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










Base de datos
Intervalo de año de publicación
1.
World J Gastrointest Surg ; 15(7): 1442-1453, 2023 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-37555108

RESUMEN

BACKGROUND: Indocyanine green (ICG) fluorescence played an important role in tumor localization and margin delineation in hepatobiliary surgery. However, the preoperative regimen of ICG administration was still controversial. Factors associated with tumor fluorescence staining effect were unclear. AIM: To investigate the preoperative laboratory indexes corelated with ICG fluorescence staining effect and establish a novel laboratory scoring system to screen specifical patients who need ICG dose adjustment. METHODS: To investigate the predictive indicators of ICG fluorescence characteristics in patients undergoing laparoscopic hepatectomy from January 2018 to January 2021 were included. Blood laboratory tests were completed within 1 wk before surgery. All patients received 5 mg ICG injection 24 h before surgery for preliminary tumor imaging. ImageJ software was used to measure the fluorescence intensity values of regions of interest. Correlation analysis was used to identify risk factors. A laboratory risk model was established to identify individuals at high risk for high liver background fluorescence. RESULTS: There were 110 patients who were enrolled in this study from January 2019 to January 2021. The mean values of fluorescence intensity of liver background (FI-LB), fluorescence intensity of gallbladder, and fluorescence intensity of target area were 18.87 ± 17.06, 54.84 ± 33.29, and 68.56 ± 36.11, respectively. The receiver operating characteristic (ROC) curve showed that FI-LB was a good indicator for liver clearance ability [area under the ROC curve (AUC) = 0.984]. Correlation analysis found pre-operative aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transpeptidase, adenosine deaminase, and lactate dehydrogenase were positively associated with FI-LB and red blood cell, cholinesterase, and were negatively associated with FI-LB. Total laboratory risk score (TLRS) was calculated according to ROC curve (AUC = 0.848, sensitivity = 0.773, specificity = 0.885). When TLRS was greater than 6.5, the liver clearance ability of ICG was considered as poor. CONCLUSION: Preoperative laboratory blood indicators can predict hepatic ICG clearance ability. Surgeons can adjust the dose and timing of ICG preoperatively to achieve better liver fluorescent staining.

2.
Mil Med Res ; 10(1): 22, 2023 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-37189155

RESUMEN

Modern medicine is reliant on various medical imaging technologies for non-invasively observing patients' anatomy. However, the interpretation of medical images can be highly subjective and dependent on the expertise of clinicians. Moreover, some potentially useful quantitative information in medical images, especially that which is not visible to the naked eye, is often ignored during clinical practice. In contrast, radiomics performs high-throughput feature extraction from medical images, which enables quantitative analysis of medical images and prediction of various clinical endpoints. Studies have reported that radiomics exhibits promising performance in diagnosis and predicting treatment responses and prognosis, demonstrating its potential to be a non-invasive auxiliary tool for personalized medicine. However, radiomics remains in a developmental phase as numerous technical challenges have yet to be solved, especially in feature engineering and statistical modeling. In this review, we introduce the current utility of radiomics by summarizing research on its application in the diagnosis, prognosis, and prediction of treatment responses in patients with cancer. We focus on machine learning approaches, for feature extraction and selection during feature engineering and for imbalanced datasets and multi-modality fusion during statistical modeling. Furthermore, we introduce the stability, reproducibility, and interpretability of features, and the generalizability and interpretability of models. Finally, we offer possible solutions to current challenges in radiomics research.


Asunto(s)
Inteligencia Artificial , Neoplasias , Humanos , Reproducibilidad de los Resultados , Neoplasias/diagnóstico por imagen , Pronóstico , Aprendizaje Automático
3.
Life (Basel) ; 12(2)2022 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-35207528

RESUMEN

Significant lymph node shrinkage is common in patients with nasopharyngeal carcinoma (NPC) throughout radiotherapy (RT) treatment, causing ill-fitted thermoplastic masks (IfTMs). To deal with this, an ad hoc adaptive radiotherapy (ART) may be required to ensure accurate and safe radiation delivery and to maintain treatment efficacy. Presently, the entire procedure for evaluating an eligible ART candidate is time-consuming, resource-demanding, and highly inefficient. In the artificial intelligence paradigm, the pre-treatment identification of NPC patients at risk for IfTMs has become greatly demanding for achieving efficient ART eligibility screening, while no relevant studies have been reported. Hence, we aimed to investigate the capability of computed tomography (CT)-based neck nodal radiomics for predicting IfTM-triggered ART events in NPC patients via a multi-center setting. Contrast-enhanced CT and the clinical data of 124 and 58 NPC patients from Queen Elizabeth Hospital (QEH) and Queen Mary Hospital (QMH), respectively, were retrospectively analyzed. Radiomic (R), clinical (C), and combined (RC) models were developed using the ridge algorithm in the QEH cohort and evaluated in the QMH cohort using the median area under the receiver operating characteristics curve (AUC). Delong's test was employed for model comparison. Model performance was further assessed on 1000 replicates in both cohorts separately via bootstrapping. The R model yielded the highest "corrected" AUC of 0.784 (BCa 95%CI: 0.673-0.859) and 0.723 (BCa 95%CI: 0.534-0.859) in the QEH and QMH cohort following bootstrapping, respectively. Delong's test indicated that the R model performed significantly better than the C model in the QMH cohort (p < 0.0001), while demonstrating no significant difference compared to the RC model (p = 0.5773). To conclude, CT-based neck nodal radiomics was capable of predicting IfTM-triggered ART events in NPC patients in this multi-center study, outperforming the traditional clinical model. The findings of this study provide valuable insights for future study into developing an effective screening strategy for ART eligibility in NPC patients in the long run, ultimately alleviating the workload of clinical practitioners, streamlining ART procedural efficiency in clinics, and achieving personalized RT for NPC patients in the future.

4.
World J Gastrointest Surg ; 13(3): 323-329, 2021 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-33796219

RESUMEN

BACKGROUND: Liver cancer is a malignant tumor with a high incidence. At present, the most effective treatment is laparoscopic hepatectomy (LH). Indocyanine green fluorescence imaging (ICG-FI) has become an important tool in LH, and the most common fluorescent types of tumors are total fluorescence, partial fluorescence, and rim fluorescence. CASE SUMMARY: We presented four cases of LH guided by ICG-FI in which we also observed the fourth special fluorescent type. When the tumor or intrahepatic stone compresses the adjacent bile duct to cause local cholestasis, the liver segment or subsegment with obstructed bile drainage will show strong fluorescence. Complete removal of the lesion together with the fluorescent liver parenchyma may help reduce the risk of tumor or stone recurrence. CONCLUSION: This type of partial fluorescence can indicate local biliary compression, and the resection method is related to bile drainage, which may be called functional anatomical hepatectomy and ensures radical resection of the lesion.

5.
Infect Genet Evol ; 39: 249-257, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26845346

RESUMEN

Japanese encephalitis (JE) is a mosquito borne viral disease, caused by Japanese encephalitis virus (JEV) infection producing severe neuroinflammation in the central nervous system (CNS) with the associated disruption of the blood brain barrier. MicroRNAs (miRNAs) are a family of 21-24 nt small non-coding RNAs that play important post-transcriptional regulatory roles in gene expression and have critical roles in virus pathogenesis. We examined the potential roles of miRNAs in JEV-infected suckling mice brains and found that JEV infection changed miRNA expression profiles when the suckling mice began showing nervous symptoms. A total of 1062 known and 71 novel miRNAs were detected in JEV-infected group, accompanied with 1088 known and 75 novel miRNAs in mock controls. Among these miRNAs, one novel and 25 known miRNAs were significantly differentially expressed, including 18 up-regulated and 8 down-regulated miRNAs which were further confirmed by real-time PCR. Gene ontology (GO) and signaling pathway analysis of the predicted target mRNAs of the modulated miRNAs showed that they are correlated with the regulation of apoptosis, neuron differentiation, antiviral immunity and infiltration of mouse brain, and the validated targets of 12 differentially expressed miRNAs were enriched for the regulation of cell programmed death, proliferation, transcription, muscle organ development, erythrocyte differentiation, gene expression, plasma membrane and protein domain specific binding. KEGG analysis further reveals that the validated target genes were involved in the Pathways in cancer, Neurotrophin signaling pathway, Toll like receptor signaling pathway, Endometrial cancer and Jak-STAT signaling pathway. We constructed the interaction networks of miRNAs and their target genes according to GO terms and KEGG pathways and the expression levels of several target genes were examined. Our data provides a valuable basis for further studies on the regulatory roles of miRNAs in JE pathogenesis.


Asunto(s)
Encéfalo/metabolismo , Encéfalo/virología , Virus de la Encefalitis Japonesa (Especie) , Encefalitis Japonesa/genética , Encefalitis Japonesa/virología , Perfilación de la Expresión Génica , MicroARNs/genética , Transcriptoma , Animales , Encéfalo/patología , Línea Celular , Biología Computacional/métodos , Modelos Animales de Enfermedad , Encefalitis Japonesa/patología , Regulación de la Expresión Génica , Redes Reguladoras de Genes , Secuenciación de Nucleótidos de Alto Rendimiento , Ratones , Interferencia de ARN , ARN Mensajero/genética , Análisis de Secuencia de ARN
6.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(2): 466-9, 2015 Feb.
Artículo en Chino | MEDLINE | ID: mdl-25970914

RESUMEN

The vapor infrared transmission spectra of varied concentration of lewisite-1 were measured by a long-path FT-IR spectrometer, and its characteristic frequencies are 814, 930, 1563 cm(-1); their infrared absorption cross section (a) were determined using Beer-Lambert law. The corresponding sigma values are 3.89 +/- 0.01, 1.43 +/- 0.06, 4.47 +/- 0.05 ( X 10(-20) cm2 x molecule(-1)). Two little teeny peaks, 1158, 1288 cm(-1) were found in the measured spectra. Density Functional Theory (DFT) was applied to calculated the infrared spectra of lewisite-1, -2, -3 on a b3lyp/6-311+g(d, p) level by Gauss09 package. The vibration modes were assigned by Gaussview5. 08. The calculated spectra and experimental spectra are in good agreement with each other in 600-1600 cm(-1) range, for the Person's r is 0.9991. The calculated spectra also showed three characteristic frequencies (293, 360, 374 cm(-1)) related to As atom. 0.977 was a scaling factor we determined for lewisite-1 through least-square error and its performance to scale lewisite-1, -2, -3 was acceptable. The results of this work are useful for monitoring environmental atmospheric concentrations of lewisite.

7.
Peptides ; 36(2): 292-8, 2012 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-22561065

RESUMEN

The bursa of Fabricius, the acknowledged central humoral immune organ, is vital to B cell differentiation. However, the regulatory function of the bursal-derived peptide on avian B cell proliferation has not been reported. BSP-II is a recently reported bursal-derived bioactive peptide. In this paper, 75 days-old chicks were twice subcutaneously immunized with BSP-II and inactivated avian influenza virus (AIV, H(9)N(2) strain). It was proved that BSP-II induced a strongly AIV-specific HI antibody production in the immunized chicks. Also, BSP-II could enhance avian pre-B lymphocyte DT40 cell viability. To investigate the global patterns of gene expression in DT40 cells after BSP-II treatment, gene microarray was carried out. It was identified that the differentially expressed genes were involved in various pathways, of which six pathways were associated with signaling transductions, including ErbB signaling, MAPK signaling, Toll-like receptor signaling, Notch signaling, mTOR signaling, and Wnt signaling. Finally, RT-qPCR was used to confirm the microarray expression data. These results indicated the molecular basis of pre-B lymphocyte viability with BSP-II treatment, which provided a potential mechanism of the bursa of Fabricius on pre-B lymphocyte viability, differentiation, and development. These results are valid for the mechanism of the bursa of Fabricius on B lymphocytes development.


Asunto(s)
Proteínas Aviares/farmacología , Bolsa de Fabricio/química , Factores Inmunológicos/farmacología , Péptidos/farmacología , Células Precursoras de Linfocitos B/inmunología , Animales , Proteínas Aviares/química , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Pollos , Factores Inmunológicos/química , Péptidos/química , Células Precursoras de Linfocitos B/citología , Células Precursoras de Linfocitos B/efectos de los fármacos
8.
Peptides ; 33(2): 258-64, 2012 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-22286032

RESUMEN

The bursa of Fabricius (BF) is the acknowledged central immune organ, which is important to the B cell differentiation and antibody production. However, due to difficult purification, the immunomodulatory peptides from BF were little reported. In this study, the extract samples of BF were taken to a chromatographic analysis by RP-HPLC. Five novel low molecular weight peptides were isolated from BF, with amino acid sequences of YEYAY, RMYEE, GPPAT, AGCCNG, and RRL, and named as Bursal pentapeptide (BPP)-III, -IV, -V, and Bursal hexapeptide (BHP), and Bursal tripeptide (BTP), respectively. BSP-I, BSP-II, BPP-I and BPP-II are recently reported to be the bursal-derived bioactive peptides. In this paper, we analyzed the chemical formula and characteristics of these nine bursal-derived peptides. The immunization comparative experiment verified the different immunomodulatory activity of these nine bursal peptides on antibody and cytokine productions. Furthermore, the results showed that at reachable concentrations, BPP-II and BPP-I induced antibody productions, lymphocyte viabilities and cytokine responses in different dose-dependent manner in the immunized mice model, respectively. These results provided important orientations for the comprehensively understanding and study of the humoral central immune system of human, and provided a novel insight on the treatment of serious disease and immune improvement of human.


Asunto(s)
Adyuvantes Inmunológicos/farmacología , Proteínas Aviares/farmacología , Bolsa de Fabricio/química , Pollos , Oligopéptidos/farmacología , Adyuvantes Inmunológicos/aislamiento & purificación , Secuencia de Aminoácidos , Animales , Formación de Anticuerpos , Antígenos Virales/inmunología , Proteínas Aviares/aislamiento & purificación , Femenino , Humanos , Inmunidad Humoral/efectos de los fármacos , Virus de la Influenza A/inmunología , Interferón gamma/sangre , Interleucina-4/sangre , Ratones , Peso Molecular , Oligopéptidos/aislamiento & purificación , Vacunación
9.
Biochem Biophys Res Commun ; 414(3): 545-50, 2011 Oct 28.
Artículo en Inglés | MEDLINE | ID: mdl-21986526

RESUMEN

Lipid rafts play an important role in the life cycle of many viruses. Cholesterol is a critical structural component of lipid rafts. Although the porcine reproductive and respiratory syndrome virus (PRRSV) has restricted cell tropism for cells of the monocyte/macrophage lineage, a non-macrophage cell MARC-145 was susceptible to PRRSV because of the expression of virus receptor CD163 on the cell surface, therefore MARC-145 cells is used as model cell for PRRSV studies. In order to determine if cholesterol is involved in PRRSV infection in MARC-145 cells, we used three pharmacological agents: methyl-ß cyclodextrin (MßCD), mevinolin, and filipin complex to deplete cholesterol in MARC-145. Although these agents act by different mechanisms, they all significantly inhibited PRRSV infection. The inhibition could be prevented by addition of exogenous cholesterol. Cell membrane cholesterol depletion after virus infection had no effect on PRRSV production and cholesterol depletion pre-infection did not reduce the virus attachment, suggesting cholesterol is involved in virus entry. Further results showed that cholesterol depletion did not change expression levels of the PRRSV receptor CD163 in MARC-145, had no effect on clathrin-mediated endocytosis, but disturbed lipid-raft-dependent endocytosis. Collectively, these studies suggest that cholesterol is critical for PRRSV entry, which is likely to be mediated by a lipid-raft-dependent pathway.


Asunto(s)
Colesterol/fisiología , Endocitosis , Microdominios de Membrana/fisiología , Síndrome Respiratorio y de la Reproducción Porcina/virología , Virus del Síndrome Respiratorio y Reproductivo Porcino/fisiología , Internalización del Virus , Animales , Línea Celular , Quelantes/química , Colesterol/química , Microdominios de Membrana/química , Microdominios de Membrana/virología , Porcinos
10.
Virol Sin ; 25(5): 369-74, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20960183

RESUMEN

Our study investigated the host cell protein which can interact with SARS-CoV N protein, and explored the functional connections. The eukaryotic expression vectors pEGFP-N1/SARS-CoVN and pdsRed2-N1/CXCL16 were constructed and used to co-transfect HEK293FT cells by the calcium phosphate method. The HIS-tagged fusion protein SARS-CoVN-GFP was then built and purified for the binding assay in vitro. The co-localization of SARS-CoVN and CXCL16 in the cytoplasm of HEK293FT cells was also shown using confocal laser scanning microscopy. It is suggested that their interaction might be through direct combination. Under a fluorescence microscope, it was observed that the purified fusion protein SARS-CoVN-GFP was attached to the cell membrane of CXCL16-transfected cells, indicating that SARS-CoVN and CXCL16 can be mutually combined.


Asunto(s)
Quimiocinas CXC/metabolismo , Proteínas de la Nucleocápside/metabolismo , Receptores Depuradores/metabolismo , Línea Celular , Quimiocina CXCL16 , Quimiocinas CXC/genética , Clonación Molecular , Proteínas de la Nucleocápside de Coronavirus , Citoplasma/química , Expresión Génica , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Microscopía Confocal , Proteínas de la Nucleocápside/genética , Plásmidos , Unión Proteica , Receptores Depuradores/genética , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo
11.
Antiviral Res ; 84(2): 142-9, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19699239

RESUMEN

Selective delivery of antiretrovirals to human immunodeficiency virus (HIV) infected cells may reduce toxicities associated with long-term highly active antiretroviral therapy (HAART), may improve therapeutic compliance and delay the emergence of resistance. We developed sterically stabilized pegylated liposomes coated with targeting ligands derived from the Fab' fragment of HIV-gp120-directed monoclonal antibody F105, and evaluated these liposomes as vehicles for targeted delivery of a novel HIV-1 protease inhibitor. We demonstrated that the immunoliposomes were selectively taken up by HIV-1-infected cells and localized intracellularly, enabling the establishment of a cytoplasmic reservoir of protease inhibitor. In antiviral experiments, the drug delivered by the immunoliposomes showed greater and longer antiviral activity than comparable concentrations of free drug or drug encapsulated in non-targeted liposomes. In conclusion, by combining a targeting moiety with drug-loaded liposomes, efficient and specific uptake by non-phagocytic HIV-infected cells was facilitated, resulting in drug delivery to infected cells. This approach to targeted delivery of antiretroviral compounds may enable the design of drug regimens for patients that allow increased therapeutic adherence and less toxic treatment of HIV infection.


Asunto(s)
Fármacos Anti-VIH/farmacología , Proteína gp120 de Envoltorio del VIH/metabolismo , Inhibidores de la Proteasa del VIH/farmacología , VIH-1/efectos de los fármacos , Liposomas/metabolismo , Liposomas/farmacología , Replicación Viral/efectos de los fármacos , Línea Celular , Portadores de Fármacos/farmacología , Infecciones por VIH/tratamiento farmacológico , Inhibidores de la Proteasa del VIH/síntesis química , Inhibidores de la Proteasa del VIH/química , VIH-1/metabolismo , VIH-1/fisiología , Humanos , Liposomas/química , Polietilenglicoles/química , Polietilenglicoles/farmacología , Linfocitos T/virología
12.
Biochim Biophys Acta ; 1668(2): 203-14, 2005 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-15737331

RESUMEN

The thermotropic phase behavior of hydrated bilayers derived from binary mixtures of dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylglycerol (DMPG) was investigated by differential scanning calorimetry, Fourier-transform infrared spectroscopy and 31P-nuclear magnetic resonance spectroscopy. Binary mixtures of DMPC and DMPG that have not been annealed at low temperatures exhibit broad, weakly energetic pretransitions (approximately 11-15 degrees C) and highly cooperative, strongly energetic gel/liquid-crystalline phase transitions (approximately 23-25 degrees C). After low temperature incubation, these mixtures also exhibit a thermotropic transition form a lamellar-crystalline to a lamellar gel phase at temperatures below the onset of the gel/liquid-crystalline phase transition. The midpoint temperatures of the pretransitions and gel/liquid-crystalline phase transitions of these lipid mixtures are both maximal in mixtures containing approximately 30 mol% DMPG but the widths and enthalpies of the same thermotropic events exhibit no discernable composition dependence. In contrast, thermotropic transitions involving the Lc phase exhibit a very strong composition dependence, and the midpoint temperatures and transition enthalpies are both maximal with mixtures containing equimolar amounts of the two lipids. Our spectroscopic studies indicate that the Lc phases formed are structurally similar as regards their modes of hydrocarbon chain packing, interfacial hydration and hydrogen-bonding interactions, as well as the range and amplitudes of the reorientational motions of their phosphate headgroups. Our results indicate that although DMPC and DMPG are highly miscible, their mixtures do not exhibit ideal mixing. We attribute the non-ideality in their mixing behavior to the formation of preferential PC/PG contacts in the Lc phase due to the combined effects of steric crowding of the DMPC headgroups and charge repulsion between the negatively charged DMPG molecules.


Asunto(s)
Dimiristoilfosfatidilcolina/química , Membrana Dobles de Lípidos/química , Fluidez de la Membrana , Fosfatidilgliceroles/química , Materiales Biomiméticos/química , Calorimetría , Mezclas Complejas/química , Membranas Artificiales , Conformación Molecular , Transición de Fase , Análisis Espectral , Temperatura
13.
Zhonghua Wai Ke Za Zhi ; 42(19): 1189-92, 2004 Oct 07.
Artículo en Chino | MEDLINE | ID: mdl-15598397

RESUMEN

OBJECTIVE: To discuss the surgical treatment of chiari-I malformation complicated with syringomyelia. METHODS: The surgical treatments of 247 cases were analyzed retrospectively. The indication of operation styles was proposed by various surgical treatment to different MRI (magnetic resonance imaging) findings. MRI findings includes: tonsillar herniation with no or slight syringomyelia (126 cases), tonsillar herniation with syringomyelia above C(2) (second cervical vertebrae) vertebral level (38 cases), serious tonsillar herniation (to C(2) approximately C(3) level) with syringomyelia of isolated spinal segments (67 cases), serious tonsillar herniation (to C(2) approximately C(3) level) with syringomyelia above C(2) vertebral level (16 cases). They were performed by posterior fossa decompression, posterior fossa decompression and incision of the syringomyelia, posterior fossa decompression and resection of the cerebellar tonsils, posterior fossa decompression and incision of the syringomyelia combined with resection of the cerebellar tonsils respectively. RESULTS: The clinical signs and symptoms had been markedly improved or improved in 197 cases (79.8%) until patients were discharged from hospital, unchanged in 39 cases (15.8%), deteriorated in 7 cases (2.8%). there were 4 death in all cases after surgery. 107 cases were followed up from 5 months to 9 years. The postoperative MRI findings in the 107 patients demonstrated that the cavities in spinal cords disappeared completely or nearly in 78 cases, reduced in 14 cases, unchanged in 15 cases. CONCLUSIONS: Posterior fossa decompression, posterior fossa decompression and incision of the syringomyelia, posterior fossa decompression and resection of the cerebellar tonsils, posterior fossa decompression and incision of the syringomyelia combined with resection of the cerebellar tonsils should be an effective method for treatment of chiari-I malformation complicated with syringomyelia. Surgical treatment may fully ameliorate the clinical syndromes.


Asunto(s)
Malformación de Arnold-Chiari/cirugía , Siringomielia/cirugía , Adolescente , Adulto , Anciano , Malformación de Arnold-Chiari/complicaciones , Niño , Craneotomía , Femenino , Humanos , Laminectomía , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Siringomielia/complicaciones
14.
Bioelectrochemistry ; 56(1-2): 135-40, 2002 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-12009460

RESUMEN

The synthetic peptide acetyl-K(2)-G-L(24)-K(2)-A-amide (P(24)) and its analogs have been successfully utilized as models of the hydrophobic transmembrane alpha-helical segments of integral membrane proteins. The central polyleucine region of these peptides was designed to form a maximally stable, very hydrophobic alpha-helix which will partition strongly into the hydrophobic environment of the lipid bilayer core, while the dilysine caps were designed to anchor the ends of these peptides to the polar surface of the lipid bilayer and to inhibit the lateral aggregation of these peptides. Moreover, the normally positively charged N-terminus and the negatively charged C-terminus have both been blocked in order to provide a symmetrical tetracationic peptide, which will more faithfully mimic the transbilayer region of natural membrane proteins and preclude favorable electrostatic interactions. In fact, P(24) adopts a very stable alpha-helical conformation and transbilayer orientation in lipid model membranes. The results of our recent studies of the interaction of this family of alpha-helical transmembrane peptides with phospholipid bilayers are summarized here.


Asunto(s)
Membrana Dobles de Lípidos/química , Péptidos/química , Fosfolípidos/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA