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1.
Environ Sci Technol ; 57(26): 9445-9458, 2023 07 04.
Artículo en Inglés | MEDLINE | ID: mdl-37339013

RESUMEN

Urbanization, slum redevelopment, and population growth will lead to unprecedented levels of residential building construction in "low- and middle-income" (LMI) countries in the coming decades. However, less than 50% of previous residential building life-cycle assessment (LCA) reviews included LMI countries. Moreover, all reviews that included LMI countries only considered formal (cement-concrete) buildings, while more than 800 million people in these countries lived in informal settlements. We analyze LCA literature and define three building types based on durability: formal, semiformal, and informal. These exhaustively represent residential buildings in LMI countries. For each type, we define dominant archetypes from across the world, based on construction materials. To address the data deficiency and lack of transparency in LCA studies, we develop a reproducibility metric for building LCAs. We find that the countries with the most reproducible studies are India, Sri Lanka, Turkey, Mexico, and Brazil. Only 7 out of 54 African countries have reproducible studies focused on either the embodied or use phase. Maintenance, refurbishment, and end-of-life phases are included in hardly any studies in the LMI LCA literature. Lastly, we highlight the necessity for studying current, traditional buildings to provide a benchmark for future studies focusing on energy and material efficiency strategies.


Asunto(s)
Huella de Carbono , Países en Desarrollo , Urbanización , Humanos , Carbono , Materiales de Construcción , Reproducibilidad de los Resultados
2.
Environ Sci Technol ; 56(7): 4565-4577, 2022 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-35302366

RESUMEN

Material efficiency (ME) can support rapid climate change mitigation and circular economy. Here, we comprehensively assess the circularity of ME strategies for copper use in the U.S. housing services (including residential buildings and major household appliances) by integrating use-phase material and energy demand. Although the ME strategies of more intensive floor space use and extended lifetime of appliances and buildings reduce the primary copper demand, employing these strategies increases the commonly neglected use-phase share of total copper requirements during the century from 23-28 to 22-42%. Use-phase copper requirements for home improvements have remained larger than the demand gap (copper demand minus scrap availability) for much of the century, limiting copper circularity in the U.S. housing services. Further, use-phase energy consumption can negate the benefits of ME strategies. For instance, the lifetime extension of lower-efficiency refrigerators increases the copper use and net environmental impact by increased electricity use despite reductions from less production. This suggests a need for more attention to the use phase when assessing circularity, especially for products that are material and energy intensive during use. To avoid burden shifting, policymakers should consider the entire life cycle of products supporting services when pursuing circular economy goals.


Asunto(s)
Artículos Domésticos , Vivienda , Cambio Climático , Cobre , Ambiente
3.
Proc Natl Acad Sci U S A ; 116(50): 25034-25041, 2019 12 10.
Artículo en Inglés | MEDLINE | ID: mdl-31754037

RESUMEN

Sustainable food systems aim to provide sufficient and nutritious food, while maximizing climate resilience and minimizing resource demands as well as negative environmental impacts. Historical practices, notably the Green Revolution, prioritized the single objective to maximize production over other nutritional and environmental dimensions. We quantitatively assess outcomes of alternative production decisions across multiple objectives using India's rice-dominated monsoon cereal production as an example. We perform a series of optimizations to maximize nutrient production (i.e., protein and iron), minimize greenhouse gas (GHG) emissions and resource use (i.e., water and energy), or maximize resilience to climate extremes. We find that increasing the area under coarse cereals (i.e., millets, sorghum) improves nutritional supply (on average, +1% to +5% protein and +5% to +49% iron), increases climate resilience (1% to 13% fewer calories lost during an extreme dry year), and reduces GHGs (-2% to -13%) and demand for irrigation water (-3% to -21%) and energy (-2% to -12%) while maintaining calorie production and cropped area. The extent of these benefits partly depends on the feasibility of switching cropped area from rice to coarse cereals. Based on current production practices in 2 states, supporting these cobenefits could require greater manure and draft power but similar or less labor, fertilizer, and machinery. National- and state-level strategies considering multiple objectives in decisions about cereal production can move beyond many shortcomings of the Green Revolution while reinforcing the benefits. This ability to realistically incorporate multiple dimensions into intervention planning and implementation is the crux of sustainable food production systems worldwide.


Asunto(s)
Agricultura/métodos , Grano Comestible , Desarrollo Sostenible , Ambiente , Abastecimiento de Alimentos , Humanos , India , Valor Nutritivo , Oryza
4.
Environ Sci Technol ; 55(5): 3175-3187, 2021 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-33577305

RESUMEN

Sustainability endorses high quality, long-lasting goods. Durable goods, however, often require substantial amounts of energy during their production and use-phase and indirectly through complementary products and services. We quantify the global household's final energy footprints (EFs) of durable goods and the complementary goods needed to operate, service and maintain durables. We calculate the EFs of 200 goods across 44 individual countries and 5 world regions for the period of 1995-2011. In 2011, we find 68% of the total global household's EF (218 EJ) is durable-related broken down as follows: 10% is due to the production of durables per se, 7% is embodied in goods complementary to durables (consumables and services) and 51% is operational energy. At the product level, the highest durable-related EFs are: transport goods (148-648 MJ/cap), housing goods (40-811 MJ/cap), electric appliances (34-181 MJ/cap), and "gas stoves and furnaces" (40-100 MJ/cap). Between 1995 and 2011, the global household EF increased by 28% (48 EJ), of which 72% was added by durable-related energy. Globally, a 10% income growth corresponded to an increase in EF by 9% in durables, 11% in complementary consumables and 13% in complementary services-with even higher elasticities in the emerging economies. The average EF of the emerging economies (35 GJ/cap) is 2.5 times lower than in advanced economies (86 GJ/cap). Efficiency gains were detected in 47 out of 49 regions, but only 16 achieved net energy reductions. The large share of durable-related EF across regions (40-88%) confirms the dominance of durables in driving EFs, but the diversity of patterns suggests that policy and social factors influence durable-dependency. Demand-side solutions targeting ownership and inter-linkages between durables and complements are key to reduce global energy demand.


Asunto(s)
Composición Familiar , Renta
5.
Environ Sci Technol ; 54(3): 1799-1807, 2020 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-31909605

RESUMEN

Energy demand in global climate scenarios is typically derived for sectors - such as buildings, transportation, and industry - rather than from underlying services that could drive energy use in all sectors. This limits the potential to model household consumption and lifestyles as mitigation options through their impact on economy-wide energy demand. We present a framework to estimate the economy-wide energy requirements and carbon emissions associated with future household consumption, by linking Industrial Ecology tools and Integrated Assessment Models (IAM). We apply the framework to assess final energy and emission pathways for meeting three essential and energy-intensive dimensions of basic well-being in India: food, housing and mobility. We show, for example, that nutrition-enhancing dietary changes can reduce emissions by a similar amount as meeting future basic mobility in Indian cities with public transportation. The relative impact of energy demand reduction measures compared to decarbonization differs across these services, with housing having the lowest and food the highest. This framework provides complementary insights to those obtained from IAM by considering a broader set of consumption and well-being-related interventions, and illustrating trade-offs between demand and supply-side options in climate stabilization scenarios.


Asunto(s)
Vivienda , Transportes , Carbono , Ciudades , India
6.
Antimicrob Agents Chemother ; 59(9): 5664-74, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26149995

RESUMEN

There are currently 18 drug classes for the treatment of tuberculosis, including those in the development pipeline. An in silico simulation enabled combing the innumerably large search space to derive multidrug combinations. Through the use of ordinary differential equations (ODE), we constructed an in silico kinetic platform in which the major metabolic pathways in Mycobacterium tuberculosis and the mechanisms of the antituberculosis drugs were integrated into a virtual proteome. The optimized model was used to evaluate 816 triplets from the set of 18 drugs. The experimentally derived cumulative fractional inhibitory concentration (∑FIC) value was within twofold of the model prediction. Bacterial enumeration revealed that a significant number of combinations that were synergistic for growth inhibition were also synergistic for bactericidal effect. The in silico-based screen provided new starting points for testing in a mouse model of tuberculosis, in which two novel triplets and five novel quartets were significantly superior to the reference drug triplet of isoniazid, rifampin, and ethambutol (HRE) or the quartet of HRE plus pyrazinamide (HREZ).


Asunto(s)
Antituberculosos/uso terapéutico , Etambutol/uso terapéutico , Isoniazida/uso terapéutico , Rifampin/uso terapéutico , Tuberculosis/tratamiento farmacológico , Animales , Ratones , Ratones Endogámicos BALB C , Pruebas de Sensibilidad Microbiana
7.
Bioorg Med Chem Lett ; 25(3): 680-4, 2015 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-25529734

RESUMEN

An efficient synthesis of a new series of tamoxifen mimics is described by employing iodine catalyzed ipsocyclization strategy followed by Suzuki coupling. A molecular docking studies of the synthesized compounds 11a-n and 12 in estrogen receptor (ER-α) showed that the scaffolds are fitting well in the groove, thereby suggesting them as promising antiproliferative agents for estrogen dependent breast cancer lines. All compounds were tested in vitro against breast cancer cell lines-ER positive, MCF-7; ER negative, MDA-MB-231; and control mammary epithelial cells, MEpiC. The biological results showed that most of the compounds are active against MCF-7 with IC50 values less than 6.5µM which corroborate the results of molecular docking studies.


Asunto(s)
Ácidos Borónicos/química , Tamoxifeno/análogos & derivados , Sitios de Unión , Ácidos Borónicos/síntesis química , Ácidos Borónicos/toxicidad , Neoplasias de la Mama/metabolismo , Neoplasias de la Mama/patología , Catálisis , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Complejos de Coordinación/química , Receptor alfa de Estrógeno/química , Receptor alfa de Estrógeno/metabolismo , Femenino , Humanos , Células MCF-7 , Simulación del Acoplamiento Molecular , Paladio/química , Estructura Terciaria de Proteína , Tamoxifeno/síntesis química , Tamoxifeno/toxicidad
8.
Artículo en Inglés | MEDLINE | ID: mdl-38271623

RESUMEN

Various technologies and strategies have been proposed to decarbonize the chemical industry. Assessing the decarbonization, environmental, and economic implications of these technologies and strategies is critical to identifying pathways to a more sustainable industrial future. This study reviews recent advancements and integration of systems analysis models, including process analysis, material flow analysis, life cycle assessment, techno-economic analysis, and machine learning. These models are categorized based on analytical methods and application scales (i.e., micro-, meso-, and macroscale) for promising decarbonization technologies (e.g., carbon capture, storage, and utilization, biomass feedstock, and electrification) and circular economy strategies. Incorporating forward-looking, data-driven approaches into existing models allows for optimizing complex industrial systems and assessing future impacts. Although advances in industrial ecology-, economic-, and planetary boundary-based modeling support a more holistic systems-level assessment, more effects are needed to consider impacts on ecosystems. Effective applications of these advanced, integrated models require cross-disciplinary collaborations across chemical engineering, industrial ecology, and economics. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering , Volume 15 is June 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

9.
Sci Data ; 11(1): 142, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38287038

RESUMEN

Social science often relies on surveys of households and individuals. Dozens of such surveys are regularly administered by the U.S. government. However, they field independent, unconnected samples with specialized questions, limiting research questions to those that can be answered by a single survey. The presented data comprise the fusion onto the American Community Survey (ACS) microdata of select donor variables from the Residential Energy Consumption Survey (RECS) of 2015, the National Household Travel Survey (NHTS) of 2017, the American Housing Survey (AHS) of 2019, and the Consumer Expenditure Survey - Interview (CEI) for the years 2015-2019. This results in an integrated microdataset of household attributes and well-being dimensions that can be analyzed to address research questions in ways that are not currently possible. The underlying statistical techniques, designed under the fusionACS project, are included in an open-source R package, fusionModel, that provides generic tools for the creation, analysis, and validation of fused microdata.

10.
Heliyon ; 9(11): e21441, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37964853

RESUMEN

The relationship between growth, inequality and poverty remains elusive, despite considerable scholarship. To what extent can governments rely on growth to eradicate poverty without reducing inequality? We derive a closed-form relationship between a minimum income threshold, changes in the Gini index of income inequality and average national income required to meet this target, independent of the form of income distribution. We develop a generalized form of redistribution and validate it against historical changes in inequality. We use this formulation to illustrate feasible growth-redistribution strategies to raise entire populations above the International Poverty Line ($1.90/day) by 2030, the Sustainable Development Goal 1, in two selective countries: India and Rwanda. We show that meeting this target would require unprecedented rates of both growth and inequality reduction in Rwanda. India could not eradicate acute poverty by 2030 with growth alone, but it could with only a modest reduction in inequality.

11.
Science ; 380(6646): eadh1463, 2023 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-37200411

RESUMEN

We welcome the analysis of Semieniuk et al. (1) as an additional sensitivity to illustrate a more extreme distribution of regional contributions to climate mitigation investments that supports our main conclusion regarding the North-South divide in mitigation investment capabilities. In response to Semieniuk et al. we would like to first point out that, in defining the required global mitigation investments for the 2020 to 2030 period, our study relies on the estimates in the sixth assessment report (AR6) of the Intergovernmental Panel on Climate Change (IPCC) WGIII (2). These are based on diverse sources and underlying models that to varying degrees reflect regional differences in technology costs and consider both purchasing power parity (PPP) and market exchange rates (MERs). We use these IPCC estimates as a starting point and focus entirely on the question of how much of the needed regional investments, given different fairness considerations, should be financed from sources within a region.

12.
Sci Rep ; 13(1): 9960, 2023 06 20.
Artículo en Inglés | MEDLINE | ID: mdl-37340018

RESUMEN

India is the world's second largest producer of wheat, with more than 40% increase in production since 2000. Increasing temperatures raise concerns about wheat's sensitivity to heat. Traditionally-grown sorghum is an alternative rabi (winter season) cereal, but area under sorghum production has declined more than 20% since 2000. We examine sensitivity of wheat and sorghum yields to historical temperature and compare water requirements in districts where both cereals are cultivated. Wheat yields are sensitive to increases in maximum daily temperature in multiple stages of the growing season, while sorghum does not display the same sensitivity. Crop water requirements (mm) are 1.4 times greater for wheat than sorghum, mainly due to extension of its growing season into summer. However, water footprints (m3 per ton) are approximately 15% less for wheat due to its higher yields. Sensitivity to future climate projections, without changes in management, suggests 5% decline in wheat yields and 12% increase in water footprints by 2040, compared with 4% increase in water footprint for sorghum. On balance, sorghum provides a climate-resilient alternative to wheat for expansion in rabi cereals. However, yields need to increase to make sorghum competitive for farmer profits and efficient use of land to provide nutrients.


Asunto(s)
Grano Comestible , Sorghum , Estaciones del Año , Productos Agrícolas , India , Triticum , Cambio Climático , Agua
13.
Science ; 378(6624): 1057-1059, 2022 12 09.
Artículo en Inglés | MEDLINE | ID: mdl-36395272

RESUMEN

Current mitigation finance flows are inadequate and unfair.

14.
Chem Biol Drug Des ; 98(5): 857-868, 2021 11.
Artículo en Inglés | MEDLINE | ID: mdl-34423559

RESUMEN

Cyclin-dependent kinase 2 (CDK2) is an established target protein for therapeutic intervention in various diseases, including cancer. Reported inhibitors of CDK2 target the ATP-binding pocket to inhibit the kinase activity. Many small molecule CDK2 inhibitors have been discovered, and their crystal structure with CDK2 or CDK2-cyclin A complex has been published. NU6140 is a CDK2 inhibitor with moderate potency and selectivity. Herein, we report the cocrystal structure determination of NU6140 in complex with CDK2 and confirmation of the binding using various biophysical methods. Our data show that NU6140 binds to CDK2 with a Kd of 800 nM as determined by SPR and stabilizes the protein against thermal denaturation (ΔTm -5°C). The cocrystal structure determined in our study shows that NU6140 binds in the ATP-binding pocket as expected for this class of compounds and interacts with Leu83 and Glu81 with regular hydrogen bonds and with Asp145 via water-mediated H-bond. Based on these data, we propose structural modifications of NU6140 to introduce new interactions with CDK2 that can improve its potency while retaining the selectivity.


Asunto(s)
Quinasa 2 Dependiente de la Ciclina/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Purinas/química , Células A549 , Adenosina Trifosfato/química , Secuencia de Aminoácidos , Sitios de Unión , Supervivencia Celular/efectos de los fármacos , Cristalografía por Rayos X , Humanos , Enlace de Hidrógeno , Unión Proteica , Conformación Proteica , Relación Estructura-Actividad , Termodinámica
15.
Chem Biol Drug Des ; 96(2): 704-713, 2020 08.
Artículo en Inglés | MEDLINE | ID: mdl-32227402

RESUMEN

Acinetobacter baumannii is an opportunistic Gram-negative bacterial pathogen, associated mostly with hospital-acquired infections. The emergence of drug resistance strains made it necessary to explore new pathways for the development of more effective antibiotics. Enoyl CoA reductase (FabI), a key enzyme in the fatty acid biosynthesis (FAS) pathway, has emerged as a potential target for antibacterial drug development. Earlier reports show that the lead SaFabI inhibitor AFN-1252 can inhibit FabI from other organisms including Escherichia coli and Burkholderia pseudomallei, but with differential potency. In the present work, we show that AFN-1252 is a moderate inhibitor of AbFabI with an IC50 of 216 nM. AFN-1252 stabilized AbFabI with a 4.2°C increase in the melting temperature (Tm ) and, interestingly, the stabilization effect was significantly increased in presence of the cofactor NADH (∆Tm  = 17°C), suggesting the formation of a ternary complex AbFabI: AFN-1252: NADH. X-ray crystallography studies of AbFabI co-crystalized with AFN-1252 and NADH confirmed the ternary complex formation. The critical interactions of AFN-1252 with AbFabI and NADH identified from the co-crystal structure may facilitate the design and development of new drugs against A. baumannii infections by targeting the FAS pathway.


Asunto(s)
Infecciones por Acinetobacter/tratamiento farmacológico , Acinetobacter baumannii/metabolismo , Antibacterianos/química , Benzofuranos/química , Inhibidores Enzimáticos/química , Ácido Graso Desaturasas/antagonistas & inhibidores , NAD/metabolismo , Pironas/química , Secuencia de Aminoácidos , Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Benzofuranos/metabolismo , Burkholderia pseudomallei/metabolismo , Cristalización , Cristalografía por Rayos X , Diseño de Fármacos , Inhibidores Enzimáticos/farmacología , Escherichia coli/metabolismo , Humanos , Pironas/metabolismo , Temperatura de Transición
16.
Soc Indic Res ; 138(1): 225-244, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29950752

RESUMEN

We define a set of universal, irreducible and essential set of material conditions for achieving basic human wellbeing, along with indicators and quantitative thresholds, which can be operationalized for societies based on local customs and preferences. We draw support for this decent living standard (DLS) from different accounts of basic justice, including the capability approach and basic needs. The DLS goes beyond existing multidimensional poverty indicators by comprehensively addressing living conditions and the means of social participation. The DLS offers a normative basis to develop minimum wage and reference budgets, and to assess the environmental impacts, such as climate change, of eradicating poverty.

17.
PLoS One ; 13(6): e0197974, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29883457

RESUMEN

The Central American nations of Guatemala, Honduras and Nicaragua are among the poorest in the Americas. While the fraction of population dependent on solid fuels has declined in these nations over the last 25 years, the number of people using them has risen. Here, we first assess current patterns of cooking energy use in these nations. We then apply a discrete model of household cooking choices and demand to simulate future pathways of clean cooking uptake and the outlook for achieving target 7.1 of the Sustainable Development Goals (SDG), which aims to ensure universal access to affordable, reliable and modern energy services by 2030. We find that by 2030, ensuing income growth is likely to enable 90% of urban populations in these nations to switch to using modern cooking energy services. However, without supporting policies, between 40% to 50% of rural Guatemalans and Hondurans, while over two-thirds of rural Nicaraguans, are likely to find clean fuels or stoves unaffordable in 2030. A targeted subsidy on modern fuels, like liquid petroleum gas (LPG), is the most effective policy mechanism we studied that could provide such support. A 50% subsidy policy on LPG targeted to the rural and urban poor population could, by 2030, make cooking with LPG affordable to an additional 7.3 million people in these countries. We estimate that such a policy would cost about $250 million per year and would have negligible greenhouse gas emissions impacts. Such a policy could also have significant health benefits, preventing about 8,890 premature deaths annually from reduced exposure to cooking-related household pollution in 2030.


Asunto(s)
Culinaria , Fuentes Generadoras de Energía/estadística & datos numéricos , América Central , Clima , Fuentes Generadoras de Energía/economía , Salud , Vivienda , Humanos , Modelos Estadísticos , Políticas , Encuestas y Cuestionarios
18.
Food Nutr Bull ; 39(3): 377-392, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-30068220

RESUMEN

BACKGROUND: Production of rice and wheat increased dramatically in India over the past decades, with reduced proportion of coarse cereals in the food supply. OBJECTIVE: We assess impacts of changes in cereal consumption in India on intake of iron and other micronutrients and whether increased consumption of coarse cereals could help alleviate anemia prevalence. METHODS: With consumption data from over 800 000 households, we calculate intake of iron and other micronutrients from 84 food items from 1983 to 2011. We use mixed-effect models to relate state-level anemia prevalence in women and children to micronutrient consumption and household characteristics. RESULTS: Coarse cereals reduced from 23% to 6% of calories from cereals in rural households (10% to 3% in urban households) between 1983 and 2011, with wide variations across states. Loss of iron from coarse cereals was only partially compensated by increased iron from other cereals and food groups, with a 21% (rural) and 11% (urban) net loss of total iron intake. Models indicate negative association between iron from cereals and anemia prevalence in women. The benefit from increased iron from coarse cereals is partially offset by the adverse effects from antinutrients. For children, anemia was negatively associated with heme-iron consumption but not with iron from cereals. CONCLUSIONS: Loss of coarse cereals in the Indian diet has substantially reduced iron intake without compensation from other food groups, particularly in states where rice rather than wheat replaced coarse cereals. Increased consumption of coarse cereals could reduce anemia prevalence in Indian women along with other interventions.


Asunto(s)
Anemia Ferropénica/etiología , Dieta , Grano Comestible , Conducta Alimentaria , Hierro/administración & dosificación , Micronutrientes/administración & dosificación , Valor Nutritivo , Adolescente , Adulto , Anemia/epidemiología , Anemia/etiología , Anemia Ferropénica/epidemiología , Anemia Ferropénica/prevención & control , Preescolar , Ingestión de Energía , Femenino , Hemo , Humanos , India/epidemiología , Lactante , Deficiencias de Hierro , Masculino , Micronutrientes/deficiencia , Persona de Mediana Edad , Estado Nutricional , Prevalencia , Población Rural , Adulto Joven
19.
J Pediatr Orthop B ; 14(1): 10-5, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15577301

RESUMEN

To study how a femoral osteotomy alters the natural evolution of Perthes' disease, records and radiographs of 640 patients with Perthes' disease were analyzed. The data of 314 patients who underwent femoral osteotomy were compared with those of non-operated patients. A new modification of classification of the stages of evolution of the disease was used to identify the timing of surgery and to monitor the progress of the disease following surgery. The duration of each stage of the disease, the extent of epiphyseal extrusion, the extent of widening of the femoral metaphysis and the dimensions of the acetabulum were noted on sequential radiographs. The changes in the femoral epiphysis and metaphysis and changes in the acetabulum were also noted. It was observed that a varus osteotomy clearly alters the natural evolution of Perthes' disease. Of patients who were operated in the stage of avascular necrosis, 34% bypassed the stage of fragmentation. The duration of the disease was shorter in these patients. The duration of the stage of fragmentation was reduced in operated children who passed through the stage of fragmentation. The extent of femoral head extrusion was minimized at the stage when it was most vulnerable for deformation. Metaphyseal widening and subsequent femoral head enlargement were also minimized in children who underwent a femoral osteotomy. The chances of retaining the sphericity of the femoral head were much higher in those children who had a femoral osteotomy. These beneficial effects of a varus osteotomy, were most evident when the operation was performed either in the stage of avascular necrosis or in the early stage of fragmentation.


Asunto(s)
Fémur/cirugía , Enfermedad de Legg-Calve-Perthes/diagnóstico por imagen , Enfermedad de Legg-Calve-Perthes/cirugía , Osteotomía/métodos , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Enfermedad de Legg-Calve-Perthes/fisiopatología , Masculino , Probabilidad , Radiografía , Rango del Movimiento Articular/fisiología , Valores de Referencia , Remisión Espontánea , Medición de Riesgo , Índice de Severidad de la Enfermedad , Resultado del Tratamiento
20.
Avicenna J Med ; 2(3): 54-59, 2012 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23826547

RESUMEN

For a total knee replacement (TKR) to function well, the patella must track centrally in the trochlear groove. Lateral retinacular release (LR) is performed as an integral step in TKR to avoid maltracking. Patellar resurfacing and infra patellar fat pad excision are other small surgical procedures performed during TKR that can also easily deprive the patella of its vascularity. A three phase bone scan helps in the assessment of patellar vascularity. Literature review reveals a variable association (10-56%) of LR and patellar hypovascularity in Caucasians. OBJECTIVE: LR release done in TKR is known to compromise patellar viability, while its extent and severity is still debated. Our prospective study was undertaken to evaluate the effects of LR on patella along with other variables like patellar resurfacement, fat pad excision, patelloplasty on knees by 99mTechnetium labeled methylene diphosphonate (99mTc MDP) three phase bone scintigraphy (TBS). MATERIALS AND METHODS: 45 TKRs were done between Jan 05 and Jan 06. Of them, 15 patients (21 knees) of primary TKR were considered prospectively. Patients undergoing uni/bilateral TKR due to symptomatic knee osteoarthritis were only selected for this study. Pre- and immediate postoperative TBS was done with modified positioning of knee joints (adducted, externally rotated and flexed to 30°) to visualize patellae away from knee joint, which otherwise gets superimposed on the femoral condyles. A follow-up TBS at 8-10 weeks was done in patients showing immediate post-op patellar hypovascularity. RESULTS: 12/21 knees (57%) needed LR. Of these 12 knees, 8 (66%) showed hypovascularity; whereas 9 knees with no LR, 1 knee showed hypovascularity. All 9 knees (8 post LR+1 without LR) with hypovascularity underwent TBS again at 8-10 weeks and were found to show improvement in their vascularity status in all cases. CONCLUSION: Our study showed a higher incidence of LR in our population (57%). Association of LR and patellar ischemia was significant, about 16 times the risk. MDP bone scintigraphy is the only objective tool to quantify patellar vascularity. Overall 42.8% knees post-TKR had a transient patellar ischemia, and 38% of them were following LR. All of them recovered at 8-10 weeks postoperatively.

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