble beta onto relaxed closed circular DNA even at low ionic strength. Hence, a 3'-end is not required for clamp loading, but a single-stranded DNA (ssDNA)/double-stranded DNA (dsDNA) junction can be utilized as a substrate, a result confirmed using synthetic oligonucleotides that form forked ssDNA/dsDNA junctions on M13 ssDNA. On a flush primed template, the gamma complex exhibits polarity; it acts specifically at the 3'-ssDNA/dsDNA junction to assemble beta onto the DNA. The gamma complex can assemble beta onto a primed site as short as 10 nucleotides, corresponding to the width of the beta ring. However, a protein block placed closer than 14 base pairs (bp) upstream from the primer 3' terminus prevents the clamp loading reaction, indicating that the gamma complex and its associated beta clamp interact with approximately 14-16 bp at a ssDNA/dsDNA junction during the clamp loading operation. A protein block positioned closer than 20-22 bp from the 3' terminus prevents use of the clamp by the polymerase in chain elongation, indicating that the polymerase has an even greater spatial requirement than the gamma complex on the duplex portion of the primed site for function with beta. Interestingly, DNA secondary structure elements placed near the 3' terminus impose similar steric limits on the gamma complex and polymerase action with beta. The possible biological significance of these structural constraints is discussed.
Bacterial Proteins↗
Crystal structure of the DNA polymerase processivity factor of T4 bacteriophage.
The protein encoded by gene 45 of T4 bacteriophage (gene 45 protein or gp45), is responsible for tethering the catalytic subunit of T4 DNA Polymerase to DNA during high-speed replication. Also referred to as a sliding DNA clamp, gp45 is similar in its function to the processivity factors of bacterial and eukaryotic DNA polymerases, the beta-clamp and PCNA, respectively. Crystallographic analysis has shown that the beta-clamp and PCNA form highly symmetrical ring-shaped structures through which duplex DNA can be threaded. Gp45 shares no sequence similarity with beta-clamp or PCNA, and sequence comparisons have not been able to establish whether it adopts a similar structure. We have determined the crystal structure of gp45 from T4 bacteriophage at 2.4 A resolution, using multiple isomorphous replacement. The protein forms a trimeric ring-shaped assembly with overall dimensions that are similar to those of the bacterial and eukaryotic processivity factors. Each monomer of gp45 contains two domains that are very similar in chain fold to those of beta-clamp and PCNA. Despite an overall negative charge, the inner surface of the ring is in a region of positive electrostatic potential, consistent with a mechanism in which DNA is threaded through the ring.
Amino Acid Sequence↗
Protein phosphatase 1beta is required for the maintenance of muscle attachments.
Type 1 serine/threonine protein phosphatases (PP1) are important regulators of many cellular and developmental processes, including glycogen metabolism, muscle contraction, and the cell cycle [1] [2] [3] [4] [5]. Drosophila and humans both have multiple genes encoding PP1 isoforms [3] [6] [7]; each has one beta and several alpha isoform genes (alpha(1), alpha(2), alpha(3) in flies, alpha and gamma in humans; mammalian PP1beta is also known as PP1delta). The alpha/beta subtype differences are highly conserved between flies and mammals [6]. Though all these proteins are >85% identical to each other and have indistinguishable activities in vitro, we show here that the Drosophila beta isoform has a distinct biological role. We show that PP1beta9C corresponds to flapwing (flw), previously identified mutants of which are viable but flightless because of defects in indirect flight muscles (IFMs) [8]. We have isolated a new, semi-lethal flw allele that shows a range of defects, especially in muscles, which break away from their attachment sites and degenerate.
Alleles↗
Case-controlled study of nursing home residents referred for treatment of vocally disruptive behavior.
The aim of this study was to identify factors associated with vocally disruptive behavior (VDB) in nursing home patients referred to aged care services for treatment, using a case-control methodology. Characteristics of the VDB, reasons for referral, perceived causal factors, and psychotropic use were noted. Twenty-five subjects and controls were examined with the Screaming Behavior Mapping Instrument, the Cornell Scale for Depression in Dementia, the Dementia Behavior Disturbance Scale, and measures of cognition, functional capacity, social activities, and emotional reactions of nursing staff. VDB was associated with other disturbed behaviors, depression, anxiety, severe dementia, functional impairment, communication difficulties, use of psychotropic medication, social isolation, and emotional distress in the nursing staff. Reasons for referral may relate more to the stress experienced by nursing home staff in managing VDB than to specific attributes of the VDB itself.
Aged↗
A longitudinal study of in vitro IFNgamma production and cytotoxic T cell responses of tuberculosis patients in the gambia.
SETTING: This study was carried out at the MRC Laboratories, The Gambia. OBJECTIVES: To characterize the antigen-specific IFNgamma production and cytotoxic T cell (CTL) responses of patients during active tuberculosis, treatment, and following recovery. DESIGN: PBMC were isolated from 37 patients with tuberculosis and incubated with either PPD, live M. bovis BCG, or no antigen and IFNgamma production measured after 7 days. CTL activity against these antigens was determined using autologous antigen-pulsed monocyte-derived macrophages as target cells. A subset of these patients (7-18 depending on antigen and assey used) were tested 2 months into drug treatment and 3 months after discharge. A group of blood bank donors (n= 21) were also tested to evaluate IFNgamma responses in endemic controls; a subset (n= 16) were also tested for CTL activity. RESULTS: The ability to produce IFNgamma in response to mycobacterial antigens correlated with the Mantoux skin test status of the patient. IFNgamma production to live M. bovis BCG was diminished at diagnosis but returned after 2 months of drug treatment, and was sustained after completion of drug therapy. The CTL responses to both PPD and live M. bovis BCG were reduced during the period of drug treatment compared to those at diagnosis, but returned to the original levels after recovery. CONCLUSIONS: Drug treatment induced marked alterations in the immune responses of tuberculosis patients with induction of IFNgamma production in response to stimulation with live M. bovis BCG. This may indicate activation of both CD4 and CD8 T cells.
Adolescent↗
Detection and importance of laxative use in adolescents with anorexia nervosa.
OBJECTIVE: The frequency of laxative use in adolescents with anorexia nervosa is poorly described. This study of adolescents with anorexia nervosa examined self-report and biochemical screening methods for the detection of laxative use, the pattern of laxative use in this population over time, and the associated medical complications and psychopathology. METHOD: Forty-three consecutive patients with anorexia nervosa were studied. Initial assessment encompassed psychiatric history, medical examination, and administration of the Eating Disorders Examination, Child Behavior Checklist, and Youth Self-Report. Biochemical investigations, including random urinary laxative screening, were performed at assessment and follow-up. RESULTS: The frequency of laxative use from self-report alone was 12%; combined with urine screening it was 19%. The frequency of laxative use increased to 32% with prospective follow-up. Medical complications were associated with laxative use at follow-up. Laxative use was associated with longer duration of disease and with higher scores on the Eating Disorders Examination subscale Eating Concern. CONCLUSIONS: Laxative use is common among adolescents with anorexia nervosa, and the risk of associated medical complications increases over time. Biochemical screening will improve detection of laxative use. Longer duration of illness and greater Eating Concern scores are associated with increased risk of laxative use, and monitoring patients at increased risk is important.
Adolescent↗
Aligned microcontact printing of micrometer-scale poly-L-lysine structures for controlled growth of cultured neurons on planar microelectrode arrays.
We describe a method for producing high-resolution chemical patterns on surfaces to control the attachment and growth of cultured neurons. Microcontact printing has been extended to allow the printing of micron-scale protein lines aligned to an underlying pattern of planar microelectrodes. Poly-L-lysine (PL) lines have been printed on the electrode array for electrical studies on cultured neural networks. Rat hippocampal neurons showed a high degree of attachment selectivity to the PL and produced neurites that faithfully grew onto the electrode recording sites.
Animals↗