Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
Cureus ; 15(7): e42734, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37654941

RESUMO

Fibroids, also known as uterine leiomyomas, are the most common solid benign lesions of the uterus. Fibroids are responsive to hormones and are stimulated by estrogens and commonly grow during pregnancy and involute as menopause progresses. The treatment is mostly conservative. When symptomatic, the treatment requires surgical intervention. We present a case of a 72-year-old post-menopausal female with a large, calcified parasitic fibroid, an extremely rare variant of uterine leiomyoma occurring outside the uterus. The number of cases reported about this pathology is minimal.

2.
Cureus ; 14(10): e30205, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36381933

RESUMO

Three clinical scenarios, premature labor; inescapable abortion; and incompetent cervix, result in the dilatation of endocervical canals before term. Ultrasonography is the modality of choice for confirming the above conditions. Here, we discuss a case of preterm primigravida with complaints of bleeding per vagina with the dilated cervix and prolapsed membranes with fetal parts within.

3.
Cureus ; 14(10): e30694, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36439605

RESUMO

Middle-aged women with ureterovaginal fistula (UVF) after hysterectomy represent a painful condition for the patients in the community. Accurate diagnosis and proper planning before surgery are essential for effective outcomes. CT urography is the modality of choice in diagnosing ureterovaginal fistula. CT urography helps in evaluating the fistula as well the associated renal complications following the condition. Here we present a case of ureterovaginal fistula reported with a history of vaginal hysterectomy for subserosal fibroid in December 2021.

4.
Oncotarget ; 7(38): 61741-61754, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27557514

RESUMO

Long noncoding RNAs play a vital role in diverse biological processes such as embryonic development, cell growth, and tumorigenesis. In this study, we report that LncRNA ANRIL, which encodes a 3834-nt RNA that contains 19 exons at the antisense orientation of the INK4B-ARF-INK4A gene cluster, generally up-regulated in nasopharyngeal carcinoma [1]. In a cohort of 88 NPC patients, ANRIL was highly expressed in advanced-stage cancer. Multivariate analyses revealed that ANRIL expression could serve as an independent predictor of overall survival (P = 0.027) and disease-free survival (P = 0.033). Further investigation showed that knockdown of ANRIL significantly repressed NPC cell proliferation and transformation. We also found that ANRIL could induce the percentage of side population cells (SP cells) in NPC. To meet the urgent needs of energy provision, ANRIL can also reprogram glucose metabolism via increasing glucose uptake for glycolysis, which was regulated by the mTOR signal pathway to affect the expression of essential genes in glycolysis. We concluded that ANRIL could promote NPC progression via increasing cell proliferation, reprograming cell glucose metabolism and inducing side-population stem-like cancer cells. Our results also suggested that ANRIL may serve as a novel diagnostic or prognostic biomarker and a candidate target for new therapies in NPC.


Assuntos
Carcinoma/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias Nasofaríngeas/metabolismo , RNA Longo não Codificante/genética , Células da Side Population/citologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores Tumorais/genética , Proliferação de Células , Transformação Celular Neoplásica , Progressão da Doença , Intervalo Livre de Doença , Éxons , Glucose/metabolismo , Glicólise , Humanos , Pessoa de Meia-Idade , Família Multigênica , Análise Multivariada , Carcinoma Nasofaríngeo , Células-Tronco Neoplásicas/citologia , Oligonucleotídeos Antissenso , Resultado do Tratamento , Regulação para Cima , Adulto Jovem
5.
J Control Release ; 212: 70-7, 2015 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-26091919

RESUMO

The manuscript reports the side-by-side comparison of therapeutic properties of polymeric micelles and nanoemulsions generated from micelles. The effect of the structure of a hydrophobic block of block copolymer on the therapeutic efficacy, tumor recurrence, and development of drug resistance was studied in pancreatic tumor bearing mice. Mice were treated with paclitaxel (PTX) loaded poly(ethylene oxide)-co-polylactide micelles or corresponding perfluorocarbon nanoemulsions. Two structures of the polylactide block differing in a physical state of micelle cores or corresponding nanodroplet shells were compared. Poly(ethylene oxide)-co-poly(d,l-lactide) (PEG-PDLA) formed micelles with elastic amorphous cores while poly(ethylene oxide)-co-poly(l-lactide) (PEG-PLLA) formed micelles with solid crystalline cores. Micelles and nanoemulsions stabilized with PEG-PDLA copolymer manifested higher therapeutic efficacy than those formed with PEG-PLLA copolymer studied earlier. Better performance of PEG-PDLA micelles and nanodroplets was attributed to the elastic physical state of micelle cores (or droplet shells) allowing adequate rate of drug release via drug diffusion and/or copolymer biodegradation. The biodegradation of PEG-PDLA stabilized nanoemulsions was monitored by the ultrasonography of nanodroplets injected directly into the tumor; the PEG-PDLA stabilized nanodroplets disappeared from the injection site within 48h. In contrast, nanodroplets stabilized with PEG-PLLA copolymer were preserved at the injection site for weeks and months indicating extremely slow biodegradation of solid PLLA blocks. Multiple injections of PTX-loaded PEG-PDLA micelles or nanoemulsions to pancreatic tumor bearing mice resulted in complete tumor resolution. Two of ten tumors treated with either PEG-PDLA micellar or nanoemulsion formulation recurred after the completion of treatment but proved sensitive to the second treatment cycle indicating that drug resistance has not been developed. This is in contrast to the treatment with PEG-PLLA micelles or nanoemulsions where all resolved tumors quickly recurred after the completion of treatment and proved resistant to the repeated treatment. The prevention of drug resistance in tumors treated with PEG-PDLA stabilized formulations was attributed to the presence and preventive effect of copolymer unimers that were in equilibrium with PEG-PDLA micelles. PEG-PDLA stabilized nanoemulsions manifested lower hematological toxicity than corresponding micelles suggesting higher drug retention in circulation. Summarizing, micelles with elastic cores appear preferable to those with solid cores as drug carriers. Micelles with elastic cores and corresponding nanoemulsions both manifest high therapeutic efficacy, with nanoemulsions exerting lower systemic toxicity than micelles. The presence of a small fraction of micelles with elastic cores in nanoemulsion formulations is desirable for prevention of the development of drug resistance.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Portadores de Fármacos/administração & dosagem , Micelas , Nanoestruturas/administração & dosagem , Paclitaxel/administração & dosagem , Neoplasias Pancreáticas/tratamento farmacológico , Animais , Antineoplásicos Fitogênicos/uso terapêutico , Linhagem Celular Tumoral , Portadores de Fármacos/uso terapêutico , Portadores de Fármacos/toxicidade , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Emulsões , Humanos , Leucócitos/efeitos dos fármacos , Masculino , Camundongos Nus , Nanoestruturas/uso terapêutico , Nanoestruturas/toxicidade , Paclitaxel/uso terapêutico , Pâncreas/patologia , Neoplasias Pancreáticas/patologia , Poliésteres/química , Polietilenoglicóis/química
6.
J Control Release ; 206: 153-60, 2015 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-25776738

RESUMO

Intravital imaging of nanoparticle extravasation and tumor accumulation has revealed, for the first time, detailed features of carrier and drug behavior in circulation and tissue that suggest new directions for optimization of drug nanocarriers. Using intravital fluorescent microscopy, the extent of the extravasation, diffusion in the tissue, internalization by tissue cells, and uptake by the RES system were studied for polymeric micelles, nanoemulsions, and nanoemulsion-encapsulated drug. Discrimination of vascular and tissue compartments in the processes of micelle and nanodroplet extravasation and tissue accumulation was possible. A simple 1-D continuum model was suggested that allowed discriminating between various kinetic regimes of nanocarrier (or released drug) internalization in tumors of various sizes and cell density. The extravasation and tumor cell internalization occurred much faster for polymeric micelles than for nanoemulsion droplets. Fast micelle internalization resulted in the formation of a perivascular fluorescent coating around blood vessels. A new mechanism of micelle extravasation and internalization was suggested, based on the fast extravasation and internalization rates of copolymer unimers while maintaining micelle/unimer equilibrium in the circulation. The data suggested that to be therapeutically effective, nanoparticles with high internalization rate should manifest fast diffusion in the tumor tissue in order to avoid generation of concentration gradients that induce drug resistance. However an extra-fast diffusion should be avoided as it may result in the flow of extravasated nanoparticles from the tumor to normal organs, which would compromise targeting efficiency. The extravasation kinetics were different for nanodroplets and nanodroplet-encapsulated drug F-PTX suggesting a premature release of some fraction of the drug from the carrier. In conclusion, the development of an "ideal" drug carrier should involve the optimization of both drug retention and carrier diffusion parameters.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Portadores de Fármacos/metabolismo , Micelas , Nanopartículas/metabolismo , Neoplasias/metabolismo , Paclitaxel/administração & dosagem , Polímeros/metabolismo , Animais , Antineoplásicos Fitogênicos/farmacocinética , Linhagem Celular Tumoral , Sistemas de Liberação de Medicamentos , Feminino , Humanos , Camundongos Nus , Microscopia , Neoplasias/irrigação sanguínea , Imagem Óptica , Paclitaxel/farmacocinética
7.
Ultrasound Med Biol ; 39(10): 1804-11, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23849384

RESUMO

The effect of ultrasound on the permeability of blood vessels to nano-emulsion droplets was investigated using excised mouse carotid arteries as model blood vessels. Perfluorocarbon nano-droplets were formed by perfluoro-15-crown-5-ether and stabilized by poly(ethylene oxide)-co-poly(DL-lactide) block co-polymer shells. Nano-droplet fluorescence was imparted by interaction with fluorescein isothiocyanate-dextran (molecular weight = 70,000 Da). The permeability of carotid arteries to nano-droplets was studied in the presence and absence of continuous wave or pulsed therapeutic 1-MHz ultrasound. The data indicated that the application of ultrasound resulted in permeabilization of the vascular wall to nano-droplets. The effect of continuous wave ultrasound was substantially stronger than that of pulsed ultrasound of the same total energy. No effect of blood vessel pre-treatment with ultrasound was observed.


Assuntos
Permeabilidade Capilar/fisiologia , Artérias Carótidas/química , Fluorocarbonos/química , Nanocápsulas/química , Sonicação/métodos , Animais , Permeabilidade Capilar/efeitos da radiação , Artérias Carótidas/efeitos da radiação , Relação Dose-Resposta à Radiação , Fluorocarbonos/efeitos da radiação , Ondas de Choque de Alta Energia , Técnicas In Vitro , Camundongos , Nanocápsulas/efeitos da radiação , Nanocápsulas/ultraestrutura , Tamanho da Partícula , Doses de Radiação
8.
J Ther Ultrasound ; 1: 11, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-25516800

RESUMO

BACKGROUND: Many aspects of the mechanisms involved in ultrasound-mediated therapy remain obscure. In particular, the relative roles of drug and ultrasound, the effect of the time of ultrasound application, and the effect of tissue heating are not yet clear. The current study was undertaken with the goal to clarify these aspects of the ultrasound-mediated drug delivery mechanism. METHODS: Focused ultrasound-mediated drug delivery was performed under magnetic resonance imaging guidance (MRgFUS) in a pancreatic ductal adenocarcinoma (PDA) model grown subcutaneously in nu/nu mice. Paclitaxel (PTX) was used as a chemotherapeutic agent because it manifests high potency in the treatment of gemcitabine-resistant PDA. Poly(ethylene oxide)-co-poly(d,l-lactide) block copolymer stabilized perfluoro-15-crown-5-ether nanoemulsions were used as drug carriers. MRgFUS was applied at sub-ablative pressure levels in both continuous wave and pulsed modes, and only a fraction of the tumor was treated. RESULTS: Positive treatment effects and even complete tumor resolution were achieved by treating the tumor with MRgFUS after injection of nanodroplet encapsulated drug. The MRgFUS treatment enhanced the action of the drug presumably through enhanced tumor perfusion and blood vessel and cell membrane permeability that increased the drug supply to tumor cells. The effect of the pulsed MRgFUS treatment with PTX-loaded nanodroplets was clearly smaller than that of continuous wave MRgFUS treatment, supposedly due to significantly lower temperature increase as measured with MR thermometry and decreased extravasation. The time of the MRgFUS application after drug injection also proved to be an important factor with the best results observed when ultrasound was applied at least 6 h after the injection of drug-loaded nanodroplets. Some collateral damage was observed with particular ultrasound protocols supposedly associated with enhanced inflammation. CONCLUSION: This presented data suggest that there exists an optimal range of ultrasound application parameters and drug injection time. Decreased tumor growth, or complete resolution, was achieved with continuous wave ultrasound pressures below or equal to 3.1 MPa and drug injection times of at least 6 h prior to treatment. Increased acoustic pressure or ultrasound application before or shortly after drug injection gave increased tumor growth when compared to other protocols.

9.
AIP Conf Proc ; 1481: 381-387, 2012 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24839333

RESUMO

Effect of ultrasound on the permeability of blood vessels and cell membranes to macromolecules and nanodroplets was investigated using mouse carotid arteries and tumor cells. Model macromolecular drug, FITC-dextran with molecular weight of 70,000 Da was used in experiments with carotid arteries. The effect of unfocused 1-MHz ultrasound and and perfluoro-15-crown-5-ether nanodroplets stabilized with the poly(ethylene oxide)-co-poly(D,L-lactide) block copolymer shells was studied. In cell culture experiments, ovarian carcinoma cells and Doxorubicin (DOX) loaded poly(ethylene oxide)-co-polycaprolactone nanodroplets were used. The data showed that the application of ultrasound resulted in permeabilization of all biological barriers tested. Under the action of ultrasound, not only FITC-dextran but also nanodroplets effectively penetrated through the arterial wall; the effect of continuous wave ultrasound was stronger than that of pulsed ultrasound. In cell culture experiments, ultrasound triggered DOX penetration into cell nuclei, presumably due to releasing the drug from the carrier. Detailed mechanisms of the observed effects require further study.

10.
J Control Release ; 153(1): 4-15, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21277919

RESUMO

Perfluorocarbon nanoemulsions can deliver lipophilic therapeutic agents to solid tumors and simultaneously provide for monitoring nanocarrier biodistribution via ultrasonography and/or (19)F MRI. In the first generation of block copolymer stabilized perfluorocarbon nanoemulsions, perfluoropentane (PFP) was used as the droplet forming compound. Although manifesting excellent therapeutic and ultrasound imaging properties, PFP nanoemulsions were unstable at storage, difficult to handle, and underwent hard to control phenomenon of irreversible droplet-to-bubble transition upon injection. To solve the above problems, perfluoro-15-crown-5-ether (PFCE) was used as a core forming compound in the second generation of block copolymer stabilized perfluorocarbon nanoemulsions. PFCE nanodroplets manifest both ultrasound and fluorine ((19)F) MR contrast properties, which allows using multimodal imaging and (19)F MR spectroscopy for monitoring nanodroplet pharmacokinetics and biodistribution. In the present paper, acoustic, imaging, and therapeutic properties of unloaded and paclitaxel (PTX) loaded PFCE nanoemulsions are reported. As manifested by the (19)F MR spectroscopy, PFCE nanodroplets are long circulating, with about 50% of the injected dose remaining in circulation 2h after the systemic injection. Sonication with 1-MHz therapeutic ultrasound triggered reversible droplet-to-bubble transition in PFCE nanoemulsions. Microbubbles formed by acoustic vaporization of nanodroplets underwent stable cavitation. The nanodroplet size (200nm to 350nm depending on a type of the shell and conditions of emulsification) as well as long residence in circulation favored their passive accumulation in tumor tissue that was confirmed by ultrasonography. In the breast and pancreatic cancer animal models, ultrasound-mediated therapy with paclitaxel-loaded PFCE nanoemulsions showed excellent therapeutic properties characterized by tumor regression and suppression of metastasis. Anticipated mechanisms of the observed effects are discussed.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Fluorocarbonos/química , Neoplasias/diagnóstico por imagem , Neoplasias/terapia , Paclitaxel/administração & dosagem , Terapia por Ultrassom/métodos , Animais , Antineoplásicos Fitogênicos/uso terapêutico , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/terapia , Linhagem Celular Tumoral , Emulsões/química , Feminino , Humanos , Camundongos , Nanomedicina/métodos , Paclitaxel/uso terapêutico , Neoplasias Pancreáticas/diagnóstico por imagem , Neoplasias Pancreáticas/terapia , Ultrassonografia
11.
J Nanosci Nanotechnol ; 9(4): 2607-15, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19438010

RESUMO

Most interactions inside living cells take place at nano-length scales. The only way to monitor these nano-scale interactions inside living cells is by utilizing the phenomenon of Fluorescence Resonance Energy Transfer (FRET). Thus, the importance of FRET in visualizing intracellular dynamics has provided continuous motivation for discovery/synthesis of biologically useful molecules exhibiting FRET. While working on intracellular uptake of coumarin loaded biodegradable polymeric nanoparticles, we have discovered a remarkable utility of 6-coumarin (Co) forming a FRET pair with propidium iodide (PI). Based on observations on intracellular behavior of Co and PI, we tested and characterized the Co-PI FRET pair in solutions. We report that Co acts as photon donor to PI (photon acceptor) with a Forster's distance of approximately 3 nanometers. We show a FRET based sensitivity enhancement (30-35%) of PI for nucleic acid detection, both inside cells and in solutions. Our results open a variety of applied avenues by utilizing the newly discovered FRET pair.


Assuntos
Cumarínicos/metabolismo , Transferência Ressonante de Energia de Fluorescência/métodos , Ácidos Nucleicos/análise , Propídio/metabolismo , Permeabilidade da Membrana Celular , Cumarínicos/química , Sistemas de Liberação de Medicamentos , Células HeLa , Humanos , Ácido Láctico/química , Nanopartículas/química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Propídio/química , Sensibilidade e Especificidade , Espectrometria de Fluorescência
12.
J Nanosci Nanotechnol ; 8(5): 2328-33, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18572645

RESUMO

Liposomes have a variety of applications as model systems to study enclosed biological membranes, as delivery vehicles for a variety of drugs and as micro- and nano-reactors, amongst others. However, preparation of liposomes requires use of expensive raw material (synthetic lipids) from specialized commercial suppliers, and ability to make reproducible preparations remains a specialized art till date. In this work, we prepared liposomes using natural lipids extracted from the bacteria Escherichia coli (E. coli), which are extremely economical compared to the synthetic lipids. We demonstrate robust procedures for convenient and reproducible preparations of 200-300 nm diameter liposomes from bacterial cells. We also show a potential application of these bacterial liposomes in delivery of aqueous molecules to cancer cells. We show not only intracellular uptake, but also biodegradation of the liposomes inside cancer cells. Our economical liposomes promise to serve as excellent model systems for studies on encapsulation of molecules inside soft materials with desired efficiencies. Additionally, they certainly show a strong potential to be tools for research in diverse areas ranging from drug delivery applications to sub-micron reaction engineering for carrying out and understanding the mechanisms of chemical reactions in small enclosed volumes.


Assuntos
Antineoplásicos/administração & dosagem , Escherichia coli/metabolismo , Escherichia coli/crescimento & desenvolvimento , Células HeLa , Humanos , Lipossomos , Fosfolipídeos/isolamento & purificação
13.
Biotechnol Bioeng ; 100(2): 284-96, 2008 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-18080345

RESUMO

Pseudomonas fluorescens cultures produce fluorescent siderophores. By utilizing optimal conditions for maximizing siderophore production in shake flask cultures of P. fluorescens, we report successful characterization of the culture broth supernatant as a robust ferric ions biosensor. For characterizing the ferric ions biosensor, we tested the effects of pH, buffers, different ferric salts and possible interference by ferrous ions under different solution conditions. We find that the biosensor is very specific to ferric ions only with sensitivity to concentrations as low as 10 microM. Further, the response time of the biosensor is the shortest (approximately 5 min or smaller) for citrate as the accompanying anion with ferric ions. While the response time is longer than that expected of normal biosensors, it is well compensated by the simplicity and economics of the biosensor production. Extremely low standard deviations in several experimental repeats also highlight the robustness of the ferric ions biosensor. Most importantly, the biosensor is extremely easy to use due to its straightforward spectrophotometric applications. We also show the utility of the biosensor with the high resolution technique of fluorescence microscopy. Finally, we report a novel mechanistic finding that siderophores present in the culture broth supernatants have two distinct optically active sites on them, which can be monitored independently in presence or absence of ferric ions.


Assuntos
Bioensaio/métodos , Técnicas Biossensoriais/métodos , Ferro/administração & dosagem , Ferro/análise , Pseudomonas fluorescens/efeitos dos fármacos , Pseudomonas fluorescens/fisiologia , Espectrometria de Fluorescência/métodos , Relação Dose-Resposta a Droga , Íons , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
14.
J Nanosci Nanotechnol ; 6(12): 3854-62, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17256341

RESUMO

Our present capabilities to build nanomachines are very limited compared to the elegance and efficiency of bio-nanomachines. The flagellar motor of bacteria is an example of a bionanomachine. It is a structured aggregate of proteins anchored in many bacterial cell membranes (formed mostly from phospholipids). While a large body of work characterizes various functional components of flagellar proteins, limited literature exists on the role of phospholipids of the membranes anchoring the protein. It is assumed that the membranes do not play any active role in the nano-propeller's functioning. However, it is relevant to question this assumption for several reasons. Firstly, the anchor for any machine on any scale is essential in terms of the work-load the machine can deliver. Secondly, it is now clear that localized protein-lipid interactions are essential for functioning of many transmembrane proteins. These interactions result in formation of "nano-domains" of specific lipid constituents around the protein providing the desired functionality. Thus, regardless of whether the bacterial membrane is primarily an anchor for flagellar proteins or specific lipid components of the membrane are actively participating in nano-propeller driven motion of bacteria, it is important to investigate the role of the membrane itself in working of this bionanomachine. Using video microscopy with a 33 ms resolution to monitor bacterial motion, we investigate effects of varying the membrane tension, by providing different osmotic environments, on the performance of the flagellar motor. Our data strongly demonstrate an active role of bacterial membranes in the nano-propeller driven bacterial motion. Our results point towards reconsidering performance of classical bionanomachines like bacterial flagellar motor and F1-F0 ATPase in view of the membranes in which they are packed in, in contrast to just the proteins by themselves.


Assuntos
Membrana Celular/fisiologia , Escherichia coli/fisiologia , Bicamadas Lipídicas/metabolismo , Fluidez de Membrana/fisiologia , Microfluídica/métodos , Proteínas Motores Moleculares/fisiologia , Nanotecnologia/métodos , Biomimética/métodos , Simulação por Computador , Escherichia coli/citologia , Modelos Biológicos , Movimento (Física)
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA