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Abstract
BACKGROUND In the 1940s and 1950s retinopathy of prematurity (ROP) was the single commonest cause of blindness in children in many industrialised countries; it now accounts for only 6-18% of blindness registrations. It is not known what proportion of blindness is due to ROP in countries that do not have blindness registers. Information on blindness in children in these countries can be obtained by examining children in schools for the blind. METHODS Between 1991 and 1996, 4121 children in 23 countries with a visual acuity in the better eye of less than 6/60 were examined with a standard method. FINDINGS The proportion of severe visual impairment or blindness due to ROP ranged from 0% in most African countries to 38.6% in Cuba. INTERPRETATION These data suggest that ROP is becoming a major cause of potentially preventable blindness among children in middle-income countries that have introduced neonatal intensive-care services for preterm and low-birthweight babies.
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Gillard J, Ford-Hutchinson AW, Chan C, Charleson S, Denis D, Foster A, Fortin R, Leger S, McFarlane CS, Morton H. L-663,536 (MK-886) (3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2,2 - dimethylpropanoic acid), a novel, orally active leukotriene biosynthesis inhibitor. Can J Physiol Pharmacol 1989; 67:456-64. [PMID: 2548691 DOI: 10.1139/y89-073] [Citation(s) in RCA: 267] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
L-663,536 (3-[1-(4-chlorobenzyl)-3-t-butyl-thio-5-isopropylindol-2-yl]-2, 2-dimethylpropanoic acid) is a potent inhibitor of leukotriene (LT) biosynthesis in intact human polymorphonuclear leukocytes (PMN) (IC50, 2.5 nM). Similarly, L-663,536 inhibited A23187-induced LTB4 formation by rat peripheral blood and elicited PMN. At concentrations where inhibition of leukotriene biosynthesis occurred in human whole blood (1.1 microM), no effect was seen on cyclooxygenase or 12-lipoxygenase, an effect also observed in washed human platelets. The compound had no effect on rat or porcine 5-lipoxygenase indicating that L-663,536 is not a direct 5-lipoxygenase inhibitor. When administered in vivo L-663,536 was a potent inhibitor of antigen-induced dyspnea in inbred rats pretreated with methysergide (ED50, 0.036 mg/kg p.o.) and of Ascaris-induced bronchoconstriction in squirrel monkeys (1 mg/kg p.o.). The compound inhibited leukotriene biosynthesis in vivo in a rat pleurisy model (ED50, 0.2 mg/kg p.o.), an inflamed rat paw model (ED50, 0.8 mg/kg), a model of leukotriene excretion in rat bile following antigen provocation, and a model in the guinea-pig ear where leukotriene synthesis was induced by topical challenge with ionophore A23187 (ED50, 2.5 mg/kg p.o. and 0.6 micrograms topically). The results indicate that L-663,536 is a potent inhibitor of leukotriene biosynthesis both in vitro and in vivo indicating that the compound is suitable for studying the role of leukotrienes in a variety of pathological situations.
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Abstract
PURPOSE The objective of this study was to summarize available data regarding pediatric blinding diseases worldwide and to present the most up-to-date information on childhood blindness in the United States. METHODS We obtained data from a complete search of the world literature and from direct contact with each of the schools for the blind in the United States. RESULTS Five percent of worldwide blindness involves children younger than 15 years of age; in developing countries 50% of the population is in this age group. By World Health Organization criteria, there are 1.5 million children worldwide who are blind: 1.0 million in Asia, 0.3 million in Africa, 0.1 million in Latin America, and 0.1 million in the rest of the world. There are marked differences in the causes of pediatric blindness in different regions, apparently based on socioeconomic factors. In developing countries, 30% to 72% of such blindness is avoidable, 9% to 58% is preventable, and 14% to 31% is treatable. The leading cause is corneal opacification caused by a combination of measles, xerophthalmia, and the use of traditional eye medicine. There is no national registry of the blind in the United States, and most of the schools for the blind do not keep data regarding the cause of blindness in their students. From those schools that do have this information, the top 3 causes are cortical visual impairment, retinopathy of prematurity, and optic nerve hypoplasia. There has been a significant increase in both cortical vision loss and retinopathy of prematurity in the past 10 years. CONCLUSIONS There are marked regional differences in the prevalence and causes of pediatric blindness, apparently based on socioeconomic factors that limit prevention and treatment schemes. In the United States the 3 leading causes of pediatric blindness are cortical visual impairment, retinopathy of prematurity, and optic nerve hypoplasia. There is a need for more complete and more uniform data based on the established World Health Organization reporting format.
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Barclay AJ, Foster A, Sommer A. Vitamin A supplements and mortality related to measles: a randomised clinical trial. BRITISH MEDICAL JOURNAL 1987; 294:294-6. [PMID: 3101849 PMCID: PMC1245303 DOI: 10.1136/bmj.294.6567.294] [Citation(s) in RCA: 202] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
One hundred and eighty children admitted with measles were randomly allocated to receive routine treatment alone or with additional large doses of vitamin A (200,000 IU orally immediately and again the next day). Baseline characteristics of the two groups were virtually identical for age, severity of measles, and vitamin A and general nutritional states. In 91% of the children serum vitamin A concentrations were less than 0.56 mumol/l. Of the 88 subjects given vitamin A supplements, six (7%) died; of the 92 controls, 12 (13%) died (p = 0.13). This difference in mortality was most obvious for children aged under 2 years (one death out of 46 children receiving supplements versus seven deaths out of 42 controls; p less than 0.05) and for cases complicated by croup or laryngotracheobronchitis. Mortality was several times higher in marasmic than in better nourished children, regardless of study allocation (p less than 0.01).
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Abstract
INTRODUCTION Recent data suggest that there are 37 million blind people and 124 million with low vision, excluding those with uncorrected refractive errors. The main causes of global blindness are cataract, glaucoma, corneal scarring (from a variety of causes), age-related macular degeneration, and diabetic retinopathy. CONCLUSION It would appear that the global Vision 2020 initiative is having an impact to reduce avoidable blindness particularly from ocular infections, but more needs to be done to address cataract, glaucoma, and diabetic retinopathy.
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Review |
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Foster A, Gilbert C, Rahi J. Epidemiology of cataract in childhood: a global perspective. J Cataract Refract Surg 1997; 23 Suppl 1:601-4. [PMID: 9278811 DOI: 10.1016/s0886-3350(97)80040-5] [Citation(s) in RCA: 172] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Cataract is the most important cause of treatable childhood blindness. There are an estimated 200,000 children blind from cataract worldwide; 20,000 to 40,000 children with developmental bilateral cataract are born each year. Rubella is still an important cause of preventable disease in many countries. In the developing world, there is a need to improve early case detection and referral services and to establish centers with expertise in the assessment, surgical treatment, and long-term management of the child with cataract.
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Review |
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Rahi JS, Sripathi S, Gilbert CE, Foster A. Childhood blindness in India: causes in 1318 blind school students in nine states. Eye (Lond) 1995; 9 ( Pt 5):545-50. [PMID: 8543070 DOI: 10.1038/eye.1995.137] [Citation(s) in RCA: 129] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
It is estimated that at least 200,000 children in India have severe visual impairment or blindness and approximately 15,000 are in schools for the blind. Although this represents a small percentage of the estimated 5 million blind in India, it is significant in terms of 'blind-years'. Strategies to combat childhood blindness require accurate data on the causes to allocate resources to appropriate preventive and curative services. Since socio-economic factors vary in different areas of this industrializing country data should be representative of the country as a whole. This is the first multi-state study to be undertaken in India using the Record for Children with Blindness and Low Vision from the World Health Organization/PBL Programme. A total of 1411 children in 22 schools from nine states in different geographical zones were examined by an ophthalmologist and optometrist. Of these, 1318 children were severely visually impaired or blind (SVI/BL). The major causes of SVI/BL in this study were: (1) corneal staphyloma, scar and phthisis bulbi (mainly attributable to vitamin A deficiency) in 26.4%; (2) microphthalmos, anophthalmos and coloboma in 20.7%; (3) retinal dystrophies and albinism in 19.3%; and (4) cataract, uncorrected aphakia and amblyopia in 12.3%. This mixed pattern of causes lies in an intermediate position between the patterns seen in developing countries and those seen in industrialised countries. The causes identified indicate the importance both of preventive public health strategies and of specialist paediatric ophthalmic and optical services in the management of childhood blindness in India.
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Warren RP, Margaretten NC, Pace NC, Foster A. Immune abnormalities in patients with autism. J Autism Dev Disord 1986; 16:189-97. [PMID: 2941410 DOI: 10.1007/bf01531729] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have begun an investigation on the immune systems of patients with autism in attempt to determine if immune mechanisms are involved in the development of this severe developmental disorder. A study of 31 autistic patients has revealed several immune-system abnormalities, including reduced responsiveness in the lymphocyte blastogenesis assay to phytohemagglutinin, concanavalin A, and pokeweed mitogen; decreased numbers of T lymphocytes; and an altered ratio of helper to suppressor T cells. Immune-system abnormalities may be directly related to underlying biologic processes of autism, or these changes may be an indirect reflection of the actual pathologic mechanism.
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Editorial |
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Faal H, Minassian D, Sowa S, Foster A. National survey of blindness and low vision in The Gambia: results. Br J Ophthalmol 1989; 73:82-7. [PMID: 2784691 PMCID: PMC1041660 DOI: 10.1136/bjo.73.2.82] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A population based survey of blindness and eye disease has been conducted throughout the whole country of The Gambia, and 8174 people were examined. The prevalence of blindness (best acuity less than 3/60) was 0.7% and low vision (6/24-3/60) 1.4%. The causes of blindness were cataract (55%), non-trachomatous corneal opacity/phthisis (20%), and trachoma (17%). An estimated 5500 people in The Gambia require cataract surgery, 4600 eyelid surgery for entropion, and 4600 people spectacles to correct a refractive error which causes a visual acuity of less than 6/18. More than half the current burden of blindness in The Gambia is potentially remediable through the provision of cataract surgery and aphakic spectacles.
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research-article |
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104 |
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Mayou R, Foster A, Williamson B. The psychological and social effects of myocardial infarction on wives. BRITISH MEDICAL JOURNAL 1978; 1:699-701. [PMID: 630303 PMCID: PMC1603086 DOI: 10.1136/bmj.1.6114.699] [Citation(s) in RCA: 99] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Eighty-two wives of men suffering a first myocardial infarction were interviewed while their husbands were in hospital, and again two months and a year after they went home. The wives had substantial and persistent psychological symptoms, and the husbands' illness had continuing effects on their work, leisure and social activities, and family life and marriage, their psychosocial disability being comparable to that of the patients. Measures of psychosocial adjustment before the illness and the quality of the marriage and of family life were good predictors of outcome for the wives. The women had a major role in the patients' readjustment during convalescence, and their attitudes and behaviour as well as the general quality of family life were important determinants of the rate and extent of the patients' recovery. The wives of patients with myocardial infarction should have more practical help and advice during the hospital period, and the whole family should be given advice and help throughout the convalescence.
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research-article |
47 |
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Gilbert CE, Anderton L, Dandona L, Foster A. Prevalence of visual impairment in children: a review of available data. Ophthalmic Epidemiol 1999; 6:73-82. [PMID: 10384686 DOI: 10.1076/opep.6.1.73.1571] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Data on the prevalence, magnitude and causes of blindness and severe visual impairment in children are needed for planning and evaluating preventive and curative services for children, and for planning special education and low vision services. Prevalence data can be obtained from a variety of different sources, each of which has limitations. The available data suggest that there may be a ten-fold difference in prevalence between the wealthiest countries of the world and the poorest, ranging from as low as 0.1/1000 children aged 0-15 years in the wealthiest countries to 1.1/1000 children in the poorest. In this paper, the available data are reviewed and the epidemiological methods and findings are discussed.
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Review |
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Liebana E, Batchelor M, Hopkins KL, Clifton-Hadley FA, Teale CJ, Foster A, Barker L, Threlfall EJ, Davies RH. Longitudinal farm study of extended-spectrum beta-lactamase-mediated resistance. J Clin Microbiol 2006; 44:1630-4. [PMID: 16672386 PMCID: PMC1479190 DOI: 10.1128/jcm.44.5.1630-1634.2006] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Extended-spectrum beta-lactamase (ESBL)-mediated resistance is of considerable importance in human medicine. Recently, such enzymes have been reported in bacteria from animals. We describe a longitudinal study of a dairy farm suffering calf scour with high mortality rates. In November 2004, two Escherichia coli isolates with resistance to a wide range of beta-lactams (including amoxicillin-clavulanate and cefotaxime) were isolated from scouring calves. Testing by PCR and sequence analysis confirmed the isolates as being both bla(CTX-M14/17) and bla(TEM-35) ((IRT-4)) positive. They had indistinguishable plasmid and pulsed-field gel electrophoresis (PFGE) profiles. Transferability studies demonstrated that bla(CTX-M) was located on a conjugative 65-MDa IncK plasmid. Following a farm visit in December 2004, 31/48 calves and 2/60 cows were positive for E. coli with bla(CTX-M). Also, 5/48 calf and 28/60 cow samples yielded bla(CTX)- and bla(TEM)-negative E. coli isolates that were resistant to cefotaxime, and sequence analysis confirmed that these presented mutations in the promoter region of the chromosomal ampC gene. Fingerprinting showed 11 different PFGE types (seven in bla(CTX-M)-positive isolates). Six different PFGE clones conjugated the same bla(CTX-M)-positive IncK plasmid. One clone carried a different-sized, bla(CTX-M)-positive, transformable plasmid. This is the first report of bla(CTX-M) from livestock in the United Kingdom, and this report demonstrates the complexity of ESBL epidemiology. Results indicate that horizontal plasmid transfer between strains as well as horizontal gene transfer between plasmids have contributed to the spread of resistance. We have also shown that some clones can persist for months, suggesting that clonal spread also contributes to the perpetuation of resistance.
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Research Support, Non-U.S. Gov't |
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Wedner SH, Ross DA, Balira R, Kaji L, Foster A. Prevalence of eye diseases in primary school children in a rural area of Tanzania. Br J Ophthalmol 2000; 84:1291-7. [PMID: 11049957 PMCID: PMC1723290 DOI: 10.1136/bjo.84.11.1291] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS The study measured the prevalence of eye diseases in primary school children between 7 and 19 years of age in a rural area of Tanzania, and investigated whether teachers could successfully provide the first component of a school eye screening service. METHODS Teachers from each of three primary schools in Mwanza Region tested visual acuity using a Snellen's E chart in 1438 pupils. 1386 of these pupils were then interviewed and underwent a full eye examination by an eye team. RESULTS 10 pupils (0.7%) had bilateral poor eyesight (visual acuity worse than 6/12), and an additional 14 pupils (1.0%) had unilateral poor eyesight. Significant refractive errors causing visual acuity less than 6/12 (1.0%), strabismus (0. 5%), and amblyopia (0.2%) were uncommon. Overall, 76 pupils (5.5%) had active trachoma, though the prevalence was 15.5% in the poorest school. 73 pupils (5.3%) reported night blindness, eight (0.6%) had Bitot's spots, and 11 (0.8%) had corneal scars. Simple screening by teachers correctly identified 80% of the pupils who were found to have bilateral poor eyesight by the eye team, with 91% specificity. CONCLUSION The prevalence of significant refractive errors was not high enough to justify a school eye screening programme solely for this purpose. However, a programme may be justified in areas where trachoma is common. Further research is needed to validate the frequent reports of night blindness and to establish the public health importance of vitamin A deficiency in this age group.
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research-article |
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Briggs C, Longair I, Slavik M, Thwaite K, Mills R, Thavaraja V, Foster A, Romanin D, Machin SJ. Can automated blood film analysis replace the manual differential? An evaluation of the CellaVision DM96 automated image analysis system. Int J Lab Hematol 2009; 31:48-60. [PMID: 18177438 DOI: 10.1111/j.1751-553x.2007.01002.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Gilbert CE, Canovas R, Hagan M, Rao S, Foster A. Causes of childhood blindness: results from west Africa, south India and Chile. Eye (Lond) 1993; 7 ( Pt 1):184-8. [PMID: 8325414 DOI: 10.1038/eye.1993.39] [Citation(s) in RCA: 89] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Using World Health Organization definitions of visual loss and a standardised methodology, 905 children were examined in Chile, West Africa and South India. Of these 806 (89%) suffered from blindness (BL) or severe visual impairment (SVI). Causes of SVI and BL were classified anatomically and aetiologically, and avoidable causes identified. In W. Africa (n = 284) the major anatomical cause of SVI/BL was corneal scar/phthisis bulbi (35.9%). Retinal disease accounted for 20.4%, cataract 15.5% and glaucoma 13.0%. Aetiologically 33.8% of SVI/BL was due to childhood factors and 21.1% to hereditary disease. In S. India (n = 305) the major anatomical cause of SVI/BL was corneal scar/phthisis bulbi (38.4%). Retinal disease accounted for 22.6%, cataract 7.4% and glaucoma 3%. Aetiologically 37.0% of SVI/BL was due to childhood factors and 29.8% to hereditary disease. In Chile (n = 217) the major anatomical cause of SVI/BL was retinal disease (47.0%). Cataract accounted for 9.2%, glaucoma 8.3% and 6.9% was due to corneal pathology. Aetiologically 30.4% of SVI/BL was due to hereditary factors, and 20.8% to perinatal factors of which four-fifths (16.6%) was due to retinopathy of prematurity. Avoidable conditions accounted for 70%, 47% and 54% of cases in W. Africa, S. India and Chile respectively.
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Wang J, Lo JC, Foster A, Yu P, Chen HM, Wang Y, Tamada K, Chen L, Fu YX. The regulation of T cell homeostasis and autoimmunity by T cell-derived LIGHT. J Clin Invest 2001; 108:1771-80. [PMID: 11748260 PMCID: PMC209470 DOI: 10.1172/jci13827] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Costimulatory molecules on antigen-presenting cells (APCs) play an important role in T cell activation and expansion. However, little is known about the surface molecules involved in direct T-T cell interaction required for their activation and expansion. LIGHT, a newly discovered TNF superfamily member (TNFSF14), is expressed on activated T cells and immature dendritic cells. Here we demonstrate that blockade of LIGHT activity can reduce anti-CD3-mediated proliferation of purified T cells, suggesting that T cell-T cell interaction is essential for this proliferation. To test the in vivo activity of T cell-derived LIGHT in immune homeostasis and function, transgenic (Tg) mice expressing LIGHT in the T cell lineage were generated. LIGHT Tg mice have a significantly enlarged T cell compartment and a hyperactivated peripheral T cell population. LIGHT Tg mice spontaneously develop severe autoimmune disease manifested by splenomegaly, lymphadenopathy, glomerulonephritis, elevated autoantibodies, and severe infiltration of various peripheral tissues. Furthermore, the blockade of LIGHT activity ameliorates the severity of T cell-mediated diseases. Collectively, these findings establish a crucial role for this T cell-derived costimulatory ligand in T cell activation and expansion; moreover, the dysregulation of T cell-derived LIGHT leads to altered T cell homeostasis and autoimmune disease.
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research-article |
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Abstract
Inguinal and testicular pain are challenging problems for which no reliable, standardized treatment exists. We report 3 patients with groin pain or orchialgia who were treated with pulsed radiofrequency of the nerves innervating these areas. All 3 patients reported complete pain relief at their 6-month follow-up visits. The techniques and settings used for the nerve blocks and radiofrequency procedures are explained in detail, along with a brief synopsis of the rationale for using it. Randomized, placebo-controlled studies are needed to better assess the efficacy of this procedure and identify eligible candidates.
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Case Reports |
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Williams B, Curtis N, McKnight A, Maguire J, Foster A, Tridgett R. Development of NK-2 selective antagonists. ACTA ACUST UNITED AC 1988. [DOI: 10.1016/0167-0115(88)90409-0] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Burton MJ, Kinteh F, Jallow O, Sillah A, Bah M, Faye M, Aryee EAN, Ikumapayi UN, Alexander NDE, Adegbola RA, Faal H, Mabey DCW, Foster A, Johnson GJ, Bailey RL. A randomised controlled trial of azithromycin following surgery for trachomatous trichiasis in the Gambia. Br J Ophthalmol 2005; 89:1282-8. [PMID: 16170117 PMCID: PMC1772881 DOI: 10.1136/bjo.2004.062489] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIM Trachomatous trichiasis frequently returns following surgery. Several factors may promote recurrence: preoperative disease severity, surgeon ability, surgical procedure, healing responses, and infection. This study investigates whether enhanced control of infection, both of Chlamydia trachomatis and other bacteria, with azithromycin can improve surgical outcome in a trachoma control programme. METHODS Individuals with trachomatous trichiasis were examined and operated. After surgery patients were randomised to the azithromycin or control group. The azithromycin group and children in their household were given a dose of azithromycin. Antibiotic treatment was repeated at 6 months. All patients were reassessed at 6 months and 12 months. Samples were collected for C trachomatis polymerase chain reaction and general microbiology at each examination. RESULTS 451 patients were enrolled. 426 (94%) were reassessed at 1 year, of whom 176 (41.3%) had one or more lashes touching the eye and 84 (19.7%) had five or more lashes. There was no difference in trichiasis recurrence between the azithromycin and control group. Recurrent trichiasis was significantly associated with more severe preoperative trichiasis, bacterial infection, and severe conjunctival inflammation at 12 months. Significant variability in outcome was found between surgeons. Visual acuity and symptoms significantly improved following surgery. CONCLUSION In this setting, with a low prevalence of active trachoma, azithromycin did not improve the outcome of trichiasis surgery conducted by a trachoma control programme. Audit of trichiasis surgery should be routine.
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Research Support, Non-U.S. Gov't |
20 |
78 |
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Kumar N, Chu A, Foster A. An empirical relationship between PM(2.5) and aerosol optical depth in Delhi Metropolitan. ATMOSPHERIC ENVIRONMENT (OXFORD, ENGLAND : 1994) 2007; 41:4492-4503. [PMID: 22180723 PMCID: PMC3237057 DOI: 10.1016/j.atmosenv.2007.01.046] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Atmospheric remote sensing offers a unique opportunity to compute indirect estimates of air quality, which are critically important for the management and surveillance of air quality in megacities of developing countries, particularly in India and China, which have experienced elevated concentration of air pollution but lack adequate spatial-temporal coverage of air pollution monitoring. This article examines the relationship between aerosol optical depth (AOD) estimated from satellite data at 5 km spatial resolution and the mass of fine particles ≤2.5 μm in aerodynamic diameter (PM(2.5)) monitored on the ground in Delhi Metropolitan where a series of environmental laws have been instituted in recent years.PM(2.5) monitored at 113 sites were collocated by time and space with the AOD computed using the data from Moderate Resolution Imaging Spectroradiometer (MODIS onboard the Terra satellite). MODIS data were acquired from NASA's Goddard Space Flight Center Earth Sciences Distributed Active Archive Center (DAAC). Our analysis shows a significant positive association between AOD and PM(2.5). After controlling for weather conditions, a 1% change in AOD explains 0.52±0.202% and 0.39±0.15% change in PM(2.5) monitored within ±45 and 150 min intervals of AOD data. This relationship will be used to estimate air quality surface for previous years, which will allow us to examine the time-space dynamics of air pollution in Delhi following recent air quality regulations, and to assess exposure to air pollution before and after the regulations and its impact on health.
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research-article |
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Review |
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