Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Nat Commun ; 14(1): 4641, 2023 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-37582830

RESUMO

The indigenous population of the Canary Islands, which colonized the archipelago around the 3rd century CE, provides both a window into the past of North Africa and a unique model to explore the effects of insularity. We generate genome-wide data from 40 individuals from the seven islands, dated between the 3rd-16rd centuries CE. Along with components already present in Moroccan Neolithic populations, the Canarian natives show signatures related to Bronze Age expansions in Eurasia and trans-Saharan migrations. The lack of gene flow between islands and constant or decreasing effective population sizes suggest that populations were isolated. While some island populations maintained relatively high genetic diversity, with the only detected bottleneck coinciding with the colonization time, other islands with fewer natural resources show the effects of insularity and isolation. Finally, consistent genetic differentiation between eastern and western islands points to a more complex colonization process than previously thought.


Assuntos
Deriva Genética , Genômica , Humanos , Espanha , África do Norte , Povos Indígenas , Ilhas , Variação Genética , Genética Populacional
2.
Materials (Basel) ; 16(4)2023 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36837097

RESUMO

The study of the provenance of dolomitic marble artefacts has become relevant since it was discovered that quarries of this marble other than that of Cape-Vathy located on the island of Thasos have been exploited since Antiquity. To improve our knowledge about the provenance of materials and the extent of their dispersion, multiple archaeometric studies were performed in the past including isotope analyses, petrography, cathodoluminescence, and elemental analyses. In the present work, solid-state nuclear magnetic resonance (NMR) spectroscopy has been added to this panel of techniques. NMR allows the characterization of the material at a molecular level by looking at different nuclei: carbon, magnesium, and calcium. Statistical analysis of the data collected on both quarry samples and archaeologic items was also implemented and clearly demonstrates the efficiency of a holistic approach for provenance elucidation. Finally, the first 25Mg NMR tests have shown the potential of this technique to discriminate between dolomitic marbles of different provenance. The results are discussed in terms of their historical meaning and illustrate the exploitation of sources of dolomitic marbles other than the Greek Thasos source.

3.
PLoS One ; 14(3): e0209125, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30893316

RESUMO

The Canary Islands' indigenous people have been the subject of substantial archaeological, anthropological, linguistic and genetic research pointing to a most probable North African Berber source. However, neither agreement about the exact point of origin nor a model for the indigenous colonization of the islands has been established. To shed light on these questions, we analyzed 48 ancient mitogenomes from 25 archaeological sites from the seven main islands. Most lineages observed in the ancient samples have a Mediterranean distribution, and belong to lineages associated with the Neolithic expansion in the Near East and Europe (T2c, J2a, X3a…). This phylogeographic analysis of Canarian ancient mitogenomes, the first of its kind, shows that some lineages are restricted to Central North Africa (H1cf, J2a2d and T2c1d3), while others have a wider distribution, including both West and Central North Africa, and, in some cases, Europe and the Near East (U6a1a1, U6a7a1, U6b, X3a, U6c1). In addition, we identify four new Canarian-specific lineages (H1e1a9, H4a1e, J2a2d1a and L3b1a12) whose coalescence dates correlate with the estimated time for the colonization of the islands (1st millennia CE). Additionally, we observe an asymmetrical distribution of mtDNA haplogroups in the ancient population, with certain haplogroups appearing more frequently in the islands closer to the continent. This reinforces results based on modern mtDNA and Y-chromosome data, and archaeological evidence suggesting the existence of two distinct migrations. Comparisons between insular populations show that some populations had high genetic diversity, while others were probably affected by genetic drift and/or bottlenecks. In spite of observing interinsular differences in the survival of indigenous lineages, modern populations, with the sole exception of La Gomera, are homogenous across the islands, supporting the theory of extensive human mobility after the European conquest.


Assuntos
Etnicidade/genética , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Mitocôndrias/genética , Migrantes/classificação , África do Norte/etnologia , Europa (Continente)/etnologia , Deriva Genética , Genética Populacional , Genoma Mitocondrial , Humanos , Oriente Médio , Filogeografia , Análise de Sequência de DNA , Espanha/etnologia
10.
J Microencapsul ; 18(1): 41-54, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11201340

RESUMO

Immunomagnetic systems have been used for positive selection of a cell fraction from a mixture using appropriate surface markers with satisfactory results, as haematopoietic CD34+ cells. This work reports on the development of poly(ethylene glycol)-grafted (PEG) immunoliposomes loaded with citrate-magnetite stabilized particles as the separation vehicles for immunomagnetic separations. The magnetic ferrofluid was encapsulated into PEG-liposomes by the DRV methodology. The magnetoliposomes had a liposomal size of approximately 450 nm and a Fe/lipid molar ratio of 1.52+/-0.26, and were retained in the magnetic field created by the MiniMACS system. Anti-CD34 immunomagnetoliposomes with 100 mAb/vesicle were prepared by coupling the My10 mAb and bound specifically for CD34+ KG-1a cells in culture and in mixtures with CD34-cells (CHO or Jurkat). The magnetic cell sorting was carried out in cell mixtures KG-1a/CHO or KG-1a/Jurkat with different initial% of CD34+ Kg-1a cells. For 10(6) positive cells and 100 microM of immunomagnetoliposomes, the capture efficiency was > 85% and independent of the starting percentage of CD34+ cells. The decrease of the final purity, when the starting percentage of CD34+ cells decreases and, dependent of the CD34- cell line used, point to the degree of non-specific cell binding of My10-immunomagnetoliposomes as being crucial, among of the methodological aspects as the number of starting CD34+ cells. The CD34+ cells isolated retained the viability with an estimated recovery of 45-50%.


Assuntos
Antígenos CD34/imunologia , Separação Imunomagnética/métodos , Ferro/química , Lipossomos/química , Óxidos/química , Polietilenoglicóis/química , Algoritmos , Linhagem Celular , Citratos , Óxido Ferroso-Férrico , Citometria de Fluxo , Humanos , Excipientes Farmacêuticos
11.
Biochim Biophys Acta ; 1509(1-2): 299-310, 2000 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-11118541

RESUMO

Several methods for the preparation of sterically stabilized immunoliposomes (SIL) have recently been described. This report examines an established method for coupling anti-CD34 My10 mAb to poly(ethylene glycol)-liposomes (PEG-liposomes) containing the anchor pyridyldithiopropionylamino-PEG-phosphatidylethanolamine (PDP-PEG-PE) via a cleavable disulfide bond. Efficient attachment of pyridyldithio-derivatized mAb took place (equivalent to coupling ca. 70% of total input protein) at 2 mol percent of the functionalized PEG-lipid. The My10-SIL bound specifically to CD34+ cells (human leukemic KG-1a and hematopoietic progenitor cells) and the extent of binding was a function of liposomal lipid concentration, the mAb density in the liposome surface and the CD34 cell expression. In mixtures with CD34- cells (CHO or Jurkat), CD34+KG-1a cells were determined by flow cytometry at percentages (1-4%) similar to those reported in clinical samples (such as cord blood, mobilized peripheral blood and bone marrow) using a direct immunostaining with My10-SIL. The disulfide bond was stable in cell culture medium (10% of fetal calf serum) during 8 h and cell-bound SIL can be released from cells by treatment with dithiothreitol as reducing agent under mild conditions (1 h of incubation with 50 mM DTT at 20 degrees C). SIL binding and subsequent dithiothreitol treatment did not influence the cell viability. Our approach should contribute to the development of targetable liposomal vehicles to CD34+ cells for use in ex vivo conditions as sorting of hematopoietic stem cells.


Assuntos
Anticorpos Monoclonais/imunologia , Antígenos CD34/imunologia , Dissulfetos/química , Células-Tronco Hematopoéticas/imunologia , Lipossomos/síntese química , Animais , Anticorpos Monoclonais/química , Reações Antígeno-Anticorpo , Células CHO , Separação Celular/métodos , Sobrevivência Celular , Cricetinae , Reagentes de Ligações Cruzadas , Meios de Cultura , Ditiotreitol , Citometria de Fluxo , Fluoresceína-5-Isotiocianato , Humanos , Lipossomos/imunologia , Microscopia Confocal , Polietilenoglicóis/química , Succinimidas , Células Tumorais Cultivadas
12.
Biochim Biophys Acta ; 1418(1): 232-8, 1999 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-10209227

RESUMO

Several methodologies for the preparation of polyethylene glycol-grafted immunoliposomes have been developed by attaching antibodies to the terminus of the polymer. Unilamellar liposomes were prepared containing a combination of a functionalized polyethylene glycol(3400) and an inert polyethylene glycol(2000) phosphatidylethanolamine derivate up to 5 mol%. The greater length of the functionalized polyethylene glycol derivate did not alter the liposomal sterical stability or the remote loading of doxorubicin. Anti-CD34 immunoliposomes were prepared by the reaction of maleimide-derivatized My10 antibody with generated thiol groups at the periphery of the liposomes and efficiencies of nearly 100% were obtained. The greater accessibility of the reactive group makes this strategy more efficient than others described. The immunoliposomes prepared bound specifically to CD34+ cells.


Assuntos
Anticorpos Monoclonais/química , Lipossomos/síntese química , Polietilenoglicóis/química , Anticorpos Monoclonais/imunologia , Reações Antígeno-Anticorpo , Antígenos CD34/imunologia , Portadores de Fármacos , Estabilidade de Medicamentos
13.
Biochim Biophys Acta ; 1371(1): 17-23, 1998 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-9565652

RESUMO

The My-10 monoclonal antibody has facilitated the search of haematopoietic stem cells by recognizing selectively the human CD34 antigen. In the present work, My-10 immunoliposomes directed specifically against CD34+ cells were prepared, characterized and tested in vitro. Binding to target cells at 4 degreesC of immunoliposomes containing carboxyfluorescein as aqueous marker was evaluated by flow cytometry and fluorescence microscopy. These immunoliposomes demonstrated their capacity to bind specifically to CD34+ cells. Studies have shown that 9 antibodies/vesicle were sufficient to obtain a good binding efficiency. The product was stable over one month at 4 degreesC in terms of leakage of encapsulated carboxyfluorescein, particle size and antigen binding capacity.


Assuntos
Anticorpos Monoclonais , Antígenos CD34/análise , Células-Tronco Hematopoéticas/química , Lipossomos , Linhagem Celular , Citometria de Fluxo , Fluoresceínas , Corantes Fluorescentes , Humanos , Microscopia de Fluorescência
15.
Biochim Biophys Acta ; 1235(2): 281-8, 1995 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-7756336

RESUMO

Liposomes containing negatively-charged phospholipid, N-palmitoylphosphatidylethanolamine (NPPE) were examined for stability in the presence of human serum, using the release of the entrapped 5,6-carboxyfluorescein as an aqueous marker. Either small unilamellar vesicles (SUV) or large unilamellar vesicles (LUV) were used. Incorporation of NPPE into PC SUV decreases leakage in the presence of serum or phosphate-buffered saline, no strictly related to size increase observed and to the surface negative charge present. The stabilizing effect of NPPE and Chol were synergistic. Inhibition of destabilization induced by serum of PC/Chol liposomes was observed when NPPE concentrations were above 12 mol%. Change in the membrane fluidity or incorporation of a monosialoganglioside into liposomes do not significantly change the half-life of liposomes in the presence of a high NPPE concentration. Incorporation of NPPE into PC/Chol liposomes increases membrane rigidity which does not change after serum incubation. The presence of NPPE in liposomes decreases lipid transfer/exchange between liposomes and lipoproteins although the same amount of serum proteins were incorporated as in PC/Chol liposomes. As expected, these proteins are accessible to trypsin digestion. In accordance with these results, the liposome agglutination assay shows no steric barrier activity. As a whole, the results obtained in this paper suggest a complex mechanism for stabilization of NPPE containing liposomes in human serum.


Assuntos
Sangue , Lipídeos/análise , Lipossomos/química , Lisofosfolipídeos/farmacologia , Proteínas Sanguíneas/metabolismo , Colesterol/metabolismo , Colesterol/farmacologia , Estabilidade de Medicamentos , Sinergismo Farmacológico , Eletroquímica , Gangliosídeo G(M1)/farmacologia , Gangliosídeos/química , Meia-Vida , Humanos , Lipossomos/metabolismo , Lisofosfolipídeos/química , Lisofosfolipídeos/metabolismo , Fluidez de Membrana , Fosfatidilcolinas/metabolismo , Fosfatidilserinas/farmacologia , Fótons , Análise Espectral , Tripsina/metabolismo
16.
Rev Esp Anestesiol Reanim ; 40(3): 153-5, 1993.
Artigo em Espanhol | MEDLINE | ID: mdl-8516528

RESUMO

The case of a patient with all manifestations of pancreatic glucagonoma is presented. The real prevalence of this disease is unknown for in many cases there are no clinical manifestations. It is usually an accidental finding during autopsy and it is considered as an infrequent entity. Patients with glucagonomas may have different hydroelectrolytic and metabolic changes causing myocardial dysfunction and thromboembolic alterations. Anesthesia for this type of patients requires a strict control of glycemia, a careful evaluation of the nutritional and hydroelectrolytic state and adequate thromboembolic prophylaxis.


Assuntos
Anestesia , Glucagonoma , Neoplasias Pancreáticas , Idoso , Feminino , Glucagonoma/cirurgia , Humanos , Neoplasias Pancreáticas/cirurgia
18.
Ann Rech Vet ; 15(4): 553-6, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6529126

RESUMO

This work describes results obtained by vaccinating pregnant ewes from a Brucella melitensis-infected flock, with 5 x 10(8) CFU (half dose) Rev 1. Only five abortions were recorded after vaccinating 600 pregnant ewes. The serological response was followed by rose bengal, complement fixation and radial immunodiffusion tests. A short-termed, low humoral immunoresponse was produced. The radial immunodiffusion test could be more useful than the other tests for differentiating infected from vaccinated sheep. It was concluded that vaccination with 5 x 10(8) CFU Rev 1 seems to have little or no effect on the normal development of pregnancy.


Assuntos
Vacinas Bacterianas/administração & dosagem , Brucella/imunologia , Brucelose/veterinária , Imunização/veterinária , Doenças dos Ovinos/prevenção & controle , Animais , Brucelose/prevenção & controle , Feminino , Gravidez , Ovinos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...