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OBJECTIVES: To characterize health-related quality of life (HRQL) and functional recovery trajectories and risk factors for prolonged impairments among critically ill children receiving greater than or equal to 3 days of invasive ventilation. DESIGN: Prospective cohort study. SETTING: Quaternary children's hospital PICU. PATIENTS: Children without a preexisting tracheostomy who received greater than or equal to 3 days of invasive ventilation, survived hospitalization, and completed greater than or equal to 1 postdischarge data collection. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We evaluated 144 children measuring HRQL using proxy-report Pediatric Quality of Life Inventory and functional status using the Functional Status Scale (FSS) reflecting preillness baseline, PICU and hospital discharge, and 1, 3, 6, and 12 months after hospital discharge. They had a median age of 5.3 years (interquartile range, 1.1-13.0 yr), 58 (40%) were female, 45 (31%) had a complex chronic condition, and 110 (76%) had normal preillness FSS scores. Respiratory failure etiologies included lung disease ( n = 49; 34%), neurologic failure ( n = 23; 16%), and septic shock ( n = 22; 15%). At 1-month postdischarge, 68 of 122 (56%) reported worsened HRQL and 35 (29%) had a new functional impairment compared with preillness baseline. This improved at 3 months to 54 (46%) and 24 (20%), respectively, and remained stable through the remaining 9 months of follow-up. We used interaction forests to evaluate relative variable importance including pairwise interactions and found that therapy consultation within 3 days of intubation was associated with better HRQL recovery in older patients and those with better preillness physical HRQL. During the postdischarge year, 76 patients (53%) had an emergency department visit or hospitalization, and 62 (43%) newly received physical, occupational, or speech therapy. CONCLUSIONS: Impairments in HRQL and functional status as well as health resource use were common among children with acute respiratory failure. Early therapy consultation was a modifiable characteristic associated with shorter duration of worsened HRQL in older patients.
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Ventilação não Invasiva , Qualidade de Vida , Criança , Humanos , Feminino , Idoso , Pré-Escolar , Masculino , Estudos Prospectivos , Assistência ao Convalescente , Alta do Paciente , RespiraçãoRESUMO
OBJECTIVES: Management of fluid refractory pediatric shock requires prompt administration of vasoactive agents. Although delivery of vasoactive therapy is generally provided via a central venous catheter, their placement can delay drug administration and is associated with complications. We characterize peripheral vasoactive administration in a cohort of critically ill children with shock, evaluate progression to central venous catheter placement, and describe complications associated with extravasation. DESIGN: Retrospective cohort study. SETTING: Single-center, quaternary PICU (January 2010 to December 2015). PATIENTS: Children (31 d to 18 yr) who received epinephrine, norepinephrine, or dopamine. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We compared patients based on the initial site of vasoactive infusion: peripheral venous access (PVA) or central venous access (CVA) and, within the PVA group, compared patients based on subsequent placement of a central catheter for vasoactive infusion. We also characterized peripheral extravasations. We evaluated 756 patients: 231 (30.6%) PVA and 525 (69.4%) CVA patients. PVA patients were older, had lower illness severity, and more frequently had vasoactive therapy initiated at night compared with CVA patients. In PVA patients, 124 (53.7%) had a central catheter placed after a median of 140 minutes (interquartile range, 65-247 min) of peripheral treatment. Patients who avoided central catheter placement had lower illness severity. Of the 93 patients with septic shock, 44 (47.3%) did not have a central catheter placed. Extravasations occurred in four of 231 (1.7% [95% CI, 0.03-3.4]) PVA patients, exclusively in the hand. Three patients received pharmacologic intervention, and none had long-term disabilities. CONCLUSIONS: In our experience, peripheral venous catheters can be used for vasoactive administration. In our series, the upper limit of the 95% CI for extravasation is approximately 1-in-30, meaning that this route may be an appropriate option while evaluating the need for central access, particularly in patients with low illness severity.
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Cateterismo Venoso Central , Cateteres Venosos Centrais , Choque , Cateterismo Venoso Central/efeitos adversos , Criança , Estudos de Coortes , Estado Terminal/terapia , Dopamina/uso terapêutico , Epinefrina , Humanos , Norepinefrina/uso terapêutico , Estudos Retrospectivos , Choque/tratamento farmacológico , Choque/etiologiaRESUMO
Background and Purpose: Long-term outcomes after pediatric neurocritical illness are poorly characterized. This study aims to characterize the frequency and risk factors for post-discharge unplanned health resource use in a pediatric neurocritical care population using insurance claims data. Methods: Retrospective cohort study evaluating children who survived a hospitalization for an acute neurologic illness or injury requiring mechanical ventilation for >72 hours and had insurance eligibility in Colorado's All Payers Claims database. Insurance claims identified unplanned readmissions and emergency department [ED] visits during the post-discharge year. For patients without pre-existing epilepsy/seizures, we evaluated for post-ICU epilepsy identified by claim(s) for a maintenance anti-seizure medication during months 6-12 post-discharge. Multivariable logistic regression identified factors associated with each outcome. Results: 101 children, median age 3.7 years (interquartile range (IQR) .4-11.9), admitted for trauma (57%), hypoxic-ischemic injury (17%) and seizures (15%). During the post-discharge year, 4 (4%) patients died, 26 (26%) were readmitted, and 48 (48%) had an ED visit. Having a pre-existing complex chronic condition was independently associated with readmission and emergency department visit. Admission for trauma was protective against readmission. Of those without pre-existing seizures (n = 86), 25 (29%) developed post-ICU epilepsy. Acute seizures during admission and prolonged ICU stays were independently associated with post-ICU epilepsy. Conclusions: Survivors of pediatric neurocritical illness are at risk of unplanned healthcare use and post-ICU epilepsy. Critical illness risk factors including prolonged ICU stay and acute seizures may identify cohorts for targeted follow up or interventions to prevent unplanned healthcare use and post-ICU epilepsy.
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BACKGROUND: Plinabulin (NPI-2358) is a vascular disrupting agent (VDA) that destabilizes tumor vascular endothelial cell architecture resulting in selective collapse of established tumor vasculature producing anti-tumor activity alone or in combination with cytotoxic agents. The objective of this study was to assess the recommended Phase 2 dose (RP2D) of plinabulin combined with docetaxel. PATIENTS AND METHODS: Patients received 75 mg/m(2) docetaxel on day 1 and plinabulin on days 1 and 8 intravenously in 21 day cycles. Plinabulin was escalated from the biologically effective dose (BED) of 13.5 mg/m(2) to the standard single agent dose of 30 mg/m(2) using a "3+3" design. RESULTS: Thirteen patients were enrolled. Adverse events were consistent with those of both agents alone. Fatigue, pain, nausea, diarrhea and vomiting were the most common events. One dose limiting toxicity of nausea, vomiting, dehydration and neutropenia occurred. The RP2D was 30 mg/m(2) of plinabulin with 75 mg/m(2) docetaxel. Pharmacokinetics did not indicate drug-drug interactions. Of the 8 patients with NSCLC evaluable for response, 2 achieved a partial response and 4 demonstrated lesser decreases in tumor measurements. CONCLUSIONS: The combination of full doses of plinabulin and docetaxel is tolerable. With encouraging antitumor activity, this supported further development of this combination.
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Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Diarreia/induzido quimicamente , Dicetopiperazinas/administração & dosagem , Dicetopiperazinas/efeitos adversos , Dicetopiperazinas/farmacocinética , Docetaxel , Fadiga/induzido quimicamente , Feminino , Humanos , Neoplasias Pulmonares/metabolismo , Masculino , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Neutropenia/induzido quimicamente , Dor/induzido quimicamente , Taxoides/administração & dosagem , Taxoides/efeitos adversos , Taxoides/farmacocinética , Vômito/induzido quimicamenteRESUMO
PURPOSE: Combining proteasome and histone deacetylase (HDAC) inhibition has been seen to provide synergistic anti-tumor activity, with complementary effects on a number of signaling pathways. The novel bi-cyclic structure of marizomib with its unique proteasome inhibition, toxicology and efficacy profiles, suggested utility in combining it with an HDAC inhibitor such as vorinostat. Thus, in this study in vitro studies assessed the potential utility of combining marizomib and vorinostat, followed by a clinical trial with the objectives of assessing the recommended phase 2 dose (RP2D), pharmacokinetics (PK), pharmacodynamics (PD), safety and preliminary anti-tumor activity of the combination in patients. EXPERIMENTAL DESIGN: Combinations of marizomib and vorinostat were assessed in vitro. Subsequently, in a Phase 1 clinical trial patients with melanoma, pancreatic carcinoma or Non-small Cell Lung Cancer (NSCLC) were given escalating doses of weekly marizomib in combination with vorinostat 300 mg daily for 16 days in 28 day cycles. In addition to standard safety studies, proteasome inhibition and pharmacokinetics were assayed. RESULTS: Marked synergy of marizomib and vorinostat was seen in tumor cell lines derived from patients with NSCLC, melanoma and pancreatic carcinoma. In the clinical trial, 22 patients were enrolled. Increased toxicity was not seen with the combination. Co-administration did not appear to affect the PK or PD of either drug in comparison to historical data. Although no responses were demonstrated using RECIST criteria, 61% of evaluable patients demonstrated stable disease with 39% having decreases in tumor measurements. CONCLUSIONS: Treatment of multiple tumor cell lines with marizomib and vorinostat resulted in a highly synergistic antitumor activity. The combination of full dose marizomib with vorinostat is tolerable in patients with safety findings consistent with either drug alone.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma/tratamento farmacológico , Neoplasias Pulmonares/tratamento farmacológico , Melanoma/tratamento farmacológico , Neoplasias Pancreáticas/tratamento farmacológico , Adulto , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/sangue , Antineoplásicos/farmacocinética , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Apoptose/efeitos dos fármacos , Carcinoma/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Combinação de Medicamentos , Feminino , Inibidores de Histona Desacetilases/administração & dosagem , Inibidores de Histona Desacetilases/sangue , Inibidores de Histona Desacetilases/farmacocinética , Humanos , Ácidos Hidroxâmicos/administração & dosagem , Ácidos Hidroxâmicos/sangue , Ácidos Hidroxâmicos/farmacocinética , Lactonas/administração & dosagem , Lactonas/sangue , Lactonas/farmacocinética , Neoplasias Pulmonares/metabolismo , Masculino , Melanoma/metabolismo , Pessoa de Meia-Idade , Neoplasias Pancreáticas/metabolismo , Inibidores de Proteassoma/administração & dosagem , Inibidores de Proteassoma/sangue , Inibidores de Proteassoma/farmacocinética , Pirróis/administração & dosagem , Pirróis/sangue , Pirróis/farmacocinética , VorinostatRESUMO
A phase I/II trial was conducted to determine the toxicities and efficacy (overall response, overall survival, and progression-free survival) of the combination of topotecan and whole brain radiation therapy (XRT) in patients with brain metastases. Patients received 30 Gy XRT given in 10 fractions to the whole brain. In phase I, patients were treated in groups of three at each topotecan dose level; dose escalation proceeded until the maximum tolerated dose (MTD) was identified. The dose-limiting toxicity proved to be grade IV neutropenia at 0.6 mg/m2/d, resulting in an MTD of 0.5 mg/m2/d. One of nine patients showed a response to treatment, and that was partial (OR 11%). Three had stable disease (33%), and four experienced progressive disease (44%). Median progression-free survival was 60 d; median overall survival was 102 d. Intravenous topotecan at 0.5 mg/m2/d concomitant to XRT with 30 Gy in 3-Gy fractions is tolerable in patients with brain metastases. This regimen has the additional advantage of providing systemic treatment to patients with metastases in other locations while whole brain radiation is in progress. Although response and survival outcomes in this small study do not appear higher than expected from historical controls, these were not primary end points, and larger studies on this topic would be useful to elucidate the efficacy of this combination treatment regimen.
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Antineoplásicos/uso terapêutico , Neoplasias Encefálicas/secundário , Neoplasias Encefálicas/terapia , Topotecan/uso terapêutico , Adulto , Idoso , Antineoplásicos/administração & dosagem , Antineoplásicos/efeitos adversos , Neoplasias Encefálicas/tratamento farmacológico , Terapia Combinada , Intervalo Livre de Doença , Feminino , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Dosagem Radioterapêutica , Topotecan/administração & dosagem , Topotecan/efeitos adversos , Resultado do TratamentoRESUMO
There are significant uses for expressing foreign peptide epitopes in viral surface attachment proteins in terms of investigating viral targeting, biology, and immunology. HSV-1 attachment, followed by fusion and entry, is mediated in large part by the binding of viral surface glycoproteins to cell surface receptors, primarily through heparan sulfate (HS) glycosaminoglycan residues. We constructed a HSV-1 amplicon plasmid (pCONGA) carrying the gC primary attachment protein gene with unique restriction sites flanking the HS binding domain (HSBD) (residues 33-176) to allow rapid, high efficiency substitution with foreign peptide domains. To test this system, a His tag with an additional unique restriction site (for selection and assay digests) was recombined into the pCONGA HSBD site to create pCONGAH. Infection of pCONGAH transfected Vero cells with HSV-1 helper virus (gCdelta2-3 or hrR3) produced His-modified gC as demonstrated by western blot analysis with co-localization of anti-gC and anti-His tag antibodies to a protein of appropriate molecular weight (50 kd). As CONGA and CONGAH amplicons carry a GFP transgene and the gCdelta2-3 and hrR3 viruses carry a lacZ transgene, vector stocks produced from 1 x 10(5) Vero cells could be titered for competent vector on cell monolayers and were demonstrated to contain 2 x 10(5) amplicon vector transducing units (t.u.)/ml and 1 x 10(7) virus t.u./ml. As the amplicon plasmids also contain the neomycin resistance gene (neo(r)), long term vector producer cell lines were created using G418 selection. This amplicon system provides means to rapidly and efficiently generate HSV-1 amplicon and viral vector expressing surface attachment proteins modified with different peptide epitopes for investigational and therapeutic uses, with the advantages of an amplicon plasmid that can be used with interchangeable helper virus vectors, is designed specifically for easy manipulation, and carries GFP and neo(r) transgenes for marker and selection functions.
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Vetores Genéticos/genética , Herpesvirus Humano 1/genética , Biblioteca de Peptídeos , Animais , Western Blotting , Linhagem Celular , Chlorocebus aethiops , Terapia Genética , Plasmídeos , Células Vero , Proteínas do Envelope Viral/genéticaAssuntos
Antineoplásicos Imunológicos/uso terapêutico , Imunoterapia Adotiva , Terapia de Alvo Molecular , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/terapia , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/efeitos adversos , Terapia Combinada/efeitos adversos , Terapia Combinada/métodos , Resistencia a Medicamentos Antineoplásicos , Feminino , Humanos , Imunoterapia Adotiva/efeitos adversos , Imunoterapia Adotiva/métodos , Masculino , Pessoa de Meia-Idade , Mieloma Múltiplo/diagnóstico , Recidiva , Retratamento , Resultado do TratamentoRESUMO
Vascular Disrupting Agents (VDA) are a potential new class of oncology drugs that have garnered attention recently as a number of these agents have entered into Phase 2-3 studies. Currently available data suggest how the subsequent evolution of these agents into clinical practice may proceed, with new therapeutic paradigms based on similarities, differences and interactions with current standard of care agents. In particular, the broadly successful group of agents targeting angiogenesis through the Vascular Endothelial Growth Factor (VEGF) pathway, can be contrasted to the VDAs that principally disrupt established tumor vasculature through a different set of molecular targets. Although the angiogenesis inhibitors may benchmark where other vascularly targeted agents such as VDAs may be successful, the differences in terms of efficacy and safety profiles lead to important differentiation in how VDAs are likely to be used. Although the majority of VDAs bind tubulin, significant differences also exist between VDAs and cytotoxic agents, including tubulin targeted agents such as taxanes and vinca alkyloids. Clinical trial data is now available for several VDAs allowing such assessment. Data of yet has been the strongest in NSCLC, with indications of how these drugs may be developed beneficially in subsets of patients such as those with squamous cell histology or at risk of bleeding events. Other indications being aggressively pursued include prostate carcinoma, ovarian carcinoma, sarcomas and astrocytomas. The field also continues to advance with investigation into how to optimally schedule administration of VDAs and what effects might be class effects and/or markers of efficacy.
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Vasos Sanguíneos/efeitos dos fármacos , Neoplasias/irrigação sanguínea , Neoplasias/tratamento farmacológico , Neovascularização Patológica/tratamento farmacológico , Inibidores da Angiogênese/farmacologia , Ensaios Clínicos como Assunto , Dicetopiperazinas/farmacologia , Humanos , Serina/análogos & derivados , Serina/farmacologia , Tubulina (Proteína)/metabolismoRESUMO
PURPOSE: Plinabulin (NPI-2358) is a vascular disrupting agent that elicits tumor vascular endothelial architectural destabilization leading to selective collapse of established tumor vasculature. Preclinical data indicated plinabulin has favorable safety and antitumor activity profiles, leading to initiation of this clinical trial to determine the recommended phase 2 dose (RP2D) and assess the safety, pharmacokinetics, and biologic activity of plinabulin in patients with advanced malignancies. EXPERIMENTAL DESIGN: Patients received a weekly infusion of plinabulin for 3 of every 4 weeks. A dynamic accelerated dose titration method was used to escalate the dose from 2 mg/m² to the RP2D, followed by enrollment of an RP2D cohort. Safety, pharmacokinetic, and cardiovascular assessments were conducted, and Dynamic contrast-enhanced MRI (DCE-MRI) scans were performed to estimate changes in tumor blood flow. RESULTS: Thirty-eight patients were enrolled. A dose of 30 mg/m² was selected as the RP2D based on the adverse events of nausea, vomiting, fatigue, fever, tumor pain, and transient blood pressure elevations, with DCE-MRI indicating decreases in tumor blood flow (Ktrans) from 13.5 mg/m² (defining a biologically effective dose) with a 16% to 82% decrease in patients evaluated at 30 mg/m². Half-life was 6.06 ± 3.03 hours, clearance was 30.50 ± 22.88 L/h, and distributive volume was 211 ± 67.9 L. CONCLUSIONS: At the RP2D of 30 mg/m², plinabulin showed a favorable safety profile, while eliciting biological effects as evidenced by decreases in tumor blood flow, tumor pain, and other mechanistically relevant adverse events. On the basis of these results additional clinical trials were initiated with plinabulin in combination with standard chemotherapy agents.
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Imidazóis/uso terapêutico , Linfoma/tratamento farmacológico , Neoplasias/tratamento farmacológico , Piperazinas/uso terapêutico , Adulto , Idoso , Inibidores da Angiogênese/administração & dosagem , Inibidores da Angiogênese/efeitos adversos , Inibidores da Angiogênese/farmacocinética , Inibidores da Angiogênese/uso terapêutico , Dicetopiperazinas , Relação Dose-Resposta a Droga , Esquema de Medicação , Feminino , Meia-Vida , Humanos , Imidazóis/administração & dosagem , Imidazóis/efeitos adversos , Imidazóis/farmacocinética , Infusões Intravenosas , Linfoma/metabolismo , Linfoma/patologia , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Neoplasias/irrigação sanguínea , Neoplasias/metabolismo , Neoplasias/patologia , Projetos Piloto , Piperazinas/administração & dosagem , Piperazinas/efeitos adversos , Piperazinas/farmacocinéticaRESUMO
Brain metastases are a frequent occurrence in cancer patients and result in significant morbidity and mortality. The three main treatments for brain metastases include surgery, radiation, and/or chemotherapy, alone or in combination. After resection alone, local recurrence rates are high. Whole brain radiation therapy can decrease the probability of recurrence; however, this has some disadvantages. Focal radiation therapy (FRT) may provide many of the same benefits without some of these disadvantages. In this study, we retrospectively analyzed patients with single brain metastases treated with FRT after surgery. Doses ranged from 14 Gy as single dose stereotactic radiosurgery (SRS) to 54 Gy in 27 2-Gy fractions as conformal fractionated radiotherapy. Four of the seven patients had a same-site recurrence, with an average time to recurrence of 115.5 d. Median dose in the patients that had same-site recurrence was 42 Gy. One of these patients is currently living. Two patients did not have recurrence, and one patient had a recurrence at a different site within the brain. The low rate of out-of-field recurrences during the patients life indicates focal radiation may be a reasonable therapeutic alternative. Given the number of patients with same-site recurrences, wide field margins around the tumor volume or higher radiation doses than those typically used in palliative regimens may be useful in post-excisional FRT. Additionally, we found that a longer delay in the initiation of FRT after initial diagnosis may result in a decreased time to same-site recurrence. However, further studies are warranted given the small number of patients in this study.
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Neoplasias Encefálicas/radioterapia , Neoplasias Encefálicas/secundário , Neoplasias/patologia , Radioterapia/métodos , Adulto , Idoso , Relação Dose-Resposta à Radiação , Feminino , Humanos , Masculino , Oncologia/métodos , Pessoa de Meia-Idade , Metástase Neoplásica , Radiometria , Radiocirurgia/métodos , Estudos RetrospectivosRESUMO
This study describes the outcomes of children treated with combinations of temozolomide and radiation therapy for various aggressive central nervous system malignancies. Their age at diagnosis ranged from 1 to 15 years. Patients with focal disease were treated with concomitant temozolomide (daily 75 mg/m) and three-dimensional conformal radiotherapy in a dose that ranged from 50 to 54 Gy, followed by temozolomide (200 mg/m/d x 5 days/month in three patients, 150 mg/m x 5 days/ month in one patient). Patients with disseminated disease were treated with craniospinal radiation (39.6 Gy) before conformal boost. One patient received temozolomide (200 mg/m x 5 days/month) before craniospinal radiation, and one patient received temozolomide (daily 95 mg/m) concomitant with craniospinal radiation and a radiosurgical boost, followed by temozolomide (200 mg/m x 5 days/month). Three patients achieved a partial response during treatment, with two of these patients dying of progressive disease after treatment. One patient has no evidence of disease. Three patients achieved stable disease, with one of these patients dying of progressive disease after treatment. Toxicities observed included low-grade neutropenia, thrombocytopenia, and lymphopenia. The combination of temozolomide and radiotherapy appears to be well tolerated in a variety of treatment schemas for aggressive pediatric central nervous system malignancies. This information is of particular use in designing future studies, given the recent positive results in a randomized study examining the use of temozolomide concomitant with radiation in the treatment of adult glioblastoma.
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Antineoplásicos Alquilantes/uso terapêutico , Neoplasias do Sistema Nervoso Central/tratamento farmacológico , Neoplasias do Sistema Nervoso Central/radioterapia , Dacarbazina/análogos & derivados , Dacarbazina/uso terapêutico , Adolescente , Neoplasias do Sistema Nervoso Central/diagnóstico , Criança , Pré-Escolar , Terapia Combinada , Evolução Fatal , Feminino , Humanos , Lactente , Imageamento por Ressonância Magnética , Masculino , TemozolomidaRESUMO
Several techniques have been developed to deliver DNA directly into mammalian cells, spanning in difficulty from simple mixing procedures to complex systems requiring expensive equipment. Viral vectors have proven able to deliver genes into mammalian cells with high efficiency and low toxicity. In particular, herpes simplex virus type-1 (HSV-1) amplicon vectors are well suited for gene transfer studies as they can infect many cell types, both non-dividing and dividing, have a large transgene capacity and are easy to manipulate. For some applications, it may be desirable to target gene delivery to specific cell populations or to transduce normally non-susceptible cells. This can be achieved by modifying one or more of the glycoproteins found in the viral envelope. Glycoprotein C (gC) has a well-characterized heparan sulfate binding domain (HSBD) necessary for HSV binding to cells. Replacing this region with unique ligands can result in less efficient binding to natural target cells and increase binding to cells which express receptors for these ligands. A method to retarget amplicon vectors by replacing gC HSBD with a model ligand, the hexameric histidine-tag, is described, as well as means to evaluate the binding of modified vector as compared to wild-type virus to cells with or without the appropriate receptor, in this case, a his-tag pseudo-receptor. This protocol demonstrates increased binding of modified virus to receptor-positive cells (at levels greater than wild-type) with no loss of infectivity. Retargeted vectors can provide an additional tool for increasing the efficiency of gene delivery to specific cell types.
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Vetores Genéticos/genética , Herpesvirus Humano 1/genética , Plasmídeos/genética , Transfecção/métodos , Proteínas do Envelope Viral/genética , Animais , Linhagem Celular , Técnicas de Transferência de Genes , Terapia Genética , Haplorrinos , Humanos , Estrutura Terciária de Proteína/genética , Vírion/metabolismoRESUMO
Expression of specific peptide epitopes on the surface of virions has significant potential for studying viral biology and designing vectors for targeted gene therapy. In this study, an HSV-1 amplicon plasmid expressing a modified glycoprotein C (gC), in which the heparan sulfate binding domain was replaced with a His-tag, was used in generating HSV-1 virions. Western blot analysis demonstrated the presence of modified gC in the purified virions. The amplicon vectors were packaged using a gC-, lacZ+ helper virus to generate a mixture of high-titer helper virus (lacZ+) and amplicon vectors (GFP+), which expressed modified gC in the virion envelope. His-tagged virions bound to 293 6H cells expressing a cell surface pseudo-His-tag receptor four-fold more efficiently than to parental 293 cells and also proved more effective than wild-type virus in binding to both cell types. Binding resulted in productive infection by the modified virions with expression of reporter genes and cytopathic effect comparable to those of wild-type virions. Thus, not only can HSV-1 tropism be manipulated to recognize a non-herpes simplex binding receptor, but it is also possible to increase the infective capacity of the vectors beyond that of the wild-type virus via specific ligand receptor combinations.