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1.
Eur J Pharmacol ; 931: 175173, 2022 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-35940236

RESUMO

Advances in biotechnology have led to improving human health with number of novel approaches to mitigate life-threatening diseases such as human immunodeficiency virus (HIV) infection, cancer, and neurodegenerative diseases. In the case of HIV, the damage caused by the retrovirus to the immune system leads to opportunistic infection as well as an elevated risk of autoimmune disease and cancer. Furthermore, clinical symptoms associated with the virus itself may arise. Antiretroviral drug therapy using reverse transcriptase inhibitors, protease inhibitors, fusion inhibitor, chemokine receptor 5 antagonist and integrase strand transfer inhibitors have shown promising results in treating HIV infection and available in market in the form of various dosage forms. However, they are unable to completely cure the disease because of complexity in pathogenesis of HIV. In addition, these drugs have some limitations of poor solubility, permeability or, poor receptor binding capacity. To overcome these drawbacks, many novel drug delivery systems for the drugs belonging to above mentioned categories have been developed. The possibility of treating HIV infection using CRISPR-Cas9 gene editing has been found in 2015. This provided a new area of research to the scientists who are working towards alternative treatment strategies for HIV infections. The present article describes about various treatment strategies used to treat HIV infections with special emphasis on the role of CRISPR/Cas9 gene-based technology. The potential benefits of specific epigenetic modification in the c-c chemokine receptor 5 gene (CCR5) via various delivery methods are also highlighted.


Assuntos
Infecções por HIV , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , Terapia Genética/métodos , Infecções por HIV/tratamento farmacológico , Infecções por HIV/genética , Humanos , Receptores de Quimiocinas/genética
2.
Chem Biol Interact ; 356: 109869, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35231453

RESUMO

Fisetin (FS) is a bioactive flavonoid obtained mostly from apple and strawberry and classified under the category of food supplements due to numerous pharmacological effects against various diseases through multiple mechanistic pathways. It acts as excellent neuroprotective, cardioprotective, anti-invasive, anti-tumorigenic, anti-angiogenic, anticancer, antidiabetics, antioxidant, anti-inflammatory agent. Despite having excellent safety and efficacy profile, FS is very less explored to clinical research either as food supplement or, as therapeutic agent due to its poor aqueous solubility, low bioavailability and reduced blood brain barrier permeability. Multiple mechanistic pathways through which FS elicits its pharmacological actions and the challenges associated with FS that compromises therapeutic efficacy are described in this article. The nanoformulations developed to enhance the bioavailability and therapeutic efficacy of FS are also covered with detailed description of research works carried by various researchers. These include nanoemulsions, liposomes, ethosomes, glycerosomes, polymeric micelles, self-nanoemulsifying drug delivery system and polymeric nanoparticles. Various patents pertaining to extraction/isolation, formula composition and therapeutic uses of FS as well as some clinical studies conducted using FS as active moiety are also enlisted.


Assuntos
Flavonóis , Nanopartículas , Disponibilidade Biológica , Sistemas de Liberação de Medicamentos
3.
Environ Sci Pollut Res Int ; 29(33): 50488-50499, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35230633

RESUMO

Fisetin is a polyphenolic flavonoid reported to have antioxidant, anti-inflammatory, and anti-cancer activities. However, it loses its importance as an effective phytochemical due to its poor water solubility and lower bioavailability. In the present study, the self-nanoemulsifying drug delivery system (SNEDDS) of fisetin was developed in order to improve its pharmacological activity. The developed SNEDDS of fisetin was evaluated for improving the rotenone-induced behavioral changes in the rats, and its efficacy was compared with naïve fisetin. It was noticed that fisetin loaded in the SNEDDS formulation significantly (p < 0.001) ameliorated the rotenone-induced alteration in the body weight, grip strength, beam walk, postural instability, etc., in rats when compared to the effect of naïve fisetin. Naïve fisetin significantly (p < 0.05) ameliorated the effect of rotenone on the level of dopamine only at a higher dose. Whereas, SNEDDS of fisetin produced a significant (p < 0.05) effect at both dose levels when compared with the diseased group as well as also produced a significant (p < 0.05) effect when compared with the naïve fisetin group. The results of histopathological examination revealed about the neuroprotective effect of SNEDDS loaded with fisetin as observed through the protection of neuronal damage. From this study, it was concluded that SNEDDS improved the anti-Parkinsonian activity of fisetin by improving the behavioral alteration produced by rotenone due to enhancement in its solubility and bioavailability.


Assuntos
Nanopartículas , Rotenona , Administração Oral , Animais , Disponibilidade Biológica , Emulsões , Flavonóis , Tamanho da Partícula , Ratos , Solubilidade
4.
Eur J Pharmacol ; 911: 174529, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34592305

RESUMO

Myrcene (Myr) has been reported to show neuroprotective effects in cerebral ischemia. In this research work, we investigated the Myr effect on neurobehavioural, and neuropathological alteration in mice induced by Aluminium trichloride (AlCl3) and D - galactose. The administration of AlCl3 (5 mg/kg; p. o.), and D - galactose (60 mg/kg; i. p.) for 90 days in mice resulted in spatial learning and memory deficits, cognitive decline, as well as neurotoxicity. The treatments with Myr low dose (100 mg/kg), Myr high dose (200 mg/kg), donepezil (2 mg/kg), and Myr low dose + donepezil (100 + 2 mg/kg) were administered via intraperitoneal route for 30 days significantly reversed the neurobehavioral, and neuropathological effects of AlCl3 and D - galactose in mice. The results of behavioural tests such as Morris water maze, elevated plus maze, and locomotor; biochemical analysis such as malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), nitrite, and acetylcholinesterase (AChE); and ELISA tests such as mouse ß - secretase (BACE), amyloid-beta peptide1-42 (Aß1 - 42), tumor necrosis factor - α (TNF-α), interleukin - 6 (IL-6), and brain-derived neurotrophic factor (BDNF) demonstrated a significant (p < 0.05) neuroprotective effect of the Myr and donepezil co-treatments. In addition, hematoxylin and eosin staining of the cerebral cortex and hippocampus revealed eosinophilic lesions and hyperchromatic nuclei in Alzheimer's disease mice, but treatments with Myr low dose, Myr high dose, donepezil, and Myr low dose + donepezil reversed these neurodegenerative effects. Myr showed these activities by enhancing synaptic plasticity and cholinergic activity, as well as reducing oxidative damage, neuroinflammation, Aß1-42 aggregations, and histopathological damage. Myr alone and in combination with donepezil may serve as a potential candidate for the treatment of Alzheimer's disease.


Assuntos
Doença de Alzheimer
5.
Chem Asian J ; 16(17): 2552-2558, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34296823

RESUMO

A pH-responsive smart nanocarrier with significant components was synthesized by conjugating the non-emissive anticancer drug methyl orange and polyethylene glycol derived folate moiety to the backbone of polynorbornene. Complete synthesis procedure and characterization methods of three monomers included in the work: norbornene-derived Chlorambucil (Monomer 1), norbornene grafted with polyethylene glycol, and folic acid (Monomer 2) and norbornene attached methyl orange (Monomer 3) connected to the norbornene backbone through ester linkage were clearly discussed. Finally, the random copolymer CHO PEG FOL METH was synthesized by ring-opening metathesis polymerization (ROMP) using Grubbs' second-generation catalyst. Advanced polymer chromatography (APC) was used to find the final polymer's molecular weight and polydispersity index (PDI). Dynamic light scattering, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were utilized to explore the prodrug's size and morphology. Release experiments of the anticancer drug, Chlorambucil and the coloring agent, methyl orange, were performed at different pH and time. Cell viability assay was carried out for determining the rate of survived cells, followed by the treatment of our final polymer named CHO PEG FOL METH.


Assuntos
Antineoplásicos/química , Portadores de Fármacos/química , Ácido Fólico/análogos & derivados , Plásticos/química , Polietilenoglicóis/química , Pró-Fármacos/química , Antineoplásicos/síntese química , Antineoplásicos/toxicidade , Compostos Azo/síntese química , Compostos Azo/química , Compostos Azo/toxicidade , Sobrevivência Celular/efeitos dos fármacos , Clorambucila/síntese química , Clorambucila/química , Clorambucila/toxicidade , Corantes/síntese química , Corantes/química , Corantes/toxicidade , Preparações de Ação Retardada/síntese química , Preparações de Ação Retardada/química , Preparações de Ação Retardada/toxicidade , Doxorrubicina/síntese química , Doxorrubicina/química , Doxorrubicina/toxicidade , Portadores de Fármacos/síntese química , Portadores de Fármacos/toxicidade , Liberação Controlada de Fármacos , Ácido Fólico/síntese química , Ácido Fólico/química , Ácido Fólico/toxicidade , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Plásticos/síntese química , Plásticos/toxicidade , Polietilenoglicóis/síntese química , Polietilenoglicóis/toxicidade , Polimerização , Pró-Fármacos/síntese química , Pró-Fármacos/toxicidade
6.
J Ethnopharmacol ; 275: 114115, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33852947

RESUMO

ETHNOPHARMACOLOGICAL RELEVANCE: Elaeagnus conferta Roxb. (Elaeagnaceae) is a subtropical shrub mainly native to India, Vietnam, Malaysia and South China, whose various parts are used for treatment of diabetes, gastric ulcers, pain, oxidative stress and pulmonary disorders. Though the other parts of the plant have been reported for their ethnic use i.e. fruits as astringent locally and for cancer systemically, leaves for body pain and flowers for pain in chest and the seeds are mentioned as edible, there is no report per se on the medicinal use of seeds. Based on the fact that seeds of closely resembling species i.e. Elaeagnus rhamnoides has demonstrated significant anti-gastroulcerative property, the probability of the seeds of E. conferta possessing similar activity seemed quite significant. AIM OF THE STUDY: Phytochemical investigation and assessment of pharmacological mechanism(s) involved in anti-ulcer effect of methanolic extract of the seeds of E. conferta. MATERIALS AND METHODS: Bioactive phytoconstituents were isolated by column chromatography. These were identified by spectroscopic techniques including infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) and mass spectrometry. Methanolic extract (MEC) of the seeds was prepared by cold maceration and its anti-ulcerogenic potential was evaluated using indomethacin (50 mg/kg) and water immersion stress models in male rats. The animals were pre-treated with different doses of MEC (400 and 800 mg/kg) and the therapeutic effect was compared with standard drug i.e. ranitidine (RANT; 50 mg/kg). The ameliorative effects of MEC were investigated on gastric juice pH, total acidity, free acidity and ulcer index. The assays of malionaldehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and pro-inflammatory cytokines i.e. interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were carried out to find out the possible mechanism(s) of protection. Further, histopathological changes were also studied. RESULTS: Chromatography studies and further confirmation by spectroscopic techniques revealed the presence of four different compounds in MEC i.e oleic acid (1), stearic acid (2), ascorbic acid (3) and quercetin (4). MEC exhibited anti-ulcerogenic effect in dose dependent manner which may be attributed to suppression of pro-inflammatory cytokines (IL-6, TNF-α) and MDA (112.7%), and up-regulation of protective factors such as CAT (90.48%), SOD (92.77%) and GSH (90.01%). Ulcer inhibition, reduction in total and free acidity and increase in gastric juice pH were observed in MEC treated rats as compared to disease control animals. Histopathological findings confirmed decreased cell infiltration, less epithelial cell damage and regeneration of gastric mucosa in dose dependent manner. CONCLUSIONS: The anti-ulcer effect of MEC may be attributed to its ability to scavenge free radicals and anti-inflammatory property via suppression of TNF-α and IL-6, thus offers a complete and holistic approach for management of peptic ulcer.


Assuntos
Antiulcerosos/farmacologia , Elaeagnaceae/química , Extratos Vegetais/farmacologia , Sementes/química , Úlcera Gástrica/prevenção & controle , Animais , Antiulcerosos/química , Antiulcerosos/uso terapêutico , Antiulcerosos/toxicidade , Peso Corporal/efeitos dos fármacos , Catalase/metabolismo , Mucosa Gástrica/patologia , Glutationa/metabolismo , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Indometacina/toxicidade , Interleucina-6/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Masculino , Malondialdeído/metabolismo , Metanol/química , Tamanho do Órgão/efeitos dos fármacos , Extratos Vegetais/química , Extratos Vegetais/uso terapêutico , Extratos Vegetais/toxicidade , Ranitidina/farmacologia , Ranitidina/uso terapêutico , Ratos Wistar , Restrição Física/efeitos adversos , Soro/química , Úlcera Gástrica/etiologia , Úlcera Gástrica/patologia , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
7.
Expert Opin Drug Deliv ; 18(4): 427-448, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33356647

RESUMO

Introduction: Diabetic neuropathy (DN) is one of the major complications arising from hyperglycaemia in diabetic patients. In recent years polyphenols present in plants have gained attention to treat DN. The main advantages associated with them are their action via different molecular pathways to manage DN and their safety. However, they failed to gain clinical attention due to challenges associated with their formulation development such as lipophilicity,poor bioavailability, rapid systemic elimination, and enzymatic degradation.Area covered: This article includes different polyphenols that have shown their potential against DN in preclinical studies and the research carried out towards development of their nanoformulations in order to overcome aforementioned issues.Expert opinion: In this review various polyphenol based nanoformulations such as nanospheres, self-nanoemulsifying drug delivery systems, niosomes, electrospun nanofibers, metallic nanoparticles explored exclusively to treat DN are discussed. However, the literature available related to polyphenol based nanoformulations to treat DN is limited. Moreover, these experiments are limited to preclinical studies. Hence, more focus is required towards  development of nanoformulations using simple and single step process as well as inexpensive and non-toxic excipients so that a stable, scalable, reproducible and non-toxic formulation could be achieved and clinical trials could be initiated.


Assuntos
Diabetes Mellitus , Neuropatias Diabéticas , Disponibilidade Biológica , Neuropatias Diabéticas/tratamento farmacológico , Sistemas de Liberação de Medicamentos , Humanos , Lipossomos , Polifenóis/farmacologia
8.
Carbohydr Polym ; 250: 116996, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33049905

RESUMO

Solid self-nanoemulsifying drug delivery system (S-SENDDS) containing Curcumin (CRM) were prepared using combination of Ganoderma lucidum extract powder (GLEP) and probiotics (PB) as carriers. Liquid SNEDDS containing CRM were prepared by mixing Capmul MCM, Labrafil M1944CS, Tween 80 and Transcutol P. These were further spray dried and finally converted into spheroids. The droplet size of reconstituted S-SNEDDS powder and spheroids was found in the range of 35 to 37 nm, zeta potential in the range of - 21.48 to -23.22 mV and drug loading in the range of 95-96%. The release of drug from formulations was found to be more than 90%. Similarly, significant improvement (p < 0.05) in permeability of CRM was observed through SNEDDS using Caco2 cell lines. The non-significant difference (p> 0.05) in drug loading, droplet size, dissolution rate and angle of repose between L-SNEDDS and S-SNEDDS indicated the potential of GLEP-PB to produce stable SNEDDS.


Assuntos
Antineoplásicos/farmacologia , Neoplasias do Colo/tratamento farmacológico , Curcumina/farmacologia , Sistemas de Liberação de Medicamentos , Extratos Vegetais/farmacologia , Probióticos/farmacologia , Reishi/química , Administração Oral , Células CACO-2 , Portadores de Fármacos , Liberação Controlada de Fármacos , Emulsões , Humanos
9.
Assay Drug Dev Technol ; 18(6): 274-281, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32608988

RESUMO

Fisetin (FS) is a polyphenolic phytoconstituent reported to have various pharmacological activities such as antioxidant, antiparkinsonian, and antidepressant. An analytical method was developed and validated for the estimation of FS by ultrafast liquid chromatography using C-18 reverse phase column. Acetonitrile and orthophosphoric acid (0.2% v/v) in the ratio of 30:70 v/v was used as mobile phase. Flow rate was set at 1 mL/min. Chromatogram of FS was detected at wavelength of 362 nm. Retention time for FS was found to be 7.06 min. The developed method was found to be linear in the range of 2-10 µg/mL with regression coefficient of 0.9985. The method was validated as per the International Conference on Harmonization (ICH) Q2 (R1) guidelines. The percentage recovery was in the range of 95%-105%, which indicated the accuracy of the method. The percentage relative standard deviation (RSD) was found to be <2%, which indicates the precision of the method. Limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.46 and 1.41 µg/mL, respectively. The developed method was found to be robust as there was no significant change in response with change in flow rate, ratio of mobile phase, and pH. The method was successfully applied for estimation of drug loading and drug release from self-nanoemulsifying drug delivery system (SNEDDS). The % drug loading of FS in prepared liquid SNEDDS formulation was found to be 101.95%. The results of dissolution studies indicated 67.78% FS release in water at the end of 60 min.


Assuntos
Sistemas de Liberação de Medicamentos , Flavonóis/análise , Acetonitrilas/química , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Ácidos Fosfóricos/química
10.
Adv Colloid Interface Sci ; 274: 102037, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31655366

RESUMO

In recent years, gold nanoparticles have emerged as unique non-invasive drug carriers for targeting drugs to their site of action. Their site specificity has helped in increasing drugs' efficacy at lower dose as well as reduction in their side effects. Moreover, their excellent optical properties and small size offer their utilization as diagnostic tools to diagnose tumors as well as other diseases. This review focuses on various approaches that have been used in last several years for preparation of gold nanoparticles, their characterization techniques and theranostic applications. Their toxicity related aspects are also highlighted. Gold nanoparticles are useful as theranostic agents, owing to their small size, biocompatible nature, size dependent physical, chemical and optical properties etc. However, the challenges associated with these nanoparticles such as scale up, cost, low drug payload, toxicity and stability have been the major impediments in their commercialization. The review looks into all these critical issues and identifies the possibilities to overcome these challenges for successful positioning of metallic nanoparticles in market.

11.
Anesth Essays Res ; 12(3): 748-753, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30283188

RESUMO

BACKGROUND: Surgery is a very stressful experience for patients. Children are the most susceptible to fear, anxiety, and stress due to their limited cognitive capabilities and dependency. In children, pharmacologic agents are frequently used as premedication to relieve the fear of surgery, to make child-parental separation easy, and to carry out a smooth induction of anesthesia. We conducted this study to compare the efficacy of intranasal fentanyl, midazolam, and dexmedetomidine as premedication in pediatric patients. MATERIALS AND METHODS: The present study was conducted prospectively on 75 patients in the age group of 2-6 years of either sex of the American Society of Anesthesiologists physical Class I or II admitted in Guru Nanak Dev Hospital, attached to Government Medical College Amritsar, scheduled to undergo surgery under general anesthesia. The patients were divided into three groups of 25 each. Group F received intranasal fentanyl 1.5 µg/kg body weight, Group M received intranasal midazolam 0.3 mg/kg body weight, and Group D received intranasal dexmedetomidine 1 µg/kg body weight as nasal drops 50 min before surgery. RESULTS: Children who received intranasal fentanyl and intranasal midazolam had early onset of anxiolysis and sedation as compared to dexmedetomidine. In child-parent separation, quality of induction was better with fentanyl and dexmedetomidine as compared to midazolam. Intravenous cannulation score was best achieved with fentanyl as premedicant. Postoperative sedation was better with dexmedetomidine as compared to fentanyl and midazolam. CONCLUSION: Onset of action of fentanyl and midazolam is early as compared to that of dexmedetomidine. However, fentanyl provided better conditions for induction and emergence than midazolam. With dexmedetomidine onset of action was delayed and duration of action was prolonged which helped child to remain calm and sedated even after the surgery.

12.
Anesth Essays Res ; 11(2): 449-452, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28663639

RESUMO

INTRODUCTION: Anesthesia and surgery have proved to be highly anxiety provoking and with the rise of elective surgery, its aspect of patient's experience has become prominent in time. However, our fault as anesthesiologists is that we have not made people get versed with what we people as anesthesiologist do in the operating room. Hence, keeping in view all this, a study was carried out, in which video information/images regarding anesthesia and surgical procedure was shown to patients on PowerPoint Presentation. Different images showing previous patient's hospital journey were shown to educate patients. METHODS: Two hundred patients scheduled to undergo elective surgery were taken and were divided into two groups of 100 each. Patients (study group or Group I) were shown video clippings/images of other previously operated patients and their hospital journey including surgery and anesthesia for which patient came in hospital. The study was carried out on the patient in each group while Group II was treated in normal way and not shown any type of images/videos. Hamilton Anxiety Rating Scale was used as a criterion to measure the level of anxiety in Group I and II at four different intervals that are before pre anesthetic check up (PAC), after showing videos and images in Group I, 1 h before surgery and 8 h after surgery. STATISTICAL ANALYSIS: The results of observation of both the groups at different intervals time were statistically compared and analyzed. These characteristics were analyzed using the "Chi-square tests" and "unpaired t-test." RESULTS: Video and images information if done preoperatively have been shown to reduce patient's anxiety, although little is known regarding the effects of the method. CONCLUSION: Showing videos/images of hospital journey for educating the patients before the operation is beneficial to patients undergoing elective surgery.

13.
ACS Appl Mater Interfaces ; 8(8): 5058-64, 2016 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-26882215

RESUMO

Solution-processed semiconductor and dielectric materials are attractive for future lightweight, low-voltage, flexible electronics, but their response to ionizing radiation environments is not well understood. Here, we investigate the radiation response of graphene field-effect transistors employing multilayer, solution-processed zirconia self-assembled nanodielectrics (Zr-SANDs) with ZrOx as a control. Total ionizing dose (TID) testing is carried out in situ using a vacuum ultraviolet source to a total radiant exposure (RE) of 23.1 µJ/cm(2). The data reveal competing charge density accumulation within and between the individual dielectric layers. Additional measurements of a modified Zr-SAND show that varying individual layer thicknesses within the gate dielectric tuned the TID response. This study thus establishes that the radiation response of graphene electronics can be tailored to achieve a desired radiation sensitivity by incorporating hybrid organic-inorganic gate dielectrics.

14.
Asian J Neurosurg ; 10(1): 53, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25767587

RESUMO

An 11-year-old boy presented with holocranial headache associated with vomiting and heaviness in right paranasal region. On examination, he had left sided upper motor neuron type facial palsy along with a subtle ipsilateral hemiparesis (grade 4/5 Medical Research Council). Magnetic resonance imaging brain revealed a contrast enhancing large well-defined extra-axial mass lesion in right middle cranial fossa with extension into the infratemporal fossa. The mass was excised in two stages. Histopathology was suggestive of clear cell meningioma (CCM). Supratentorial pediatric CCM is a rare entity. The case is discussed along with review of literature on this rare clinico-pathological entity.

15.
J Biomol Struct Dyn ; 33(6): 1291-301, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25105795

RESUMO

ABRAXAS is an integral member of BRCA1-complex, which helps in its recruitment to the DNA damage site. It interacts with BRCA1 via its C-terminal phospho-peptide binding motif while the N-terminal associates with RAP80, and thereby recruits the BRCA1-complex at the site of DNA damage. Nonetheless, how ABRAXAS helps in the structural integrity of BRCA1-complex, and its DNA repair mechanism remains elusive. To elucidate the role of ABRAXAS in the DNA repair process, we characterized the ABRAXAS wild type and Arg361Gln mutant using in silico and in vitro approach. It has been observed that ABRAXAS Arg361Gln mutant is responsible for defective nuclear localization of BRCA1-complex, and hence important for DNA repair function. We found conformational changes in ABRAXAS mutant, which impaired binding to RAP80 and further disturb BRCA1-complex localization. The results presented in this paper will help to understand the cause of BRCA1 mislocalization, and various DNA repair defects that occur due to substitution. Comparative study of ABRAXAS wild type and mutant will provide helpful perspective for inhibitor designing that can potentially recompense the deleterious effect(s) of Arg361Gln mutation, and have therapeutic application.


Assuntos
Proteína BRCA1/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Mutação , Sequência de Aminoácidos , Substituição de Aminoácidos , Proteína BRCA1/química , Proteínas de Transporte/química , Códon , Humanos , Modelos Biológicos , Modelos Moleculares , Dados de Sequência Molecular , Peso Molecular , Ligação Proteica , Conformação Proteica , Estabilidade Proteica , Transporte Proteico , Termodinâmica
16.
Asian J Neurosurg ; 9(4): 223-32, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25685220

RESUMO

INTRODUCTION: Surgical management of foramen magnum (FM) tumors is challenging by virtue of their location and vital neurovascular relationships. The ideal approach to anterior/anterolateral tumors continue to evoke controversy even in the modern era. In this article, we present and discuss our experience in the surgical management of these tumors. MATERIALS AND METHODS: This retrospective study includes 29 consecutive patients (mean age 36.6 years, M: F = 2.63:1) of extramedullary tumors at the surgical foramen magnum, operated at our center, between 2007 and 2012. RESULTS: Their mean duration of symptoms was 14. 6 months. A majority of the patients presented with motor symptoms (quadri/paraparesis, n = 21, 72.4%), neck pain with/without suboccipital radiation (n = 16, 55.2%) and sensory symptoms like tingling/numbness (n = 16, 55.2%). There were nine extradural (31%) and 20 intradural tumors (69%). Most of the tumors were located posterolateral to the neuraxis (n = 13, 44.8%). Nerve sheath tumors (n = 11, 38%) and meningiomas (n = 5, 17.2%) were the most commonly encountered histologies in our series. The standard posterior approach was the most frequently employed surgical approach (n = 20, 69%). Operative mortality and morbidity were 3.4 and 18.9%, respectively. At a mean follow-up of 27.3 months, 13 out of the 18 available patients improved. CONCLUSION: A majority of the foramen magnum tumors are amenable to excision via the standard posterior approach. Small anterior dural-based meningiomas/recurrent tumors may require a lateral approach like the far lateral approach.

17.
J Biomol Struct Dyn ; 32(12): 2017-32, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24125081

RESUMO

MERIT40 (MEdiator of RAP80 Interaction and Targeting 40) is a novel associate of the BRCA1-complex and plays an essential role in DNA damage repair. It is the least characterized protein of BRCA1-complex and mainly responsible for maintaining the complex integrity. However, its structural and functional aspects of regulating the complex stability still remain elusive. Here, we carried out a comprehensive examination of MERIT40 biophysical properties and identified its novel interacting partner which would help to understand its role in BRCA1-complex. The recombinant protein was purified by affinity chromatography and unfolding pathway was determined using spectroscopic and calorimetric methods. Molecular model was generated using combinatorial approaches of modeling, and monomer-monomer docking was carried out to identify dimeric interface. Disordered region of MERIT40 was hatchet using trypsin and chymotrypsin to illustrate the existence of stable domain whose function was speculated through DALI search. Our findings suggest that MERIT40 forms a dimer in a concentration-independent manner. Its central region shows remarkable stability towards the protease digestion and has structural similarity with vWA-like region, a domain mainly present in complement activation factors. MERIT40 undergoes a three-state unfolding transition pathway with a dimeric intermediate. It interacts with adaptor molecule of BRCA1-complex, called ABRAXAS, thus help in extending the bridging interaction among various members which further stabilizes the whole complex. The results presented in this paper provide first-hand information on structural and folding behavior of MERIT40. These findings will help in elucidating the role of protein-protein interactions in stabilization of BRCA1-complex.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/química , Dano ao DNA , Reparo do DNA , Proteínas Adaptadoras de Transdução de Sinal/genética , Sequência de Aminoácidos , Proteína BRCA1/química , Proteínas de Transporte/química , Humanos , Simulação de Acoplamento Molecular , Dados de Sequência Molecular , Mutação , Isoformas de Proteínas/química , Multimerização Proteica , Estabilidade Proteica , Estrutura Terciária de Proteína , Termodinâmica
18.
PLoS One ; 8(9): e72707, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24039796

RESUMO

Receptor Associated Protein 80 (RAP80) is a member of RAP80-BRCA1-CCDC98 complex family and helps in its recruitment to the DNA damage site for effective homologous recombination repair. It encompasses two tandem UIMs (UIM1 and UIM2) motif at its N-terminus, which interact with K-63 linked polyubiquitin chain(s) on H2AX and thereby assemble the RAP80-BRCA1 complex at the damage site. Nevertheless, how RAP80 helps in the structural integrity of BRCA1 complex is still elusive. Considering the role of RAP80 in the recruitment of BRCA1 complex at the DNA damage site, we attempted to explore the molecular mechanism associated with RAP80 and mutation that causes chromosomal aberrations due to its loss of function. There is a significant loss in structural characteristics of RAP80 ΔE81, which impairs its binding affinity with the polyubiquitin chain. This leads to the defective recruitment of RAP80 and BRCA1 complex at the DNA damage site. The results presented here are very useful in understanding the cause of various repair defects (chromosomal aberration) that arise due to this mutation. Comparative study of wild type and ΔE81 could be helpful in designing the small molecules that can potentially compensate the deleterious effect(s) of ΔE81 and hence useful for therapeutic application.


Assuntos
Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proteínas Nucleares/química , Proteínas Nucleares/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Proteínas de Transporte/genética , Proteínas de Ligação a DNA , Chaperonas de Histonas , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Peso Molecular , Mutação , Proteínas Nucleares/genética , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Estabilidade Proteica , Proteólise , Proteínas Recombinantes , Alinhamento de Sequência , Termodinâmica
19.
J Comput Assist Tomogr ; 37(3): 321-6, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23673999

RESUMO

INTRODUCTION: The study was performed to compare dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) with 3-dimensional (3D) pseudocontinuous arterial spin labeling (PCASL) MRI in gliomas with an aim to see whether arterial spin labeling (ASL)-derived cerebral blood flow (CBF) values can be used as an alternative to DCE-MRI for its grading. MATERIALS AND METHODS: Sixty-four patients with glioma (37 male; mean age, 43 years; 38 high grade and 26 low grade) underwent 3D-PCASL and DCE-MRI. The DCE indices (relative cerebral blood volume, rCBV; relative CBF, rCBF; permeability, k and kep; and leakage, ve) and ASL (absolute and rCBF) values were quantified from the tumors. Student independent t test was used to compare ASL and DCE-MRI indices. Pearson correlation was used to see correlation between DCE- and ASL-derived CBF values in tumor and normal parenchyma. RESULTS: On Student t test, neither ASL-derived absolute CBF (P = 0.78) nor rCBF (P = 0.12) values were found to be significantly different in 2 groups, whereas DCE indices except ve were significantly higher in high-grade gliomas. Arterial spin labeling-derived rCBF values weakly correlated with DCE-derived rCBF values, whereas these did not show correlation in normal grey (P = 0.12, r = 0.2) and white (P = 0.26, r = 0.14) matter regions. CONCLUSIONS: Three-dimensional pseudocontinuous arterial spin labeling does not appear to be a reliable technique in the current form and may not be a suitable replacement for DCE in grading of glioma.


Assuntos
Neoplasias Encefálicas/patologia , Glioma/patologia , Imageamento Tridimensional , Imageamento por Ressonância Magnética/métodos , Marcadores de Spin , Adulto , Circulação Cerebrovascular , Meios de Contraste , Feminino , Humanos , Masculino , Gradação de Tumores
20.
Lab Chip ; 12(9): 1646-55, 2012 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-22415775

RESUMO

We describe a method to detect the expression of a surface protein in single cells without prior labeling or manipulation using a microfluidic device. When the protein is expressed on a cell surface, it undergoes transient bond formation with an immobilized ligand as the cell is pumped through a microfluidic channel, resulting in a specific decrease in the cell's velocity. We were able to detect the expression of interleukin 13 receptor alpha 2 (IL13Rα2) differentially expressed on LM2 cells, a subline of MDA-MB-231 human breast cancer cells with a unique lung metastatic capability. The detection of cells with high expression of the protein was near 100% sensitive and 100% specific. We also provided proof of principle of multiplexing by tracking the same cell over two, differentially-coated patches. The method is non-destructive and cells can be collected for reanalysis. The system can identify positive cells in a cell mixture. This method will have a potential impact in analyzing cancer cells when only a few are available, such as the case with needle aspirates and when labeling and manipulation result in cell loss.


Assuntos
Citometria de Fluxo/instrumentação , Citometria de Fluxo/métodos , Subunidade alfa2 de Receptor de Interleucina-13/análise , Técnicas Analíticas Microfluídicas/instrumentação , Análise de Célula Única/instrumentação , Análise de Célula Única/métodos , Linhagem Celular Tumoral , Humanos , Processamento de Imagem Assistida por Computador , Subunidade alfa2 de Receptor de Interleucina-13/metabolismo
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