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1.
PLoS One ; 14(3): e0213723, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30921334

RESUMO

INTRODUCTION: Health interventions implemented with self-help groups (SHGs) enhance the relevance and acceptability of the health services. The Parivartan program was implemented in eight districts of Bihar with women's self-help groups to increase adoption of maternal and newborn health behaviors through layering health behavior change communication. This study estimates the cost and cost-effectiveness of a health behavior change program with SHGs in Bihar. METHODS: Cost analysis was conducted from a provider's perspective. All costs have been presented in US dollars for the purpose of international comparisons and converted to constant values. The effectiveness estimate was based on the reported changes in select newborn care practices. A decision model approach was used to estimate the potential number of neonatal deaths averted based on adoption of key newborn care practices. Using India's life expectancy of 65 years, cost per life year saved was calculated. A one-way sensitivity analysis was conducted using the upper and lower estimates for various variables in the model, and functionality of SHGs. RESULTS: The cost of forming an SHG group was US$254 and that of reaching a woman within the group was US$19. The unit cost for delivering health interventions through the Parivartan program was US$148 per group and US$11 per woman reached. During an 18 months period, Parivartan program reached around 17,120 SHGs and an estimated 20,544 pregnant women resulting in an estimated prevention of 23 neonatal deaths at a cost of US$3,825 per life year saved. CONCLUSION: SHGs can be an effective platform to increase uptake of women's health interventions and follow-up care, and also to broaden their utility beyond microfinance, particularly when they operate at a larger scale.


Assuntos
Comportamentos Relacionados com a Saúde , Saúde da Mulher/economia , Análise Custo-Benefício , Feminino , Humanos , Índia
2.
Nutr Metab Cardiovasc Dis ; 27(1): 32-40, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27612985

RESUMO

Cardiovascular disease (CVD) is one of the main causes of mortality and morbidity worldwide. As an emerging population, South Asians (SAs) bear a disproportionately high burden of CVD relative to underlying classical risk factors, partly attributable to a greater prevalence of insulin resistance and diabetes and distinct genetic and epigenetic influences. While the phenotypic distinctions between SAs and other ethnicities in CVD risk are becoming increasingly clear, the biology of these conditions remains an area of active investigation, with emerging studies involving metabolism, genetic variation and epigenetic modifiers (e.g., extracellular RNA). In this review, we describe the current literature on prevalence, prognosis and CVD risk in SAs, and provide a landscape of translational research in this field toward ameliorating CVD risk in SAs.


Assuntos
Povo Asiático , Doenças Cardiovasculares/etnologia , Síndrome Metabólica/etnologia , Crescimento Demográfico , Ásia/epidemiologia , Povo Asiático/genética , Doenças Cardiovasculares/diagnóstico , Doenças Cardiovasculares/genética , Emigrantes e Imigrantes , Emigração e Imigração , Epigênese Genética , Predisposição Genética para Doença , Disparidades nos Níveis de Saúde , Humanos , Síndrome Metabólica/diagnóstico , Síndrome Metabólica/genética , Obesidade/etnologia , Fenótipo , Prevalência , Medição de Risco , Fatores de Risco
3.
Ind Psychiatry J ; 25(2): 179-183, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-28659697

RESUMO

BACKGROUND: Medical students undergo significant stress during training which may lead to own suffering or problem in patient care. High level of burnouts and depression is also not uncommon. The transition from preclinical to clinical training has been regarded as crucial to student in relation to the stress. METHODOLOGY: An assessment of perceived stress and its relation to general psychopathology, the pattern of coping, and burnout in the final-year medical student was done to bring out clear nature, pattern, and extent of the problem. RESULTS: Perceived stress had statistically significant association with general psychopathology and depressive-anxiety component of burnout. Acceptance, positive reframing, humor, planning, and active coping correlated with lower score on perceived stress. CONCLUSION: Higher score on perceived stress was associated with higher scores on general psychopathology and burnout. Age of joining MBBS course and doctor in the family did not affect the stress significantly. People who displayed positive coping strategies had lesser stress and general psychopathology.

4.
5.
Andrologia ; 46(2): 191-3, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23163819

RESUMO

Ovotesticular disorder of sexual differentiation (OTDSD) is a rare cause of disorder of sexual differentiation predominantly having 46,XX karyotype, female phenotype and ambiguous genitalia. We report a 15-year-old having male body habitus, axillary and pubic hair, well-developed penis and right-descended testis with history of penoscrotal hypospadias correction, presenting with three episodes of cyclical haematuria, who biochemically had normal serum testosterone (338 ng dl(-1) ) which increased following hCG stimulation (614 ng dl(-1) ), elevated estradiol (17.35 pg ml(-1) ) along with elevated luteinising hormone (11.3 mIU l(-1) ) and follicle-stimulating hormone (31 mIU l(-1) ). Ultrasonography followed by micturating cystourethrogram and cystoscopy confirmed the presence of prostate, uterus, cervix and vagina draining into the urogenital sinus continuing till the penile urethra and left intra-abdominal gonad. Patient underwent hysterectomy and left gonadectomy. Histopathologic study of resected gonad confirmed presence of ovotestis. Low estradiol (1.2 pg ml(-1) ) following gonadectomy confirmed the ovotestis origin of estradiol. Chromosomal analysis revealed complex karyotype predominant being 47,XYY (50%) followed by 46,XY (26%) and 45,X (24%). This is perhaps the first report of 47,XYY/46,XY/45,X causing OTDSD in a phenotypic male.


Assuntos
Disgenesia Gonadal Mista/diagnóstico , Hematúria/diagnóstico , Transtornos Ovotesticulares do Desenvolvimento Sexual/diagnóstico , Adolescente , Gonadotropina Coriônica , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Disgenesia Gonadal Mista/patologia , Humanos , Cariótipo , Hormônio Luteinizante/sangue , Masculino , Transtornos Ovotesticulares do Desenvolvimento Sexual/patologia , Testículo/patologia , Testosterona/sangue
6.
Hugo J ; 3(1-4): 51-62, 2009 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21119755

RESUMO

UNLABELLED: Thalassaemia and sickle cell disease have been recognized by the World Health Organization as important inherited disorders principally impacting on the populations of low income countries. To create a national and regional profile of ß-thalassaemia mutations in the population of India, a meta-analysis was conducted on 17 selected studies comprising 8,505 alleles and offering near-national coverage for the disease. At the national level 52 mutations accounted for 97.5% of all ß-thalassaemia alleles, with IVSI-5(G>C) the most common disease allele (54.7%). Population stratification was apparent in the mutation profiles at regional level with, for example, the prevalence of IVSI-5(G>C) varying from 44.8% in the North to 71.4% in the East. A number of major mutations, such as Poly A(T>C), were apparently restricted to a particular region of the country, although these findings may in part reflect the variant test protocols adopted by different centres. Given the size and genetic complexity of the Indian population, and with specific mutations for ß-thalassaemia known to be strongly associated with individual communities, comprehensive disease registries need to be compiled at state, district and community levels to ensure the efficacy of genetic education, screening and counselling programmes. At the same, time appropriately designed community-based studies are required as a health priority to correct earlier sampling inequities which resulted in the under-representation of many communities, in particular rural and socioeconomically under-privileged groups. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11568-010-9132-3) contains supplementary material, which is available to authorized users.

7.
Can J Urol ; 14(1): 3416-23, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17324320

RESUMO

OBJECTIVE: A multidisciplinary panel of experts from Canada and the United States was convened by the Ontario Neurotrauma Foundation (ONF) to establish research priorities in the area of urological care following spinal cord injury (SCI). DESIGN: The panel reviewed a synthesis of published literature in five areas of urology, identified emerging opportunities in the private and public sector, and used a modified Delphi approach to reach consensus on priorities for funding. RESULTS: The panel recommendations included: clinical trials of the safety and efficacy of M3 receptor specific anti-muscarinic agents for bladder hyperactivity in SCI patients; development and testing of protocols for sacral nerve electrostimulation without sacral afferent neurectomy for management of micturition - including selective stimulation of sacral nerve fibers, high frequency blocking of the pudendal nerve to minimize the risk of urethral sphincter co-contraction and genital nerve stimulation for bladder inhibition and incontinence management; clinical trials of the efficacy and safety of intra-urethral valve catheters; trials of the efficacy of probiotics for bacterial interference i.e. to reduce colonization by uropathogens and manage the dual problems of infection and pathogen resistance to anti-microbials: innovations in the prevention or treatment of stone disease (ureteral, bladder and kidney). CONCLUSIONS: The recommendations form the strategic priorities of the ONF SCI grants program for Ontario-based investigators and their partnerships with out-of-province collaborators and organizations.


Assuntos
Pesquisa Biomédica/tendências , Ensaios Clínicos como Assunto/tendências , Traumatismos da Medula Espinal/complicações , Sistema Urinário/fisiopatologia , Pesquisa Biomédica/economia , Canadá , Técnica Delphi , Estimulação Elétrica/métodos , Humanos , Cálculos Renais/etiologia , Cálculos Renais/prevenção & controle , Cálculos Renais/terapia , Apoio à Pesquisa como Assunto/economia , Apoio à Pesquisa como Assunto/tendências , Incontinência Urinária/etiologia , Incontinência Urinária/fisiopatologia , Incontinência Urinária/terapia , Infecções Urinárias/etiologia , Infecções Urinárias/prevenção & controle , Infecções Urinárias/terapia , Urologia/economia , Urologia/métodos
8.
Pharmeuropa Bio ; 2007(1): 1-6, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18413132

RESUMO

The European Directorate for the Quality of Medicines (EDQM) supplies Chemical Reference Substances (CRS) for Interferon (IFN) alfa-2a (CRS I0320300) and for IFN alfa-2b (CRS I0320301) for specified physicochemical tests. However, no information is provided as to their biological activity. In contrast, the World Health Organization (WHO) provides the 2nd International Standards (IS) for IFN alfa-2a (code 95/650) and for IFN alfa-2b (code 95/566), with activity defined in International Units (IU) for calibration of biological activity of preparations of IFN. We have compared the EDQM CRSs with the WHO ISs in two bioassay systems, one measuring the anti-proliferative activity in the Daudi cell line and the other measuring a reporter gene activation in an A549 cell line. In each of these assay systems, the CRSs gave dose - response relations, which were similar to those for the WHO ISs. Estimates of relative activity for each CRS, in terms of the respective IS, showed specific biological activity for the CRSs of the same order as the nominal specific activity for the ISs. However, the estimates of relative activity were not consistent between the two assays systems, emphasizing the need for calibration within each system, if the CRS were to be used as a working standard for bioassays. For structure-activity studies, both physicochemical and biological activity characterisation are required for the same biopharmaceutical preparation. CRS I0320300 and CRS I0320301 may prove useful as working standards for some bioassay systems.


Assuntos
Antineoplásicos/análise , Antineoplásicos/normas , Interferon-alfa/análise , Interferon-alfa/normas , Antineoplásicos/farmacologia , Bioensaio , Calibragem , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Fenômenos Químicos , Físico-Química , Relação Dose-Resposta a Droga , Europa (Continente) , Genes Reporter/efeitos dos fármacos , Humanos , Interferon alfa-2 , Interferon-alfa/farmacologia , Luciferases/genética , Proteínas Recombinantes , Padrões de Referência
9.
Int J Cardiol ; 107(3): 327-32, 2006 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-15923049

RESUMO

BACKGROUND: Using the simple risk index (SRI) that is based on age, heart rate and systolic blood pressure, we sought to evaluate the ability to predict outcome in AMI patients in a community-based population. METHODS AND RESULTS: We identified and evaluated 3684 consecutive patients with an admission diagnosis of possible AMI, who attended between 1st September and 30th November 1995. Two thousand one hundred fifty three patients had confirmed evidence of WHO definition AMI, of whom 1656 survived to hospital discharge. We evaluated the ability of the SRI to predict mortality over 30 days using the score generated by the equation (heart ratex[age/10]2)/systolic blood pressure. The SRI was a strong (c-statistic = 0.77 CI 0.74-0.79) predictor of 30-day mortality in both STEMI and all consecutive cases of WHO definition AMI. However, the model showed poor calibration when used on a community-based population with 30-day mortality being underestimated across all risk quintiles. Consequently we sought to recalibrate the quantitative aspects of the model for the total AMI population in the following way (Risk Index; 30-day mortality) (< or = 29.2; 9.2%), (29.3-37.8; 23.9%), (37.9-47.3; 34.6%), (47.4-61.5; 40.3%), (> or = 61.6; 65.5%). CONCLUSION: We have externally validated the SRI in an unselected cohort of consecutive WHO definition AMI patients. However, the original model consistently underestimated the likelihood of death at 30 days regardless of the calculated risk score. We have therefore suggested corrections to the risk estimates, to allow its application in an unselected community cohort.


Assuntos
Pressão Sanguínea , Indicadores Básicos de Saúde , Frequência Cardíaca , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/mortalidade , Fatores Etários , Idoso , Calibragem , Feminino , Humanos , Masculino , Prognóstico , Reprodutibilidade dos Testes , Medição de Risco , Análise de Sobrevida , Reino Unido/epidemiologia
10.
Vaccine ; 20(29-30): 3535-42, 2002 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-12297399

RESUMO

Pertussis toxin (PT) in its detoxified form is an important antigenic component of both acellular and whole cell pertussis vaccines. Limits on the content of active PT in acellular vaccines are set in official monographs (EP, WHO, USP) and evidence of compliance is therefore, required by regulatory authorities. The two assay methods which are currently used by most manufacturers and official national control laboratories to monitor residual PT activity in acellular pertussis vaccines (and also in whole cell vaccines) are histamine sensitising (HIST) assays and Chinese hamster ovary (CHO) cell assays. Currently, different reference preparations of PT are used by individual laboratories for these tests. We therefore organised an international collaborative study to examine, by these two assay methods, two freeze-dried purified preparations of PT, one preparation in ampoules coded JNIH-5 and one preparation in ampoules coded 90/518, together with in-house reference (IHR) preparations in current use. Data from this study confirm that both JNIH-5 and 90/518 show biological activity both in HIST assays and in CHO-cell assays. Both HSD50 and ED50 values obtained in this study differ significantly between laboratories and thus show that biological activity is not determined by the nominal masses of preparations. Estimates of relative potency of 90/518 in terms of JNIH-5 per ampoule for the HIST assays do not differ significantly between laboratories. The overall mean estimates of relative potency of 90/518 in terms of JNIH-5 do not differ significantly between the two methods. Data from this study further indicate that the biological activity of different preparations was not directly related to their stated protein content. The use of protein content to indicate the level of PT activity in different preparations would give misleading results. Thus, use of a common standard is shown to greatly improve between laboratory agreement of estimates.


Assuntos
Histamina/farmacologia , Toxina Pertussis/análise , Toxina Pertussis/farmacologia , Vacina contra Coqueluche/normas , Animais , Células CHO , Cricetinae , Padrões de Referência
11.
J Immunol Methods ; 257(1-2): 17-33, 2001 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-11687235

RESUMO

The complexity of the human interferon-alpha (IFN-alpha) family, with its multiple molecular forms and various biological activities, raises a number of scientific issues with regard to the biological standardisation of natural and recombinant IFN-alpha products. To address such issues and to achieve an appropriate biological standardisation of human interferon-alpha (IFN-alpha) preparations, the National Institute for Biological Standards and Control (NIBSC) of the United Kingdom (UK), in association with the Centre for Biologics Evaluation and Research (CBER) of the United States of America (USA), organised an international collaborative study, which was subsequently divided into two parts. Ninety-three participating laboratories from 29 countries worldwide participated in the first part of the study. They performed titrations on up to 15 different IFN-alpha preparations and one IFN-omega (omega) preparation in a variety of assays, including those based upon antiviral, antiproliferative, and other biological activities of IFN, and contributed raw data from these assays to NIBSC for analysis and calculation of relative activities. Analysis of data from this part of the study showed a greater than expected assay-dependent disparity between the relative activities of different IFN-alpha preparations. This disparity was found when only antiviral assays were considered and even when there were only small molecular dissimilarities between two otherwise closely related IFN-alpha preparations. The lack of assay independence and relative activity equivalence has indicated that a single biological potency standard for all IFN-alpha subtypes and mixtures would be inappropriate. Hence, individual, homologous standards, each with a separate unitage, were required for biological standardisation and potency determinations of individual IFN-alpha subtypes. At this stage, potency assignments to the IFN-alpha and -omega preparations included in the study were made as far as possible on the basis of comparison of antiviral activity with that of the 1st International Reference Preparation (IRP) for IFN, human leukocyte, 69/19. However, it was recognised that other standards had been used in assays to estimate potencies of widely available, current, therapeutic IFN-alpha products. Thus, to ensure the continuity of unitages already in use for IFN-alpha products, the second part of the study, which involved 12 members of the International Federation of Pharmaceutical Manufacturers Association (IFPMA), was carried out using for calibration of antiviral assays those IFN-alpha preparations that most closely matched manufacturers' products or that had been previously used for assay calibration by a manufacturer for a particular product. On the basis of data analysis from the second part of the study, potency assignments to the IFN-alpha preparations, as made in the first part of the study, were either left unchanged or changed to potency assignments that ensured as far as possible continuity with existing unitages. From among the IFN preparations evaluated, the following were recommended as the most suitable to continue or replace existing WHO international standards (IS) and have subsequently been formally established as WHO IS at the 51st meeting (October 1999) of the WHO ECBS: 83/514, 1st WHO IS for human IFN-alpha1 8000 international units (IU); 95/650, 2nd WHO IS for human IFN-alpha2a, 63,000 IU; 95/566, 2nd WHO IS for human IFN-alpha2b, 70,000 IU; 95/580, 1st WHO IS for human IFN-alpha2c, 40,000 IU; 95/572, 1st WHO IS for human IFN-alpha1/8, 27,000 IU; 94/786, 1st WHO IS for human IFN-alphaCon1, 100,000 IU; 94/784, 2nd WHO IS for human IFN-alpha (leukocyte), 11,000 IU; 95/574, 1st WHO IS for human IFN-alpha (leukocyte n3), 60,000 IU; 95/568, 2nd WHO IS for human IFN-alpha (lymphoblastoid n1), 38,000 IU; 94/754, 1st WHO IS for human IFN-omega, 20,000 IU. These WHO IS are available upon request to NIBSC.


Assuntos
Interferon Tipo I/normas , Interferon-alfa/normas , Antivirais/administração & dosagem , Antivirais/normas , Bioensaio/normas , Relação Dose-Resposta a Droga , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Humanos , Imunoensaio/normas , Interferon Tipo I/administração & dosagem , Interferon-alfa/administração & dosagem , Cooperação Internacional , Laboratórios/normas , Proteínas Recombinantes , Padrões de Referência , Organização Mundial da Saúde
13.
J Immunol Methods ; 258(1-2): 1-11, 2001 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11684118

RESUMO

Hepatocyte growth factor/scatter factor (HGF/SF) is a potent paracrine growth factor with motogenic, mitogenic and morphogenic activities, and a potential therapeutic role in hepatic and renal disease, as well as diagnostic and prognostic applications. It is synthesised as an inactive, single-chain precursor that is cleaved by serine proteases to give a biologically active, heterodimeric form. To develop World Health Organization (WHO) International Standards (IS) for HGF/SF, candidate preparations of the two forms were assessed in a multicentre study in which they were compared with local standards by bioassay and immunoassay. Among laboratories, there was a wide variation in the estimates of potencies of the candidate standards in terms of in-house reference preparations, but between-assay and within-assay variabilities were low within laboratories. In some assay systems, the precursor and heterodimer showed different responses. Since both molecular forms are widely used in current assay systems, this suggested that a reference preparation was required for each form of the HGF/SF molecule. Accordingly, the Expert Committee on Biological Standardization of WHO established the heterodimeric material (96/564) as the first IS for HGF/SF, human, recombinant, with an assigned unitage of 4000 IU/ampoule and, for the purpose of immunoassay calibration, a nominal HGF/SF content of 4 microg/ampoule. The precursor preparation (96/556) was established as the first IS for HGF/SF (precursor) with an assigned unitage of 2000 IU/ampoule and, for the purpose of immunoassay calibration, a nominal HGF/SF (precursor) content of 4 microg/ampoule. The preparations can be obtained upon written request to the National Institute for Biological Standards and Control (NIBSC, PO Box 1193), by e-mail (standards@nibsc.ac.uk) or ordered at http://www.nibsc.ac.uk.


Assuntos
Fator de Crescimento de Hepatócito/normas , Animais , Bioensaio/normas , Células CHO , Linhagem Celular , Cricetinae , Dimerização , Fator de Crescimento de Hepatócito/química , Humanos , Imunoensaio/normas , Cooperação Internacional , Camundongos , Precursores de Proteínas/química , Precursores de Proteínas/normas , Estrutura Quaternária de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/normas , Padrões de Referência , Organização Mundial da Saúde
14.
Med Phys ; 28(8): 1770-5, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11548948

RESUMO

Studies of intravascular brachytherapy to prevent restenosis following angioplasty have shown many promising results. Accurate dose rate tables based on detailed models of the brachytherapy sources are necessary for treatment planning. This work will present an away and along dose rate table for a 27 mm long catheter based 32P beta source. MD-55-2 radiochromic film has been exposed at five different depths (0.5 mm-4 mm) in a polystyrene phantom using a 27 mm long Guidant 32P beta source. The total dose to the active region of the film was determined using the absolute detector response of the MD-55-2 radiochromic film. The Monte Carlo code MCNP4B2 was also used to calculate the dose to the active region of the film using a detailed model of the source, encapsulation, and radiochromic film. The dose to film calculations showed good agreement with the measurements presented in this work with an average difference of 7%. The Monte Carlo calculations were also verified against previously published depth dose in water measurements determined using radiochromic film and plastic scintillator. The depth dose calculations in water showed good agreement with the previously published measurements with the calculations being about 2.5% lower than the film measurements and about 2.5% higher than the scintillator measurements. This work then uses the verified Monte Carlo code to present a dose rate table for the 32P intravascular beta source.


Assuntos
Braquiterapia/métodos , Método de Monte Carlo , Radioisótopos de Fósforo/uso terapêutico , Braquiterapia/estatística & dados numéricos , Reestenose Coronária/prevenção & controle , Elétrons , Humanos , Modelos Estatísticos , Imagens de Fantasmas , Valores de Referência , Filme para Raios X
15.
Med Phys ; 28(2): 142-6, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11243336

RESUMO

GafChromic (MD-55-2) radiochromic film has become increasingly popular for medical applications and has proven to be useful for brachytherapy dosimetry. To measure the absolute dose near a brachytherapy source, the response of the proposed detector in the measurement conditions relative to the response of the detector in calibration conditions must be known. MD-55-2 radiochromic film has been exposed in four different photon beams, a 30 and 40 kVp tungsten anode x-ray beam, a 75 kVp orthovoltage therapy beam, and a 60Co teletherapy beam to measure the relative detector response. These measurements were combined with coupled photon/electron Monte Carlo transport calculations to determine the absolute detector response. The Los Alamos National Laboratory Monte Carlo transport code MCNP4B2 was used. The measured relative response of this batch of MD-55-2 film varies from 8.79 mOD/Gy, measured for the 60Co beam, by as much as 42% for the low-energy x-ray beams. However, the absolute detector response varies from 4.32 mOD/Gy for the 60Co beam by, at most, only 6.3%. In this work we demonstrate that the absolute detector response of MD-55-2 radiochromic film is a constant and independent of beam quality. Further, this work shows that MCNP4B2 accurately simulates the energy response and geometry artifacts of the radiochromic film.


Assuntos
Braquiterapia/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Fenômenos Biofísicos , Biofísica , Braquiterapia/estatística & dados numéricos , Elétrons/uso terapêutico , Humanos , Método de Monte Carlo , Fótons/uso terapêutico , Radiometria/métodos , Radiometria/estatística & dados numéricos , Planejamento da Radioterapia Assistida por Computador/estatística & dados numéricos , Filme para Raios X
16.
Biologicals ; 27(2): 125-31, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10600201

RESUMO

Assay evaluation and validation is essential to ensure that assays are sufficiently specific and provide estimates with sufficient precision for the required purposes. This must be an on-going process, and assays should therefore be designed to permit some degree of both direct and indirect measurement of intra- and inter-assay variation. Quality control procedures may contribute relevant information, but may not be sufficient. Results obtained by two laboratories using as nearly as possible identical reagents and samples in an ELISA for anti-pertussis antibodies are described. These results illustrate aspects of assay performance which may be overlooked once a formal "validation exercise" has been carried out and assays are in routine use. This study also illustrates the information, in addition to that available from in-house studies, which may be provided by appropriately designed inter-laboratory studies, such as the collaborative studies carried out for characterization and calibration of reference materials and standards.


Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Fatores de Virulência de Bordetella/imunologia , Relação Dose-Resposta a Droga , Humanos , Padrões de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Fatores de Virulência de Bordetella/administração & dosagem
18.
J R Soc Med ; 91(3): 129-32, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9659323

RESUMO

Radiographic images can now be produced without the requirement of film processing and development, and can be displayed rapidly on a computer monitor. We assessed junior doctors' performance in interpreting images from 25 patients being investigated for possible fracture and also compared the diagnostic abilities of casualty officers with those of radiology specialist registrars. For interpretation of images viewed at a workstation or as filmed laser images, respectively, sensitivities were 75% and 78%, and specificities were 65% and 76%. These differences were not significant. There was a tendency for radiology specialist registrars to be less specific when reviewing images at a workstation. The demonstration that there is no loss in diagnostic quality when casualty officers interpret fracture images in a purely digitally acquired and viewed format forms a robust basis for economic evaluation of the technology.


Assuntos
Competência Clínica , Serviço Hospitalar de Emergência/normas , Fraturas Ósseas/diagnóstico por imagem , Intensificação de Imagem Radiográfica , Radiologia/normas , Inglaterra , Humanos , Corpo Clínico Hospitalar/normas , Fraturas do Rádio/diagnóstico por imagem , Sensibilidade e Especificidade , Fraturas da Ulna/diagnóstico por imagem
19.
Int J Radiat Oncol Biol Phys ; 38(4): 843-53, 1997 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-9240654

RESUMO

PURPOSE: Dose distributions around low energy (< 60 keV) brachytherapy sources, such as 125I, are known to be very sensitive to changes in tissue composition. Available 125I dosimetry data describe the effects of replacing the entire water medium by heterogeneous material. This work extends our knowledge of tissue heterogeneity effects to the domain of bounded tissue heterogeneities, simulating clinical situations. Our goals are three-fold: (a) to experimentally characterize the variation of dose rate as a function of location and dimensions of the heterogeneity, (b) to confirm the accuracy of Monte Carlo dose calculation methods in the presence of bounded tissue heterogeneities, and (c) to use the Monte Carlo method to characterize the dependence of heterogeneity correction factors (HCF) on the irradiation geometry. METHODS AND MATERIALS: Thermoluminescent dosimeters (TLD) were used to measure the deviations from the homogeneous dose distribution of an 125I seed due to cylindrical tissue heterogeneities. A solid water phantom was machined accurately to accommodate the long axis of the heterogeneous cylinder in the transverse plane of a 125I source. Profiles were obtained perpendicular to and along the cylinder axis, in the region downstream of the heterogeneity. Measurements were repeated at the corresponding points in homogeneous solid water. The measured heterogeneity correction factor (HCF) was defined as the ratio of the detector reading in the heterogeneous medium to that in the homogeneous medium at that point. The same ratio was simulated by a Monte Carlo photon transport (MCPT) code, using accurate modeling of the source, phantom, and detector geometry. In addition, Monte Carlo-based parametric studies were performed to identify the dependence of HCF on heterogeneity dimensions and distance from the source. RESULTS: Measured and calculated HCFs reveal excellent agreement (< or = 5% average) over a wide range of materials and geometries. HCFs downstream of 20 mm diameter by 10 mm thick hard bone cylinders vary from 0.12 to 0.30 with respect to distance, while for an inner bone cylinder of the same dimension, it varies from 0.72 to 0.83. For 6 mm diameter by 10 mm thick hard bone and inner bone cylinders, HCF varies 0.27-0.58 and 0.77-0.88, respectively. For lucite, fat, and air, the dependence of HCF on the 3D irradiation geometry was much less pronounced. CONCLUSION: Monte Carlo simulation is a powerful, convenient, and accurate tool for investigating the long neglected area of tissue composition heterogeneity corrections. Simple one dimensional dose calculation models that depend only on the heterogeneity thickness cannot accurately characterize 125I dose distributions in the presence of bone-like heterogeneities.


Assuntos
Radioisótopos do Iodo , Método de Monte Carlo , Imagens de Fantasmas , Compostos Radiofarmacêuticos , Dosagem Radioterapêutica
20.
Neurosurgery ; 40(6): 1323-32; discussion 1333-4, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9179912

RESUMO

OBJECTIVE: To explore the presence of MDR-1 drug resistance in human glioma utilizing a Single Photon Emission Computerized Tomography (SPECT) imaging agent, sesta-MIBI, and testing cases interpreted as positive for drug resistance with molecular characterization of subsequent tissue biopsy, including RNA, Northern blot analysis, and polymerase chain reaction, and in situ hybridization. METHODS: Six patients that carried a diagnosis of biopsy-proven glioma underwent dual isotope SPECT imaging with thallium 201 and technetium sesta-MIBI. All six patients underwent subsequent surgical reexcision of their tumors, and tissue was immediately flash frozen for further analysis. PolyA RNA was isolated and subsequently analyzed by both Northern blot analysis and RT-PCR utilizing an MDR-1 probe (ATCC) and MDR-1 primers. RESULTS: Four patients with SPECT concordance yielded tumors without MDR-1 expression whereas two patients with SPECT discordance yielded tumors with MDR-1 gene expression. In one discordant case we subsequently performed RT-PCR in situ amplification/ hybridisation and immunohistochemistry with, respectively, an MDR-1 sense primer with Biotin labeled probes and an MDR-1 monoclonal antibody, and both analyses revealed MDR-1 expression in tumor cells. CONCLUSION: These data support the use of SPECT technetium sesta-MIBI to evaluate the presence of MDR-1 gene expression in gliomas.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Glioma/tratamento farmacológico , Tomografia Computadorizada de Emissão de Fóton Único , Adulto , Biópsia , Encéfalo/diagnóstico por imagem , Encéfalo/patologia , Encéfalo/cirurgia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/cirurgia , Resistência a Múltiplos Medicamentos/genética , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Regulação Neoplásica da Expressão Gênica/fisiologia , Glioma/diagnóstico por imagem , Glioma/genética , Glioma/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Tecnécio Tc 99m Sestamibi , Radioisótopos de Tálio
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