Improved PET/MRI accuracy by use of static transmission source in empirically derived hardware attenuation correction

Background Accurate quantification of radioactivity, measured by an integrated positron emission tomography (PET) and magnetic resonance imaging (MRI) system, is still a challenge. One aspect of such a challenge is to correct for the hardware attenuation, such as the patient table and radio frequency (RF) resonators. For PET/MRI systems, computed tomography (CT) is commonly used to produce hardware attenuation correction (AC) maps, by converting Hounsfield units (HU) to a linear attenuation coefficients (LAC) map at the PET energy level 511 keV, using a bilinear model. The model does not address beam hardening, nor higher density materials, which can lead to inaccurate corrections. Purpose In this study, we introduce a transmission-based (TX-based) AC technique with a static Germanium-68 (Ge-68) transmission source to generate hardware AC maps using the PET/MRI system itself, without the need for PET or medical CT scanners. The AC TX-based maps were generated for a homogeneous cylinder, made of acrylic as a validator. The technique thereafter was applied to the patient table and posterior part of an RF-phased array used in cardiovascular PET/MRI imaging. The proposed TX-based, and the CT-based, hardware maps were used in reconstructing PET images of one cardiac patient, and the results were analysed and compared. Results The LAC derived by the TX-based method for the acrylic cylinder is estimated to be 0.10851 ± 0.00380 cm−1 compared to the 0.10698 ± 0.00321 cm−1 theoretical value reported in the literature. The PET photon counts were reduced by 8.7 ± 1.1% with the patient table, at the region used in cardiac scans, while the CT-based map, used for correction, over-estimated counts by 4.3 ± 1.3%. Reconstructed in vivo images using TX-based AC hardware maps have shown 4.1 ± 0.9% mean difference compared to those reconstructed images using CT-based AC. Conclusions The LAC of the acrylic cylinder measurements using the TX-based technique was in agreement with those in the literature confirming the validity of the technique. The over-estimation of photon counts caused by the CT-based model used for the patient table was improved by the TX-based technique. Therefore, TX-based AC of hardware using the PET/MRI system itself is possible and can produce more accurate images when compared to the CT-based hardware AC in cardiac PET images

Preoperative bowel stimulation prior to ileostomy closure to restore bowel function more quickly and improve postoperative outcomes: a systematic review

Aim Closure of a diverting ileostomy following restorative surgery is often associated with significant short‐term morbidity and variable long‐term bowel function. The aim of this systematic review was to investigate if preoperative stimulation of the defunctioned bowel restores bowel function more quickly after ileostomy closure and improves postoperative outcomes when compared with standard preoperative care. Method MEDLINE, Embase, CENTRAL, Google Scholar and ClinicalTrials.gov were searched for studies evaluating preoperative bowel stimulation in patients with a temporary ileostomy after low anterior resection or ileal pouch–anal anastomosis, regardless of their design, publication type or language. Study selection, data extraction and study assessment were performed by one reviewer and verified by another. Study results were synthesized narratively. The GRADE approach was used to assess the quality of evidence. Results Eight studies involving a total of 267 participants were included. The studies had a moderate to high risk of bias and were of varying methodological quality. Preoperative stimulation of the defunctioned bowel reduced the time to postoperative restoration of bowel function and the length of hospital stay when compared with standard preoperative care. Other functional outcomes and postoperative complication rates were similar to those of standard preoperative care. The overall quality of evidence was very low. Conclusion Despite these promising early results, there is insufficient high‐quality evidence to recommend routine implementation of preoperative bowel stimulation in clinical practice. Nevertheless, there is no evidence suggesting that the intervention worsens outcomes or is unsafe, paving the way for rigorous assessment of effectiveness, acceptability and cost‐effectiveness within the context of well‐designed clinical trials

Assessment of a novel 32-channel phased array for cardiovascular hybrid PET/MRI imaging: MRI performance.

BACKGROUND: Cardiovascular imaging using hybrid positron emission tomography (PET) and magnetic resonance imaging (MRI) requires a radio frequency phased array resonator capable of high acceleration factors in order to achieve the shortest breath-holds while maintaining optimal MRI signal-to-noise ratio (SNR) and minimum PET photon attenuation. To our knowledge, the only two arrays used today for hybrid PET/MRI cardiovascular imaging are either incapable of achieving high acceleration or affect the PET photon count greatly. PURPOSE: This study is focused on the evaluation of the MRI performance of a novel third-party prototype 32-channel phased array designed for simultaneous PET/MRI cardiovascular imaging. The study compares the quality parameters of MRI parallel imaging, such as g-factor, noise correlation coefficients, and SNR, to the conventional arrays (mMR 12-channel and MRI-only 32-channel) currently used with hybrid PET/MRI systems. The quality parameters of parallel imaging were estimated for multiple acceleration factors on a phantom and three healthy volunteers. Using a Germanium-68 (Ge-68) phantom, preliminary measurements of PET photon attenuation caused by the novel array were briefly compared to the photon counts produced from no-array measurements. RESULTS: The global mean of the g-factor and SNR CONCLUSIONS: The MRI performance of the novel PET/MRI 32-channel array qualifies it to be a viable alternative to the conventional arrays for cardiovascular hybrid PET/MRI. A detailed evaluation of the novel array\u27s PET performance remains to be conducted, but cursory assessment promises significantly reduced attenuation

Rice Bran as an Alternative Feedstuff in Broiler Nutrition and Impact of Liposorb® and Vitamin E-Se on Sustainability of Performance, Carcass Traits, Blood Biochemistry, and Antioxidant Indices

The impact of dietary rice bran with or without feed additives on the performance, carcasses, and blood profiles of chickens was examined. A total of 245 unsexed one-week-old broiler chicks were divided into seven groups, with seven replications of five chicks each. The treatments were: (1) control, (2) 5% rice bran, (3) 5% rice bran + 0.5 g/kg of Liposorb®, (4) 5% rice bran + 1 g/kg of vitamin E-Se, (5) 10% rice bran, (6) 10% rice bran + 0.5 g/kg Liposorb®, and (7) 10% rice bran + 1 g/kg of vitamin E–selenium. Considering the entire experimental period, it did not affect the in vivo performance of the broilers. However, all the experimental diets decreased dressing % compared with the control (p < 0.01) and the worst values were obtained for the 10% RB groups (75.7, 75.9, and 75.8%, respectively, for 10%RB, 10%RB + Liposorb, and 10%RB + Vit. E-Se groups). All the experimental diets decreased (p < 0.01) the albumin/globulin ratio due to an increased level of serum globulins. Differences in lipid profiles, antioxidants, and immunity parameters in plasma were not related to dietary treatments. In conclusion, the use of rice bran up to 10% in diets had no harmful effect on the overall growth performance of the broilers from 1 to 5 weeks of age. Still, carcass characteristics were negatively affected, except for heart percentage. In addition, the supplementation of Liposorb® or vitamin E-Se to rice bran diets did not recover these harmful effects. Thus, rice bran could be utilized at 10% in broiler diets when growth performance was considered; further research is required

High-dose Sitagliptin for Systemic Inhibition of Dipeptidylpeptidase-4 to Enhance Engraftment of Single Cord Umbilical Cord Blood Transplantation

Delayed engraftment remains a limitation of umbilical cord blood (UCB) transplantation. We previously showed that inhibition of dipeptidylpeptidase (DPP)-4 using sitagliptin 600 mg daily was safe with encouraging results on engraftment, but inhibition was not sustained. We evaluated the efficacy and feasibility of higher doses of sitagliptin to enhance engraftment of UCB in patients with hematological cancers. Fifteen patients, median age 41 (range, 18-59) years, received single UCB grafts matched at 4 (n=11) or 5 (n=4) of 6 HLA loci with median nucleated cell dose of 3.5 (range, 2.57-4.57) x10(7)/kg. Sitagliptin 600 mg every 12 hours was administered days -1 to +2. All patients engrafted by day 30, with 12 (80%) engrafting by day 21. The median time to neutrophil engraftment was 19 (range, 12-30) days. Plasma DPP-4 activity was better inhibited with a mean residual trough DPP-4 activity of 70%+/-19%. Compared to patients previously treated with 600 mg/day, sitagliptin 600 mg every 12 hours appeared to improve engraftment, supporting the hypothesis that more sustained DPP-4 inhibition is required. In-vivo inhibition of DPP-4 using high-dose sitagliptin compares favorably with other approaches to enhance UCB engraftment with greater simplicity, and may show synergy in combination with other strategies

Influencia del tratamiento con microondas sobre la estabilidad del aceite de oliva.

The fruits of Picual and Shemlalli olive cultivars were exposed to microwaves generated from an oven at low and moderate power settings for 3, 6, 9 and 12 min. The physicochemical constants and fatty acid composition of the olive oil samples extracted from nonmicrowaved and microwaved fruits were determined. The data demonstrated that microwaves did not alter the values of the above mentioned parameters compared with the oil extracted from nonmicrowaved fruits. Quality assurance tests (acid, peroxide and TBA values) elucidated that microwaves generally increased the olive oil stability of Picual and Shemlalli cultivars during storage. In addition, microwaves generated from oven at moderate power setting for 12 min. exhibited an antioxidant power on olive oil equivalent to that possessed by BHT at 200 ppm.Aceitunas de las variedades Picual y Shemlalli fueron expuestas a una fuente de microondas generadas en un horno a potencia baja y moderada durante 3, 6, 9 y 12 minutos. Se determinaron las constantes físico-químicas y la composición en ácidos grasos de muestras de aceite de oliva extraído de aceitunas irradiadas y no irradiadas con microondas. Los datos demostraron que la irradiación con microondas no altera los valores de los parámetros antes mencionados si se compara con el aceite extraído de aceitunas no irradiadas. Los tests de garantía de calidad (índice de acidez, índice de peróxido y TBA) mostraron que la irradiación con microonda aumentó la estabilidad del aceite de oliva de las variedades Picual y Shemlalli durante su almacenamiento. En suma, la irradiación con microondas generadas en horno a potencia moderada durante 12 minutos produce un poder antioxidante sobre el aceite de oliva equivalente al que se obtuvo con el BHT a 200 ppm

Modulatory effect of thymol on the immune response and susceptibility to Aeromonas hydrophila infection in Nile tilapia fish exposed to zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO-NPs) have many exciting properties that make their use in a continuous increase in various biomedical, industrial, and agricultural applications. This is associated with accumulation in the aquatic ecosystems and fish exposure with consequent deleterious effects. To determine the potential of thymol to counteract the immunotoxic effects of ZnO-NPs, Oreochromis niloticus was exposed to ZnO-NPs (⅕ LC50 =1.14 mg/L, for 28 days) with or without feeding a thymol-incorporated diet (1 or 2 g/kg diet). Our data demonstrated a reduction of aquaria water quality, leukopenia, and lymphopenia with a decrease in serum total protein, albumin, and globulin levels in exposed fish. At the same time, the stress indices (cortisol and glucose) were elevated in response to ZnO-NPs exposure. The exposed fish also revealed a decline in serum immunoglobulins, nitric oxide, and the activities of lysozyme and myeloperoxidase, in addition to reduced resistance to the Aeromonas hydrophila challenge. The RT-PCR analysis showed downregulation of antioxidant (SOD) superoxide dismutase and (CAT) catalase gene expression in the liver tissue with overexpression of the immune-related genes (TNF-α and IL-1β). Importantly, we found that thymol markedly protected against ZnO-NPs-induced immunotoxicity in fish co-supplemented with thymol (1 or 2 g/kg diet) in a dose-dependent manner. Our data confirm the immunoprotective and antibacterial effects of thymol in ZnO-NPs exposed fish, supporting the potential utility of thymol as a possible immunostimulant agent

Modeling Sitagliptin Effect on Dipeptidyl Peptidase 4 (DPP4) Activity in Adults with Hematological Malignancies After Umbilical Cord Blood (UCB) Hematopoietic Cell Transplant (HCT)

Background and Objectives— Dipeptidyl peptidase-4 (DPP4) inhibition is a potential strategy to increase the engraftment rate of hematopoietic stem/progenitor cells. A recent clinical trial using sitagliptin, a DPP4 inhibitor approved for type 2 diabetes mellitus, has shown to be a promising approach in adults with hematological malignancies after umbilical cord blood (UCB) hematopoietic cell transplant (HCT). Based on data from this clinical trial, a semi-mechanistic model was developed to simultaneously describe DPP4 activity after multiple doses of sitagliptin in subjects with hematological malignancies after a single-unit UCB HCT. Methods— The clinical study included 24 patients that received myeloablative conditioning followed by 4 oral sitagliptin 600mg with single-unit UCB HCT. Using a nonlinear mixed effects approach, a semi-mechanistic pharmacokinetic/pharmacodynamic model was developed to describe DPP4 activity from this trial data using NONMEM 7.2. The model was used to drive Monte-Carlo simulations to probe various dosage schedules and the attendant DPP4 response. Results— The disposition of sitagliptin in plasma was best described by a 2-compartment model. The relationship between sitagliptin concentration and DPP4 activity was best described by an indirect response model with a negative feedback loop. Simulations showed that twice a day or three times a day dosage schedules were superior to once daily schedule for maximal DPP4 inhibition at the lowest sitagliptin exposure. Conclusion— This study provides the first pharmacokinetic/pharmacodynamic model of sitagliptin in the context of HCT, and provides a valuable tool for exploration of optimal dosing regimens, critical for improving time to engraftment in patients after UCB HCT

Cera de abejas y su insaponificable como conservante natural para mantequilla y aceites de semilla de algodón

Simple model systems consisting of butter oil or refined cottonseed oil mixed with melted bees wax and its unsaponifiables were designated to study their hydrolytic and oxidative rancidity during storage. Whole bees wax at 0,5 and 1% levels possessed significant pro-hydrolytic activity whilst its unsaponifiables at 0,25 and 0,5% exhibited antihydrolytic effect on butter oil. The addition of whole bees wax at 0,5 and 1 % caused no effect on peroxide and thiobarbituric acid values of butter oil. However, bees wax unsaponifiables significantly reduced both peroxide and thiobarbituric acid values of stored butter oil. Bees wax unsaponifiables added to refined cottonseed oil had no effect on the acid value, whilst whole bees wax possessed significant prohydrolytic activity. The data for peroxide and thiobarbituric acid values of refined cottonseed oil demonstrated that both whole bees wax and its unsaponifiables had approximately the same antioxidant efficacy. The effectiveness of the added materials on the secondary oxidation products of refined cottonseed oil can be ranked according to its inhibition activity as follows: BHT (200 ppm) > bees wax (1%) > bees wax (0,5%) > bees wax unsaponifiables (0,5%) > bees wax unsaponifiables (0,25%) > control.aceites de semilla de algodón Sistemas modelo simples consistentes en aceite de mantequilla o aceite de semilla de algodón refinado mezclado con cera de abeja derretida y su insaponificable fueron diseñados para estudiar su rancidez oxidativa e hidrolítica durante el almacenamiento. La cera de abeja íntegra a niveles del 0,5 y 1% tuvo una actividad pro-hidrolítica significativa, mientras que su insaponificable al 0,25 y 0,5% exhibió efecto antihidrolítico sobre el aceite de mantequilla. La adición de cera de abeja íntegra al 0,5 y 1% no causó efecto sobre el índice de peróxido y ácido tiobarbitúrico del aceite de mantequilla. Sin embargo, el insaponificable de cera de abeja redujo significativamente tanto el índice de peróxido como el de ácido tiobarbitúrico de aceite de mantequilla almacenado. El insaponificable de cera de abeja añadido al aceite de semilla de algodón refinado no tuvo efecto sobre el índice de acidez, mientras la cera de abeja íntegra mostró una actividad prohidrolítica significativa. Los valores para el índice de peróxido y ácido tiobarbitúrico del aceite de semilla de algodón refinado demostraron que tanto la cera de abeja íntegra como su insaponificable tuvieron aproximadamente la misma eficacia antioxidante. La efectividad de las sustancias añadidas sobre los productos de oxidación secundarios del aceite de semilla de algodón refinado pueden ser colocados de acuerdo con su actividad inhibitoria de la siguiente forma: BHT (200 ppm) > cera de abeja (1%) > cera de abeja (0,5%) > insaponificable de cera de abeja (0,5%) > insaponificable de cera de abeja (0,25%) > control