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1.
Eur J Nucl Med Mol Imaging ; 51(9): 2794-2805, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38658392

RESUMO

PURPOSE: Prostate-specific membrane antigen (PSMA) is a promising target for diagnosis and radioligand therapy (RLT) of prostate cancer. Two novel PSMA-targeting radionuclide therapy agents, [177Lu]Lu-P17-087, and its albumin binder modified derivative, [177Lu]Lu-P17-088, were evaluated in metastatic castration-resistant prostate cancer (mCRPC) patients. The primary endpoint was dosimetry evaluation, the second endpoint was radiation toxicity assessment (CTCAE 5.0) and PSA response (PCWG3). METHODS: Patients with PSMA-positive tumors were enrolled after [68Ga]Ga-PSMA-11 PET/CT scan. Five mCRPC patients received [177Lu]Lu-P17-087 and four other patients received [177Lu]Lu-P17-088 (1.2 GBq/patient). Multiple whole body planar scintigraphy was performed at 1.5, 4, 24, 48, 72, 120 and 168 h after injection and one SPECT/CT imaging was performed at 24 h post-injection for each patient. Dosimetry evaluation was compared in both patient groups. RESULTS: Patients showed no major clinical side-effects under this low dose treatment. As expected [177Lu]Lu-P17-088 with longer blood circulation (due to its albumin binding) exhibited higher effective doses than [177Lu]Lu-P17-087 (0.151 ± 0.036 vs. 0.056 ± 0.019 mGy/MBq, P = 0.001). Similarly, red marrow received 0.119 ± 0.068 and 0.048 ± 0.020 mGy/MBq, while kidney doses were 0.119 ± 0.068 and 0.046 ± 0.022 mGy/MBq, respectively. [177Lu]Lu-P17-087 demonstrated excellent tumor uptake and faster kinetics; while [177Lu]Lu-P17-088 displayed a slower washout and higher average dose (7.75 ± 4.18 vs. 4.72 ± 2.29 mGy/MBq, P = 0.018). After administration of [177Lu]Lu-P17-087 and [177Lu]Lu-P17-088, 3/5 and 3/4 patients showed reducing PSA values, respectively. CONCLUSION: [177Lu]Lu-P17-088 and [177Lu]Lu-P17-087 displayed different pharmacokinetics but excellent PSMA-targeting dose delivery in mCRPC patients. These two agents are promising RLT agents for personalized treatment of mCRPC. Further studies with increased dose and frequency of RLT are warranted to evaluate the potential therapeutic efficacy. TRIAL REGISTRATION: 177Lu-P17-087/177Lu-P17-088 in Patients with Metastatic Castration-resistant Prostate Cancer (NCT05603559, Registered at 25 October, 2022). URL OF REGISTRY: https://classic. CLINICALTRIALS: gov/ct2/show/NCT05603559 .


Assuntos
Antígenos de Superfície , Glutamato Carboxipeptidase II , Lutécio , Metástase Neoplásica , Neoplasias de Próstata Resistentes à Castração , Humanos , Masculino , Neoplasias de Próstata Resistentes à Castração/radioterapia , Neoplasias de Próstata Resistentes à Castração/diagnóstico por imagem , Idoso , Glutamato Carboxipeptidase II/metabolismo , Lutécio/uso terapêutico , Antígenos de Superfície/metabolismo , Pessoa de Meia-Idade , Albuminas , Compostos Radiofarmacêuticos/uso terapêutico , Compostos Radiofarmacêuticos/farmacocinética , Idoso de 80 Anos ou mais , Radioisótopos/uso terapêutico , Radiometria
2.
Mol Pharm ; 21(7): 3256-3267, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38856975

RESUMO

Prostate-specific membrane antigen (PSMA) overexpressed in prostate cancer cells can serve as a target for imaging and radioligand therapy (RLT). Previously, [68Ga]Ga-P16-093, containing a Ga(III) chelator, N,N'-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N'-diacetic acid (HBED-CC), displayed excellent PSMA-targeting properties and showed a high tumor uptake and retention useful for diagnosis in prostate cancer patients. Recently, [177Lu]Lu-PSMA-617 has been approved by the U.S. food and drug administration (FDA) for the treatment of prostate cancer patients. Derivatives of PSMA-093 using AAZTA (6-amino-6-methylperhydro-1,4-diazepinetetraacetic acid), as the chelator, were designed as alternative agents forming complexes with both diagnostic and therapeutic radiometals, such as gallium-68 (log K = 22.18) or lutetium-177 (log K = 21.85). The aim of this study is to evaluate AAZTA-Gly-O-(methylcarboxy)-Tyr-Phe-Lys-NH-CO-NH-Glu (designated as AZ-093, 1) leading to a gallium-68/lutetium-177 theranostic pair as potential PSMA targeting agents. Synthesis of the desired precursor, AZ-093, 1, was effectively accomplished. Labeling with either [68Ga]GaCl3 or [177Lu]LuCl3 in a sodium acetate buffer solution (pH 4-5) at 50 °C in 5 to 15 min produced either [68Ga]Ga-1 or [177Lu]Lu-1 with high yields and excellent radiochemical purities. Results of in vitro binding studies, cell uptake, and retention (using PSMA-positive prostate carcinoma cells line, 22Rv1-FOLH1-oe) were comparable to that of [68Ga]Ga-P16-093 and [177Lu]Lu-PSMA-617, respectively. Specific cellular uptake was determined with or without the competitive blocking agent (2 µM of "cold" PSMA-11). Cellular binding and internalization showed a time-dependent increase over 2 h at 37 °C in the PSMA-positive cells. The cell uptakes were completely blocked by the "cold" PSMA-11 suggesting that they are competing for the same PSMA binding sites. In the mouse model with implanted PSMA-positive tumor cells, both [68Ga]Ga-1 and [177Lu]Lu-1 displayed excellent uptake and retention in the tumor. Results indicate that [68Ga]Ga/[177Lu]Lu-1 (68Ga]Ga/[177Lu]Lu-AZ-093) is potentially useful as PSMA-targeting agent for both diagnosis and radiotherapy of prostate cancer.


Assuntos
Antígenos de Superfície , Radioisótopos de Gálio , Glutamato Carboxipeptidase II , Lutécio , Neoplasias da Próstata , Compostos Radiofarmacêuticos , Masculino , Humanos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/radioterapia , Neoplasias da Próstata/metabolismo , Lutécio/química , Antígenos de Superfície/metabolismo , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacologia , Compostos Radiofarmacêuticos/farmacocinética , Glutamato Carboxipeptidase II/metabolismo , Glutamato Carboxipeptidase II/antagonistas & inibidores , Linhagem Celular Tumoral , Radioisótopos/química , Animais , Quelantes/química , Antígeno Prostático Específico/metabolismo , Distribuição Tecidual , Camundongos , Ácido Edético/análogos & derivados , Ácido Edético/química , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos
3.
Phys Rev Lett ; 131(21): 218402, 2023 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-38072617

RESUMO

The tenth domain of type III fibronectin (FNIII_{10}) mediates cell adhesion to the extracellular matrix. Despite its structural similarity to immunoglobulin domains, FNIII_{10} exhibits unique unfolding behaviors. We employed magnetic tweezers to investigate the unfolding and folding dynamics of FNIII_{10} under physiological forces (4-50 pN). Our results showed that FNIII_{10} follows a consistent transition pathway with an intermediate state characterized by detached A and G ß strands. We determined the folding free energies and all force-dependent transition rates of FNIII_{10} and found that both unfolding rates from the native state to the intermediate state and from the intermediate state to the unfolded state deviate from Bell's model. We constructed a quantitative free energy landscape with well-defined traps and barriers that exhibits a hierarchical symmetrical pattern. Our findings provide a comprehensive understanding of FNIII_{10} conformational dynamics and demonstrate how free energy landscape of multistate biomolecules can be precisely mapped, illuminating the relationship between thermal stability, intermediate states, and folding rates in protein folding.


Assuntos
Fibronectinas , Dobramento de Proteína , Fibronectinas/metabolismo , Fenômenos Mecânicos
4.
Mol Pharm ; 20(4): 2159-2169, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-36942924

RESUMO

Fibroblast activation protein (FAP) is selectively expressed in tumors and highly important for maintaining the microenvironment in malignant tumors. Radioisotope-labeled FAP inhibitors (FAPIs) were proven to be useful for diagnosis and radionuclide therapy of cancer and are under active clinical investigations. Ga-HBED complex displays a higher in vivo stability constant (log KGaL: 38.5), compared to that of Ga-DOTA (log KGaL: 21.3). Such advantage in stability constant suggests that it may be useful for development of alternative FAPI imaging agents. In this study, previously reported [68Ga]Ga-DOTA-FAPI-02 and -04 were converted to the corresponding [68Ga]Ga-HBED-CC-FAPI-02 and -04 derivatives ([68Ga]Ga-4, [68Ga]Ga-5, [68Ga]Ga-6, and [68Ga]Ga-7). It was found that substituting the DOTA chelating group with HBED-CC led to several unique and desirable tumor-targeting properties: (1) robust, fast, and high yield labeling─readily adaptable to a kit formulation; (2) high stabilities in vitro; (3) excellent FAP binding affinities (IC50 ranging between 4 and 7 nM) and improved cell uptake and retention (in HT1080 (FAP+) cells); and (4) excellent selective in vivo tumor uptake in nude mice bearing U87MG tumor. It appeared that Ga(III) chelation with HBED-CC improved the in vivo kinetics favoring higher tumor uptake and retention compared to the corresponding Ga-DOTA complex. Out of the four tested ligands the new [68Ga]Ga-HBED-CC-FAPI dimer, [68Ga]Ga-6, displayed the best tumor localization properties, and further studies are warranted to demonstrate that it is an alternative FAP imaging agent for cancer patients.


Assuntos
Radioisótopos de Gálio , Tomografia por Emissão de Pósitrons , Animais , Camundongos , Radioisótopos de Gálio/química , Tomografia por Emissão de Pósitrons/métodos , Camundongos Nus , Linhagem Celular Tumoral , Quelantes , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada
5.
Eur J Nucl Med Mol Imaging ; 49(3): 1052-1062, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34557930

RESUMO

PURPOSE: This study was prospectively designed to evaluate the early dynamic organ distribution and tumor detection capability of [68 Ga]Ga-P16-093, which was compared with [68 Ga]Ga-PSMA-617 in the same group of recurrent prostate cancer patients. METHODS: Twenty patients with recurrent prostate cancer were enrolled. In 2 consecutive days, each patient underwent a 60-min dynamic PET/CT scan after intravenous administration of 148-185 MBq (4-5 mCi) [68 Ga]Ga-P16-093 and [68 Ga]Ga-PSMA-617, respectively. Following a low-dose CT scan, serial dynamic PET scans were performed from head to proximal thigh at 9 time points (30 s/bed at 4, 7, 10, 13, and 16 min; 1 min/bed at 20, 30, and 45 min; and 2 min/bed at 60 min). Standardized uptake values were measured for semi-quantitative comparison. RESULTS: [68 Ga]Ga-P16-093 PET/CT revealed a significantly higher tumor uptake at 4 min (SUVmax 7.88 ± 5.26 vs. 6.01 ± 3.88, P < 0.001), less blood pool retention at 4 min (SUVmean 5.12 ± 1.16 vs. 6.14 ± 0.98, P < 0.001), and lower bladder accumulation at 60 min (SUVmean 31.33 ± 27.47 vs. 48.74 ± 34.01, P = 0.042) than [68 Ga]Ga-PSMA-617 scan. Significantly higher [68 Ga]Ga-P16-093 uptakes were also observed in the parotid gland, liver, spleen, and kidney. Besides, [68 Ga]Ga-P16-093 exhibited a better detectability of tumor than [68 Ga]Ga-PSMA-617 (366 vs. 321, P = 0.009). CONCLUSIONS: [68 Ga]Ga-P16-093 showed advantages over [68 Ga]Ga-PSMA-617 with higher tumor uptakes, tumor-to-blood pool ratio and detection capability, less blood pool, and bladder accumulation in recurrent prostate cancer patients. TRIAL REGISTRATION: [68 Ga]Ga-P16-093 and [68 Ga]Ga-PSMA-617 PET/CT Imaging in the Same Group of Prostate Cancer Patients (NCT04796467, Registered 12 March 2021, retrospectively registered) URL of registry: https://clinicaltrials.gov/ct2/show/NCT04796467.


Assuntos
Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata , Dipeptídeos , Ácido Edético , Radioisótopos de Gálio , Compostos Heterocíclicos com 1 Anel , Humanos , Masculino , Recidiva Local de Neoplasia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons , Antígeno Prostático Específico , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia
6.
J Clin Lab Anal ; 36(7): e24485, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35614030

RESUMO

PURPOSE: To explore the value of the expression of serum miR-92 and miR-122 combined with lung ultrasound score (LUS) in the prognosis of neonatal acute respiratory distress syndrome (ARDS). PATIENTS AND METHODS: This study involved 148 neonatal ARDS cases from January 2018 to October 2021, of which 77 children were discharged from hospital and 31 died. The children with ARDS were classified according to disease severity based on X-ray examination as mild (n = 69 cases) and severe (n = 39 cases). The expression of serum miR-92 and miR-122 was detected by real-time fluorescence quantitative PCR and the LUS score was recorded. The data were subjected to ROC curve analysis and Pearson correlation analysis. RESULTS: The expression of serum miR-92, miR-122, and LUS score in the patients that died were significantly higher than in those who survived (p < 0.05). These indicators were also significantly higher in the severe disease group compared to the mild disease group (p < 0.05). ROC curve showed that serum miR-92 and miR-122 combined with the LUS score had the largest area under the curve (0.920, 95% CI: 0.860-0.977) for predicting death, with a sensitivity and specificity of 92.0% and 87.0%, respectively. Pearson correlation analysis showed that the expression levels of serum miR-92 and miR-122 were positively correlated with the LUS score (all p < 0.01). CONCLUSIONS: The increased expression of serum miR-92 and miR-122 is related to the severity and prognosis of children with ARDS, combined with the LUS score are of value to predict the prognosis of children with ARDS.


Assuntos
MicroRNAs , Síndrome do Desconforto Respiratório , Humanos , Recém-Nascido , Pulmão/diagnóstico por imagem , MicroRNAs/sangue , MicroRNAs/genética , Prognóstico , Curva ROC , Síndrome do Desconforto Respiratório/diagnóstico por imagem , Síndrome do Desconforto Respiratório/genética , Ultrassonografia
7.
J Labelled Comp Radiopharm ; 65(14): 354-360, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36261868

RESUMO

Diabetes mellitus (DM) and insulinoma are mainly affected by the status of pancreatic ß-cell mass (BCM). Development of imaging agents for BCM allows to study pancreatic ß cells and the relationship between ß cells and DM or insulinoma. In this study, we investigated the density of dopamine D1 receptor on the ß cells and measured BCM by statistical image processing. The pancreatic uptakes of [125 I]I-R-(+)-7-chloro-8-hydroxy-1-(3'-iodopheny1)-3-methyl-2,3,4,5-tetrahydro-1H-3-benzazepine ([125 I]I-R-(+)-TISCH), dopamine D1 receptor tracer, in normal and diabetic rats displayed significant differences at 30 min (1.11 ± 0.08% ID/g vs. 0.63 ± 0.09% ID/g, p < 0.0001). In the presence of SCH23390, the pancreatic uptake of [125 I]I-R-(+)-TISCH at 30 min in normal rats was lower (1.01 ± 0.04% ID/g, p < 0.05). Although the blocking was not complete, [125 I]I-R-(+)-TISCH showed specific binding signals to the pancreas. Furthermore, the uptakes of [125 I]I-R-(+)-TISCH in INS-1 cells were reduced in the presence of SCH23390 at different concentrations. [125 I]I-R-(+)-TISCH displayed a respectable uptake in insulinoma. Overall, [125 I]I-R-(+)-TISCH provided specific binding signals to pancreatic ß cells. Although the specific signal may not be sufficient for imaging in vivo, the dopamine D1 receptor can still be considered as a potential target for studying BCM. Further investigation will be required to optimize the ligand.


Assuntos
Diabetes Mellitus Experimental , Células Secretoras de Insulina , Insulinoma , Neoplasias Pancreáticas , Animais , Ratos , Dopamina , Receptores de Dopamina D1/metabolismo , Ligantes , Células Secretoras de Insulina/metabolismo , Benzazepinas/metabolismo
8.
Phys Rev Lett ; 125(19): 198101, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-33216575

RESUMO

Atomic force microscopy experiments found that GB1, a typical two-state model protein used for study of folding and unfolding dynamics, can sustain forces of more than 100 pN, but its response to low forces still remains unclear. Using ultrastable magnetic tweezers, we discovered that GB1 has an unexpected nonmonotonic force-dependent unfolding rate at 5-160 pN, from which a free energy landscape with two main barriers and a hidden intermediate state was constructed. A model combining two separate models by Dudko et al. with two pathways between the native state and this intermediate state is proposed to rebuild the unfolding dynamics over the full experimental force range. One candidate of this transient intermediate state is the theoretically proposed molten globule state with a loosely collapsed conformation, which might exist universally in the folding and unfolding processes of two-state proteins.


Assuntos
Proteínas de Bactérias/química , Modelos Químicos , Cinética , Magnetismo , Microscopia de Força Atômica , Domínios Proteicos , Dobramento de Proteína , Termodinâmica
9.
J Labelled Comp Radiopharm ; 63(3): 108-118, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31697847

RESUMO

Amyvid (florbetapir f18, [18 F]AV-45, [18 F]5) was the first FDA-approved positron emission tomography imaging agent targeting ß-amyloid (Aß) plaques for assisting the diagnosis of Alzheimer disease. This work aimed to improve the [18 F]AV-45 ([18 F]5) preparation by using solid-phase extraction (SPE) purification. [18 F]AV-45 ([18 F]5) was synthesized by direct nucleophilic radiofluorination of O-tosylated precursor (1 mg) at 120°C in anhydrous dimethyl sulfoxide (DMSO), followed by acid hydrolysis of the N-Boc protecting group. Purification was accomplished by loading the crude reaction mixture to a cartridge (Oasis HLB 3 cc) and eluting with different combinations of solvents. This method removed the chemical impurity while leaving [18 F]AV-45 ([18 F]5) on the cartridge. The final dose was eluted by ethanol. [18 F]AV-45 ([18 F]5) was produced within 51 minutes (radiochemical yield 42.7 ± 5.9%, decay corrected, n = 3), and the radiochemical purity was greater than 95%. Total chemical impurity per batch (24.1 ± 2.7 µg per batch) was below the limit described in the package insert of Amyvid, florbetapir f18 (chemical mass: less than 50 µg/dose). In summary, [18 F]AV-45 ([18 F]5) was produced efficiently and reproducibly using a cartridge-based SPE purification. This method brings the process closer for routine preparation, similar to the commercially used [18 F]FDG.


Assuntos
Compostos de Anilina/química , Compostos de Anilina/isolamento & purificação , Etilenoglicóis/química , Etilenoglicóis/isolamento & purificação , Extração em Fase Sólida , Tomografia por Emissão de Pósitrons , Radioquímica
10.
Mol Pharm ; 16(3): 1156-1166, 2019 03 04.
Artigo em Inglês | MEDLINE | ID: mdl-30676751

RESUMO

Hypoxia is an important biochemical and physiological condition associated with uncontrolled growth of tumor. Measurement of hypoxia in tumor tissue may be useful in characterization of tumor progression and monitoring drug treatment. [18F]FMISO is the most widely employed radiotracer for imaging of hypoxic tissue with positron emission tomography (PET). However, it showed relatively low uptake in hypoxic tissues, which led to low target-to-background contrast in PET images. To overcome these shortcomings, two novel 2-fluoroproprioic acid esters, nitroimidazole derivatives 2-fluoropropionic acid 2-(2-nitro-imidazol-1-yl)-ethyl ester (FNPFT, [19F]5) and 2-fluoropropionic acid 2-(2-methyl-5-nitro-imidazol-1-yl)-ethyl ester (FMNPFT, [19F]8), were prepared and tested. Radiolabeling of [18F]5 and [18F]8 was accomplished in 45 min (radiochemical purity >95%, the decay-corrected radiochemical yield of [18F]5 was 11 ± 2%, and that of [18F]8 was 13 ± 2%, n = 5). In vitro cell uptake studies using EMT-6 tumor cells showed that both radiotracers [18F]5 and [18F]8 displayed significantly higher uptake in hypoxic cells than those under normoxic condition, while 2-[18F]fluoropropionic acid (2-[18F]FPA) displayed no difference. Biodistribution studies in mice bearing EMT-6 tumor showed that [18F]5, [18F]8, and 2-[18F]FPA displayed similar tumor and major organ uptakes. Tumor uptake values for all three agents were higher than those of [18F]FMISO, respectively ( P < 0.05). This is likely due to a rapid in vivo hydrolysis of [18F]5 and [18F]8 to their metabolite, 2-[18F]FPA. Micro PET imaging studies in the same EMT-6 implanted mice tumor model also demonstrated that both [18F]5 and [18F]8 displayed similar tumor uptake comparable to that of 2-[18F]FPA. In conclusion, two new fluorine-18 labeled nitroimidazole derivatives, [18F]5 and [18F]8, showed good tumor uptakes in mice bearing EMT-6 tumor. However, in vivo biodistribution results suggested that they were more likely reflect the predominance of in vivo produced metabolite, 2-[18F]FPA, which may not be related to tumor hypoxic condition.


Assuntos
Ésteres/química , Ésteres/farmacocinética , Hipóxia/diagnóstico por imagem , Nitroimidazóis/química , Nitroimidazóis/farmacocinética , Tomografia por Emissão de Pósitrons/métodos , Traçadores Radioativos , Animais , Hipóxia Celular , Linhagem Celular Tumoral , Modelos Animais de Doenças , Feminino , Radioisótopos de Flúor/química , Hidrólise , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/metabolismo , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/farmacocinética , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
11.
Bioorg Med Chem Lett ; 29(9): 1047-1050, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30871772

RESUMO

We report the preparation of a novel glutamine derivative, (2S,4S)-2,5-diamino-4-(4-(2-fluoroethoxy)benzyl)-5-oxopentanoic acid, (2S, 4S)4-[18F]FEBGln ([18F]4), through efficient organic and radiosyntheses. In vitro assays of [18F]4 using MCF-7 cells showed that it entered cells via multiple amino acid transporter systems including system L and ASC2 transporters but not through the system A transporter. [18F]4 showed promising properties for tumor imaging and may serve as a lead compound for further optimizing and targeting the system L transporter associated with enhanced glutamine metabolism in cancer cells.


Assuntos
Glutamina/análogos & derivados , Compostos Radiofarmacêuticos/síntese química , Proteínas Reguladoras de Apoptose/química , Proteínas Reguladoras de Apoptose/metabolismo , Linhagem Celular Tumoral , Éteres de Coroa/química , Radioisótopos de Flúor/química , Glutamina/síntese química , Glutamina/metabolismo , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/metabolismo , Ribonucleoproteínas/química , Ribonucleoproteínas/metabolismo
12.
BMC Struct Biol ; 14: 2, 2014 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-24423233

RESUMO

BACKGROUND: p300/CBP associating factor (PCAF, also known as KAT2B for lysine acetyltransferase 2B) is a catalytic subunit of megadalton metazoan complex ATAC (Ada-Two-A containing complex) for acetylation of histones. However, relatively little is known about the regulation of the enzymatic activity of PCAF. RESULTS: Here we present two dimeric structures of the PCAF acetyltransferase (HAT) domain. These dimerizations are mediated by either four-helical hydrophobic interactions or a ß-sheet extension. Our chemical cross-linking experiments in combined with site-directed mutagenesis demonstrated that the PCAF HAT domain mainly forms a dimer in solution through one of the observed interfaces. The results of maltose binding protein (MBP)-pulldown, co-immunoprecipitation and multiangle static light scattering experiments further indicated that PCAF dimeric state is detectable and may possibly exist in vivo. CONCLUSIONS: Taken together, our structural and biochemical studies indicate that PCAF appears to be a dimer in its functional ATAC complex.


Assuntos
Fatores de Transcrição de p300-CBP/química , Fatores de Transcrição de p300-CBP/metabolismo , Domínio Catalítico , Humanos , Modelos Moleculares , Mutagênese Sítio-Dirigida , Conformação Proteica , Multimerização Proteica , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Fatores de Transcrição de p300-CBP/genética
13.
Nucl Med Biol ; 130-131: 108894, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38422917

RESUMO

OBJECTIVE: Diabetes mellitus (DM) is one of the major diseases in the world. Nuclear medicine imaging may be able to detect functional status of pancreatic ß cells in vivo, which might elucidate the pathological mechanisms of diabetes and develop individualized treatment plans. In this study, we evaluated the ability of [125I]ADAM, a serotonin transporter (SERT) imaging agent, as a probe for detecting pancreatic ß-cell mass (BCM). METHODS: In vitro cell studies were evaluated in INS-1 cells (rat islet ß cell line). Biodistribution studies were performed in male normal Sprague-Dawley rats and alloxan-induced type 1 diabetes mellitus (T1DM) rats. Distribution and expression of SERT protein in pancreas of rats were also measured by immunofluorescence staining and Western blot. RESULTS: In vitro cell studies showed that the concentration of [125I]ADAM associated with the INS-1 cells was increased gradually with incubation time, and the SERT specific inhibitor, escitalopram, exhibited the inhibitory effect on this interaction. Biodistribution studies also showed that the uptake of [125I]ADAM in the pancreas of normal rats was decreased in the presence of escitalopram. However, in the T1DM rat model with a significant ß cells reduction, the uptake of pancreas was increased when compared with the control. Through immunofluorescence staining and Western blot, it was found that both the endocrine and exocrine cells of the normal pancreas expressed SERT protein, and the level of SERT protein in the exocrine cells was higher than islets. In the diabetic state, the expression of SERT in the exocrine cells was further increased. CONCLUSIONS: The SERT imaging agent, [125I]ADAM, at the present form will not be suitable for imaging ß cells, specifically because there were extraordinarily high non-specific signals contributing from the exocrine cells of pancreas. In addition, we noticed that the level of SERT expression was abnormally elevated in the diabetic state, which might provide an unexpected target for studying the pathological mechanisms of diabetes.


Assuntos
Diabetes Mellitus Tipo 1 , Células Secretoras de Insulina , Ratos , Masculino , Animais , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Ratos Sprague-Dawley , Diabetes Mellitus Tipo 1/metabolismo , Escitalopram , Distribuição Tecidual , Pâncreas/metabolismo , Serotonina/metabolismo
14.
Clin Nucl Med ; 48(4): 289-295, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36727866

RESUMO

PURPOSE: We aimed to compare the diagnostic performance of 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT in primary prostate cancer (PCa) patients. PATIENTS AND METHODS: Thirty untreated primary PCa patients were enrolled. Each patient underwent 68 Ga-P16-093 and 68 Ga-PSMA-617 PET/CT within a week. In addition to visual analysis, SUV was measured for semiquantitative comparison and correlation analysis. RESULTS: 68 Ga-P16-093 PET/CT detected more positive tumors than 68 Ga-PSMA-617 PET/CT (67 vs 56, P = 0.002), especially for intraprostatic lesions (29 vs 24, P = 0.025) and lymph node metastases (23 vs 17, P = 0.034). Further, 68 Ga-P16-093 PET/CT exhibited significantly higher SUV max of matched tumors (18.3 ± 14.4 vs 13.9 ± 11.8, P < 0.001). Besides, the SUV max of high-risk patients (based on D'Amico classification) on 68 Ga-P16-093 PET/CT was significantly higher than that of low- and intermediate-risk PCa patients (20.9 ± 9.9 vs 8.9 ± 9.1 vs 10.1 ± 5.2, P = 0.007). The SUV max of tumor measured by 68 Ga-P16-093 PET/CT had a moderate association with biopsy Gleason score ( r = 0.462, P = 0.005) and prostate-specific antigen value ( r = 0.491, P = 0.002), and significantly correlated with PSMA expression ( r = 0.732, P < 0.001). CONCLUSIONS: 68 Ga-P16-093 PET/CT exhibited higher tumor uptake and potentially better tumor detection capability than 68 Ga-PSMA-617 PET/CT, which suggested that 68 Ga-P16-093 may be more suitable in the diagnosis and staging of primary PCa patients.


Assuntos
Antígeno Prostático Específico , Neoplasias da Próstata , Humanos , Masculino , Ácido Edético , Isótopos de Gálio , Radioisótopos de Gálio , Oligopeptídeos , Projetos Piloto , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata/patologia
15.
Phys Rev E ; 106(2-1): 024404, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36109974

RESUMO

Acylphosphatase (AcP) is a small protein with 98 amino acid residues that catalyzes the hydrolysis of carboxyl-phosphate bonds. AcP is a typical two-state protein with slow folding rate due to its relatively large contact order in the native structure. The mechanical properties and unfolding behavior of AcP has been studied by atomic force microscope. Here using stable magnetic tweezers, we measured the force-dependent folding rates within a force range 1-3 pN, and unfolding rates 15-40 pN. The obtained unfolding rates show different force sensitivities at forces below and above ∼27 pN, which determines a free-energy landscape with two energy barriers. Our results indicate that the free-energy landscape of small globule proteins have general Bactrian camel shape, and large contact order of the native state produces a high barrier dominate at low forces.


Assuntos
Dobramento de Proteína , Proteínas , Hidrolases Anidrido Ácido , Aminoácidos , Fosfatos , Proteínas/química , Acilfosfatase
16.
Nucl Med Biol ; 106-107: 1-9, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34952347

RESUMO

PURPOSE: Prostate-specific membrane antigen (PSMA) is an important biomarker for molecular imaging and a target for radionuclide therapy of prostate cancer. Recently, U.S. Food and Drug Administration (FDA) has approved [68Ga]Ga-PSMA-11 as a PSMA-targeted positron emission tomography (PET) imaging agent for the diagnosis of prostate cancer. As an alternative PSMA imaging agent, [68Ga]Ga-P16-093 ([68Ga]Ga-PSMA-093) showed excellent blood clearance and rapid tumor uptake, desirable in vivo properties for avidly detecting primary tumor and metastatic lesions in patients. To improve the availability and test the robustness of radiolabeling reaction, eluents of 68Ga/HCl from different sources of generators were evaluated. PROCEDURES: Commercially available 68Ge/68Ga generators from Eckert & Ziegler, ITG and iThemba were eluted with varying molarities of hydrochloric acid (0.05-0.6 M, as recommended by each company) and reacted with P16-093 kits. Radiolabeling yields, in vitro stabilities, in vitro cell uptakes and drug release criteria of different preparations were investigated. PET/computed tomography (CT) imaging of prostate cancer patients with [68Ga]Ga-P16-093 produced by using different sources of 68Ga were performed. RESULTS: Optimized P16-093 kit containing 15 µg of P16-093 (precursor) and 68 mg of sodium acetate trihydrate (buffer), a formulation previously tested in humans, was successfully labeled with eluents from Eckert & Ziegler, ITG and iThemba's generators. In vitro cell uptake studies showed that [68Ga]Ga-P16-093, formulated with ITG and iThemba's generators, exhibited equivalent PSMA-specific uptakes. Clinical studies in prostate cancer patients exhibited exceedingly comparable maximum standardized uptake value (SUVmax) for each lesion regardless of source of the generator used in preparation. CONCLUSION: Using different vendors' generator and lyophilized P16-093 kits, [68Ga]Ga-P16-093 could be conveniently and reliably prepared by a simple one-step reaction with excellent yields. Clinically useful doses of [68Ga]Ga-P16-093 imaging tracer could be made available using different 68Ge/68Ga generators.


Assuntos
Radioisótopos de Gálio , Neoplasias da Próstata , Ácido Edético , Humanos , Masculino , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Tomografia por Emissão de Pósitrons/métodos , Neoplasias da Próstata/diagnóstico por imagem , Neoplasias da Próstata/patologia
17.
Chemistry ; 17(9): 2763-8, 2011 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-21271619

RESUMO

A novel ultrathin platinum nanowire with uniform length and a diameter of 1.5 nm was synthesized by acidic etching of FePt nanowire in methanol. This nanowire was characterized by high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) data indicated that the main plane is (111). The ability of this nanowire to catalyze the heterogeneous hydrogenation of nitroaromatics to give the corresponding amines has been investigated. The catalyst showed satisfactory activity in various solvents under mild conditions and showed excellent stability. The catalytic performance was also evaluated in the one-pot reduction of nitroaromatics and amidation with carboxylic acids under a hydrogen atmosphere at 100 °C. These methods for the hydrogenation of nitroaromatics and the direct amidation of nitroaromatics with carboxylic acids are simple, economical, and environmentally benign, and have practical advantages for the synthesis of amines and amides without the production of toxic byproducts.

18.
Chemistry ; 17(31): 8726-30, 2011 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-21678501

RESUMO

Iron oxide coated platinum nanowires (Pt@Fe(2)O(3)NWs) with a diameter of 2.8 nm have been prepared by the oxygen oxidation of FePt NWs in oleylamine. These "cable"-like NWs were characterised by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and X-ray absorption fine structure analysis. These Pt@Fe(2)O(3) NWs were used as "non-support" heterogeneous catalysts in oxidation of olefins and alcohols. The results revealed that it is an active and highly selective catalyst. Styrene derivatives were tested with molecular oxygen as the sole oxidant, with benzaldehyde successfully obtained from styrene in an absolute yield of 31%, whereas the use of tert-butyl hydroperoxide as the sole oxidant in the oxidation of alcohols led to yields of more than 80% of the corresponding ketone or aldehyde. This unsupported catalyst was found to be more active (TOF=96.5 h(-1)) than other reported Fe(2)O(3) nanoparticle catalysts and could be recycled multiple times without any notable decrease in activity. Our findings will extend the use of such nanomaterial catalysts to new catalytic systems.


Assuntos
Álcoois/química , Alcenos/química , Compostos Ferrosos/síntese química , Nanofios , Compostos de Platina/síntese química , Catálise , Técnicas de Química Combinatória , Compostos Ferrosos/química , Estrutura Molecular , Oxirredução , Oxigênio/química , Compostos de Platina/química
19.
Chemistry ; 17(50): 14283-7, 2011 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-22076951

RESUMO

Traditionally important in the pharmaceutical, agrochemical, and synthetic dye industries, C-N coupling has proved useful for the preparation of a number of valuable organic compounds. Here, a new method for the direct one-pot reductive C-N coupling from carbonyl and aromatic nitro compounds is described. Employing ultrathin platinum nanowires as the catalyst and hydrogen as the reducing agent, N-alkylamines were achieved in high yields. Debenzylation products were not detected after prolonged reaction times. Time-dependent analysis, ReactIR spectroscopy and DFT calculations revealed that the C-N coupling proceeded through a different mechanism than traditional "reductive amination." N-Alkylamines were directly obtained by intermolecular dehydration over platinum nanowires under a hydrogen atmosphere, instead of intramolecular water elimination and imine hydrogenation.


Assuntos
Hidrogênio/química , Iminas/química , Nanofios/química , Nitrocompostos/química , Platina/química , Catálise , Oxirredução , Teoria Quântica
20.
Front Med (Lausanne) ; 8: 762890, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35127743

RESUMO

BACKGROUND: Few studies have used quantitative methods to explore the key factors affecting shared decision-making (SDM) in nursing decision-making from the perspective of orthopedic nurses. PURPOSE: To understand the intercorrelations among shared decision-making questionnaire-nurse (SDM-Q-NUR) factors and identify key factors for clinical nursing care decisions in orthopedics. METHODS: In May 2021, this study investigated the interdependence of the SDM-Q-NUR scale and developed an influential network-relation map (INRM) from the clinical experience of 13 trained orthopedic nurses using the Decision-making Trial and Evaluation Laboratory method. RESULTS: The INRM results showed that the nine criteria corresponded to three stages: preparation, discussion, and decision. "I helped my patient or patient's family understand all the information" (C 5) and "I wanted to know from my patient or patient's family how they want to be involved in making the nursing care decision" (C 2) are the main key factors for the beginning of nursing decision. In the discussion and decision stages, the corresponding key factors are "I made it clear to my patient or patient's family that a nursing care decision needs to be made" (C 1) and "I asked my patient or patient's family which nursing care option they prefer" (C 6). The result's statistical significance confidence and gap error were 98.106% and 1.894%, respectively. CONCLUSIONS: When making nursing decisions with patients, orthopedic nurses need to have detailed information about how patients are involved in SDM and all relevant information. Nurses should also inform patients and their families regarding the purpose of the discussion, namely, to help one understand the content, advantages, and disadvantages of the nursing care options, and finally, make a decision.

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