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1.
Haemophilia ; 23(4): 598-612, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28429878

RESUMEN

The purpose of this study was to semi-quantitatively assess the evidence on the value of ultrasound (US) for assessment of haemophilic arthropathy (HA) in children and adults based on the following questions: (1) Does early diagnosis of pathological findings, using available US techniques, impact the functional status of the joint? (2) Do current available US techniques have the ability to accurately detect pathological changes in target joints in haemophilic patients? (3) Does treatment (prophylaxis) improve US evidence of haemophilic arthropathy in children and adults? (4) Is there any association between various US scoring systems and other clinical/radiological constructs? Of the 6880 citations identified searching databases such as MEDLINE, Embase, CENTRAL and Web of Science, 20 articles investigating either the diagnostic accuracy of US and/or US scanning protocols and scoring systems for assessment of HA met the inclusion criteria for the study. Of these, 14 articles evaluating the diagnostic accuracy of US were assessed by two independent reviewers for reporting quality using the Standards for Reporting of Diagnostic Accuracy (STARD) tool and for methodological quality using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Using STARD, 1/14 studies (7%) was scored as of high reporting quality and 8/14 (57%), of moderate quality. Assessment with QUADAS-2 reported 2/14 (14%) studies as having high methodological quality and 6/14 (43%) as having moderate quality. There is fair evidence (Grade B) to recommend US as an accurate technique for early diagnosis of HA, to demonstrate that US scores correlate with clinical/US constructs and to prove an association between US findings and functional status of the joint. However, there is insufficient evidence (Grade I) to conclude that US-detectable findings in HA are sensitive to changes in therapy.


Asunto(s)
Hemofilia A/complicaciones , Artropatías/complicaciones , Artropatías/diagnóstico por imagen , Ultrasonografía/métodos , Adulto , Niño , Humanos
2.
Neurology ; 78(24): 1974-80, 2012 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-22689735

RESUMEN

OBJECTIVE: To update the 2004 American Academy of Neurology/Child Neurology Society practice parameter on treatment of infantile spasms in children. METHODS: MEDLINE and EMBASE were searched from 2002 to 2011 and searches of reference lists of retrieved articles were performed. Sixty-eight articles were selected for detailed review; 26 were included in the analysis. RECOMMENDATIONS were based on a 4-tiered classification scheme combining pre-2002 evidence and more recent evidence. RESULTS: There is insufficient evidence to determine whether other forms of corticosteroids are as effective as adrenocorticotropic hormone (ACTH) for short-term treatment of infantile spasms. However, low-dose ACTH is probably as effective as high-dose ACTH. ACTH is more effective than vigabatrin (VGB) for short-term treatment of children with infantile spasms (excluding those with tuberous sclerosis complex). There is insufficient evidence to show that other agents and combination therapy are effective for short-term treatment of infantile spasms. Short lag time to treatment leads to better long-term developmental outcome. Successful short-term treatment of cryptogenic infantile spasms with ACTH or prednisolone leads to better long-term developmental outcome than treatment with VGB. RECOMMENDATIONS: Low-dose ACTH should be considered for treatment of infantile spasms. ACTH or VGB may be useful for short-term treatment of infantile spasms, with ACTH considered preferentially over VGB. Hormonal therapy (ACTH or prednisolone) may be considered for use in preference to VGB in infants with cryptogenic infantile spasms, to possibly improve developmental outcome. A shorter lag time to treatment of infantile spasms with either hormonal therapy or VGB possibly improves long-term developmental outcomes.


Asunto(s)
Hormona Adrenocorticotrópica/uso terapéutico , Anticonvulsivantes/uso terapéutico , Espasmos Infantiles/tratamiento farmacológico , Vigabatrin/uso terapéutico , Hormona Adrenocorticotrópica/administración & dosificación , Anticonvulsivantes/administración & dosificación , Medicina Basada en la Evidencia , Humanos , Lactante , Resultado del Tratamiento , Vigabatrin/administración & dosificación
3.
J Environ Health ; 72(1): 24-8, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19681385

RESUMEN

Reducing occupant exposure to mold growing on damp gypsum wallboard and controlling mold contamination in the indoor environment was studied through 1) delineation of environmental conditions required to promote and avoid mold growth and 2) efficacy testing of antimicrobial products, specifically cleaners and paints, on gypsum wallboard (GWB) surfaces. The effects of moisture and relative humidity (RH) on mold growth and transport are important in avoiding and eliminating problems. These effects have been demonstrated on GWB and are discussed in this article for use as control guidance. The authors discuss the efficacy of antimicrobial cleaners and paints to remove, eliminate, or control mold growth on GWB. Research to control Stachybotrys chartarum growth using 13 separate antimicrobial cleaners and nine varieties of antimicrobial paint on contaminated GWB was performed in laboratory testing. GWB surfaces were subjected to high RH. GWB control measures are summarized and combined, and the antimicrobial product results are explained.


Asunto(s)
Antiinfecciosos , Sulfato de Calcio , Materiales de Construcción/microbiología , Detergentes , Micosis/prevención & control , Pintura , Stachybotrys/efectos de los fármacos , Humanos
4.
J Occup Environ Hyg ; 5(2): 63-6, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18041646

RESUMEN

The goal of this research was to reduce occupant exposure to indoor mold through the efficacy testing of antimicrobial paints. An accepted method for handling Stachybotrys chartarum-contaminated gypsum wallboard (GWB) is removal and replacement. This practice is also recommended for water-damaged or mold-contaminated GWB but is not always followed completely. The efficacy of antimicrobial paints to eliminate or control mold regrowth on surfaces can be tested easily on nonporous surfaces. The testing of antimicrobial efficacy on porous surfaces found in the indoor environment, such as gypsum wallboard, can be more complicated and prone to incorrect conclusions regarding residual organisms. The mold S. chartarum has been studied for toxin production and its occurrence in water-damaged buildings. Research to control its growth using seven different antimicrobial paints and two commonly used paints on contaminated, common gypsum wallboard was performed in laboratory testing at high relative humidity. The results indicate differences in antimicrobial efficacy for the period of testing, and that proper cleaning and resurfacing of GWB with an antimicrobial paint can be an option in those unique circumstances when removal may not be possible.


Asunto(s)
Contaminación del Aire Interior/prevención & control , Antifúngicos/farmacología , Sulfato de Calcio , Materiales de Construcción/microbiología , Pintura/normas , Stachybotrys/efectos de los fármacos , Microbiología Ambiental , Stachybotrys/crecimiento & desarrollo , Propiedades de Superficie
5.
J Mol Endocrinol ; 36(1): 163-74, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16461936

RESUMEN

Obesity is typically associated with resistance to leptin, yet the mechanism by which leptin signaling becomes impaired is poorly understood. Here we sought to determine if the development of obesity and leptin resistance correlates with increased expression of protein tyrosine phosphatase 1B (PTP1B) in peripheral tissues and whether over-expression of this phosphatase, specifically in liver, could alter the leptin-mediated effects on feeding and glucose metabolism. Obesity was induced in mice through a high-fat diet that resulted in hyperglycemia, hyperinsulinemia and hyperleptinemia. Resistance to leptin was confirmed as exogenous leptin administration reduced food intake in animals on low-fat, but not high-fat diets. Diet-induced resistance to leptin and insulin was associated with increased hepatic levels of PTP1B. Intriguingly, hepatic adenoviral over-expression of PTP1B in ob/ob mice attenuated the ability of exogenous leptin to reduce both plasma glucose levels and food intake. These findings suggest that leptin reduces both plasma glucose and food intake in part through actions on the liver, and hepatic leptin resistance resulting from over-expression of PTP1B may contribute to the development of both diabetes and obesity.


Asunto(s)
Leptina/fisiología , Hígado/enzimología , Proteínas Tirosina Fosfatasas/metabolismo , Adenoviridae/genética , Animales , Secuencia de Bases , Glucemia/análisis , Células CHO , Cricetinae , Cartilla de ADN , Grasas de la Dieta/administración & dosificación , Conducta Alimentaria , Vectores Genéticos , Hiperglucemia/etiología , Hiperinsulinismo/etiología , Leptina/sangre , Masculino , Ratones , Ratones Endogámicos BALB C , Reacción en Cadena de la Polimerasa , Proteína Tirosina Fosfatasa no Receptora Tipo 1
6.
Neurology ; 62(10): 1668-81, 2004 May 25.
Artículo en Inglés | MEDLINE | ID: mdl-15159460

RESUMEN

OBJECTIVE: To determine the current best practice for treatment of infantile spasms in children. METHODS: Database searches of MEDLINE from 1966 and EMBASE from 1980 and searches of reference lists of retrieved articles were performed. Inclusion criteria were the documented presence of infantile spasms and hypsarrhythmia. Outcome measures included complete cessation of spasms, resolution of hypsarrhythmia, relapse rate, developmental outcome, and presence or absence of epilepsy or an epileptiform EEG. One hundred fifty-nine articles were selected for detailed review. Recommendations were based on a four-tiered classification scheme. RESULTS: Adrenocorticotropic hormone (ACTH) is probably effective for the short-term treatment of infantile spasms, but there is insufficient evidence to recommend the optimum dosage and duration of treatment. There is insufficient evidence to determine whether oral corticosteroids are effective. Vigabatrin is possibly effective for the short-term treatment of infantile spasm and is possibly also effective for children with tuberous sclerosis. Concerns about retinal toxicity suggest that serial ophthalmologic screening is required in patients on vigabatrin; however, the data are insufficient to make recommendations regarding the frequency or type of screening. There is insufficient evidence to recommend any other treatment of infantile spasms. There is insufficient evidence to conclude that successful treatment of infantile spasms improves the long-term prognosis. CONCLUSIONS: ACTH is probably an effective agent in the short-term treatment of infantile spasms. Vigabatrin is possibly effective.


Asunto(s)
Anticonvulsivantes/uso terapéutico , Espasmos Infantiles/tratamiento farmacológico , Administración Oral , Corticoesteroides/administración & dosificación , Corticoesteroides/uso terapéutico , Hormona Adrenocorticotrópica/administración & dosificación , Hormona Adrenocorticotrópica/uso terapéutico , Preescolar , Quimioterapia Combinada , Medicina Basada en la Evidencia , Femenino , Estudios de Seguimiento , Predicción , Humanos , Lactante , Masculino , Nitrazepam/uso terapéutico , Estudios Prospectivos , Piridoxina/uso terapéutico , Ensayos Clínicos Controlados Aleatorios como Asunto , Estudios Retrospectivos , Resultado del Tratamiento , Ácido Valproico/uso terapéutico , Vigabatrin/uso terapéutico
7.
Proc Natl Acad Sci U S A ; 96(17): 9797-802, 1999 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-10449774

RESUMEN

To study molecular events involved in B lymphocyte development and V(D)J rearrangement, we have established an efficient system for the differentiation of embryonic stem (ES) cells into mature Ig-secreting B lymphocytes. Here, we show that B lineage cells generated in vitro from ES cells are functionally analogous to normal fetal liver-derived or bone marrow-derived B lineage cells at three important developmental stages: first, they respond to Flt-3 ligand during an early lymphopoietic progenitor stage; second, they become targets for Abelson murine leukemia virus (A-MuLV) infection at a pre-B cell stage; third, they secrete Ig upon stimulation with lipopolysaccharide at a mature mitogen-responsive stage. Moreover, the ES cell-derived A-MuLV-transformed pre-B (EAB) cells are phenotypically and functionally indistinguishable from standard A-MuLV-transformed pre-B cells derived from infection of mouse fetal liver or bone marrow. Notably, EAB cells possess functional V(D)J recombinase activity. In particular, the generation of A-MuLV transformants from ES cells will provide an advantageous system to investigate genetic modifications that will help to elucidate molecular mechanisms in V(D)J recombination and in A-MuLV-mediated transformation.


Asunto(s)
Linfocitos B/fisiología , Reordenamiento Génico de Linfocito B , Células Madre Hematopoyéticas/fisiología , Virus de la Leucemia Murina de Abelson , Animales , Diferenciación Celular/efectos de los fármacos , Técnicas de Cocultivo , Hematopoyesis , Células Madre Hematopoyéticas/efectos de los fármacos , Ligandos , Proteínas de la Membrana/farmacología , Ratones , Reacción en Cadena de la Polimerasa
8.
Exp Brain Res ; 124(3): 295-303, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9989435

RESUMEN

Previous work from this laboratory has demonstrated that monosynaptic inputs from the brachium of the inferior colliculus (BIC) to the medial subdivision of the medial geniculate nucleus (mMG) strengthen as a result of associative conditioning with an acoustic conditioned stimulus (i.e., fear conditioning). One model that has been proposed to underlie certain types of neuronal plasticity involves the recruitment of N-methyl-D-aspartic acid (NMDA)-type glutamate receptors. The purpose of the present study was to examine the relative contributions of glutamatergic NMDA and non-NMDA receptors to synaptic transmission within this pathway. Individual contributions of the specific receptor types were assessed through the use of 2-amino-5-phosphonovaleric acid (AP5), a selective NMDA receptor antagonist, and 6-cyano-5-nitroquinoxaline-2,3-dione (CNQX), a non-NMDA receptor antagonist. Bipolar stimulating electrodes were stereotaxically implanted in BIC and recording electrodes (attached to dual 32-gauge cannulae for delivery of drug) were positioned in mMG of New Zealand albino rabbits. Single pulses (150 micros, 100-350 microA) delivered to BIC resulted in short-latency (<4 ms) responses in mMG. BIC-evoked single-unit activity was recorded from mMG before, during, and at several intervals after injection of AP5, CNQX, and/or artificial cerebrospinal fluid (ACSF). Injection of either AP5 or CNQX, but not ACSF, significantly attenuated the short-latency BIC-evoked responses in the vast majority of cells tested. These findings suggest that the monosynaptic pathway from BIC to mMG is glutamatergic and that this pathway frequently employs NMDA-type receptors during electrically stimulated synaptic transmission. Due to the NMDA receptors' proposed role in plasticity (e.g., long-term potentiation), these results may have implications for understanding the mechanisms of synaptic plasticity observed at this synapse during associative learning.


Asunto(s)
Cuerpos Geniculados/fisiología , Colículos Inferiores/fisiología , Receptores de Aminoácidos/fisiología , Receptores de N-Metil-D-Aspartato/fisiología , Transmisión Sináptica/fisiología , 2-Amino-5-fosfonovalerato/farmacología , 6-Ciano 7-nitroquinoxalina 2,3-diona/farmacología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Estimulación Eléctrica , Antagonistas de Aminoácidos Excitadores/farmacología , Femenino , Colículos Inferiores/efectos de los fármacos , Inyecciones , Masculino , Conejos
10.
New Microbiol ; 16(2): 141-7, 1993 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-8510568

RESUMEN

We have shown by combining lipopolysaccharide (LPS) extracted and purified from Francisella tularensis live vaccine strain (LVS) with normal complement and back titrating with sensitised sheep red blood cells that the LPS activates complement. Deionising the LPS and converting it into the single salt forms of pyridine, ethanolamine and triethylamine altered the ability to activate complement according to the apparent molecular weight due to aggregation. Francisella tularensis LPS activated complement deficient in a component of the alternative pathway (factor B) but failed to activate complement deficient in a component of the classical pathway (C1q). In addition normal complement suspended in ethyleneglycol-bis-(beta-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA) which inactivates the classic pathway was not activated by LPS, and we concluded that the LPS activates complement predominantly via the classical pathway. LPS bound to specific monoclonal antibodies activated complement more than LPS alone. An anti-core monoclonal antibody was approximately tenfold more potent when bound to LPS then an anti-O side chain monoclonal antibody in activating complement.


Asunto(s)
Activación de Complemento/inmunología , Francisella tularensis/inmunología , Lipopolisacáridos/farmacología , Anticuerpos Antibacterianos/inmunología , Anticuerpos Monoclonales , Vía Alternativa del Complemento , Vía Clásica del Complemento , Lipopolisacáridos/inmunología
11.
Anal Biochem ; 203(1): 141-5, 1992 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-1524210

RESUMEN

A method for the partial restoration of the antibody binding capacity of Francisella tularensis lipopolysaccharide (LPS) following denaturation (dissociation) in boiling sodium dodecyl sulfate (SDS) is described. The method relies on the presence of a zwitterionic detergent in the matrix of an SDS-polyacrylamide gel and in the transfer buffer during an immunoblot. F. tularensis LPS, which had lost its earlier capacity to bind to a particular monoclonal antibody in the normal blot procedure, did bind following the addition of the zwitterionic detergent to the polyacrylamide gel and transfer buffer. A number of detergents were tested but most success in restoring antibody binding was achieved with Zwittergent 3-08. This simple modification to the immunoblot procedure proved helpful in identifying a monoclonal antibody specific to hot phenol-extracted F. tularensis LPS.


Asunto(s)
Detergentes , Francisella tularensis/inmunología , Immunoblotting , Lipopolisacáridos/inmunología , Compuestos de Amonio Cuaternario , Animales , Anticuerpos Antibacterianos/inmunología , Anticuerpos Monoclonales/inmunología , Reacciones Antígeno-Anticuerpo/efectos de los fármacos , Electroforesis en Gel de Poliacrilamida , Ensayo de Inmunoadsorción Enzimática , Lipopolisacáridos/química , Ratones , Ratones Endogámicos BALB C
12.
Biochim Biophys Acta ; 1105(2): 221-9, 1992 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-1375099

RESUMEN

Cells exposed to dextran (Dx)-rich bottom phase prior to cell partitioning in Dx-poly(ethylene glycol) (PEG) aqueous two-phase systems have lower partition ratios than cells exposed to PEG-rich top phase. Aspects of this previously observed phenomenon were explored. In the present work charge-sensitive phases made with Dx T500 and PEG 8000 were used exclusively. It was found that: (1) even on countercurrent distribution (CCD) red cells (RBC) loaded in bottom phase have a lower apparent partition ratio, G, than the same cells loaded in top phase; (2) when part of the same cell population is loaded into top phase and part into bottom phase of the same load cavities for CCD, with the cells loaded into top or bottom bearing an isotopic tracer (51Cr), the cells loaded into top phase have a higher G value than the cells loaded into bottom phase; (3) the shift in the CCD curves of human or of rat RBC between cells loaded in top or bottom phase using systems having the same polymer concentration (though different salt compositions) shows no striking difference and is, for the number of experiments run, not statistically significant; (4) when the quantity of cells loaded for CCD is reduced from 10(9) to 10(8), the G value of cells loaded in top phase is reduced slightly while that of cells loaded in bottom phase is diminished more appreciably; (5) increasing polymer concentrations yield larger differences in G values between (rat) RBC loaded in top or bottom phase; (6) when cells exposed to top or bottom phase, respectively, are centrifuged and suspended in bottom or top phase, respectively, their CCD patterns are qualitatively similar to cells exposed to these latter respective phases initially; (7) rat RBC populations containing 59Fe-labeled cells of different but distinct age are fractionated on CCD irrespective of whether loaded in top or bottom phase. An exception are populations containing very young mature labeled cells (e.g., 4-d old) which are resolved when loaded in top phase but not in bottom phase. Thus cell populations exist which can be resolved by CCD when loaded in one of the phases but not when loaded in the other. Glutaraldehyde-fixed rat RBC containing 4-d old labeled cells are fractionated by CCD irrespective of whether loaded in top or bottom phase.


Asunto(s)
Separación Celular , Dextranos/farmacología , Eritrocitos/efectos de los fármacos , Polietilenglicoles/farmacología , Animales , Cromo , Distribución en Contracorriente , Membrana Eritrocítica/efectos de los fármacos , Humanos , Masculino , Modelos Biológicos , Ratas , Ratas Endogámicas
13.
J Clin Microbiol ; 29(7): 1407-12, 1991 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-1885735

RESUMEN

Two monoclonal antibodies (FT14 and FT2F11) directed against the lipopolysaccharide (LPS) of Francisella tularensis were produced for use in tests to detect the organism in environmental samples and clinical specimens. The specificity of the antibodies was determined by enzyme-linked immunosorbent assay (ELISA) and immunoblotting. Both antibodies detected LPS from F. tularensis by ELISA, but only one antibody, FT14, was serologically active in an immunoblot. Treatment of the LPS with detergents prior to ELISA eliminated its binding to FT2F11 but not FT14. Qualitatively, both antibodies detected 10 different strains of F. tularensis by ELISA, but quantitatively, FT14 gave a detectable reaction with 10(3) organisms, whereas FT2F11 was able to detect only 10(5) organisms. FT14 did not cross-react with LPS from a range of other gram-negative species of bacteria, whereas FT2F11 cross-reacted against Vibrio cholerae LPS. Neither antibody showed cross-reactions when entire gram-negative organisms were used as antigens. In a competition ELISA, the two monoclonal antibodies were shown to compete for different epitopes. FT14 was strongly inhibited by purified O side chain from F. tularensis LPS, but FT2F11 was only weakly inhibited. It was inferred from those results that FT14 is directed against the O side chain and that FT2F11 is directed against the core.


Asunto(s)
Anticuerpos Monoclonales , Francisella tularensis/inmunología , Lipopolisacáridos/inmunología , Anticuerpos Antibacterianos , Especificidad de Anticuerpos , Antígenos Bacterianos , Reacciones Cruzadas , Ensayo de Inmunoadsorción Enzimática , Francisella tularensis/clasificación , Humanos , Immunoblotting , Tularemia/diagnóstico
14.
Mutat Res ; 230(1): 71-80, 1990 May.
Artículo en Inglés | MEDLINE | ID: mdl-2342499

RESUMEN

The ability of 1-methoxy-1,3,5-cycloheptatriene (MCHT) to induce gene mutations and chromosome breaks has been examined in a battery of standard assays. MCHT was not mutagenic to 5 strains of Salmonella, with or without S9 fraction. In L5178Y TK+/- mouse lymphoma cells, MCHT induced TK-/- mutants in the presence but not in the absence of S9 fraction. In V79 Chinese hamster cells, MCHT induced azaguanine-resistant mutants in the presence and absence of S9 but the effect was considerably reduced in the absence of S9. MCHT resulted in no increases in chromosome aberrations in cultured human lymphocytes, with or without S9 fraction, neither was there any increase in micro-nucleated polychromatic erythrocytes in treated mice. MCHT thus appears on the basis of these results, to be possibly a specific gene mutagen (rather than clastogen) for mammalian cells. This uncommon mutagenicity profile has been investigated further in an accompanying paper (Cole et al., 1990) and has proved to be an oversimplification.


Asunto(s)
Aberraciones Cromosómicas , Cicloheptanos/toxicidad , Mutágenos , Mutación , Animales , Azaguanina/farmacología , Células Cultivadas , Cromosomas , Cromosomas Humanos , Cricetinae , Resistencia a Medicamentos/genética , Genes , Humanos , Masculino , Ratones , Pruebas de Micronúcleos , Pruebas de Mutagenicidad , Células Tumorales Cultivadas , Xantina Oxidasa/metabolismo
15.
J Med Chem ; 32(3): 555-62, 1989 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-2918501

RESUMEN

Forty-two analogues and reaction products derived from T-2 toxin or neosolaniol were assayed for their cytotoxicity to cultured mouse lymphoma cells. Structure-activity relationships confirmed the stereospecific nature of the cytotoxic action of T-2. Cytotoxicity was particularly susceptible to changes at C3, C4, C9, and C10 but was relatively unaffected by changes at C8, which appears to represent a region of steric tolerance in the interaction of T-2 with a cellular constituent. The most potent compounds were T-2, diacetoxyscirpenol, and a series of C8 ester analogues 11 and 31-35.


Asunto(s)
Antineoplásicos/síntesis química , Sesquiterpenos/síntesis química , Tricotecenos/síntesis química , Animales , Antineoplásicos/uso terapéutico , Fenómenos Químicos , Química , Ensayos de Selección de Medicamentos Antitumorales , Linfoma/tratamiento farmacológico , Ratones , Relación Estructura-Actividad , Toxina T-2 , Tricotecenos/uso terapéutico , Células Tumorales Cultivadas
16.
Exp Cell Res ; 164(2): 366-78, 1986 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2423347

RESUMEN

When mixed in aqueous solution at low concentrations, the neutral polymers dextran and poly(ethylene glycol) (PEG) rapidly form a two-phase system, consisting of a dextran-enriched lower phase and a PEG-enriched upper phase. Two B16 mouse melanoma cell lines, B16-F1 (low lung colonizing capability) and B16-F10 (high lung colonizing capability) were found to partition differentially into the upper phase in a variety of two-phase systems. Upper-phase partition depends primarily on either hydrophilic (i.e., surface charge density) or hydrophobic (i.e., affinity for the hydrocarbon chain of a PEG-fatty acid ester) cell surface properties, depending on the system used. In single-step partition studies, cells of the B16-F10 subline displayed a greater preference than B16-F1 cells for the upper phase in the hydrophilic system and less preference in systems sensitive to hydrophobic properties. Countercurrent distribution (CCD) experiments, performed with [125I]deoxyuridine DNA-labelled cells, were consistent with single-step partition results. These CCD results demonstrated that B16-F10 cells exhibited greater DNA synthesis than B16-F1 cells and that considerable heterogeneity, in both hydrophobic and hydrophilic surface properties, was present in subpopulations of cells of both sublines. The data also showed considerable enrichment of 125I-specific cell activity in certain sections of the distributions, indicating that differences in cellular DNA synthesis are reflected in the surface properties to which partition is sensitive.


Asunto(s)
Separación Celular/métodos , Melanoma/patología , Animales , Línea Celular , Supervivencia Celular , Distribución en Contracorriente , Dextranos , Ratones , Metástasis de la Neoplasia , Polietilenglicoles , Propiedades de Superficie
17.
Biorheology ; 23(4): 311-30, 1986.
Artículo en Inglés | MEDLINE | ID: mdl-3779058

RESUMEN

The present study was undertaken with two objectives in view. The first was to distinguish between the "instantaneous" deformation and creep of articular cartilage when subjected to a step loading in unconfined compression. This was done by observing changes in the specimen's diameter rather than its thickness. The second objective was to investigate experimentally the anisotropic behaviour of cartilage in a compressive loading mode, corresponding to the physiological situation. An apparatus was thus developed and constructed which enabled us to follow the "instantaneous" changes of the surface area of the sample as the latter was being loaded in unconfined compression. Specimens of human articular cartilage from normal femoral heads and condyles were tested. Full thickness specimens were tested with and without the underlying bone, as well as partial thickness specimens, characterizing the different zones of cartilage. Solutions of different ionic strength were used to vary the osmotic stress and specimens covering a considerable range of proteoglycan concentrations were selected. The effects of hydration and proteoglycan removal on the "instantaneous" deformation were also studied. The "instantaneous" deformation was found to be of a strongly anisotropic nature in all zones. The deformation was always smaller along the Indian-ink prick pattern than at 90 degrees to it, and this effect was most pronounced in the superficial zone of cartilage. The results reveal an analogy with the tensile properties of cartilage and indicate that the collagen network is mainly responsible for controlling the "instantaneous" deformation. The proteoglycans play an indirect role by modulating the stiffness of the collagen network through their osmotic pressure.


Asunto(s)
Cartílago Articular/fisiología , Colágeno/fisiología , Anciano , Agua Corporal/análisis , Huesos/fisiología , Cartílago Articular/análisis , Cartílago Articular/anatomía & histología , Humanos , Persona de Mediana Edad , Concentración Osmolar , Presión Osmótica , Presión
18.
Toxicol Lett ; 16(1-2): 85-8, 1983 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-6836618

RESUMEN

The mutagenic activity of a cyanide antidote, dimethylaminophenol (DMAP), has been studied at the hypoxanthine-guanine-phosphoribosyltransferase (HPRT) locus in a line of Chinese hamster cells (V79), using induced resistance to 8-azaguanine as a marker for forward, point mutation. In a replating type of assay DMAP produced a dose-dependent increase in mutation frequency in suspension-treated cells, in the absence of any extrinsic metabolic activation system. The incorporation of a liver microsome preparation raised the concentration of DMAP required to induce mutation, but similar levels of induced mutation frequency (IMF) were produced.


Asunto(s)
Aminofenoles/toxicidad , Mutágenos , Animales , Azaguanina/farmacología , Supervivencia Celular/efectos de los fármacos , Cricetinae , Cricetulus , Técnicas In Vitro , Pruebas de Mutagenicidad , Ratas
20.
J Immunol ; 123(4): 1687-95, 1979 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-314469

RESUMEN

Partitioning of cells in dextran-poly(ethylene glycol) aqueous-aqueous two-phase systems is a sensitive method for separating cells and for obtaining information on their surface properties. Highly purified lymphocytes were obtained by velocity sedimentation of human peripheral blood mononuclear cells and fractionated by countercurrent distribution (CCD, a multiple-step extraction procedure) in a charged two-polymer aqueous phase system. The lymphocytes remained viable after separation (order of 90%) and the E-rosetting cells responded (after adding back monocytes) to mitogens (PHA, Con A, PWM). Not only was the total lymphocyte population found to be highly heterogeneous (as evidenced by a broad and skewed distribution curve), but we were able to show that cells that rosetted with E, or had complement or Fc receptors were composed of additional subpopulations as well. The bulk of complement-receptor-bearing cells had the lowest partition coefficient (K), E-rosetting cells an intermediate K, and Fc-receptor-containing cells the highest K. The largest lymphocytes were among the subpopulation having the highest K and neither responded to T cell mitogens nor rosetted with E. Our results thus demonstrate that human peripheral blood lymphocytes can be subfractionated by CCD. The fractions are differentially enriched with lymphocyte subpopulations having characteristic surface markers and functional abilities.


Asunto(s)
Linfocitos/clasificación , Animales , Membrana Celular/inmunología , Separación Celular , Supervivencia Celular , Distribución en Contracorriente , Dextranos/farmacología , Humanos , Monocitos , Polietilenglicoles/farmacología , Conejos , Formación de Roseta , Ovinos , Linfocitos T
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