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1.
Proc Natl Acad Sci U S A ; 121(4): e2317054121, 2024 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-38227671

RESUMO

Kelp forests are highly productive and economically important ecosystems worldwide, especially in the North Pacific Ocean. However, current hypotheses for their evolutionary origins are reliant on a scant fossil record. Here, we report fossil hapteral kelp holdfasts from western Washington State, USA, indicating that kelp has existed in the northeastern Pacific Ocean since the earliest Oligocene. This is consistent with the proposed North Pacific origin of kelp associated with global cooling around the Eocene-Oligocene transition. These fossils also support the hypotheses that a hapteral holdfast, rather than a discoid holdfast, is the ancestral state in complex kelps and suggest that early kelps likely had a flexible rather than a stiff stipe. Early kelps were possibly grazed upon by mammals like desmostylians, but fossil evidence of the complex ecological interactions known from extant kelp forests is lacking. The fossil record further indicates that the present-day, multi-story kelp forest had developed at latest after the mid-Miocene climate optimum. In summary, the fossils signify a stepwise evolution of the kelp ecosystem in the North Pacific, likely enabled by changes in the ocean-climate system.


Assuntos
Ecossistema , Kelp , Animais , Florestas , Clima , Oceano Pacífico , Mamíferos
2.
Br J Haematol ; 2024 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-39087522

RESUMO

Acute myeloid leukaemia (AML) is a heterogeneous disease characterized by complex molecular and cytogenetic abnormalities. Pro-oxidant cellular redox status is a common hallmark of AML cells, providing a rationale for redox-based anticancer strategy. We previously discovered that auranofin (AUF), initially used for the treatment of rheumatoid arthritis and repositioned for its anticancer activity, can synergize with a pharmacological concentration of vitamin C (VC) against breast cancer cell line models. In this study, we observed that this drug combination synergistically and efficiently killed cells of leukaemic cell lines established from different myeloid subtypes. In addition to an induced elevation of reactive oxygen species and ATP depletion, a rapid dephosphorylation of 4E-BP1 and p70S6K, together with a strong inhibition of protein synthesis were early events in response to AUF/VC treatment, suggesting their implication in AUF/VC-induced cytotoxicity. Importantly, a study on 22 primary AML specimens from various AML subtypes showed that AUF/VC combinations at pharmacologically achievable concentrations were effective to eradicate primary leukaemic CD34+ cells from the majority of these samples, while being less toxic to normal cord blood CD34+ cells. Our findings indicate that targeting the redox vulnerability of AML with AUF/VC combinations could present a potential anti-AML therapeutic approach.

3.
J Pharmacol Exp Ther ; 388(2): 333-346, 2024 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-37770203

RESUMO

Synthesis of the acetylcholinesterase inhibitor paraoxon (POX) as a carbon-11 positron emission tomography tracer ([11C]POX) and profiling in live rats is reported. Naïve rats intravenously injected with [11C]POX showed a rapid decrease in parent tracer to ∼1%, with an increase in radiolabeled serum proteins to 87% and red blood cells (RBCs) to 9%. Protein and RBC leveled over 60 minutes, reflecting covalent modification of proteins by [11C]POX. Ex vivo biodistribution and imaging profiles in naïve rats had the highest radioactivity levels in lung followed by heart and kidney, and brain and liver the lowest. Brain radioactivity levels were low but observed immediately after injection and persisted over the 60-minute experiment. This showed for the first time that even low POX exposures (∼200 ng tracer) can rapidly enter brain. Rats given an LD50 dose of nonradioactive paraoxon at the LD50 20 or 60 minutes prior to [11C]POX tracer revealed that protein pools were blocked. Blood radioactivity at 20 minutes was markedly lower than naïve levels due to rapid protein modification by nonradioactive POX; however, by 60 minutes the blood radioactivity returned to near naïve levels. Live rat tissue imaging-derived radioactivity values were 10%-37% of naïve levels in nonradioactive POX pretreated rats at 20 minutes, but by 60 minutes the area under the curve (AUC) values had recovered to 25%-80% of naïve. The live rat imaging supported blockade by nonradioactive POX pretreatment at 20 minutes and recovery of proteins by 60 minutes. SIGNIFICANCE STATEMENT: Paraoxon (POX) is an organophosphorus (OP) compound and a powerful prototype and substitute for OP chemical warfare agents (CWAs) such as sarin, VX, etc. To study the distribution and penetration of POX into the central nervous system (CNS) and other tissues, a positron emission tomography (PET) tracer analog, carbon-11-labeled paraoxon ([11C]POX), was prepared. Blood and tissue radioactivity levels in live rats demonstrated immediate penetration into the CNS and persistent radioactivity levels in tissues indicative of covalent target modification.


Assuntos
Acetilcolinesterase , Radioisótopos de Carbono , Paraoxon , Ratos , Animais , Distribuição Tecidual , Tomografia por Emissão de Pósitrons , Compostos Organofosforados
4.
Artigo em Inglês | MEDLINE | ID: mdl-38164825

RESUMO

The elucidation of the underlying cause of polyuria-polydipsia syndrome (PPS) is a challenging-especially in the differentiation of partial defects of arginine vasopressin (AVP) secretion or action from primary polydipsia. The water deprivation test has been utilized for many decades, and its application in the paediatric population has been applied using parameters predominantly established in adult cohorts. In more recent times, the development of automated commercial assays for copeptin, a surrogate marker for AVP, has represented a significant advancement in the diagnostic approach to PPS. Measurement of copeptin concentrations has major advantages and has essentially superseded measurement of AVP in diagnostic protocols for PPS. Additionally, stimulated-copeptin protocols utilizing hypertonic saline infusion, arginine, and glucagon have been investigated, and are promising. However, further studies are required in the population-incorporating the differences in physiological regulation of water homeostasis, and safety requirements-before there is widespread adoption into clinical practice.

5.
Diabet Med ; : e15419, 2024 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-39129150

RESUMO

AIM: One third of Australian children diagnosed with type 1 diabetes present with life-threatening diabetic ketoacidosis (DKA) at diagnosis. Screening for early-stage, presymptomatic type 1 diabetes, with ongoing follow-up, can substantially reduce this risk (<5% risk). Several screening models are being trialled internationally, without consensus on the optimal approach. This pilot study aims to assess three models for a routine, population-wide screening programme in Australia. METHODS: An implementation science-guided pilot study to evaluate the feasibility, acceptability and costs of three screening models in children will be conducted between July 2022 and June 2024. These models are as follows: (1) Genetic risk-stratified screening using newborn heel prick dried bloodspots, followed by autoantibody testing from 11 months of age; (2) genetic risk-stratified screening of infant (6-12 months) saliva followed by autoantibody testing from 10 months of age; and (3) autoantibody screening using capillary dried bloodspots collected from children aged 2, 6 or 10 years. Cohorts for each model will be recruited from targeted geographic areas across Australia involving ≥2 states per cohort, with a recruitment target of up to 3000 children per cohort (total up to 9000 children). The primary outcome is screening uptake for each cohort. Secondary outcomes include programme feasibility, costs, parental anxiety, risk perception, satisfaction, well-being and quality of life, and health professional attitudes and satisfaction. CONCLUSIONS: This pilot is the first direct comparison of three screening implementation models for general population screening. Findings will provide evidence to inform a potential national screening programme for Australian children. TRIAL REGISTRATION: ACTRN12622000381785.

6.
Clin Chem Lab Med ; 62(1): 41-49, 2024 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-37349976

RESUMO

Type 1 diabetes (T1D) is well-recognised as a continuum heralded by the development of islet autoantibodies, progression to islet autoimmunity causing beta cell destruction, culminating in insulin deficiency and clinical disease. Abnormalities of glucose homeostasis are known to exist well before the onset of typical symptoms. Laboratory-based tests such as the oral glucose tolerance test (OGTT) and glycated haemoglobin (HbA1c) have been used to stage T1D and assess the risk of progression to clinical T1D. Continuous glucose monitoring (CGM) can detect early glycaemic abnormalities and can therefore be used to monitor for metabolic deterioration in pre-symptomatic, islet autoantibody positive, at-risk individuals. Early identification of these children can not only reduce the risk of presentation with diabetic ketoacidosis (DKA), but also determine eligibility for prevention trials, which aim to prevent or delay progression to clinical T1D. Here, we describe the current state with regard to the use of the OGTT, HbA1c, fructosamine and glycated albumin in pre-symptomatic T1D. Using illustrative cases, we present our clinical experience with the use of CGM, and advocate for an increased role of this diabetes technology, for monitoring metabolic deterioration and disease progression in children with pre-symptomatic T1D.


Assuntos
Diabetes Mellitus Tipo 1 , Criança , Humanos , Diabetes Mellitus Tipo 1/diagnóstico , Glicemia , Automonitorização da Glicemia , Teste de Tolerância a Glucose , Hemoglobinas Glicadas , Autoanticorpos
7.
Proc Natl Acad Sci U S A ; 118(18)2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33903257

RESUMO

The role of integrins, in particular αv integrins, in regulating insulin resistance is incompletely understood. We have previously shown that the αvß5 integrin ligand milk fat globule epidermal growth factor like 8 (MFGE8) regulates cellular uptake of fatty acids. In this work, we evaluated the impact of MFGE8 on glucose homeostasis. We show that acute blockade of the MFGE8/ß5 pathway enhances while acute augmentation dampens insulin-stimulated glucose uptake. Moreover, we find that insulin itself induces cell-surface enrichment of MFGE8 in skeletal muscle, which then promotes interaction between the αvß5 integrin and the insulin receptor leading to dampening of skeletal-muscle insulin receptor signaling. Blockade of the MFGE8/ß5 pathway also enhances hepatic insulin sensitivity. Our work identifies an autoregulatory mechanism by which insulin-stimulated signaling through its cognate receptor is terminated through up-regulation of MFGE8 and its consequent interaction with the αvß5 integrin, thereby establishing a pathway that can potentially be targeted to improve insulin sensitivity.


Assuntos
Antígenos de Superfície/genética , Resistência à Insulina/genética , Insulina/genética , Proteínas do Leite/genética , Receptores de Vitronectina/genética , Animais , Antígenos CD/genética , Ácidos Graxos/genética , Ácidos Graxos/metabolismo , Glucose/metabolismo , Glicolipídeos/genética , Glicoproteínas/genética , Homeostase/genética , Humanos , Integrina alfaVbeta3/genética , Gotículas Lipídicas , Camundongos , Músculo Esquelético/metabolismo , Receptor de Insulina/genética , Transdução de Sinais/genética
8.
Haematologica ; 107(2): 403-416, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-33406814

RESUMO

APR-246 is a promising new therapeutic agent that targets p53 mutated proteins in myelodysplastic syndromes and in acute myeloid leukemia (AML). APR-246 reactivates the transcriptional activity of p53 mutants by facilitating their binding to DNA target sites. Recent studies in solid cancers have found that APR-246 can also induce p53-independent cell death. In this study, we demonstrate that AML cell death occurring early after APR-246 exposure is suppressed by iron chelators, lipophilic antioxidants and inhibitors of lipid peroxidation, and correlates with the accumulation of markers of lipid peroxidation, thus fulfilling the definition of ferroptosis, a recently described cell death process. The capacity of AML cells to detoxify lipid peroxides by increasing their cystine uptake to maintain major antioxidant molecule glutathione biosynthesis after exposure to APR-246 may be a key determinant of sensitivity to this compound. The association of APR-246 with induction of ferroptosis (either by pharmacological compounds, or genetic inactivation of SLC7A11 or GPX4) had a synergistic effect on the promotion of cell death, both in vivo and ex vivo.


Assuntos
Ferroptose , Leucemia Mieloide Aguda , Morte Celular , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Quinuclidinas/uso terapêutico
9.
J Vasc Interv Radiol ; 33(6): 687-694, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35301127

RESUMO

PURPOSE: To evaluate radiolabeled doxorubicin (Dox) analogs as tracers of baseline Dox biodistribution in vivo during hepatic intra-arterial chemotherapy and to assess the efficacy of ChemoFilter devices to bind Dox in vitro. MATERIALS AND METHODS: In an in vitro static experiment, [fluorine-18]N-succinimidyl 4-fluorobenzoate ([18F]SFB) and [fluorine-18]fluorobenzoyl-doxorubicin ([18F]FB-Dox) were added to a beaker containing a filter material (Dowex cation exchange resin, single-stranded DNA (ssDNA) resin, or sulfonated polymer coated mesh). In an in vitro flow model, [18F]FB-Dox was added into a Dox solution in phosphate-buffered saline, and the solution flowed via a syringe column containing the filter materials. In an in vitro flow experiment, using micro-positron emission tomography (PET), images were taken as [18F]SFB and [18F]FB-Dox moved through a phantom. For in vivo biodistribution testing, a catheter was placed into the common hepatic artery of a swine, and [18F]FB-Dox was infused over 30 seconds. A 10-minute dynamic image and three 20-minute static images were acquired using 3T PET/MR imaging. RESULTS: In the in vitro static experiment, [18F]FB-Dox demonstrated 76.7%, 88.0%, and 52.4% binding to the Dowex resin, ssDNA resin, and coated mesh, respectively. In the in vitro flow model, the first-pass binding of [18F]FB-Dox to the Dowex resin, ssDNA resin, and coated mesh was 76.7%, 74.2%, and 76.2%, respectively, and the total bound fraction was 80.9%, 84.6%, and 79.9%, respectively. In the in vitro flow experiment using micro-PET, the phantom demonstrated a greater amount of [18F]FB-Dox bound to both filter cartridges than of the control [18F]SFB. In in vivo biodistribution testing, the first 10 minutes depicted [18F]FB-Dox moving through the right upper quadrant of the abdomen. A region-of-interest analysis showed that the relative amount increased by 2.97 times in the gallbladder and 1.08 times in the kidney. The amount decreased by 0.74 times in the brain and 0.57 times in the heart. CONCLUSIONS: [18F]FB-Dox can be used to assess Dox binding to ChemoFilters as well as in vivo biodistribution. This sets the stage for the evaluation of ChemoFilter effectiveness in reducing systemic toxicity from intra-arterial chemotherapy.


Assuntos
Doxorrubicina , Tomografia por Emissão de Pósitrons , Animais , Artéria Hepática , Humanos , Imageamento por Ressonância Magnética , Tomografia por Emissão de Pósitrons/métodos , Suínos , Distribuição Tecidual
10.
Clin Chem Lab Med ; 60(10): 1551-1561, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-35998658

RESUMO

OBJECTIVES: Since its implementation 50 years ago in Quebec, Canada, newborn screening for congenital hypothyroidism has become one of the most successful public health measures worldwide. Screening programmes across Australia and New Zealand are characterised by significant commonalities in screening algorithms, and a high degree of regional cooperation in harmonisation efforts. We aimed to conduct a comprehensive survey of current performance and practices related to the total testing process for congenital hypothyroidism screening and provide recommendations for harmonisation priorities within our region. METHODS: A survey was conducted involving the six newborn screening laboratories which provide complete geographic coverage across Australasia. Approximately 360,000 newborns are screened annually. Survey questions incorporated pre-analytical, analytical, and post-analytical aspects of the screening programmes and an extensive 5-year (2016-2020) retrospective analysis of individual programme performance data. Responses from individual screening programmes were collated. RESULTS: The uptake of newborn screening was over 98% for the six major jurisdictions. All programmes have adopted a single-tier thyroid stimulating hormone (TSH) strategy using the Perkin Elmer GSP instrument. Significant similarities exist between programmes for recommended age of collection and recollection protocols for low birthweight newborns. The process for the determination of TSH cutoffs varies between programmes. TSH lower cut-offs for borderline-positive and positive notifications between 12-15 and 12-25 mIU/L blood, respectively. Recall rates vary between 0.08 and 0.20%. The case definition for congenital hypothyroidism generally includes biochemical and radiological parameters in addition to the commencement of thyroxine. All programmes reported collecting biochemical and clinical data on infants with positive screening tests, and positive predictive values vary between 23.6 and 77.3%. Variation in reported incidence (1:1,300-2,000) cannot be entirely explained by cutoff or recall rate (although one programme reporting fewer cases includes only permanent disease). CONCLUSIONS: Despite similarities between newborn screening algorithms for congenital hypothyroidism across Australia and New Zealand, differences in reported programme performance provide the basis for further harmonisation. Surveillance of a large population offers the potential for the ongoing development of evidence-based screening guidelines.


Assuntos
Hipotireoidismo Congênito , Australásia , Humanos , Lactente , Recém-Nascido , Triagem Neonatal , Estudos Retrospectivos , Tireotropina , Tiroxina
11.
Math Program ; 192(1-2): 29-50, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35300154

RESUMO

A clutter is k-wise intersecting if every k members have a common element, yet no element belongs to all members. We conjecture that, for some integer k ≥ 4 , every k-wise intersecting clutter is non-ideal. As evidence for our conjecture, we prove it for k = 4 for the class of binary clutters. Two key ingredients for our proof are Jaeger's 8-flow theorem for graphs, and Seymour's characterization of the binary matroids with the sums of circuits property. As further evidence for our conjecture, we also note that it follows from an unpublished conjecture of Seymour from 1975. We also discuss connections to the chromatic number of a clutter, projective geometries over the two-element field, uniform cycle covers in graphs, and quarter-integral packings of value two in ideal clutters.

12.
Chem Res Toxicol ; 34(1): 63-69, 2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-33373198

RESUMO

Organophosphorus esters (OPs) were originally developed as pesticides but were repurposed as easily manufactured, inexpensive, and highly toxic chemical warfare agents. Acute OP toxicity is primarily due to inhibition of acetylcholinesterase (AChE), an enzyme in the central and peripheral nervous system. OP inhibition of AChE can be reversed using oxime reactivators but many show poor CNS penetration, indicating a need for new clinically viable reactivators. However, challenges exist on how to best measure restored AChE activity in vivo and assess the reactivating agent efficacy. This work reports the development of molecular imaging tools using radiolabeled OP analog tracers that are less toxic to handle in the laboratory, yet inhibit AChE in a similar fashion to the actual OPs. Carbon-11 and fluorine-18 radiolabeled analog tracers of VX and sarin OP agents were prepared. Following intravenous injection in normal Sprague-Dawley rats (n = 3-4/tracer), the tracers were evaluated and compared using noninvasive microPET/CT imaging, biodistribution assay, and arterial blood analyses. All showed rapid uptake and stable retention in brain, heart, liver, and kidney tissues determined by imaging and biodistribution. Lung uptake of the sarin analog tracers was elevated, 2-fold and 4-fold higher uptake at 5 and 30 min, respectively, compared to that for the VX analog tracers. All tracers rapidly bound to red blood cells (RBC) and blood proteins as measured in the biodistribution and arterial blood samples. Analysis of the plasma soluble activity (nonprotein/cell bound activity) showed only 1-6% parent tracer and 88-95% of the activity in the combined solid fractions (RBC and protein bound) as early as 0.5 min post injection. Multivariate analysis of tracer production yield, molar activity, brain uptake, brain area under the curve over 0-15 min, and the amount of parent tracer in the plasma at 5 min revealed the [18F]VX analog tracer had the most favorable values for each metric. This tracer was considered the more optimal tracer relative to the other tracers studied and suitable for future in vivo OP exposure and reactivation studies.


Assuntos
Substâncias para a Guerra Química/farmacologia , Inibidores da Colinesterase/farmacologia , Compostos Organotiofosforados/farmacologia , Sarina/farmacologia , Acetilcolinesterase/metabolismo , Animais , Radioisótopos de Carbono , Substâncias para a Guerra Química/química , Inibidores da Colinesterase/química , Radioisótopos de Flúor , Masculino , Estrutura Molecular , Compostos Organotiofosforados/química , Ratos , Ratos Sprague-Dawley , Sarina/química , Distribuição Tecidual
13.
Math Program ; 190(1-2): 467-482, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34776534

RESUMO

In convex integer programming, various procedures have been developed to strengthen convex relaxations of sets of integer points. On the one hand, there exist several general-purpose methods that strengthen relaxations without specific knowledge of the set S of feasible integer points, such as popular linear programming or semi-definite programming hierarchies. On the other hand, various methods have been designed for obtaining strengthened relaxations for very specific sets S that arise in combinatorial optimization. We propose a new efficient method that interpolates between these two approaches. Our procedure strengthens any convex set containing a set S ⊆ { 0 , 1 } n by exploiting certain additional information about S. Namely, the required extra information will be in the form of a Boolean formula ϕ defining the target set S. The new relaxation is obtained by "feeding" the convex set into the formula ϕ . We analyze various aspects regarding the strength of our procedure. As one application, interpreting an iterated application of our procedure as a hierarchy, our findings simplify, improve, and extend previous results by Bienstock and Zuckerberg on covering problems.

14.
FASEB J ; 33(10): 11247-11257, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31299174

RESUMO

Interstitial cells of Cajal, which express the calcium-activated chloride channel transmembrane member 16A (TMEM16A), are an important determinant of gastrointestinal (GI) motility. We previously identified the acylaminocycloalkylthiophene class of TMEM16A inhibitors, which, following medicinal chemistry, gave analog 2-bromodifluoroacetylamino-5,6,7,8-tetrahydro-4H-cyclohepta[b]thiophene-3-carboxylic acid o-tolylamide (TMinh-23) with 30 nM half-maximal inhibitory concentration. Here, we tested the efficacy of TMinh-23 for inhibition of GI motility in mice. In isolated murine gastric antrum, TMinh-23 strongly inhibited spontaneous and carbachol-stimulated rhythmic contractions. Pharmacokinetic analysis showed predicted therapeutic concentrations of TMinh-23 for at least 4 h following a single oral or intraperitoneal dose at 10 mg/kg. Gastric emptying, as assessed following an oral bolus of phenol red or independently by [99mTc]-diethylenetriamine pentaacetic acid scintigraphy, was reduced by TMinh-23 by ∼60% at 20 min. Interestingly, there was little effect of TMinh-23 on baseline whole-gut transit time or time to diarrhea induced by castor oil. Consequent to the delay in gastric emptying, TMinh-23 administration significantly reduced the elevation in blood sugar in mice following an oral but not intraperitoneal glucose load. These results provide pharmacological evidence for involvement of TMEM16A in gastric emptying and suggest the utility of TMEM16A inhibition in disorders of accelerated gastric emptying, such as dumping syndrome, and potentially for improving glucose tolerance in diabetes mellitus/metabolic syndrome and enhancing satiety in obesity.-Cil, O., Anderson, M. O., Yen, R., Kelleher, B., Huynh, T. L., Seo, Y., Nilsen, S. P., Turner, J. R., Verkman, A. S. Slowed gastric emptying and improved oral glucose tolerance produced by a nanomolar-potency inhibitor of calcium-activated chloride channel TMEM16A.


Assuntos
Anoctamina-1/metabolismo , Cálcio/metabolismo , Agonistas dos Canais de Cloreto/farmacologia , Canais de Cloreto/metabolismo , Esvaziamento Gástrico/efeitos dos fármacos , Glucose/metabolismo , Proteínas de Neoplasias/metabolismo , Animais , Glicemia/efeitos dos fármacos , Cloretos/metabolismo , Feminino , Motilidade Gastrointestinal/efeitos dos fármacos , Teste de Tolerância a Glucose/métodos , Humanos , Camundongos
15.
Eur J Haematol ; 105(5): 588-596, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32659848

RESUMO

OBJECTIVES: Venetoclax combined with hypomethylating agents is a new therapeutic strategy frequently used for treating AML patients who are not eligible for conventional chemotherapy. However, high response rates are heterogeneous due to different mechanisms mediating resistance to venetoclax such as up-regulation of MCL-1 expression. We thus tested the anti-leukemic activity of S63845, a specific MCL-1 inhibitor. METHODS: Apoptosis induces by S63845 with or without venetoclax was evaluated in primary AML samples and in AML cell lines co-cultured or not with bone marrow (BM) mesenchymal stromal cells. Sensitivity of leukemic cells to S63845 was correlated to the expression level of BCL-2, MCL-1, and BCL-XL determined by Western Blot and mass spectrometry-based proteomics. RESULTS: We observed that even if MCL-1 expression is weak compared to BCL-2, S63845 induces apoptosis of AML cells and strongly synergizes with venetoclax. Furthermore, AML cells resistant to venetoclax are highly sensitive to S63845. Interestingly, the synergistic effect of S63845 toward venetoclax-mediated apoptosis of AML cells is still observed in a context of interaction with the BM microenvironment that intrinsically mediates resistance to BCL2 inhibition. CONCLUSION: These results are therefore of great relevance for clinicians as they provide the rational for combining BCL-2 and MCL-1 inhibition in AML.


Assuntos
Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Proteína de Sequência 1 de Leucemia de Células Mieloides/antagonistas & inibidores , Pirimidinas/farmacologia , Sulfonamidas/farmacologia , Tiofenos/farmacologia , Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Compostos Bicíclicos Heterocíclicos com Pontes/administração & dosagem , Linhagem Celular Tumoral , Células Cultivadas , Técnicas de Cocultura , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Sinergismo Farmacológico , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Pirimidinas/administração & dosagem , Sulfonamidas/administração & dosagem , Tiofenos/administração & dosagem
17.
Mol Pharm ; 16(9): 3831-3841, 2019 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-31381351

RESUMO

Boron neutron capture therapy (BNCT) is a therapeutic modality which has been used for the treatment of cancers, including brain and head and neck tumors. For effective treatment via BNCT, efficient and selective delivery of a high boron dose to cancer cells is needed. Prostate-specific membrane antigen (PSMA) is a target for prostate cancer imaging and drug delivery. In this study, we conjugated boronic acid or carborane functional groups to a well-established PSMA inhibitor scaffold to deliver boron to prostate cancer cells and prostate tumor xenograft models. Eight boron-containing PSMA inhibitors were synthesized. All of these compounds showed a strong binding affinity to PSMA in a competition radioligand binding assay (IC50 from 555.7 to 20.3 nM). Three selected compounds 1a, 1d, and 1f were administered to mice, and their in vivo blocking of 68Ga-PSMA-11 uptake was demonstrated through a positron emission tomography (PET) imaging and biodistribution experiment. Biodistribution analysis demonstrated boron uptake of 4-7 µg/g in 22Rv1 prostate xenograft tumors and similar tumor/muscle ratios compared to the ratio for the most commonly used BNCT compound, 4-borono-l-phenylalanine (BPA). Taken together, these data suggest a potential role for PSMA targeted BNCT agents in prostate cancer therapy following suitable optimization.


Assuntos
Antígenos de Superfície/metabolismo , Terapia por Captura de Nêutron de Boro/métodos , Ácidos Borônicos/química , Ácidos Borônicos/farmacocinética , Sistemas de Liberação de Medicamentos/métodos , Glutamato Carboxipeptidase II/antagonistas & inibidores , Glutamato Carboxipeptidase II/metabolismo , Neoplasias da Próstata/radioterapia , Animais , Compostos de Boro/química , Compostos de Boro/farmacocinética , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ácido Edético/análogos & derivados , Ácido Edético/farmacocinética , Isótopos de Gálio , Radioisótopos de Gálio , Humanos , Concentração Inibidora 50 , Ligantes , Masculino , Camundongos , Camundongos Nus , Oligopeptídeos/farmacocinética , Fenilalanina/análogos & derivados , Fenilalanina/química , Fenilalanina/farmacocinética , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Próstata/patologia , Radiossensibilizantes/química , Radiossensibilizantes/farmacocinética , Distribuição Tecidual , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Emerg Radiol ; 26(5): 541-548, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31286323

RESUMO

OBJECTIVE: Determine the incidence of tibial neuropathy following talus fractures and CT's ability to stratify patients at risk for developing post-traumatic neuropathy. MATERIALS AND METHODS: In this IRB-approved retrospective analysis, 71 talus fractures and 8 contralateral control ankle CTs were reviewed by one observer blinded to clinical information. CT evidence suggestive of tibial neurovascular bundle injury included nerve displacement, perineural fat effacement/edema, and bone touching nerve. The association between these CT findings and clinically evident tibial neuropathy was analyzed. A semi-quantitative likelihood score was assigned based on the degree of the CT findings around the nerve. Interobserver agreement was calculated between 2 other readers. RESULTS: Twenty-five percent of patients in this cohort had clinical evidence of tibial neuropathy. There was a high specificity (0.87-0.93) and negative predictive value (0.83-0.87), a moderate accuracy (0.80-0.82), but a lower sensitivity (0.33-0.56) associated with the CT findings. Among the CT findings, nerve displacement (p < 0.0001) and bone touching nerve (p = 0.01) were associated with tibial neuropathy. A likelihood score of 2-5 was associated (p = 0.007-0.015) with tibial neuropathy. The presence of tibial neuropathy and nerve recovery were not associated with hospital length of stay, while CT findings were. There was substantial agreement between the three readers: likelihood scores 2+ (k = 0.78) and 3+ (k = 0.72). CONCLUSIONS: Tibial neuropathy occurs following talus fractures, and CT findings may help surgeons narrow down the number of patients requiring close neurological follow-up.


Assuntos
Fraturas Ósseas/complicações , Fraturas Ósseas/diagnóstico por imagem , Tálus/lesões , Neuropatia Tibial/diagnóstico por imagem , Neuropatia Tibial/etiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X
19.
Bioconjug Chem ; 29(8): 2526-2530, 2018 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-30059611

RESUMO

Atherosclerosis is a cardiovascular disease characterized by the formation of lipid-rich plaques within the walls of large arteries. Over time, a portion of these lesions can detach and lead to serious complications, such as strokes or heart attacks. Currently, there is no clinically effective way to detect the presence of atherosclerosis in patients until it has reached a relatively advanced stage. Furthermore, increasing evidence suggests that the pathobiological behavior of plaques is determined mainly by their composition, and not their size, which is the parameter usually monitored with current imaging techniques. In this work, we report protein-based agents that target the vascular cell adhesion molecule (VCAM1), a protein that plays a crucial role in atherosclerosis progression. In vivo experiments with murine atherosclerosis models indicated that the targeted protein nanoparticles were successful in detecting plaques of various sizes in the descending aorta and the aortic arch. This finding encourages the further development of these nanoscale agents for applications in the imaging, diagnosis, and treatment of cardiovascular diseases.


Assuntos
Capsídeo/metabolismo , Placa Aterosclerótica/diagnóstico , Molécula 1 de Adesão de Célula Vascular/metabolismo , Animais , Apolipoproteínas E/genética , Modelos Animais de Doenças , Progressão da Doença , Diagnóstico Precoce , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Camundongos Knockout , Placa Aterosclerótica/patologia
20.
Pediatr Diabetes ; 19(1): 171-179, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28370959

RESUMO

BACKGROUND: Insulin autoimmune syndrome (IAS), characterized by glycemic dysregulation and life-threatening hypoglycemia, can occur in patients with type 1 diabetes (T1D). Diagnostic confirmation is complex but important in order to ensure timely initiation of definitive therapy. AIMS: We aimed to quantitate the degree of immunoglobulin-insulin complex (IIC) formation and its effects on glycemic control in a patient with T1D and IAS compared with T1D and non-T1D controls and before and after therapeutic plasma exchange (TPE). MATERIALS & METHODS: The prospective descriptive study was conducted between June 2015 and December 2015 in a quaternary children's hospital in Brisbane, Australia. Percent Free "Immunoreactive" Insulin (%FII) as assessed by polyethylene glycol precipitation studies and its relationship to plasma glucose and serum insulin concentration. RESULTS: Samples from the patient with T1D and IAS demonstrated lower mean %FII compared to T1D (23.8 ± 2.0 vs 52.0 ± 6.7; P < .0001) and non-T1D (23.8 ± 2.0 vs 102.9 ± 2.7; P < .0001) controls. This was associated with loss of glycemic predictability and frequent severe hypoglycemia. TPE increased %FII (23.8 ± 2.0 before TPE vs 83.6 ± 2.5 after TPE, P < .0001) and reestablished plasma glucose responsiveness to exogenous insulin. DISCUSSION: IAS should be considered in T1D patients with unexplained glycemic instability and hypoglycemia. The laboratory plays an integral diagnostic role. CONCLUSION: TPE is an effective method for removing IICs and normalizing insulin-mediated glucose responses.


Assuntos
Doenças Autoimunes/terapia , Diabetes Mellitus Tipo 1/complicações , Hipoglicemia/imunologia , Insulina/imunologia , Troca Plasmática , Doenças Autoimunes/diagnóstico , Doenças Autoimunes/etiologia , Criança , Diabetes Mellitus Tipo 1/imunologia , Humanos , Masculino , Estudos Prospectivos
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