Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 610
Filtrar
1.
Biomed Phys Eng Express ; 10(5)2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-38906125

RESUMEN

Purpose/Objective. Small-field measurement poses challenges. Although many high-resolution detectors are commercially available, the EPID for small-field dosimetry remains underexplored. This study aimed to evaluate the performance of EPID for small-field measurements and to derive tailored correction factors for precise small-field dosimetry verification.Material/Methods. Six high-resolution radiation detectors, including W2 and W1 plastic scintillators, Edge-detector, microSilicon, microDiamond and EPID were utilized. The output factors, depth doses and profiles, were measured for various beam energies (6 MV-FF, 6 MV-FFF, 10 MV-FF, and 10 MV-FFF) and field sizes (10 × 10 cm2, 5 × 5 cm2, 4 × 4 cm2, 3 × 3 cm2, 2 × 2 cm2, 1 × 1 cm2, 0.5 × 0.5 cm2) using a Varian Truebeam linear accelerator. During measurements, acrylic plates of appropriate depth were placed on the EPID, while a 3D water tank was used with five-point detectors. EPID measured data were compared with W2 plastic scintillator and measurements from other high-resolution detectors. The analysis included percentage deviations in output factors, differences in percentage for PDD and for the profiles, FWHM, maximum difference in the flat region, penumbra, and 1D gamma were analyzed. The output factor and depth dose ratios were fitted using exponential functions and fractional polynomial fitting in STATA 16.2, with W2 scintillator as reference, and corresponding formulae were obtained. The established correction factors were validated using two Truebeam machines.Results. When comparing EPID and W2-PSD across all field-sizes and energies, the deviation for output factors ranged from 1% to 15%. Depth doses, the percentage difference beyond dmax ranged from 1% to 19%. For profiles, maximum of 4% was observed in the 100%-80% region. The correction factor formulae were validated with two independent EPIDs and closely matched within 3%.Conclusion. EPID can effectively serve as small-field dosimetry verification tool with appropriate correction factors.


Asunto(s)
Aceleradores de Partículas , Radiometría , Radiometría/instrumentación , Radiometría/métodos , Aceleradores de Partículas/instrumentación , Diseño de Equipo , Fantasmas de Imagen , Calibración , Humanos , Conteo por Cintilación/instrumentación , Conteo por Cintilación/métodos , Reproducibilidad de los Resultados
2.
Hernia ; 28(3): 857-862, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38388814

RESUMEN

PURPOSE: The aim of this study was to examine the postoperative outcomes and follow-up QOL of patients after AWR at a level-1 trauma centre in India. METHODS: The study cohort included AWR patients treated between January 2011 and July 2022. The Activities Assessment Scale (AAS) was used to measure QOL, and the Ventral Hernia Recurrence Inventory (VHRI) was used to determine the occurrence of recurrence. In patients suspected of having recurrence, thorough clinical examination and relevant imaging were performed to confirm or rule out recurrence. RESULTS: Out of 89 patients, 35 patients whose complete perioperative and follow-up data were available were enrolled. The mean age of the patients was 28 (SD, 9) years. The mean defect size was 14. 9 (SD, 7) cm. The mean time from laparotomy to AWR surgery was 21 months. During the postoperative course, 37% of patients developed complications, such as SSI and seroma. The mean follow-up time was 53 (SD, 43) months. Upon comparing procedures involving the mesh placed in the sublay position with procedures involving the mesh placed in other positions, no statistically significant difference in the recurrence rate (one in each group, p = 0.99), surgical complication rate (33% v/s 66%, p = 0.6), or mean AAS QOL score (94.7 v/s 98, p = 0.4) was observed. The specificity of the VHRI for diagnosing recurrence was 79%. CONCLUSION: Overall, the recurrence rate was low in these patients despite the presence of large hernia defects. Long-term QOL was not affected by the specific procedure used. Timely planning and execution are more important than the specific repair approach for post-trauma laparotomy ventral hernia.


Asunto(s)
Hernia Ventral , Herniorrafia , Calidad de Vida , Centros Traumatológicos , Humanos , Hernia Ventral/cirugía , Masculino , Adulto , India , Femenino , Herniorrafia/efectos adversos , Herniorrafia/métodos , Laparotomía , Recurrencia , Pared Abdominal/cirugía , Mallas Quirúrgicas , Adulto Joven , Estudios de Seguimiento , Persona de Mediana Edad , Complicaciones Posoperatorias
3.
Environ Sci Technol ; 57(48): 19545-19556, 2023 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-37956986

RESUMEN

Methane emissions from oil and gas production provide an important contribution to global warming. We investigate 2020 emissions from the largest gas field in Algeria, Hassi R'Mel, and the oil-production-dominated area Hassi Messaoud. We use methane data from the high-resolution (20 m) Sentinel-2 instruments to identify and estimate emission time series for 11 superemitters (including 10 unlit flares). We integrate this information in a transport model inversion that uses methane data from the coarser (7 km × 5.5 km) but higher-precision TROPOMI instrument to estimate emissions from both the 11 superemitters (>1 t/h individually) and the remaining diffuse area source (not detected as point sources with Sentinel-2). Compared to a bottom-up inventory for 2019 that is aligned with UNFCCC-reported emissions, we find that 2020 emissions in Hassi R'Mel (0.16 [0.11-0.22] Tg/yr) are lower by 53 [24-73]%, and emissions in Hassi Messaoud (0.22 [0.13-0.28] Tg/yr) are higher by 79 [4-188]%. Our analysis indicates that a larger fraction of Algeria's methane emissions (∼75%) come from oil production than national reporting suggests (5%). Although in both regions the diffuse area source constitutes the majority of emissions, relatively few satellite-detected superemitters provide a significant contribution (24 [12-40]% in Hassi R'Mel; 49 [27-71]% in Hassi Messaoud), indicating that mitigation efforts should address both. Our synergistic use of Sentinel-2 and TROPOMI can produce a unique and detailed emission characterization of oil and gas production areas.


Asunto(s)
Contaminantes Atmosféricos , Gas Natural , Gas Natural/análisis , Metano/análisis , Argelia , Contaminantes Atmosféricos/análisis , Yacimiento de Petróleo y Gas
4.
Lymphology ; 56(1): 3-12, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38019875

RESUMEN

Liposuction for treatment of lymphedema is an effective and time-tested treatment. However, as there is a fear regarding further lymphatic damage caused by liposuction, we objectively compared lymphatic function pre- and post-liposuction. All patients with solid-predominant lymphedema who were treated during the study period of June 2014 and November 2018 were included. Patients were assessed using patient-reported baselines/outcomes, lymphedema- specific quality of life scale (LYMQOL), limb circumference/volume measurements, and indocyanine green lymphography (ICGL) preoperatively and at predefined postoperative time intervals. Fifty-seven limbs from 41 patients were included. Mean lipoaspirate volumes were 2035 mL, 5385 mL, and 3106 mL for the arm, thigh, and leg, respectively with a mean adipose fraction of the lipoaspirate of 71%. All patients underwent redundant skin excision with the "flying squirrel" technique. The mean follow-up was 10.7 months (range 3 - 48 months) with a mean limb volume reduction of 32.2% and all patients reporting satisfactory relief of symptoms. All showed statistically significant improvement in LYMQOL in symptoms, appearance, and function. On ICGL, none showed worsened lymphatic drainage, rather, all showed improved lymph drainage. Furthermore, the improved lymph drainage was found to be progressive during the study period in all patients. Our study results demonstrate that treating extremity lymphedema with liposuction does not worsen lymphatic function and in fact, paradoxically, it induces progressive improvement in lymph drainage.


Asunto(s)
Lipectomía , Vasos Linfáticos , Linfedema , Humanos , Lipectomía/efectos adversos , Lipectomía/métodos , Calidad de Vida , Linfedema/diagnóstico , Linfedema/etiología , Linfedema/cirugía , Vasos Linfáticos/cirugía , Linfografía/métodos , Verde de Indocianina
5.
Mymensingh Med J ; 32(4): 1189-1197, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37777920

RESUMEN

In an attempt to deal with their workload and stressful atmosphere, medical students often cut down on their sleep. Sleep not only has an impact on cognitive functions, but it is also essential for stress recovery and tiredness removal. The study was done to determine the quality of sleep using the Pittsburgh Sleep Quality Index (PSQI) among medical students in Bhopal. This cross-sectional descriptive questionnaire study of 408 medical (MBBS or MD) students from AIIMS and GMC, Bhopal, was undertaken from June 2020 to September 2020. They were presented with online self-administered questionnaire (Google forms). The Google forms were organized into four sections: student's information sheet, consent form, demographic data (gender, age, and year of education separately for PG and UG) and PSQI questionnaires. The mean age of all undergraduate and post graduate students (n=408) volunteered to participated in this study was 21.76±3.01 years of which 170 students (41.7%) had age less than: ≤20 years, 23(56.9%) between 21-30 years and 06(1.5%) of the participants had age between 31-40 years. The age (years) ranged from 18-38 years. The number of male and female students were 251(61.5%) and 157(38.5%) respectively. Out of the total number of participants, 335(82.1%) were MBBS students and 73(17.9%) were MD/MS students. N-parametric tests (Kruskal Wallis Test) were used to make group comparisons. The mean global score for MBBS and Post graduate students were 6.11±3.06 and 6.00±3.64 respectively which reflect poor quality of sleep. Variables of sleep latency, sleep duration and daytime dysfunction were variables were significantly associated (p<0.05). There should be more academic counseling facilities at medical schools that emphasize the need of getting enough sleep.


Asunto(s)
Estudiantes de Medicina , Humanos , Masculino , Femenino , Adulto , Adolescente , Adulto Joven , Calidad del Sueño , Estudios Transversales , Sueño , Encuestas y Cuestionarios
6.
Plant Biol (Stuttg) ; 25(5): 757-770, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37249151

RESUMEN

Withania somnifera is an important medicinal plant, however, its cultivation and quality are compromised through infestation by leaf spot disease caused by the fungus, Alternaria alternata. To find suitable strategies against this disease, studies on post-infectional changes are important. ROS are critical as they interact with other defence signalling pathways. We analyzed ROS-generating and scavenging systems in healthy and diseased leaf samples of W. somnifera and ROS-driven downstream defence pathways. We used DAB and NBT assays for ROS detection, spectrophotometry and in-gel assays for ROS scavenging enzymes, a thioglycolic acid (TGA) based assay, histochemical staining for lignin, and qRT-PCR for transcript-level expression. Leaf spot infection in W. somnifera increased NADPH oxidase activity and ROS accumulation in infected leaves, together with enhanced antioxidant enzyme activity. Leaf spot-infected leaves had increased lignin content and higher expression of lignin biosynthesis genes. In addition, transcript levels of defence-related genes, NPR1 and PR, were also upregulated. The present work provides insights into responses to leaf spot disease through defence-related signalling in W. somnifera. It demonstrates crosstalk between ROS and lignin biosynthesis. This work identified potential targets for developing strategies to confer disease resistance against A. alternata in W. somnifera.


Asunto(s)
Plantas Medicinales , Withania , Especies Reactivas de Oxígeno/metabolismo , Withania/genética , Withania/metabolismo , Lignina/metabolismo , Plantas Medicinales/química , Metabolismo Secundario , Antioxidantes/metabolismo
7.
J Hand Surg Am ; 48(5): 515.e1-515.e5, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36922292

RESUMEN

Peripheral neuropathy can affect sensory, motor, or autonomic nerves and manifest with a variety of symptoms. Tuberculosis as a major infectious disease that often affects many organs of the body. However, primary involvement of peripheral nerves is unusual. Peripheral neuropathy in patients with tuberculosis often is associated with other comorbidities, such as immunocompromised states, diabetes mellitus, malnutrition, and some antitubercular medications. This report describes the rare finding of peripheral tubercular neuritis with caseating abscesses of right median and radial nerve in a healthy 24-year man.


Asunto(s)
Neuritis , Enfermedades del Sistema Nervioso Periférico , Tuberculosis , Masculino , Humanos , Nervios Periféricos , Nervio Radial
8.
Artículo en Inglés | MEDLINE | ID: mdl-36689111

RESUMEN

Previous research on solar box cookers focusing on the bulk usage of energy storage materials is a costly technique for performance enhancement. Bulk energy storage materials take much time to charge and, thus, result in a low rate of cooking at the start. Therefore, a hot box solar cooker has been developed and experimentally studied for thermal performance enhancement in a hilly region of Uttarakhand, India. A bed of phase change material (paraffin wax) filled with small capsule-shaped containers was prepared (detachable) and placed over the cooking tray of the tested cooker. These containers were vertically positioned over the bed to enhance the heat transfer rate inside the cooker to attain a fast-cooking response. Notably, the combined effect of extended geometry with PCM is an excellent method to increase the efficiency of a solar cooker. As per the author's knowledge, likely techniques have not been studied for a box cooker to achieve a fast-cooking rate in any hilly region up to date. The results of cooking tests show that the cooking plate attained a maximum temperature of about 150 °C. It is because of the combined effect of extended fins (vertical capsules) and PCM filled inside them. The results of the experimental study show that the thermal efficiency of the cooker was found to be about 45.7%, the cooking power was calculated about 54.71 W, the heat transfer coefficient was estimated about 311 W/m2 °C, and the overall heat loss coefficient was computed about 5.71 W/m2 °C. This modified cooker costs about $48.19, and the payback period is about 03 years and 11 months. Cooking trials also showed that the present SBC could cook almost all the dishes commonly cooked in Uttarakhand.

9.
Nature ; 612(7939): 228-231, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36477127

RESUMEN

Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive stars1, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars2. A third class of events with hybrid high-energy properties was identified3, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions4-6, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented7,8. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 1042 erg per second) kilonova possibly formed in the ejecta of a compact object merger.


Asunto(s)
Estrellas Celestiales
10.
Front Genet ; 13: 854936, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35991570

RESUMEN

Advances in sugarcane breeding have contributed significantly to improvements in agronomic traits and crop yield. However, the growing global demand for sugar and biofuel in the context of climate change requires further improvements in cane and sugar yields. Attempts to achieve the desired rates of genetic gain in sugarcane by conventional breeding means are difficult as many agronomic traits are genetically complex and polygenic, with each gene exerting small effects. Unlike those of many other crops, the sugarcane genome is highly heterozygous due to its autopolyploid nature, which further hinders the development of a comprehensive genetic map. Despite these limitations, many superior agronomic traits/genes for higher cane yield, sugar production, and disease/pest resistance have been identified through the mapping of quantitative trait loci, genome-wide association studies, and transcriptome approaches. Improvements in traits controlled by one or two loci are relatively easy to achieve; however, this is not the case for traits governed by many genes. Many desirable phenotypic traits are controlled by quantitative trait nucleotides (QTNs) with small and variable effects. Assembling these desired QTNs by conventional breeding methods is time consuming and inefficient due to genetic drift. However, recent developments in genomics selection (GS) have allowed sugarcane researchers to select and accumulate desirable alleles imparting superior traits as GS is based on genomic estimated breeding values, which substantially increases the selection efficiency and genetic gain in sugarcane breeding programs. Next-generation sequencing techniques coupled with genome-editing technologies have provided new vistas in harnessing the sugarcane genome to look for desirable agronomic traits such as erect canopy, leaf angle, prolonged greening, high biomass, deep root system, and the non-flowering nature of the crop. Many desirable cane-yielding traits, such as single cane weight, numbers of tillers, numbers of millable canes, as well as cane quality traits, such as sucrose and sugar yield, have been explored using these recent biotechnological tools. This review will focus on the recent advances in sugarcane genomics related to genetic gain and the identification of favorable alleles for superior agronomic traits for further utilization in sugarcane breeding programs.

12.
Indian Pediatr ; 59(1): 13-20, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34480470

RESUMEN

BACKGROUND: There is minimal information about the association of head growth at different stages of childhood with cognitive ability. OBJECTIVE: To determine the relationship of newborn head size and head growth during infancy, childhood and adolescence with attained education, a proxy for cognitive ability. STUDY DESIGN: Prospective birth cohort study. SETTING: Married women living in South Delhi between 1969 and 1973. PARTICIPANTS: The New Delhi Birth Cohort study followed up 8030 newborns born in 1969-1973 with head circumference, weight and height measurements at birth and 6-12 monthly until adulthood. Of these, 1526 men and women were followed up at the age of 26-32 years. OUTCOMES: Association between years of schooling, as an indicator of cognitive ability, and newborn head circumference and conditional measures of head growth during infancy, childhood and adolescence. RESULTS: In unadjusted analyses, newborn head size was positively associated with years of education [(b (95% CI)=0.30 (0.14 to 0.47) years per SD head circumference], as was head growth from birth to 6 months [b (95% CI)=0.44 (0.28 to 0.60) years per SD conditional head growth], 6 months to 2 years [b (95% CI)=0.31 (0.15 to 0.47) years per SD conditional head growth] and 2 to 11 years [b (95% CI)=0.20 (0.03 to 0.36) years per SD conditional head growth]. There were similar findings for height and body mass index (BMI). In the adjusted model containing all growth measures, gestational age, and socio-economic status (SES) at birth as predictors, only SES was positively associated with educational attainment. CONCLUSION: Educational attainment in this population is positively associated with socioeconomic status and its influence on inter-related early life (fetal, infant and childhood) factors like nutritional status and brain growth.


Asunto(s)
Estatura , Adolescente , Adulto , Peso al Nacer , Índice de Masa Corporal , Estudios de Cohortes , Escolaridad , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Persona de Mediana Edad , Estudios Prospectivos
13.
Kathmandu Univ Med J (KUMJ) ; 20(80): 456-460, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-37795724

RESUMEN

Background Fasciocutaneous reverse sural artery flap is a popular option to treat soft tissue defects in the distal leg, ankle, and foot region. Objective To compare the results of sural artery flap reconstruction between the above ankle and below ankle soft tissue defect. Method It was a retrospective study of sural flap reconstruction of varied etiology for the defect grouped as above ankle and below ankle operated over a period of five years. Flap and graft take-up, rate of primary healing, margin necrosis, and complications were the assessed outcome variables. Result There were a total of 37 patients, 17 cases of the above ankle and 20 cases of below ankle sural flap reconstruction analyzed in the study. Road traffic accident was the most common cause and the mean size of the defect was 40.70 cm2 . The overall flap take-up rate was 94.6%, partial margin necrosis was in 6 patients, and > 50% flap necrosis was in 2 cases. The rate of primary healing, margin necrosis and mean healing time were 17 (100%) vs 12 (60%), 0 vs 8 cases (6 margin necrosis and 2 cases of > 50% of flap necrosis), and 20.04 days vs 22.50 days respectively in the above ankle and below ankle flap reconstruction groups. These differences were statistically significant. Conclusion Fasciocutaneous reverse sural artery flap is an excellent choice for reconstruction of the defect at the distal leg and around the ankle region with a high success rate. Below ankle flap reconstruction showed a higher rate of margin necrosis, longer healing time, and less rate of primary healing as compared to the above ankle group.


Asunto(s)
Procedimientos de Cirugía Plástica , Traumatismos de los Tejidos Blandos , Humanos , Tobillo , Estudios Retrospectivos , Traumatismos de los Tejidos Blandos/cirugía , Complicaciones Posoperatorias , Necrosis/cirugía , Arterias/cirugía
14.
Nature ; 600(7890): 621-624, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34937892

RESUMEN

Magnetars are strongly magnetized, isolated neutron stars1-3 with magnetic fields up to around 1015 gauss, luminosities of approximately 1031-1036 ergs per second and rotation periods of about 0.3-12.0 s. Very energetic giant flares from galactic magnetars (peak luminosities of 1044-1047 ergs per second, lasting approximately 0.1 s) have been detected in hard X-rays and soft γ-rays4, and only one has been detected from outside our galaxy5. During such giant flares, quasi-periodic oscillations (QPOs) with low (less than 150 hertz) and high (greater than 500 hertz) frequencies have been observed6-9, but their statistical significance has been questioned10. High-frequency QPOs have been seen only during the tail phase of the flare9. Here we report the observation of two broad QPOs at approximately 2,132 hertz and 4,250 hertz in the main peak of a giant γ-ray flare11 in the direction of the NGC 253 galaxy12-17, disappearing after 3.5 milliseconds. The flare was detected on 15 April 2020 by the Atmosphere-Space Interactions Monitor instrument18,19 aboard the International Space Station, which was the only instrument that recorded the main burst phase (0.8-3.2 milliseconds) in the full energy range (50 × 103 to 40 × 106 electronvolts) without suffering from saturation effects such as deadtime and pile-up. Along with sudden spectral variations, these extremely high-frequency oscillations in the burst peak are a crucial component that will aid our understanding of magnetar giant flares.


Asunto(s)
Estrellas Celestiales , Atmósfera
15.
Mater Today Bio ; 11: 100123, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-34458715

RESUMEN

Quantum dots (QDs) are semiconductor nanocrystals with unique size-tunable emissions. To obtain a precise emission spectrum, monodispersity in size is imperative, which is achieved by controlling the reaction kinetics in a continuous flow of active microreactors. Further, a multivariate approach (dimensional analysis) is employed to impose stringent control on the reaction process resulting in monodispersed preparation of cadmium telluride (CdTe) quantum dots. Dimensional analysis knits multiple variables into a dimensionless mathematical form which not only predicts parameters precisely to obtain narrow size tunability but also guarantees reproducibility in synthesis. Analytical, structural, and optical characterization of the microreactor synthesized polydimethylsiloxane (PDMS) coated CdTe QDs reveal quantum efficient (61.5%), photostable (44%), and biocompatible nanocrystals of 5-15 nm. Further, PDMS-coated QDs (P-QDs) are conjugated with organelle-specific antibodies/biomarkers for in-vitro imaging in NIH 3T3 cells. Likewise, proliferating cell nuclear antigen (PCNA) and anti-myosin (MF20), cardiomyocytes antibodies are conjugated with P-QDs (red and green, respectively) to image the zebrafish's cardiac tissue. Antibodies tagged with quantum dots are imaged simultaneously using confocal microscopy. Thus, multiplexed bio-imaging of in-vitro and zebrafish tissue is demonstrated successfully. The results indicate the suitability of continuous flow active microreactor in conjunction with the mathematical prediction of process parameters to synthesize reproducibly monodispersed and quantum efficient QDs.

16.
Plant Biol (Stuttg) ; 23(5): 686-694, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33768665

RESUMEN

Reactive oxygen species (ROS) generation within a cell is a natural process of specific subcellular components involved in redox reactions. Within a plant cell, chloroplasts are one of the major sources of ROS generation. Plastid-generated ROS molecules include singlet oxygen (1 O2 ), superoxide radical (O2 - ), hydroxyl radical (OH• ) and hydrogen peroxide (H2 O2 ), which are produced mainly during photochemical reactions of photosynthesis and chlorophyll biosynthetic process. Under normal growth and developmental, generated ROS molecules act as a secondary messenger controlling several metabolic reactions; however, perturbed environmental conditions lead to multi-fold amplification of cellular ROS that eventually kill the target cell. To maintain homeostasis between production and scavenging of ROS, the cell has instituted several enzymatic and non-enzymatic antioxidant machineries to maintain ROS at a physiological level. Among chloroplastic ROS molecules, excess generation of singlet oxygen (1 O2 ) is highly deleterious to the cell metabolic functions and survival. Interestingly, within cellular antioxidant machinery, enzymes involved in detoxification of 1 O2 are lacking. Recent studies suggest that under optimal concentrations, 1 O2 acts as a signalling molecule and drives the cell to either the acclimation pathway or regulated cell death (RCD). Stress-induced RCD is a survival mechanism for the whole plant, while the involvement of chloroplasts and chloroplast-localized molecules that execute RCD are not well understood. In this review, we advocate for participation of chloroplasts-generated 1 O2 in signalling and RCD in plants.


Asunto(s)
Muerte Celular Regulada , Oxígeno Singlete , Cloroplastos , Plastidios , Especies Reactivas de Oxígeno
19.
Tech Coloproctol ; 25(4): 439-447, 2021 04.
Artículo en Inglés | MEDLINE | ID: mdl-33606129

RESUMEN

BACKGROUND: Transanal TME (TaTME) was introduced to improve access to the pelvis in difficult cases (male sex, obesity and mid to low rectal cancers) and reduce the risk of anastomotic leak by avoiding cross stapling. In April 2018 the Norwegian hospital to whom all local; recurrences for rectal cancer are referred reported an unexpected rise in early multifocal local recurrences of 9.5% following TaTME compared with 3.4% following conventional TME leading to a nationwide moratorium on the procedure and ending, in an editorial published on the British Journal of Surgery in August 2020, by saying that other countries should consider the issue in the context of local practices and results. There are limited data concerning oncological outcomes of TaTME compared to conventional TME. The aim of this study was to report perioperative and oncological outcomes for patients with rectal cancer treated with TaTME in a high-volume, experienced UK centre. METHODS: From January 2015 to January 2020 consecutive patients with histologically confirmed rectal cancer having TaTME at Worcestershire Royal Hospital NHS were prospectively entered into an online international registry. Patients were followed according to local protocol with clinical examination, tumour markers, endoscopy and radiology. RESULTS: Seventy patients underwent TaTME for rectal cancer. The median distance of the tumour from the anorectal junction was 4 cm (IQR 2-5). The mesorectal margin was involved in 20 (1%) patients, all of whom received neoadjuvant chemoradiotherapy. Overall survival was 94% at a median follow-up of 15 months (IQR 9-31 months). Distant recurrence occurred in 12 (17%) of patients at a median of 14 months (IQR 10-17 months). The 18-month stoma-free survival rate was 66%. CONCLUSIONS: A local recurrence rate of 5.7% supports the oncological safety of TaTME for rectal cancer.


Asunto(s)
Neoplasias del Recto , Cirugía Endoscópica Transanal , Humanos , Masculino , Recurrencia Local de Neoplasia , Noruega , Estudios Prospectivos , Neoplasias del Recto/cirugía , Recto
20.
Eur J Nucl Med Mol Imaging ; 48(8): 2351-2362, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33420915

RESUMEN

PURPOSE: The aim of this work was to demonstrate the suitability of AAZTA conjugated to PSMA inhibitor (B28110) labeled with scandium-44 as a new PET tracer for diagnostic imaging of prostate cancer. BACKGROUND: Nowadays, scandium-44 has received significant attention as a potential radionuclide with favorable characteristics for PET applications. A polyaminopolycarboxylate heptadentate ligand based on a 1,4-diazepine scaffold (AAZTA) has been thoroughly studied as chelator for Gd3+ ions for MRI applications. The excellent results of the equilibrium, kinetic, and labeling studies led to a preliminary assessment of the in vitro and in vivo behavior of [44Sc][Sc-(AAZTA)]- and two derivatives, i.e., [44Sc][Sc (CNAAZTA-BSA)] and [44Sc][Sc (CNAAZTA-cRGDfK)]. RESULTS: B28110 was synthesized by hybrid approach, combining solid-phase peptide synthesis (SPPS) and solution chemistry to obtain high purity (97%) product with an overall yield of 9%. Subsequently, the radioactive labeling was performed with scandium-44 produced from natural calcium target in cyclotron, in good radiochemical yields (RCY) under mild condition (pH 4, 298 K). Stability study in human plasma showed good RCP% of [44Sc]Sc-B28110 up to 24 h (94.32%). In vivo PET/MRI imaging on LNCaP tumor-bearing mice showed high tracer accumulation in the tumor regions as early as 20 min post-injection. Ex vivo biodistribution studies confirmed that the accumulation of 44Sc-PSMA-617 was two-fold lower than that of the radiolabeled B28110 probes. CONCLUSIONS: This work demonstrated the suitability of B28110 for the complexation with scandium-44 at room temperature and the high performance of the resulting new tracer based on AAZTA chelator for the diagnosis of prostate cancer using PET.


Asunto(s)
Tomografía de Emisión de Positrones , Neoplasias de la Próstata , Animales , Línea Celular Tumoral , Glutamato Carboxipeptidasa II/metabolismo , Humanos , Masculino , Ratones , Neoplasias de la Próstata/diagnóstico por imagen , Radioquímica , Radiofármacos , Distribución Tisular
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...