Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
J Org Chem ; 2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-38935873

RESUMO

A nickel-catalyzed direct sulfonylation of alkenes with sulfonyl chlorides has been developed using 1,10-phenanthroline-5,6-dione as the ligand. Unactivated alkenes and styrenes including 1,1-, 1,2-disubstituted alkenes can be subjected to the protocol, and a wide range of vinyl sulfones was obtained in high to excellent yields with good functional group compatibility. Notably, the process did not allow the desulfonylation of sulfonyl chloride or chlorosulfonylation of alkenes. Radical-trapping experiment supported that a sulfonyl free-radical was likely produced and triggered subsequent transformation in the process.

2.
Int Immunopharmacol ; 114: 109595, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36700774

RESUMO

Methotrexate (MTX) is used to treat rheumatoid arthritis, acute leukemia, and psoriasis. MTX can cause certain side effects, such as myelosuppression, while the exact mechanism of myelosuppression caused by MTX is unknown. Notch signaling pathway has been considered to be essential to regulate hematopoietic stem cell (HSC) regeneration and homeostasis, thus contributing to bone marrow hematopoiesis. However, whether MTX affects Notch signaling remains unexplored. Here, our study provides evidence that MTX strongly suppresses the Notch signaling pathway. We found that MTX inhibited the interaction between Nedd4 with Numb, thus restricting K48-linked polyubiquitination of Numb and stabilizing Numb proteins. This in turn inhibited the Notch signaling pathway by reducing Notch1 protein levels. Interestingly, we found that a monomeric drug, Triptolide, is capable of alleviating the inhibitory effect of MTX on Notch signaling pathway. This study promotes our understanding of MTX-mediated regulation of Notch signaling and could provide ideas to alleviate MTX-induced myelosuppression.


Assuntos
Metotrexato , Receptores Notch , Proteínas de Membrana/metabolismo , Metotrexato/farmacologia , Metotrexato/uso terapêutico , Receptor Notch1 , Receptores Notch/metabolismo , Transdução de Sinais , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo
3.
Exp Ther Med ; 23(3): 246, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35222723

RESUMO

Long non-coding RNA (lncRNA) HLA complex group 22 (HCG22) is known to be involved in the occurrence and development of cancer; however, its role in oral squamous cell carcinoma (OSCC) remains unclear. Therefore, the main aim of the present study was to investigate the role and mechanisms of action of lncRNA HCG22 in OSCC cells. The expression levels of lncRNA HCG22 and microRNA (miR)-425-5p in OSCC cells were assessed using reverse transcription-quantitative PCR analysis. Cell proliferation was detected using Cell Counting Kit-8 and colony formation assays. In addition, the expression levels of cell proliferation-related proteins, p27, cyclin E and cyclin-dependent kinase 2, were detected by western blot analysis. The cell invasive ability was detected by Transwell assay, while the cell migratory ability was detected via a wound healing assay. The expression levels of the invasion- and migration-related proteins, MMP2 and MMP9, were measured by western blot analysis. The targeted association between lncRNA HCG22 and miR-425-5p was verified by RNA immunoprecipitation and dual-luciferase reporter assays. The results revealed that lncRNA LCG22 was expressed at low levels, while miR-425-5p was highly expressed in OSCC cell lines, based on bioinformatics analysis. The overexpression of lncRNA HCG22 inhibited the proliferation, invasion and migration of OSCC cells. Moreover, lncRNA HCG22 and miR-425-5p were found to have a direct targeted association, and lncRNA HCG22 inhibited cell proliferation, invasion and migration by targeting miR-425-5p. Collectively, the findings of the present study demonstrated that lncRNA HCG22 may inhibit the proliferation, invasion and migration of OSCC cells by downregulating miR-425-5p expression.

4.
Inorg Chem ; 61(4): 1949-1960, 2022 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-35049293

RESUMO

An organic-inorganic hybrid trigonal pyramidal {SeO3} group, bridged cerium-inlaid polyoxometalate (POM) Na16[Se2Ce4(H2O)8W4(HPIC)4O10][B-ß-SeW8O30]2[Se2W12O46]2·60H2O (1) (HPIC = 2-picolinic acid), containing two disparate selenotungstate (ST) building blocks was synthesized by a one-step assembly strategy, which is established by two asymmetric sandwich-type {[Ce2(H2O)4W2(HPIC)2O4][B-ß-SeW8O30][Se2W12O46]}10- moieties joined by double trigonal pyramidal {SeO3} groups. Its outstanding structural trait is that it contains two types of ST building blocks, Keggin-type [B-ß-SeW8O30]8- and Dawson-like [Se2W12O46]12-, which are extremely rare in ST chemistry. Remarkably, [Se2W12O46]12- is first obtained in lanthanide-inlaid STs. Furthermore, 1@PPy conductive film (PPy = polypyrrole) was prepared by electrochemical polymerization and served as the electrode material, and then nano-gold particles (NGPs) were deposited on the surface of 1@PPy conductive film by an electrochemical deposition method in order to immobilize the aptamer of ochratoxin A. With the help of exonuclease I (EN I), the oxidation peak of the metalized Ag works as the detection signal to achieve the detection of ochratoxin A (OTXA). This study offers an available approach for creating organic-inorganic hybrid heteroatom-bridged lanthanide-inlaid POMs and reveals the likelihood of extending heteroatom-bridged lanthanide-inlaid POMs into electrochemical biosensing applications.


Assuntos
Ânions , Polieletrólitos
5.
Pediatr Nephrol ; 37(9): 2157-2166, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35091836

RESUMO

BACKGROUND: Both the development of kidney function in healthy children and autoregulation ability of kidney function in patients with asymmetric kidneys are important in clinical diagnosis and treatment of kidney-related diseases, but there are however only limited studies. This study aimed to investigate development of kidney function in normal children with healthy symmetric kidneys and autoregulation of the healthy kidney compensating the functional loss of a diseased one in children with asymmetric kidneys. METHODS: Two hundred thirty-seven children (156 male, 81 female) from 0 to 20y (average 4.6y ± 5.1) undergoing 99mTc-MAG3 renography were included, comprising 134 with healthy symmetrically functioning kidneys and 103 with asymmetric kidneys. Clearance was calculated from kidney uptakes at 1-2 min. A developmental model between MAG3 clearance (CL) and patient age in normal group was identified (CL = 84.39Age0.395 ml/min, r = 0.957, p < 0.001). The clearance autoregulation rate in abnormal group with asymmetric kidneys was defined as the ratio of the measured MAG3 clearance and the normal value predicted from the renal developmental model of normal group. RESULTS: No significant difference of MAG3 clearance (p = 0.723) was found between independent abnormal group and normal group. The autoregulation rate of kidney clearance in abnormal group was 94.2% on average, and no significant differences were found between two age groups (p = 0.49), male and female (p = 0.39), and left kidney and right kidney (p = 0.92) but two different grades of asymmetric kidneys (p = 0.02). CONCLUSIONS: The healthy kidney of two asymmetric kidneys can automatically regulate total kidney function up to 94% of two symmetric kidneys in normal children.


Assuntos
Nefropatias , Renografia por Radioisótopo , Criança , Feminino , Homeostase , Humanos , Rim , Masculino , Compostos Radiofarmacêuticos , Estudos Retrospectivos , Tecnécio Tc 99m Mertiatida
6.
Phys Med Biol ; 65(23): 235026, 2020 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-33245053

RESUMO

Current guidelines for administered activity (AA) in pediatric nuclear medicine imaging studies are based on a 2016 harmonization of the 2010 North American Consensus guidelines and the 2007 European Association of Nuclear Medicine pediatric dosage card. These guidelines assign AA scaled to patient body mass, with further constraints on maximum and minimum values of radiopharmaceutical activity. These guidelines, however, are not formulated based upon a rigor-ous evaluation of diagnostic image quality. In a recent study of the renal cortex imaging agent 99mTc-DMSA (Li Y et al 2019), body mass-based dosing guidelines were shown to not give the same level of image quality for patients of differing body mass. Their data suggest that patient girth at the level of the kidneys may be a better morphometric parameter to consider when selecting AA for renal nuclear medicine imaging. The objective of the present work was thus to develop a dedicated series of computational phantoms to support image quality and organ dose studies in pediatric renal imaging using 99mTc-DMSA or 99mTc-MAG3. The final library consists of 50 male and female phantoms of ages 0 to 15 years, with percentile variations (5th to 95th) in waist circumference (WC) at each age. For each phantom, nominal values of kidney volume, length, and depth were incorporated into the phantom design. Organ absorbed doses, detriment-weighted doses, and stochastic risks were assessed using ICRP reference biokinetic models for both agents. In Monte Carlo radiation transport simulations, organ doses for these agents yielded detriment-weighted dose coefficients (mSv/MBq) that were in general larger than current ICRP values of the effective dose coefficients (age and WC-averaged ratios of eDW/e were 1.40 for the male phantoms and 1.49 for the female phantoms). Values of risk index (ratio of radiation-induced to natural background cancer incidence risk x 100) varied between 0.062 (newborns) to 0.108 (15-year-olds) for 99mTc-DMSA and between 0.026 (newborns) to 0.122 (15-year-olds) for 99mTc-MAG3. Using tallies of photon exit fluence as a rough surrogate for uniform image quality, our study demonstrated that through body region-of-interest optimization of AA, there is the potential for further dose and risk reductions of between factors of 1.5 to 3.0 beyond simple weight-based dosing guidance.


Assuntos
Diagnóstico por Imagem/instrumentação , Rim/diagnóstico por imagem , Imagens de Fantasmas , Ácido Dimercaptossuccínico Tecnécio Tc 99m , Tecnécio Tc 99m Mertiatida , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Método de Monte Carlo , Medição de Risco
7.
Cancer Cell Int ; 20: 124, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32322171

RESUMO

BACKGROUND: LNK adaptor protein is a crucial regulator of normal hematopoiesis, which down-regulates activated tyrosine kinases at the cell surface resulting in an antitumor effect. To date, little studies have examined activities of LNK in solid tumors except ovarian cancer. METHODS: Clinical tissue chips were obtained from 16 clinical patients after surgery. Western blotting assay and quantitative real time PCR was performed to measure the expression of LNK. We investigate the in vivo and vitro effect of LNK in Triple Negative Breast Cancer by using cell proliferation、migration assays and an in vivo murine xenograft model. Western blotting assay was performed to investigate the mechanism of LNK in triple negative breast cancer. RESULTS: We found that the levels of LNK expression were elevated in high grade triple-negative breast cancer through Clinical tissue chips. Remarkably, overexpression of LNK can promote breast cancer cell proliferation and migration in vivo and vitro, while silencing of LNK show the opposite phenomenon. We also found that LNK can promote breast cancer cell to proliferate and migrate via activating JAK/STAT3 and ERK1/2 pathway. CONCLUSIONS: Our results suggest that the adaptor protein LNK acts as a positive signal transduction modulator in TNBC.

8.
J Magn Reson Imaging ; 52(4): 1227-1236, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32167652

RESUMO

BACKGROUND: Approximately one-fourth of all cancer metastases are found in the brain. MRI is the primary technique for detection of brain metastasis, planning of radiotherapy, and the monitoring of treatment response. Progress in tumor treatment now requires detection of new or growing metastases at the small subcentimeter size, when these therapies are most effective. PURPOSE: To develop a deep-learning-based approach for finding brain metastasis on MRI. STUDY TYPE: Retrospective. SEQUENCE: Axial postcontrast 3D T1 -weighted imaging. FIELD STRENGTH: 1.5T and 3T. POPULATION: A total of 361 scans of 121 patients were used to train and test the Faster region-based convolutional neural network (Faster R-CNN): 1565 lesions in 270 scans of 73 patients for training; 488 lesions in 91 scans of 48 patients for testing. From the 48 outputs of Faster R-CNN, 212 lesions in 46 scans of 18 patients were used for training the RUSBoost algorithm (MatLab) and 276 lesions in 45 scans of 30 patients for testing. ASSESSMENT: Two radiologists diagnosed and supervised annotation of metastases on brain MRI as ground truth. This data were used to produce a 2-step pipeline consisting of a Faster R-CNN for detecting abnormal hyperintensity that may represent brain metastasis and a RUSBoost classifier to reduce the number of false-positive foci detected. STATISTICAL TESTS: The performance of the algorithm was evaluated by using sensitivity, false-positive rate, and receiver's operating characteristic (ROC) curves. The detection performance was assessed both per-metastases and per-slice. RESULTS: Testing on held-out brain MRI data demonstrated 96% sensitivity and 20 false-positive metastases per scan. The results showed an 87.1% sensitivity and 0.24 false-positive metastases per slice. The area under the ROC curve was 0.79. CONCLUSION: Our results showed that deep-learning-based computer-aided detection (CAD) had the potential of detecting brain metastases with high sensitivity and reasonable specificity. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 2 J. Magn. Reson. Imaging 2020;52:1227-1236.


Assuntos
Aprendizado Profundo , Neoplasias , Encéfalo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Sensibilidade e Especificidade
9.
Chem Commun (Camb) ; 56(18): 2759-2762, 2020 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-32022003

RESUMO

We describe a colorimetric and fluorescent probe 3a to detect cellular peroxynitrite with high selectivity and sensitivity. 3a was successfully applied in the bioimaging of exogenous and endogenous peroxynitrite in living cells. The up-regulation of peroxynitrite in cancer cells and normal cells during 5-fluorouracil treatment was finally monitored.


Assuntos
Antineoplásicos/farmacologia , Corantes Fluorescentes/farmacologia , Fluoruracila/farmacologia , Ácido Peroxinitroso/biossíntese , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Corantes Fluorescentes/química , Fluoruracila/química , Humanos , Células MCF-7 , Estrutura Molecular , Imagem Óptica , Ácido Peroxinitroso/química , Relação Estrutura-Atividade
10.
Int J Clin Exp Pathol ; 12(3): 1015-1021, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31933913

RESUMO

Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), which affects collagen synthesis, is associated with breast cancer. The purpose of the study is to detect the expression of PLOD2 in breast cancer and to evaluate the correlation between PLOD2 and clinicopathologic characteristics and prognosis of patients with breast cancer. 50 paired samples including breast cancer tissues and adjacent non-tumor tissues were formalin-fixed and evaluated by immunohistochemistry. The results revealed that PLOD2 expression in breast cancer tissues was much higher than that in tissues adjacent to breast cancer. High expression of PLOD2 was positively associated with tumor stage (P = 0.003) and lymph node metastasis (P = 0.001). However, high expression of PLOD2 was negatively related to Ki-67 (P < 0.001) while positively related to progesterone receptor (PR) (P = 0.001). PLOD2 expression was positively related to the metastasis of breast cancer. Therefore, high expression of PLOD2 was identified as a poor prognostic biomarker for patients with breast cancer. These results suggest a novel molecular mechanism in breast cancer tumorigenesis, thus providing a potential therapeutic target of breast cancer.

11.
Phys Med Biol ; 63(16): 165012, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30022768

RESUMO

Because of the concerns associated with radiation exposure at a young age, there is an increased interest in pediatric absorbed dose estimates for imaging agents. Almost all reported pediatric absorbed dose estimates, however, have been determined using adult pharmacokinetic data with radionuclide S values that take into account the anatomical differences between adults and children based upon the older Cristy-Eckerman (C-E) stylized phantoms. In this work, we use pediatric model-derived pharmacokinetics to compare absorbed dose and effective dose estimates for 18F-FDG in pediatric patients using S values generated from two different geometries of computational phantoms. Time-integrated activity coefficients of 18F-FDG in brain, lungs, heart wall, kidneys and liver, retrospectively, calculated from 35 pediatric patients at the Boston's Children Hospital were used. The absorbed dose calculation was performed in accordance with the Medical Internal Radiation Dose method using S values generated from the University of Florida/National Cancer Institute (UF/NCI) hybrid phantoms, as well as those from C-E stylized computational phantoms. The effective dose was computed using tissue-weighting factors from ICRP Publication 60 and ICRP Publication 103 for the C-E and UF/NCI, respectively. Substantial differences in the absorbed dose estimates between UF/NCI hybrid pediatric phantoms and the C-E stylized phantoms were found for the lungs, ovaries, red bone marrow and urinary bladder wall. Large discrepancies in the calculated dose values were observed in the bone marrow; ranging between -26% to +199%. The effective doses computed by the UF/NCI hybrid phantom S values were slightly different than those seen using the C-E stylized phantoms with percent differences of -0.7%, 2.9% and 2.5% for a newborn, 1 year old and 5 year old, respectively. Differences in anatomical modeling features among computational phantoms used to perform Monte Carlo-based photon and electron transport simulations for 18F, and very likely for other radionuclides, impact internal organ dosimetry computations for pediatric nuclear medicine studies.


Assuntos
Fluordesoxiglucose F18/metabolismo , Neoplasias/diagnóstico por imagem , Neoplasias/radioterapia , Órgãos em Risco/efeitos da radiação , Imagens de Fantasmas , Radiometria/instrumentação , Radiometria/métodos , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Método de Monte Carlo , Fótons , Doses de Radiação , Exposição à Radiação , Estudos Retrospectivos
12.
Langmuir ; 34(25): 7404-7415, 2018 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-29874461

RESUMO

A series of naphthalimide derivative gelators (G-o, G-m, and G-p) with three molecular isomers as their terminal groups were designed and synthesized. Only G-m and G-p could form stable organogels in some solvents including methanol, acetonitrile, n-hexane, toluene, ethanol, DMSO, DMF, and mixed solvents of acetonitrile/H2O (1/1, v/v). The different self-assembly structures were obtained from the self-assembly process of G-o, G-m, and G-p such as structures like a Chinese chestnut formed by irregular micrometer pieces, microbelts, and microbelt structures mingled with the bird's nest structures which exhibited different surface hydrophobicity with water contact angles of 121-139° due to their different intermolecular noncovalent interactions. To our surprise, G-p acetonitrile solution emitted 492 nm light with a red-shift of 72 nm compared with that emitted from G-o and G-m acetonitrile solution under 350 nm light excitation. Three gelators showed different detection abilities toward metal ions. G-o did not have any ability for sensitive and selective detection toward any ion. In contrast, G-m and G-p could sensitively and selectively detect Hg2+ and Fe3+. The detection limits for Fe3+ and Hg 2+ by G-m were 4.76 × 10-5 M and 7.01 × 10-6 M with the corresponding association constants ( K) of 1.64 × 104 and 3.79 × 104 M-1, respectively. The detection limits for Fe3+ and Hg2+ by G-p were 3.26 × 10-5 and 1.77 × 10-6 M with the corresponding K of 1.44 × 105 and 1.99 × 104 M-1, respectively. More interestingly, the back-titration of SCN- could distinguish Hg2+ from Fe3+. At the same time, xerogels G-m and G-p also exhibited responsiveness toward Fe3+ and Hg2+ through fluorescence changes. The photophysical properties, gel formation, hierarchical structures, surface wettability, and their function in this self-assembly system could be tuned through the molecular isomer effect. This work provides a new research paradigm for molecular isomer tuned supramolecular self-assembly materials from noncovalent interaction to molecular function.

13.
Semin Nucl Med ; 47(2): 118-125, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28237000

RESUMO

The practice of nuclear medicine in children is well established for imaging practically all physiologic systems but particularly in the fields of oncology, neurology, urology, and orthopedics. Pediatric nuclear medicine yields images of physiologic and molecular processes that can provide essential diagnostic information to the clinician. However, nuclear medicine involves the administration of radiopharmaceuticals that expose the patient to ionizing radiation and children are thought to be at a higher risk for adverse effects from radiation exposure than adults. Therefore it may be considered prudent to take extra care to optimize the radiation dose associated with pediatric nuclear medicine. This requires a solid understanding of the dosimetry associated with the administration of radiopharmaceuticals in children. Models for estimating the internal radiation dose from radiopharmaceuticals have been developed by the Medical Internal Radiation Dosimetry Committee of the Society of Nuclear Medicine and Molecular Imaging and other groups. But to use these models accurately in children, better pharmacokinetic data for the radiopharmaceuticals and anatomical models specifically for children need to be developed. The use of CT in the context of hybrid imaging has also increased significantly in the past 15 years, and thus CT dosimetry as it applies to children needs to be better understood. The concept of effective dose has been used to compare different practices involving radiation on a dosimetric level, but this approach may not be appropriate when applied to a population of children of different ages as the radiosensitivity weights utilized in the calculation of effective dose are not specific to children and may vary as a function of age on an organ-by-organ bias. As these gaps in knowledge of dosimetry and radiation risk as they apply to children are filled, more accurate models can be developed that allow for better approaches to dose optimization. In turn, this will lead to an overall improvement in the practice of pediatric nuclear medicine by providing excellent diagnostic image quality at the lowest radiation dose possible.


Assuntos
Medicina Nuclear/métodos , Doses de Radiação , Radiometria/métodos , Criança , Humanos , Modelos Biológicos , Distribuição Tecidual , Tomografia Computadorizada por Raios X
14.
Environ Sci Pollut Res Int ; 22(22): 17644-52, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26150298

RESUMO

Lakes along the Yangzte River are very important for inhabitants due to their ecosystem service values. In this study, the level of eight endocrine-disrupting compounds (EDCs) was studied in the Honghu Lake and East Dongting Lake. In each lake, 21 water samples and 21 sediment samples were collected. The total concentrations of eight EDCs in surface water (47.60-419.82 ng L(-1), mean value: 225.65 ng L(-1)) and sediments (202.71-635.36 ng g(-1) dry weight (dw), mean value 371.90 ng g(-1) dw) of Honghu Lake were significantly higher than those in surface water (43.52-394.21 ng L(-1), mean value 153.03 ng L(-1)) and sediment (70.01-464.63 ng g(-1) dw, mean value 238.42 ng g(-1) dw) in East Dongting Lake. 4-Nonylphenol (NP), 4-octylphenol (OP), and bisphenol A (BPA) in surface water and sediments were main EDCs in two lakes. No correlation relationships were found between concentrations of EDCs in water and sediment from two lakes. The concentrations of OP and 17α-ethinylestradiol (EE2) in sediments of Honghu Lake had significant positive correlation with the content of total organic carbon (TOC). The concentrations of EDCs in outlet of Honghu Lake were comparable to those in the main lake, whereas the EDCs in outlet of East Dongting Lake were lower than those in the main lake. The EDCs in Honghu Lake and East Dongting Lake may have a significant potential biological effect on fish based on the estimation of EDC estrogenicity.


Assuntos
Disruptores Endócrinos/análise , Lagos/química , Poluentes Químicos da Água/análise , Animais , Compostos Benzidrílicos/análise , China , Monitoramento Ambiental , Estradiol/análise , Estriol/análise , Estrona/análise , Etinilestradiol/análise , Humanos , Fenóis/análise , Rios/química
15.
Radiology ; 261(3): 907-15, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21900613

RESUMO

PURPOSE: To determine the minimum dose of technetium 99m ((99m)Tc) mercaptoacetyltriglycerine (MAG3) needed to perform dynamic renal scintigraphy in the pediatric population without loss of diagnostic quality or accurate quantification of renal function and to investigate whether adaptive noise reduction could help further reduce the minimum dose required. MATERIALS AND METHODS: Approval for this retrospective study was obtained from the institutional review board, with waiver of informed consent. A retrospective review was conducted in 33 pediatric patients consecutively referred for a (99m)Tc-MAG3 study. In each patient, a 20-minute dynamic study was performed after administration of 7.4 MBq/kg. Binomial subsampling was used to simulate studies performed with 50%, 30%, 20%, and 10% of the administered dose. Four nuclear medicine physicians independently reviewed the original and subsampled images, with and without noise reduction, for image quality. Two observers independently performed a quantitative analysis of renal function. Subjective rater confidence was analyzed by using a logistic regression model, and the quantitative analysis was performed by using the paired Student t test. RESULTS: Reducing the administered dose to 30% did not substantially affect image quality, with or without noise reduction. When the dose was reduced to 20%, there was a slight but significant decrease (P = .0074) in image quality, which resolved with noise reduction. Reducing the dose to 10% caused a decrease in image quality (P = .0003) that was not corrected with noise reduction. However, the dose could be reduced to 10% without a substantial change in the quantitative evaluation of renal function independent of the application of noise reduction. CONCLUSION: Decreasing the dose of (99m)Tc-MAG3 from 7.4 to 2.2 MBq/kg did not compromise image quality. With noise reduction, the dose can be reduced to 1.5 MBq/kg without subjective loss in image quality. The quantitative evaluation of renal function was not substantially altered, even with a theoretical dose as low as 0.74 MBq/kg.


Assuntos
Nefropatias/diagnóstico por imagem , Doses de Radiação , Renografia por Radioisótopo/métodos , Compostos Radiofarmacêuticos , Tecnécio Tc 99m Mertiatida , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Modelos Logísticos , Masculino , Compostos Radiofarmacêuticos/administração & dosagem , Estudos Retrospectivos , Tecnécio Tc 99m Mertiatida/administração & dosagem , Adulto Jovem
16.
J Nucl Med ; 52(6): 905-25, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21622894

RESUMO

Nuclear medicine has an important role in the care of newborns and children less than 1 y old. Patients in this age group present with a spectrum of diseases different from those of older children or adults. These patients can benefit from the full range of nuclear medicine studies. In these young children, nuclear medicine studies are more likely to be used to evaluate a wide range of congenital conditions but also can be helpful for evaluating acquired conditions such as infection, cancer, and trauma. This review first will cover the general aspects of nuclear medicine practice with these patients, including the special considerations that can help achieve successful diagnostic imaging. These topics will include clinical indications, imaging technology, instrumentation, software, positioning and immobilization, sedation, local and general anesthesia, radiopharmaceutical doses, radiation risk, and dose reduction. The review then will discuss the specific nuclear medicine studies that typically are obtained in patients in this age group. With extra care and attention to the special needs of this population, nuclear medicine departments can successfully study patients less than 1 y old.


Assuntos
Medicina Nuclear/métodos , Cintilografia/métodos , Envelhecimento/fisiologia , Anestesia Geral , Sedação Consciente , Relação Dose-Resposta à Radiação , Feminino , Humanos , Imobilização , Lactente , Recém-Nascido , Recém-Nascido Prematuro , Masculino , Neoplasias/diagnóstico por imagem , Medicina Nuclear/instrumentação , Cintilografia/instrumentação , Compostos Radiofarmacêuticos/efeitos adversos , Compostos Radiofarmacêuticos/farmacocinética , Medição de Risco , Software , Contagem Corporal Total
17.
Chemistry ; 16(30): 9099-106, 2010 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-20572172

RESUMO

Two new peptide-based isomers containing cholesterol and naphthalic groups have been designed and synthesized. We found that the position of L-alanine in the linker could tune the gelation properties and morphologies. The molecule with the L-alanine residue positioned in the middle of the linker (1b) shows better gelation behavior than that with L-alanine directly linked to the naphthalimido moiety (1a). As a result, a highly thermostable organogel of 1b with a unique core-shell structure was obtained at high temperature and pressure in acetonitrile. Moreover, the gels of 1a and 1b could undergo an instantaneous gel-to-gel transition triggered by sonication. Ultrasound could break the core-shell microsphere of 1b and the micelle structure of 1a into entangled fibers. By studying the mechanism of the sonication-triggered gel-to-gel transition process of these compounds, it can be concluded that ultrasound has a variety of effects on the morphology, such as cutting, knitting, unfolding, homogenizing, and even cross-linking. Typically, ultrasound can cleave and homogenize pi-stacking and hydrophobic interactions among the gel molecules and then reshape the morphologies to form a new gel. This mechanism of morphology transformation triggered by sonication might be attractive in the field of material storage and controlled release.


Assuntos
Alanina/análogos & derivados , Colesterol/análogos & derivados , Colesterol/síntese química , Géis/química , Naftalenos/síntese química , Peptídeos/síntese química , Sonicação , Alanina/química , Colesterol/química , Microscopia Eletrônica de Varredura , Modelos Moleculares , Estrutura Molecular , Naftalenos/química , Peptídeos/química
18.
Neuroinformatics ; 2(1): 101-18, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15067170

RESUMO

There is an increasing need to efficiently share diverse clinical and image data among different clinics, labs, and departments of a medical center enterprise to facilitate better quality care and more effective clinical research. In this paper, we describe a web-based, federated information model as a viable technical solution with applications in medical refractory epilepsy and other neurological disorders. We describe four such online applications developed in a federated system prototype: surgical planning, image analysis, statistical data analysis, and dynamic extraction, transforming, and loading (ETL) of data from a heterogeneous collection of data sources into an epilepsy multimedia data warehouse (EMDW). The federated information system adopts a three-tiered architecture, consisting of a user-interface layer, an application logic layer, and a data service layer. We implemented two complementary federated information technologies, i.e., XML (eXtensible Markup Language) and CORBA (Common Object Request Broker Architecture), in the prototype to enable multimedia data exchange and brain images transmission. The preliminary results show that the federated prototype system provides a uniform interface, heterogeneous information integration and efficient data sharing for users in our institution who are concerned with the care of patients with epilepsy and who pursue research in this area.


Assuntos
Bases de Dados Factuais/normas , Epilepsia/cirurgia , Informática Médica/normas , Procedimentos Neurocirúrgicos , Planejamento de Assistência ao Paciente/normas , Cuidados Pré-Operatórios/métodos , Animais , Encéfalo/anatomia & histologia , Encéfalo/cirurgia , Interpretação Estatística de Dados , Epilepsia/diagnóstico , Feminino , Humanos , Processamento de Imagem Assistida por Computador/métodos , Internet/normas , Imageamento por Ressonância Magnética/tendências , Informática Médica/métodos , Metanálise como Assunto , Pessoa de Meia-Idade , Procedimentos Neurocirúrgicos/normas , Linguagens de Programação , Radiocirurgia/normas , Software/normas , Software/tendências , Técnicas Estereotáxicas/normas , Tomografia Computadorizada de Emissão/tendências , Interface Usuário-Computador
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA