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1.
Curr Oncol ; 31(4): 1961-1970, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38668050

RESUMO

Transarterial chemoembolization (TACE) is a minimally invasive treatment for liver cancer, often employed as a bridging therapy or destination treatment for non-operable cases. This case report discusses an 82-year-old woman with a large hepatocellular carcinoma (HCC) who underwent elective TACE due to the high surgical risk associated with her tumor size. Unexpectedly, the patient experienced liver rupture 20 h post-procedure, leading to acute surgical intervention. Despite successful hemostasis during surgery, the patient succumbed to progressive multi-organ failure. We aimed to search the PubMed database for documented cases of ruptured HCC after TACE. This study highlights risk factors for spontaneous HCC rupture and specific factors associated with TACE-induced rupture. Transarterial embolization (TAE) is currently favored as the treatment method for spontaneous ruptures, while the optimal therapy for TACE-induced ruptures remains unclear. In conclusion, this case underscores the importance of recognizing the rare complication of HCC rupture post-TACE and the need for personalized risk assessment. While TAE emerges as a primary treatment choice, the lack of consensus necessitates further studies to establish evidence-based approaches for managing this uncommon yet life-threatening complication.


Assuntos
Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Feminino , Quimioembolização Terapêutica/efeitos adversos , Quimioembolização Terapêutica/métodos , Neoplasias Hepáticas/terapia , Idoso de 80 Anos ou mais , Carcinoma Hepatocelular/terapia , Evolução Fatal
2.
Int J Mol Sci ; 25(7)2024 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-38612827

RESUMO

The signaling lymphocytic activation molecule (SLAM) receptor family (SLAMF) consists of nine glycoproteins that belong to the CD2 superfamily of immunoglobulin (Ig) domain-containing molecules. SLAMF receptors modulate the differentiation and activation of a wide range of immune cells. Individual SLAMF receptors are expressed on the surface of hematopoietic stem cells, hematopoietic progenitor cells, B cells, T cells, NK cells, NKT cells, monocytes, macrophages, dendritic cells, neutrophils, and platelets. The expression of SLAMF receptors was studied during normal B cell maturation. Several SLAMF receptors were also detected in cancer cell lines of B-lymphoid origin and in pathological B cells from patients with B cell chronic lymphoproliferative disorders (B-CLPD), the most frequent hematological malignancies in adults. This review summarizes current knowledge on the expression of SLAMF receptors and their adaptor proteins SAP and EAT-2 in B-CLPD. Several SLAMF receptors could be regarded as potential diagnostic and differential diagnostic markers, prognostic factors, and targets for the development of novel drugs for patients with B-CLPD.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Transtornos Linfoproliferativos , Adulto , Humanos , Linfócitos B , Plaquetas , Família de Moléculas de Sinalização da Ativação Linfocitária/genética , Transtornos Linfoproliferativos/genética
3.
Bratisl Lek Listy ; 125(1): 9-11, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38041839

RESUMO

OBJECTIVES: ASCT has been considered the standard of care for younger patients with NDMM, however, not all the studies published so far have uniformly demonstrated the complete superiority of ASCT over chemotherapy at standard doses. A systematic review and meta-analysis of randomized studies has shown a significant benefit with single ASCT in terms of prolonged progression-free survival (PFS), but not of overall survival (OS). In our retrospective analysis we investigated the impact of high dose (HD) chemotherapy followed by ASCT in special population of patients with high risk cytogenetic profile on the PFS and treatment outcome. METHODS: Retrospective analysis of NDMM patients eligible for HD chemotherapy followed by upfront ASCT in the era of novel agents, who underwent the ASCT in the Department of hematology and oncohematology LF UPJS and UNLP Kosice in the timeframe of 54 months (from 01/JAN/2019 to 30/JUN/2023). Patients were stratified according to their cytogenetic profile. PFS was defined by the time from ASCT to the disease progression. The OS was defined as the time from the the start of treatment to the death from disease progression. The high risk cytogenetic abnormalities (HRCA) were defined as t(4;14), del(17/17p), t(14;16), t(14;20), nonhyperploidy, gain (1q). RESULTS: Inclusion criteria were met by 65 patients with NDMM who received HD chemotherpy followed by ASCT. We identified 22 (33.8 %) patients with HRCA and 43 (66.2 %) patients with standard cytogenetic risk. During the monitored period we recorded 4 deaths due to disease progression, all of them in the HCRA subgroup. The response was enhanced by the ASCT in both subgroups. The very good partial response (VGPR) increased from 42 % to 46 % and complete remission (CR) increased from 23 % to 45 % after the ASCT. The number of patients achieving only partial response (PR) decreased from 35 % to 9 % after ASCT. In the subgroup of patients with HRCA the median PFS after ASCT was lower compared to the patients with standard cytogenetic risk (17 vs 38 months). The average PFS in both subgroups was 22.9 months. The median OS in both subgroups was not reached, however the only deaths due to disease progression were recorded in the HRCA subgroup. At the time of analysis, 100 % (43) of patients are alive in the standard cytogenetic subgroup versus 72 % (18) of patients in HRCA subgroup. CONCLUSION: HD chemotherapy followed by ASCT remains the standard of care for NDMM eligible for high dose chemotherapy. Our results confirm the benefit of ASCT even in the presence of HRCA. Lower PFS in the HRCA subgroup might indicate the need for more intensive treatment, which may be achieved by tandem ASCT defined as two ASCT performed within a period of no more than six months. Additionally, as three- and four-drug induction therapies are becoming increasingly available and effective, resulting in high minimal residual disease (MRD) negative rates, it is important to continue discussing and further personalizing upfront ASCT to avoid overtreatment and possible toxicities especially in the non-high-risk patient population (Tab. 5, Fig. 2, Ref. 9).


Assuntos
Transplante de Células-Tronco Hematopoéticas , Mieloma Múltiplo , Humanos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Aberrações Cromossômicas , Progressão da Doença , Intervalo Livre de Doença , Transplante de Células-Tronco Hematopoéticas/métodos , Mieloma Múltiplo/genética , Mieloma Múltiplo/terapia , Intervalo Livre de Progressão , Estudos Retrospectivos , Transplante de Células-Tronco , Transplante Autólogo , Resultado do Tratamento
4.
J Proteome Res ; 22(6): 1936-1946, 2023 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-37018516

RESUMO

Nuclear magnetic resonance (NMR) metabolomics was used for identification of metabolic changes in pancreatic cancer (PC) blood plasma samples when compared to healthy controls or diabetes mellitus patients. An increased number of PC samples enabled a subdivision of the group according to individual PC stages and the construction of predictive models for finer classification of at-risk individuals recruited from patients with recently diagnosed diabetes mellitus. High-performance values of orthogonal partial least squares (OPLS) discriminant analysis were found for discrimination between individual PC stages and both control groups. The discrimination between early and metastatic stages was achieved with only 71.5% accuracy. A predictive model based on discriminant analyses between individual PC stages and the diabetes mellitus group identified 12 individuals out of 59 as at-risk of development of pathological changes in the pancreas, and four of them were classified as at moderate risk.


Assuntos
Diabetes Mellitus , Metabolômica , Humanos , Espectroscopia de Ressonância Magnética , Pâncreas , Análise Discriminante , Neoplasias Pancreáticas
5.
CVIR Endovasc ; 4(1): 61, 2021 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-34357452

RESUMO

BACKGROUND: Venous thoracic outlet syndrome resulting in the upper limb deep venous thrombosis is known as Paget-Schroetter syndrome or effort thrombosis. A general treatment algorithm includes catheter-directed thrombolysis followed by surgical thoracic outlet decompression. There are limited data regarding endovascular treatment of rethrombosis presenting early after the surgery. CASE PRESENTATION: Two cases of early rethrombosis successfully treated with percutaneous mechanical thrombectomy by two different techniques are described. In both cases, rethrombosis was diagnosed soon after thrombolysis and first rib resection with scalenectomy. After 12 months, both patients remain symptom-free, with patent subclavian veins confirmed by duplex ultrasonography. CONCLUSION: Percutaneous mechanical thrombectomy devices may offer a safe treatment option for patients with recurrent thrombosis after thoracic outlet surgery, even when thrombolytic therapy is contraindicated.

6.
J Proteome Res ; 20(3): 1744-1753, 2021 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-33617266

RESUMO

The association of pancreatic cancer with type 2 diabetes mellitus was investigated by 1H NMR metabolomic analysis of blood plasma. Concentration data of 58 metabolites enabled discrimination of pancreatic cancer (PC) patients from healthy controls (HC) and long-term type 2 diabetes mellitus (T2DM) patients. A panel of eight metabolites was proposed and successfully tested for group discrimination. Furthermore, a prediction model for the identification of at-risk individuals for future development of pancreatic cancer was built and tested on recent-onset diabetes mellitus (RODM) patients. Six of 59 RODM samples were assessed as PC with an accuracy of more than 80%. The health condition of these individuals was re-examined, and in four cases, a correlation to the prediction was found. The current health condition can be retrospectively attributed to misdiagnosed pancreatogenic diabetes or to early-stage pancreatic cancer.


Assuntos
Diabetes Mellitus Tipo 2 , Diabetes Mellitus , Neoplasias Pancreáticas , Diabetes Mellitus Tipo 2/diagnóstico , Detecção Precoce de Câncer , Humanos , Metabolômica , Neoplasias Pancreáticas/diagnóstico , Espectroscopia de Prótons por Ressonância Magnética , Estudos Retrospectivos
7.
Vnitr Lek ; 66(6): 14-18, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33380148

RESUMO

Hemodialysed patients with end stage renal disease are reliant to proper function of vascular access - mostly arterio-venous fistula (AVF). AVF patency is jeopardized by stenosis formation, which needs to be treated before thrombosis. Angioplasty is primarily indicated and prolongs vascular access patency. High pressure balloons and cutting balloons aid to high technical success rate. Angioplasty needs to be repeated in order to maintain long term patency. Drug-eluting balloons prolong long term patency. Stents and stentgrafts are seldom used in inoperable patients and in selected locations. Technical advances allowed endovascular treatment in AVF thrombosis followed by angioplasty of culprit lesion. Vascular access endovascular occlusion is alternative for surgery in inoperable patients. In patients with residual renal function or iodine allergy, intervention could be ultrasound guided or carbon dioxide could be used without the need of iodine contrast.


Assuntos
Angioplastia com Balão , Derivação Arteriovenosa Cirúrgica , Angioplastia , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Humanos , Diálise Renal , Estudos Retrospectivos , Stents , Resultado do Tratamento , Grau de Desobstrução Vascular
8.
Analyst ; 143(24): 5974-5978, 2018 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-30270368

RESUMO

Metabolic changes induced by pancreatic cancer were investigated by 1H NMR spectroscopy of plasma samples of patients and healthy controls. The acquired data were submitted to multivariate statistical analysis providing clear discrimination between both groups. The most significant differences were found in levels of 3-hydroxybutyrate and lactate. The obtained results (100% sensitivity, 90% specificity) clearly show the potential of 1H NMR spectroscopy in pancreatic cancer diagnosis. Therefore, the NMR-based metabolomics may contribute to the early diagnosis, prevention and/or therapy of diseases in the future. On the other hand, the number of samples in the presented pilot study is limited and has to be significantly increased in the future in order to obtain solid statistical models and to confirm the current findings.


Assuntos
Biomarcadores Tumorais/sangue , Sangue/metabolismo , Metabolômica/métodos , Neoplasias Pancreáticas/sangue , Neoplasias Pancreáticas/diagnóstico , Ácido 3-Hidroxibutírico/sangue , Idoso , Idoso de 80 Anos ou mais , Aminoácidos/sangue , Feminino , Humanos , Ácido Láctico/sangue , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Espectroscopia de Prótons por Ressonância Magnética
9.
Methods Appl Fluoresc ; 6(3): 035016, 2018 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-29901450

RESUMO

Oligomerization plays a crucial role in the function of nucleophosmin (NPM), an abundant nucleolar phosphoprotein. Two dual-color methods based on modern fluorescence confocal microscopy are applied for tracking NPM aggregates in live cells: cross-correlation Number and Brightness analysis (ccN&B) combined with pulsed interleaved excitation (PIE) and fluorescence-lifetime imaging microscopy (FLIM) utilizing resonance energy transfer (FRET). HEK-293T cells were transfected with mixture of plasmids designed for tagging with fluorescent proteins so that the cells express mixed population of NPM labeled either with eGFP or mRFP1. We observe joint oligomers formed from the fluorescently labeled NPM. Having validated the in vivo methods, we study an effect of substitutions in cysteine 21 (Cys21) of the NPM N-terminus on the oligomerization to demonstrate applicability of the methods. Inhibitory effect of mutations of the Cys21 to nonpolar Ala or to aromatic Phe on the oligomerization was reported in literature using in vitro semi-native electrophoresis. However, we do not detect any break-up of the joint NPM oligomers due to the Cys21 mutations in live cells. In vivo microscopy observations are supported by an in vitro method, the GFP-Trap immunoprecipitation assay. Our results therefore show importance of utilizing several methods for detection of biologically relevant protein aggregates. In vivo monitoring of the NPM oligomerization, a potential cancer therapy target, by the presented methods offers a new way to monitor effects of drugs that are tested as NPM oligomerization inhibitors directly in live cells.


Assuntos
Transferência Ressonante de Energia de Fluorescência/métodos , Proteínas Nucleares/metabolismo , Agregados Proteicos/fisiologia , Humanos , Nucleofosmina
10.
Beilstein J Org Chem ; 12: 750-9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27340467

RESUMO

BACKGROUND: Derivatives of D-glucosamine and D-galactosamine represent an important family of the cell surface glycan components and their fluorinated analogs found use as metabolic inhibitors of complex glycan biosynthesis, or as probes for the study of protein-carbohydrate interactions. This work is focused on the synthesis of acetylated 3-deoxy-3-fluoro, 4-deoxy-4-fluoro and 3,4-dideoxy-3,4-difluoro analogs of D-glucosamine and D-galactosamine via 1,6-anhydrohexopyranose chemistry. Moreover, the cytotoxicity of the target compounds towards selected cancer cells is determined. RESULTS: Introduction of fluorine at C-3 was achieved by the reaction of 1,6-anhydro-2-azido-2-deoxy-4-O-benzyl-ß-D-glucopyranose or its 4-fluoro analog with DAST. The retention of configuration in this reaction is discussed. Fluorine at C-4 was installed by the reaction of 1,6:2,3-dianhydro-ß-D-talopyranose with DAST, or by fluoridolysis of 1,6:3,4-dianhydro-2-azido-ß-D-galactopyranose with KHF2. The amino group was introduced and masked as an azide in the synthesis. The 1-O-deacetylated 3-fluoro and 4-fluoro analogs of acetylated D-galactosamine inhibited proliferation of the human prostate cancer cell line PC-3 more than cisplatin and 5-fluorouracil (IC50 28 ± 3 µM and 54 ± 5 µM, respectively). CONCLUSION: A complete series of acetylated 3-fluoro, 4-fluoro and 3,4-difluoro analogs of D-glucosamine and D-galactosamine is now accessible by 1,6-anhydrohexopyranose chemistry. Intermediate fluorinated 1,6-anhydro-2-azido-hexopyranoses have potential as synthons in oligosaccharide assembly.

11.
Molecules ; 20(4): 6093-112, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25856060

RESUMO

Grape cane, leaves and grape marc are waste products from viticulture, which can be used to obtain secondary stilbene derivatives with high antioxidant value. The presented work compares several extraction methods: maceration at laboratory temperature, extraction at elevated temperature, fluidized-bed extraction, Soxhlet extraction, microwave-assisted extraction, and accelerated solvent extraction. To obtain trans-resveratrol, trans-ε-viniferin and r2-viniferin from grape cane of the V. vinifera variety Cabernet Moravia, various conditions were studied: different solvents, using powdered versus cut cane material, different extraction times, and one-step or multiple extractions. The largest concentrations found were 6030 ± 680 µg/g dry weight (d.w.) for trans-resveratrol, 2260 ± 90 µg/g d.w. for trans-ε-viniferin, and 510 ± 40 µg/g d.w. for r2-viniferin. The highest amounts of stilbenes (8500 ± 1100 µg/g d.w.) were obtained using accelerated solvent extraction in methanol.


Assuntos
Bengala , Fracionamento Químico/métodos , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Estilbenos/química , Estilbenos/isolamento & purificação , Vitis/química , Cromatografia Líquida de Alta Pressão , Ressonância Magnética Nuclear Biomolecular , Polifenóis/química , Polifenóis/isolamento & purificação , Solventes , Temperatura , Fatores de Tempo
12.
Chem Res Toxicol ; 28(2): 216-24, 2015 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-25621379

RESUMO

There is mounting evidence that cyanobacterial lipopeptides can kill mammalian cells, presenting a hazard to human health. Unfortunately, their mechanism of toxicity is poorly understood. We have isolated new cyclic undecalipopeptides muscotoxin A and B containing unique lipophilicresidue 3-amino-2,5-dihydroxydecanoic acid (5-OH Ahdoa). Muscotoxin B was not used for biological studies due to its poor yield. Muscotoxin A was cytotoxic to YAC-1, Sp/2, and HeLa cancer cell lines (LC(50) ranged from 9.9 to 13.2 µM after 24 h of exposure), causing membrane damage and influx of calcium ions. Subsequently, we studied this lytic mechanism using synthetic liposomes with encapsulated fluorescent probes. Muscotoxin A permeabilized liposomes composed exclusively of phospholipids, demonstrating that no proteins or carbohydrates present in biomembranes are essential for its activity. Paradoxically, the permeabilization activity of muscotoxin A was mediated by a significant reduction in membrane surface fluidity (stiffening), the opposite of that caused by synthetic detergents and cytolytic lipopeptide puwainaphycin F. At 25 °C, muscotoxin A disrupted liposomes with and without cholesterol/sphingomyelin; however, at 37 °C, it was selective against liposomes with cholesterol/sphingomyelin. It appears that both membrane fluidity and organization can affect the lytic activity of muscotoxin A. Our findings strengthen the evidence that cyanobacterial lipopeptides specifically disrupt mammalian cell membranes and bring new insights into the mechanism of this effect.


Assuntos
Permeabilidade da Membrana Celular/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Cianobactérias/química , Lipopeptídeos/toxicidade , Fluidez de Membrana/efeitos dos fármacos , Peptídeos Cíclicos/toxicidade , Fosfolipídeos/química , Animais , Morte Celular/efeitos dos fármacos , Membrana Celular/química , Imunofluorescência , Células HeLa , Humanos , Lipopeptídeos/química , Lipopeptídeos/isolamento & purificação , Camundongos , Conformação Molecular , Peptídeos Cíclicos/química , Peptídeos Cíclicos/isolamento & purificação , Células Tumorais Cultivadas
13.
J Phys Chem B ; 118(34): 10085-91, 2014 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-25079965

RESUMO

Fluorescence of 2-(N,N-dimethylamino)-6-propionylnaphthalene dyes Badan and Prodan is quenched by tryptophan in Brij 58 micelles as well as in two cytochrome P450 proteins (CYP102, CYP119) with Badan covalently attached to a cysteine residue. Formation of nonemissive complexes between a dye molecule and tryptophan accounts for about 76% of the fluorescence intensity quenching in micelles, the rest is due to diffusive encounters. In the absence of tryptophan, fluorescence of Badan-labeled cytochromes decays with triexponential kinetics characterized by lifetimes of about 100 ps, 700-800 ps, and 3 ns. Site mutation of a histidine residue in the vicinity of the Badan label by tryptophan results in shortening of all three decay lifetimes. The relative amplitude of the fastest component increases at the expense of the two slower ones. The average quenching rate constants are 4.5 × 10(8) s(-1) (CYP102) and 3.7 × 10(8) s(-1) (CYP119), at 288 K. Cyclic voltammetry of Prodan in MeCN shows a reversible reduction peak at -1.85 V vs NHE that becomes chemically irreversible and shifts positively upon addition of water. A quasireversible reduction at -0.88 V was observed in an aqueous buffer (pH 7.3). The excited-state reduction potential of Prodan (and Badan) is estimated to vary from about +0.6 V (vs NHE) in polar aprotic media (MeCN) to approximately +1.6 V in water. Tryptophan quenching of Badan/Prodan fluorescence in CYPs and Brij 58 micelles is exergonic by ≤0.5 V and involves tryptophan oxidation by excited Badan/Prodan, coupled with a fast reaction between the reduced dye and water. Photoreduction is a new quenching mechanism for 2-(N,N-dimethylamino)-6-propionylnaphthalene dyes that are often used as solvatochromic polarity probes, FRET donors and acceptors, as well as reporters of solvation dynamics.


Assuntos
2-Naftilamina/análogos & derivados , Proteínas Arqueais/química , Proteínas de Bactérias/química , Sistema Enzimático do Citocromo P-450/química , Corantes Fluorescentes/química , NADPH-Ferri-Hemoproteína Redutase/química , Triptofano/química , 2-Naftilamina/química , Fluorescência , Cinética , Micelas , Modelos Moleculares , Espectrometria de Fluorescência , Água
14.
J Phys Chem A ; 112(16): 3506-14, 2008 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-18373366

RESUMO

Excited-state dynamics of [Re(Etpy)(CO)3(bpy)]+ was studied in three imidazolium ionic liquids by time-resolved IR and emission spectroscopy on the picosecond to nanosecond time scale. Low-lying excited states were characterized by TD-DFT calculations, which also provided molecular dipole moment vectors in the relevant electronic states. TRIR spectra in ionic liquids show initial populations of two excited states: predominantly bpy-localized 3IL and 3MLCT, characterized by nu(CO) bands shifted to lower and higher frequencies, respectively, relative to the ground state. Internal conversion of 3IL to the lowest triplet 3MLCT occurred on a time scale commensurate with solvent relaxation. The nu(CO) IR bands of the 3MLCT state undergo a dynamic shift to higher wavenumbers during relaxation. Its three-exponential kinetics were determined and attributed to vibrational cooling (units of picoseconds), energy dissipation to the bulk solvent (tens of picoseconds), and solvent relaxation, the lifetime of which increases with increasing viscosity: [EMIM]BF4 (330 ps) < [BMIM]BF4 (470 ps) < [BMIM]PF6 (1570 ps). Time-resolved phosphorescence spectra in [BMIM]PF6 show a approximately 2 ns drop in intensity due to the 3IL --> 3MLCT conversion and a dynamic Stokes shift to lower energies with a lifetime decreasing from 1.8 ns at 21 degrees C to 1.1 ns at 37 degrees C, due to decreasing viscosity of the ionic liquid. It is proposed that solvent relaxation predominantly involves collective translational motions of ions. It drives the 3IL --> 3MLCT conversion, increases charge reorganization in the lowest excited-state 3MLCT, and affects vibrational anharmonic coupling, which together cause the dynamic shift of excited-state IR bands. TRIR spectroscopy of carbonyl-diimine complexes emerges as a new way to investigate various aspects of solvation dynamics, while the use of slowly relaxing ionic liquids offers new insight into the photophysics of Re(I) carbonyl polypyridyls.


Assuntos
Imidazóis/química , Líquidos Iônicos/química , Compostos Organometálicos/química , Solventes/química , Absorção , Elétrons , Transferência de Energia , Fluorescência , Medições Luminescentes , Teoria Quântica , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Vibração
15.
Magn Reson Chem ; 44(7): 669-74, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16602078

RESUMO

29Si-13C couplings were measured in para substituted silylated phenols, X--C6H4--O--SiR1R2R3 (X = NO2, CF3, Cl, F, H, CH3, CH3O). The SiR1R2R3 silyl groups included trimethylsilyl (Si(CH3)3, TMS), tert-butyldimethylsilyl (Si(CH3)2C(CH3)3, TBDMS), dimethylsilyl (SiH(CH3)2, DMS), and tert- butyldiphenylsilyl (Si(C6H5)2C(CH3)3, TBDPS). Previously developed (Si,C,Si)gHMQC methods and narrow 29Si lines allowed the determination of coupling constants over up to five bonds. Besides the number of intervening bonds between the silicon and carbon atoms, all the measurable couplings depend also on the nature of the substituents on the silicon. The two- and three-bond couplings are not affected by ring substitution in the para position. These properties render the 29Si-13C couplings suitable for line assignment in the spectra of silylated polyphenols. The experimental results are in reasonable agreement with theoretical calculations. The calculations show, in agreement with the data reported in the literature for couplings between other nuclei, that the two-bond and three-bond couplings, which are of similar magnitudes, are of opposite signs. If the signs of these geminal and vicinal couplings could be determined experimentally, they would greatly facilitate the line assignment. The four- and five-bond couplings are affected by the substituent X in a nontrivial manner.

16.
Artigo em Inglês | MEDLINE | ID: mdl-16597516

RESUMO

Blackcurrant (Ribes nigrum) seed oil is rich in alpha- and gamma-linolenic acids, the latter in particular being of potential use in medicine. The enzymatic hydrolysis of the oil was carried out in supercritical carbon dioxide using lipase Lipozyme as catalyst and changes in the composition of acylglycerols were recorded. Mono-, di-, and triacylglycerols and free fatty acids were separated by non-aqueous high-performance liquid chromatography in reversed phase mode and detected by UV diode array and 1H NMR detectors. Lipozyme was found to exert low specificity to individual fatty acids in the hydrolysed oil.


Assuntos
Dióxido de Carbono/química , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia com Fluido Supercrítico/métodos , Ácidos Linolênicos/química , Ácidos Linolênicos/metabolismo , Lipólise , Óleos de Plantas/química , Óleos de Plantas/metabolismo , Diglicerídeos/análise , Diglicerídeos/isolamento & purificação , Ácidos Graxos/análise , Ácidos Graxos/química , Hidrólise , Cinética , Ressonância Magnética Nuclear Biomolecular , Padrões de Referência
17.
C R Biol ; 328(12): 1057-64, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16314284

RESUMO

Evidence has been accumulated that the plasma membrane of various mammalian cell types is heterogeneous in structure and may contain lipid microdomains (lipid rafts). This study focuses on the membrane organization of living oligodendrocytes, which are the myelin-producing cells of the central nervous system. Fluorescence correlation spectroscopy (FCS) was used to monitor the lateral diffusion of a lipid and of a protein in the oligodendroglial cell line OLN-93. The lipid was fluorescently labelled sphingomyelin (Bodipy FL-C5 SM). The protein was the myelin oligodendrocyte glycoprotein (MOG). In order to monitor the lateral diffusion of MOG, OLN-93 cells were transfected with a MOG-EGFP (enhanced green fluorescent protein) fusion plasmid. The measurements were performed at room temperature. FCS data were analyzed for two-dimensional (2D) diffusion according to three models which all included a triplet fraction: (a) 2D 1 component (2D1C), (b) 2D anomalous diffusion (2D1Calpha), and (c) 2D 2 components (2D2C). Preliminary results indicate that for the lipid case, the best fits are obtained with 2D2C. In the case of MOG-EGFP, 2D2C and 2D1Calpha give fits of similar quality. The parameter estimates obtained with 2D1Calpha, however, have a lower standard deviation. The anomaly parameter for MOG-EGFP is 0.59+/-0.01.


Assuntos
Membrana Celular/metabolismo , Glicoproteína Associada a Mielina/metabolismo , Oligodendroglia/metabolismo , Esfingomielinas/metabolismo , Animais , Linhagem Celular , Linhagem Celular Tumoral , Membrana Celular/ultraestrutura , Difusão , Cinética , Proteínas da Mielina , Glicoproteína Mielina-Oligodendrócito , Oligodendroglia/ultraestrutura , Oligodendroglioma , Ratos , Espectrometria de Fluorescência
18.
Magn Reson Chem ; 43(10): 829-34, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16041773

RESUMO

The lines in (29)Si NMR spectra of silylated polyphenols and some other compounds are difficult to assign owing to the absence of couplings with protons outside the silyl group. The assignment can be derived through small (n)J((29)Si, (13)C) couplings (n > 1). Using a previously described method for measurements of these couplings, the assignment procedure is demonstrated here on three examples of trimethylsilylated phenols: 7-hydroxyflavone, ferulic acid, and quercetin. In some cases the procedure can be used to identify carbon atoms to which the siloxy groups are attached.


Assuntos
Flavonoides/química , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/normas , Fenóis/química , Silício/química , Isótopos de Carbono , Flavonoides/síntese química , Isótopos , Estrutura Molecular , Fenóis/síntese química , Plantas/química , Polifenóis , Padrões de Referência
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