Adverse drug reactions.
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Biomedical subjects
Publications and source records attributed to A Cox.
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Alopecia areata (AA) is a chronic inflammatory disease characterised by patchy hair loss with T cell infiltration of hair follicles. AA occurs in approximately 0.1% of the general population, but this is increased to 9% in Down syndrome (DS). DS is associated with an additional copy (full or partial) of chromosome 21, and the DS region may potentially include genes involved in the pathogenesis of AA. MX1 is the gene encoding the interferon-induced p78 protein (MxA). MxA protein confers resistance to influenza viruses, and we have previously shown that MxA protein is strongly expressed in lesional anagen hair bulbs from patients with AA but not in normal follicles. We therefore studied the possible involvement of MX1 in the pathogenesis of AA. To establish markers in the MX1 region which could be screened by PCR-based methods, we defined the human MX1 exon/intron organisation and screened the exons and the introns by conformation-sensitive gel electrophoresis. We found that the MX1 gene contains 17 exons extending over 33 kb. The size and sequence of the region from exon 6 to exon 16 are highly conserved between human and mouse. Screening of 4747 bp within the MX1 gene revealed four single nucleotide polymorphisms in intron 6. These polymorphisms are concentrated within 147 bp and show strong linkage disequilibrium. In a case-control association study for the MX1 (+9959) polymorphism in 165 AA patients and 510 controls we found a significant association of this marker with AA (odds ratio 1.79, 95% CI 1.21-2.66, chi2 = 8.464, P = 0.0036). The risk of disease was greater for patchy AA (mild disease) and with early age at onset (odds ratio 2.34, 95% CI 1.24-4.43, P = 0.0072), providing new evidence of genetic heterogeneity in AA. Our demonstration of genetic association between the MX1 gene and disease supports the hypothesis that this is a new candidate gene in AA.
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Lack of standardized phenotypic definition has made outcome studies of Asperger syndrome (AS) difficult to interpret. This paper reports psychosocial functioning in 20 male adolescents with AS, defined according to current ICD-10 criteria, and a comparison group of 20 male adolescents with severe conduct disorder. Subjects were gathered from clinical referral. Evaluation used standardized interviewer rated assessments of social functioning and psychiatric morbidity. The AS group showed severe impairments in practical social functioning despite good cognitive ability and lack of significant early language delay. High levels of anxiety and obsessional disorders were found in AS; depression, suicidal ideation, tempers, and defiance in both groups. Results are compared with those from other studies. Relevance to clinical ascertainment and treatment is discussed.
Serratia sp. ATCC 39006 produces the carbapenem antibiotic, carbapen-2-em-3-carboxylic acid and the red pigment, prodigiosin. We have previously reported the characterization of a gene, carR, controlling production of carbapenem in this strain. We now describe further characterization of the carR locus to locate the genes encoding carbapenem biosynthetic and resistance functions. A novel family of diverse proteins showing sequence similarity to the C-terminal domain of CarF (required for carbapenem resistance) is described. We also report the isolation of the locus involved in the biosynthesis of the red pigment, prodigiosin. A cosmid containing approximately 35 kb of the Serratia chromosome encodes synthesis of the pigment in the heterologous host, Erwinia carotovora, demonstrating, for the first time, that the complete prodigiosin biosynthetic gene cluster had been cloned and functionally expressed. We report the isolation of a third locus in Serratia, containing convergently transcribed genes, smaI and smaR, encoding LuxI and LuxR homologues respectively. SmaI directs the synthesis of N-acyl homoserine lactones involved in the quorum sensing process. We demonstrate that biosynthesis of the two secondary metabolites, carbapenem antibiotic and prodigiosin pigment, is under pheromone-mediated transcriptional regulation in this bacterium. Finally, we describe a new prodigiosin-based bioassay for detection of some N-acyl homoserine lactones.
BACKGROUND: Angiotensin II (Ang II) is associated with cell proliferation and apoptosis. The role of the angiotensin type 2 receptor (AT2R) in these processes remains controversial. Conventional radioligand binding of 125I-Sar1, Ile8 Ang II in adult kidney has failed to demonstrate the binding for the AT2R. METHODS: The presence of the AT2R was explored in adult rat kidney by in vitro and in vivo autoradiography using the selective AT2R radioligand 125I-CGP 42112B. The roles of the angiotensin type 1 receptor (AT1R) and the AT2R in mediating cellular proliferation and apoptosis were assessed using selective AT1R or AT2R antagonists in Ang II-infused Sprague-Dawley (SD) rats. RESULTS: 125I-CGP 42112B binding was demonstrated by in vitro and in vivo autoradiography techniques in the glomeruli and proximal tubules of SD rats. This binding could be displaced by Ang II and the AT2R antagonist PD123319 but not by the AT1R antagonist valsartan. Subcutaneous infusion of Ang II for 14 days in eight-week-old SD rats induced proliferation of proximal tubular epithelial cells, as assessed by a twofold increase in proliferating cell nuclear antigen (PCNA)-positive cells and apoptosis, as assessed by a threefold increase in terminal dUTP nick end labeling (TUNEL)-positive cells. The administration of the AT2R antagonist PD123319 or the AT1R antagonist valsartan was associated with attenuation of the increases in both PCNA- and TUNEL-positive cells following Ang II infusion. Ang II infusion was associated with increased osteopontin gene and protein expression, which could be reduced by treatment with either valsartan or PD123319. CONCLUSION: These findings indicate that there is significant expression of the AT2R in the adult kidney, and that the AT2R has a role in mediating Ang II-induced proliferation and apoptosis in proximal tubular epithelial cells and expression of osteopontin.
OBJECTIVES: A population of 16,235 children aged 18 months was screened using the Checklist for Autism in Toddlers (CHAT) to identify childhood autism (CA). Two further screening procedures were conducted at age 3 and 5 years. The population was followed up at age 7 years in order to establish the sensitivity, specificity, and positive predictive value of the instrument. METHOD: A brief checklist assessing joint attention and pretend play behaviors was administered by primary health care practitioners when the children were 18 months old. Follow-up methods included screening through parents and health practitioners and checking medical and educational records. RESULTS: Nineteen cases of CA were successfully identified by the CHAT at 18 months. At follow-up a total of 50 cases of CA were identified via all surveillance methods. Thus, the CHAT has a sensitivity of 38% and a specificity of 98% for identifying CA. The positive predictive value of the instrument was maximized by concentration on the highest-risk group. Repeated screening 1 month later increased the positive predictive value to 75% for identification of CA but reduced the sensitivity to 20%, although the specificity was close to 100%. The screen also identified cases of pervasive developmental disorder as well as children with language and other developmental disorders. CONCLUSIONS: The CHAT can be used to identify cases of autism and related pervasive developmental disorders at 18 months of age. It is emphasized that the CHAT is not a diagnostic instrument but can identify potential cases of autism spectrum disorders for a full diagnostic assessment.
Haemophilus somnus undergoes antigenic and structural phase variation in its lipooligosaccharide (LOS). A gene (lob-1) containing repetitive 5'-CAAT-3' sequences that may, in part, contribute to phase variation was cloned and sequenced (T. J. Inzana et al., Infect. Immun. 65:4675-4681, 1997). We have now identified another putative gene (lob-2A) immediately upstream from lob-1. Lob-2A contained homology to several LOS biosynthesis proteins of the family Pasteurellaceae and the LgtB and LgtE galactosyltransferases of Neisseria meningitidis and N. gonorrhoeae. Unlike lob-1, lob-2A contained 18 to 20 5'-GA-3' repeats 141 bp upstream of the termination codon as determined by PCR amplification of DNA from individual colonies. Twenty repeats were most common, but when 19 5'-GA-3' repeats were present a stop codon would occur 1 bp after the last 5'-GA-3' repeat. A 630-bp SalI-BsgI fragment within lob-2A was deleted, and a kanamycin resistance (Km(r)) gene was inserted into this site to create pCAATDeltalob2A. Following electroporation of pCAATDeltalob2A into H. somnus 738, several allelic exchange mutants were isolated. The LOS electrophoretic profile of one mutant, strain 738-lob2A1::Km, was altered, and the phase variation rate was reduced but phase variation was not eliminated. A variant with 19 5'-GA-3' repeats in lob-2A had an LOS profile similar to that of 738-lob2A1::Km, suggesting that lob-2A was turned off in this phase. Nanoelectrospray mass spectrometry (nES-MS) and nuclear magnetic resonance spectroscopy showed that 738-lob2A1::Km was deficient in the terminal betaGal(1-3)betaGlcNAc residue present in parent strain 738. Mutant 738-lob2A1::Km was significantly more sensitive to the bactericidal action of normal bovine serum and was less virulent in mice than was parent strain 738. When H. somnus 129Pt was electrotransformed with shuttle vector pLS88 containing lob-2A, its LOS electrophoretic profile was modified and additional N-acetylhexosamine residues were present, as determined by nES-MS analysis. These results indicated that lob-2A may be an N-acetylglucosamine transferase involved in LOS biosynthesis and phase variation and that LOS structure is important to H. somnus virulence.
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BACKGROUND: The practice nurse is central to the development of a primary care-led National Health Service. Skin diseases can have a major impact on patients' lives but general practitioners (GPs) lack many of the skills of practical dermatology care and support. AIM: To determine whether a primary care dermatology liaison nurse should be introduced by our health authority. We identified the resources consumed and the benefits that accrued from a practice nurse who had received training in practical dermatology care. METHOD: A cost consequence study in parallel with a randomised controlled trial was undertaken in a group of nine GPs and 109 patients between the ages of 18 and 65 years who had a diagnosis of psoriasis or eczema. RESULTS: Although there was a significant improvement in our primary outcome measure within group, when compared with the control group significance was not achieved. There was no significant change in the Euroqol measure but the clinical instrument showed a significant change when compared with control. On entry, our qualitative data identified three main themes--the embarrassment caused by these skin conditions, the wish for a cure rather than treatment, and concern over the long-term effects of steroids. On completion, 20% of patients expressed that they had received a positive benefit from the clinic. CONCLUSION: This study demonstrates the difficulties of obtaining relevant information to facilitate decisions on how resources should be allocated in primary care. Not all questions can be answered by large multi-centred trials and studies themselves have an opportunity cost consuming resources that could otherwise be spent on direct health care. Often, local resource decisions will be based on partial evidence-yielding solutions that are satisfactory rather than optimum but which are, nevertheless, better than decisions taken with no evidence at all.
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Ras proteins regulate cell growth, differentiation and apoptosis. Their activities depend on their anchorage to the inner surface of the plasma membrane, which is promoted by their common carboxy-terminal S-farnesylcysteine and either a stretch of lysine residues (K-Ras 4B) or S-palmitoyl moieties (H-Ras, N-Ras and K-Ras 4A). We previously demonstrated dislodgment of H-Ras from EJ cell membranes by S-trans,trans-farnesylthiosalicylic acid (FTS), and proposed that FTS disrupts the interactions between the S-prenyl moiety of Ras and the membrane anchorage domains. In support of this hypothesis, we now show that FTS, which is not a farnesyltransferase inhibitor, inhibits growth of NIH3T3 cells transformed by the non-palmitoylated K-Ras 4B(12V) or by its farnesylated, but unmethylated, K-Ras 4B(12) CVYM mutant. The growth-inhibitory effects of FTS followed the dislodgment and accelerated degradation of K-Ras 4B(12V), leading in turn to a decrease in its amount in the cells and inhibition of MAPK activity. FTS did not affect the rate of degradation of the K-Ras 4B, SVIM mutant which is not modified post-translationally, suggesting that only farnesylated Ras isoforms are substrates for facilitated degradation. The putative Ras-recognition sites (within domains in the cell membrane) appear to tolerate both C(15) and C(20) S-prenyl moeities, since geranylgeranyl thiosalicylic acid mimicked the growth-inhibitory effects of FTS in K-Ras 4B(12V)-transformed cells and FTS inhibited the growth of cells transformed by the geranylgeranylated K-Ras 4B(12V) CVIL isoform. The results suggest that FTS acts as a domain-targeted compound that disrupts Ras-membrane interactions. The fact that FTS can target K-Ras 4B(12V), which is insensitive to inhibition by farnesyltransfarase inhibitors, suggests that FTS may target Ras (and other prenylated proteins important for transformed cell growth) in an efficient manner that speaks well for its potential as an anticancer therapeutic agent.
Increasing evidence indicates that tissue transglutaminase (tTG) plays a role in the assembly and remodeling of extracellular matrices and promotes cell adhesion. Using an inducible system we have previously shown that tTG associates with the extracellular matrix deposited by stably transfected 3T3 fibroblasts overexpressing the enzyme. We now show by confocal microscopy that tTG colocalizes with pericellular fibronectin in these cells, and by immunogold electron microscopy that the two proteins are found in clusters at the cell surface. Expression vectors encoding the full-length tTG or a N-terminal truncated tTG lacking the proposed fibronectin-binding site (fused to the bacterial reporter enzyme beta-galactosidase) were generated to characterize the role of fibronectin in sequestration of tTG in the pericellular matrix. Enzyme-linked immunosorbent assay style procedures using extracts of transiently transfected COS-7 cells and immobilized fibronectin showed that the truncation abolished fibronectin binding. Similarly, the association of tTG with the pericellular matrix of cells in suspension or with the extracellular matrix deposited by cell monolayers was prevented by the truncation. These results demonstrate that tTG binds to the pericellular fibronectin coat of cells via its N-terminal beta-sandwich domain and that this interaction is crucial for cell surface association of tTG.
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The finding that the systemic renin-angiotensin system (RAS) is not activated in most types of chronic renal disease has led to the suggestion that a local, intrarenal RAS may be an important determinant in the relentless progression of renal disease. Therefore, cell specific changes in various components of the RAS in response to renal mass reduction and angiotensin converting enzyme (ACE) inhibition were examined. Thirty Sprague-Dawley rats were randomly assigned to sham surgery, subtotal nephrectomy (STNx) alone or STNx treated with the ACE inhibitor, perindopril, and sacrificed after 12 weeks. In sham rats, renin mRNA and protein were only present in the juxtaglomerular apparatus. In contrast, in STNx kidneys, renin and angiotensin II expression were noted predominantly in renal tubular epithelial cells in association with overexpression of the prosclerotic cytokine, transforming growth factor-beta1 (TGF-beta1). In perindopril-treated STNx rats expression of renin and TGF-beta1 were similar to control animals. These finding indicate that following renal mass reduction there is pathological tubular expression of various components of the RAS. Furthermore, in contrast to the juxtaglomerular apparatus, tubular renin expression was reduced with ACE inhibition. These changes within the intrarenal RAS may be pathogenetically linked to the development of tubulointerstitial injury.
The authors assessed the relative benefits of 3 styles of adult book reading for preschoolers' emergent literacy. A describer style focused on describing pictures during the reading, a comprehender style focused on story meaning, and a performance-oriented style introduced the book and discussed story meaning on completion. Forty-eight 4-year-olds were randomly assigned to receive 1 of the 3 reading styles over a 6-week period. Pretests and posttests measured children's receptive vocabulary, print, and story comprehension skills. A describer style of reading resulted in the greatest overall benefits for children's vocabulary and print skills, but a performance-oriented style was also beneficial when children's initial skill levels were taken into account. Future book-reading interventions should be tailored to children's initial skill levels.
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PURPOSE: To investigate the long-term effects of total body irradiation (TBI) on the incidence and time course of ocular complications. MATERIALS AND METHODS: Rhesus monkeys treated with TBI photon doses up to 8.5 Gy and proton doses up to 7.5 Gy were studied at intervals up to 25 years post-irradiation. They were compared with control groups with a similar age distribution. Cataract formation and ocular fundus lesions were scored according to a standardized protocol. Fluorescein angiography and histopathology was performed in selected animals. RESULTS: Cataract formation occurred after a latent period of 3-5 years. Significant cataract induction was observed for photon-doses of 8 and 8.5 Gy and beyond 20 years after proton irradiation. The severity of the lesions represents significant impairment of vision and would require cataract surgery if similar results occurred in human bone marrow transplant patients. Fluorescein angiography demonstrated a normal pattern of retinal vessels in 13 out of 14 animals (93%) from the irradiated group and in eight out of nine animals (89%) from the control group. No additional lesions apart from age-related degenerative changes could be demonstrated. Histological evaluation revealed no radiation-associated vasculopathy. CONCLUSIONS: Radiation alone for doses up to 8.5 Gy of photons does not carry a potential risk for fundus pathology, whereas clinically important cataract induction should be anticipated within 5 years after photon doses of 8.0 and 8.5 Gy and proton doses in excess of 2.5 Gy.