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1.
Clin Radiol ; 79(3): 163-169, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38114374

RESUMEN

Architectural distortion (AD) is the third most common abnormality detected on mammograms. In the absence of an accurate non-invasive tool to evaluate ADs, clinical management often requires surgical excision for histological diagnosis. This problem is expected to worsen with the growing use of digital breast tomosynthesis (DBT) and the resultant increasing detection of ADs. There is therefore a great clinical need for a diagnostic imaging tool to complement non-enhanced mammography for the evaluation of AD. Contrast-enhanced mammography (CEM) is an emerging breast imaging method that uses contrast media and the principle of dual-energy subtraction to evaluate vascularity of suspicious breast lesions. CEM, a cost-effective alternative to breast magnetic resonance imaging (MRI), can be used to evaluate AD by juxtaposing CEM images with non-enhanced mammograms for comparison. In this review, the authors aim to provide readers with an overview of the interpretation of AD on CEM using imaging examples. Relevant imaging features of CEM and their respective significance will be matched with information from a literature review. Finally, the authors would like to highlight the added value of CEM in relevant clinical applications in the assessment of AD.


Asunto(s)
Neoplasias de la Mama , Mamografía , Humanos , Femenino , Mamografía/métodos , Mama/diagnóstico por imagen , Medios de Contraste , Imagen por Resonancia Magnética , Detección Precoz del Cáncer/métodos , Neoplasias de la Mama/diagnóstico por imagen
2.
Obesity (Silver Spring) ; 21(5): 968-75, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23784898

RESUMEN

OBJECTIVE: To determine the cardiometabolic risks of testosterone and growth hormone (GH) replacement therapy to youthful levels during aging. DESIGN AND METHODS: A double-masked, partially placebo controlled study in 112 men 65-90 years-old was conducted. Transdermal testosterone (5 g vs. 10 g/day) using a Leydig Cell Clamp and subcutaneous recombinant GH (rhGH) (0 vs. 3 vs. 5 µg/kg/day) were administered for 16-weeks. Measurements included testosterone and IGF-1 levels, body composition by DEXA, and cardiometabolic risk factors (upper body fat, blood pressure, insulin sensitivity, fasting triglycerides, HDL-cholesterol, and serum adiponectin) at baseline and after 16 weeks of treatment. RESULTS: Some cardiometabolic factors improved (total and trunk fat, triglycerides, HDL-cholesterol) and others worsened (systolic blood pressure, insulin sensitivity index [QUICKI], adiponectin). Cardiometabolic risk composite scores (CRCSs) improved (-0.69 ± 1.55, P < 0.001). In multivariate analyses, QUICKI, triglycerides, and HDL-cholesterol contributed 33%, 16%, and 14% of the variance in CRCS, respectively. Pathway analyses indicated that changes in fat and lean mass were related to individual cardiometabolic variables and CRCS in a complex manner. Changes in BMI, reflecting composite effects of changes in fat and lean mass, were more robustly associated with cardiometabolic risks than changes in fat mass or LBM individually. CONCLUSIONS: Testosterone and rhGH administration was associated with diverse changes in individual cardiometabolic risk factors, but in aggregate appeared not to worsen cardiometabolic risk in healthy older men after 4-months. The long-term effects of these and similar anabolic therapies on cardiovascular events should be investigated in populations with greater functional limitations along with important health disabilities including upper body obesity and other cardiometabolic risks.


Asunto(s)
Anabolizantes/efectos adversos , Composición Corporal/efectos de los fármacos , Enfermedades Cardiovasculares , Suplementos Dietéticos/efectos adversos , Terapia de Reemplazo de Hormonas/efectos adversos , Hormona de Crecimiento Humana/efectos adversos , Testosterona/efectos adversos , Adiponectina/sangre , Tejido Adiposo/metabolismo , Anciano , Anciano de 80 o más Años , Envejecimiento , Anabolizantes/farmacología , Presión Sanguínea/efectos de los fármacos , Compartimentos de Líquidos Corporales/metabolismo , Índice de Masa Corporal , Enfermedades Cardiovasculares/etiología , HDL-Colesterol/sangre , Método Doble Ciego , Hormona de Crecimiento Humana/farmacología , Humanos , Resistencia a la Insulina , Masculino , Análisis Multivariante , Factores de Riesgo , Testosterona/farmacología , Triglicéridos/sangre
3.
Pediatr Obes ; 8(1): 70-7, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22991241

RESUMEN

UNLABELLED: What is already known about this subject Physical activity declines as children enter puberty. Leptin is cross-sectionally associated with physical activity, but there are conflicting findings on the magnitude and direction of this association. Leptin concentrations fluctuate during puberty, and may impact energy balance. What this study adds Leptin predicts the decline in physical activity during the start of puberty independent of central adiposity. Based on a median split of leptin, girls with low leptin levels have higher levels of physical activity than girls with high leptin levels at the start of puberty. Leptin levels at the start of puberty may provide a biological basis for the age-related physical activity decline in girls. BACKGROUND: Leptin may influence moderate to vigorous physical activity (MVPA) at the start of puberty. The direction and magnitude of this association are unclear. OBJECTIVES: To determine the effect of baseline leptin on MVPA over 1 year in minority girls at high risk for obesity. METHODS: Data came from TRANSITIONS, a longitudinal observational study on the age-related MVPA decline. Fifty peripubertal girls aged 8-11 years at baseline participated. Baseline leptin (ng mL(-1) ) was collected via a duplicated assay using a double antibody radio immune assay. MVPA (min d(-1) ) was measured using accelerometers for at least four 10-h days on a quarterly basis for up to 1 year. RESULTS: Continuous leptin was negatively related to MVPA (P = 0.001) independent of central adiposity at baseline and predicted the MVPA decline over 1 year (P = 0.002). For descriptive purposes, baseline leptin was dichotomized at the sample median into 'high leptin' and 'low leptin' categories to determine whether MVPA trajectories differed between these groups. Girls with 'low leptin' at baseline had significantly higher levels of MPVA at baseline, visit 1 and visit 2 compared to girls with 'high leptin'. CONCLUSIONS: High leptin levels predicted nearly a 12.6% decline in MVPA over 1 year. These findings provide support for the biological basis of declining MVPA as girls enter puberty.


Asunto(s)
Ejercicio Físico , Leptina/sangre , Grupos Minoritarios/estadística & datos numéricos , Actividad Motora , Obesidad/sangre , Pubertad/sangre , Composición Corporal , Niño , Femenino , Humanos , Estudios Longitudinales , Los Angeles/epidemiología , Obesidad/epidemiología , Esfuerzo Físico , Valor Predictivo de las Pruebas , Factores de Riesgo
4.
Biotechnol Adv ; 27(6): 764-781, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19539744

RESUMEN

Worldwide demand for energy has been the impetus for research to produce alcohol biofuels from renewable resources. This review focuses on the biosynthesis of butanol, which is regarded to be superior to ethanol as a fuel. Although acetone/butanol fermentation is one of the oldest large-scale fermentation processes, butanol yield by anaerobic fermentation remains sub-optimal. Metabolic engineering provides a means for fermentation improvements. Consequently, a comprehensive assessment of the intermediary enzymes involved in butanol formation from carbohydrates by the saccharolytic bacterium, Clostridium acetobutylicum and other closely allied clostridia was performed to provide guidelines for potentially enhancing butanol productivity. The activity of the enzymes, their regulation and contribution to the metabolic pathways was reviewed. Published kinetic data for each important enzymatic reaction were assessed. For most enzymatic reactions, the systematic investigation of the kinetic data and the properties of the enzymes led to the development of rate equations that were able to describe activity as the function of the substrates, products, and allosteric effectors.


Asunto(s)
Butanoles/metabolismo , Clostridium/metabolismo , Clostridium/enzimología , Fermentación , Cinética
5.
Acta Radiol ; 48(4): 401-4, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17453520

RESUMEN

We report a 21-year-old woman with a penetrating abdominal wound. Injuries of the abdominal aorta and alimentary tract were found during emergency surgery. The patient had a follow-up computed tomography (CT) scan 3 months after surgery. Arterial-phase 16-row multidetector computed tomography (MDCT) showed a suspicious dilated vessel adjacent to the repaired aorta on 5-mm transverse images. A fistula between a lumbar artery and the inferior vena cava was clearly demonstrated on images reformatted with two- (2D) and three-dimensional (3D) techniques. The patient suffered from symptoms of high-output heart failure 8 months after surgery.


Asunto(s)
Fístula Arteriovenosa/etiología , Procesamiento de Imagen Asistido por Computador/métodos , Vértebras Lumbares/irrigación sanguínea , Tomografía Computarizada por Rayos X/métodos , Vena Cava Inferior/patología , Heridas Punzantes/complicaciones , Adulto , Aorta Abdominal/lesiones , Arterias/patología , Fístula Arteriovenosa/diagnóstico por imagen , Medios de Contraste , Femenino , Estudios de Seguimiento , Humanos , Imagenología Tridimensional/métodos , Yopamidol , Mesenterio/lesiones , Intensificación de Imagen Radiográfica/métodos , Estómago/lesiones , Vena Cava Inferior/diagnóstico por imagen
6.
Int J Obes (Lond) ; 29(9): 1137-43, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-15925956

RESUMEN

OBJECTIVE: To examine relationships between body mass index (BMI) and psychological correlates in Chinese school adolescents during the period of economic transition. DESIGN: Baseline data of 1655 Chinese adolescents aged 11-15 y were retrieved from a longitudinal smoking cessation and health promotion program in Wuhan, China. Assessments of body weight and height, depressive symptoms, perceived peer isolation (PPI) and perceived availability of social support (PASS) were collected. RESULTS: Based on the International Obesity Task Force (IOTF) age-and sex-specific BMI cutoffs, 12.5% of boys and 9.2% of girls were overweight. In girls, high BMI was significantly related to higher self-reported depressive symptoms, and was dominantly mediated by PPI. On the contrary, high BMI boys reported significantly lower levels of PPI although high PPI level aggravated depressive symptoms. For both girls and boys, the observed effect of PPI on the relationship between BMI and depressive symptoms was sustained only in low PASS boys and girls. CONCLUSIONS: The present study revealed different effects of PPI on the association of BMI and depressive symptoms between boys and girls, which were buffered by levels of PASS. The findings of this study may contribute to our understanding of the influences of psychological correlates in pediatric overweight in the Eastern cultural environment.


Asunto(s)
Índice de Masa Corporal , Depresión/psicología , Grupo Paritario , Aislamiento Social/psicología , Apoyo Social , Adolescente , Niño , Femenino , Humanos , Masculino , Obesidad/psicología , Psicología del Adolescente , Autoimagen , Autoevaluación (Psicología) , Factores Sexuales
7.
Biotechnol Prog ; 18(6): 1458-61, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12467487

RESUMEN

Using fed-batch operation for high-cell-density cultivation, efforts are frequently made for optimization of culture parameters, particularly feeding strategy. The current study also emphasized the importance of selecting strains for the production of recombinant proteins in high-cell-density cultures. With Escherichia coli penicillin acylase (PAC) as a target protein, the host/vector system of MDdeltaP7 harboring pTrcKnPAC2902 and pKS12 was designed for optimization of fed-batch cultivation for recombinant protein production. The host, MDdeltaP7, potentially had a high translational and periplasmic processing efficiency for pac expression. On the other hand, the vector, pTrcKnPAC2902, was genetically constructed for pac overexpression. Coexistence of the other vector, pKS12, significantly enhanced PAC production by improving cell physiology and reducing the amount of inclusion body formation upon pac overexpression. An extremely high volumetric PAC activity at 37,500 U/L was obtained with the use of the developed host/vector system under optimum fed-batch culture conditions.


Asunto(s)
Escherichia coli/metabolismo , Penicilina Amidasa/biosíntesis , Escherichia coli/crecimiento & desarrollo , Vectores Genéticos , Cuerpos de Inclusión , Organismos Modificados Genéticamente , Plásmidos , Proteínas Recombinantes/biosíntesis
8.
Biotechnol Prog ; 18(3): 668-71, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12052092

RESUMEN

High-temperature-oriented production of bacterial penicillin acylase (PAC), which is usually expressed at low temperatures (less than 30 degrees C), was demonstrated in this study via heterologous expression of the Providencia rettgeri (P. rettgeri) pac gene in Escherichia coli (E. coli). While it is possible to produce PAC at a temperature as high as 37 degrees C, the environmental condition (specifically, culture pH) critically affected culture performance. Production of PAC at 37 degrees C was feasible only when culture pH was close to neutral (i.e., 6.5-7.5). Outside this pH range, cell physiology for the host/vector system was seriously affected, resulting in poor culture performance. In acidic culture environments, temperature significantly affected the pac expression level and specific PAC activity decreased with an increase in culture temperature. In basic culture environments, cell growth was seriously inhibited though the pac expression level was minimally affected by temperature. Such unusual types of pH and temperature effects on pac expression were never reported for bacterial PACs. The results suggest that culture pH should be precisely controlled for the current host/vector systems being applied on the overproduction of P. rettgeri PAC in E. coli at high temperatures.


Asunto(s)
Escherichia coli/genética , Calor , Concentración de Iones de Hidrógeno , Penicilina Amidasa/biosíntesis , Providencia/enzimología
9.
Am J Prev Med ; 21(3): 162-9, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11567835

RESUMEN

BACKGROUND: This study reports the prevalence of adolescent smoking in the urban and rural areas of Wuhan, China, the capital of Hubei Province, on the Yangtze River in central China. METHODS: Smoking behavior was examined by age, gender, and urbanicity as part of the Wuhan Smoking Prevention Trial. Subjects included 6994 seventh- to ninth-grade students attending 22 randomly selected schools in urban and rural districts. Outcome measures included lifetime smoking, past-30-day smoking, established smoking (>100 cigarettes in lifetime), and susceptibility to smoking (absence of a firm commitment not to smoke). RESULTS: Lifetime smoking prevalence was 47% among boys and 18% among girls. Past-30-day smoking prevalence was 16% among boys and 4% among girls. Established smoking prevalence was 2% among boys and 0% among girls. The prevalence of susceptibility to smoking was 31% among boys and 10% among girls. Smoking increased significantly with age (p<.0005). Susceptibility was more prevalent in rural areas than in urban areas (p<.05), but there were no urban-rural differences in lifetime, past 30-day smoking, or established smoking. Trend analyses revealed that smoking increased with age more rapidly among boys than among girls (p<.05). Smoking was more prevalent among rural boys than among urban boys, but it was more prevalent among urban girls than among rural girls (p<.05). CONCLUSIONS: Adolescent smoking is a significant public health problem in China. Boys are at particularly high risk, as are girls living in urban areas. Effective smoking prevention programs for adolescents, as well as restrictions on tobacco industry marketing and youth access to tobacco, are needed to prevent tobacco-related morbidity and mortality in China.


Asunto(s)
Fumar/epidemiología , Adolescente , Niño , China/epidemiología , Estudios de Cohortes , Femenino , Humanos , Masculino , Distribución por Sexo , Prevención del Hábito de Fumar , Encuestas y Cuestionarios
10.
Biotechnol Bioeng ; 73(6): 484-92, 2001 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-11344453

RESUMEN

We demonstrated the enhancement of recombinant penicillin acylase (PAC) production in Escherichia coli by increasing the intracellular concentration of the periplasmic protease DegP. Using appropriate host/vector systems (e.g., HB101 harboring pTrcKnPAC2902 or MDDeltaP7 harboring pTrcKnPAC2902) in which the expression of the pac gene was regulated by the strong trc promoter, the overproduction of PAC was often limited by periplasmic processing and inclusion bodies composed of protein aggregates of PAC precursors were formed in the periplasm. The amount of these periplasmic inclusion bodies was significantly reduced and PAC activity was significantly increased upon coexpression of DegP. The specific PAC activity reached an extremely high level of 674 U/L/OD(600) for MDDeltaP7 harboring pTrcKnPAC2902 and pKS12 under optimum culture conditions. However, such improvement in the production of PAC was not observed for the expression systems (e.g., MDDeltaP7 harboring pCLL2902) in which the periplasmic processing was not the step limiting the production of PAC. The results suggest that DegP could in vivo assist the periplasmic processing though the enzyme is shown to be not absolutely required for the formation of active PAC in E. coli. In addition, the steps limiting the production of PAC are identified and the reasons for the formation of PAC inclusion bodies are discussed here.


Asunto(s)
Escherichia coli/genética , Proteínas de Choque Térmico , Cuerpos de Inclusión/metabolismo , Penicilina Amidasa/genética , Proteínas Periplasmáticas , Ingeniería de Proteínas/métodos , Serina Endopeptidasas/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Precursores Enzimáticos/genética , Precursores Enzimáticos/metabolismo , Regulación Bacteriana de la Expresión Génica , Penicilina Amidasa/metabolismo , Plásmidos/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Serina Endopeptidasas/metabolismo
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