Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
1.
Pharmacol Biochem Behav ; 233: 173661, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37879445

RESUMEN

This study aimed to evaluate the effects of sertraline associated with gold nanoparticles (AuNPs) in vitro cell viability and in vivo behavior and inflammatory biomarkers in a mouse model of anxiety. Sertraline associated with AuNPs were synthesized and characterized. For the in vitro study, NIH3T3 and HT-22 cells were treated with different doses of sertraline, AuNPs, and sertraline + AuNPs and their viability was evaluated using the MTT assay. For the in vivo study, pregnant Swiss mice were administered a single dose of lipopolysaccharide (LPS) on the ninth day of gestation. The female and male offspring were divided into five treatment groups on PND 60 and administered chronic treatment for 28 days. The animals were subjected to behavioral testing and were subsequently euthanized. Their brains were collected and analyzed for inflammatory biomarkers. Sertraline associated with AuNPs exhibited significant changes in surface characteristics and increased diameters. Different doses of sertraline + AuNPs showed higher cell viability in NIH3T3 and HT-22 cells compared with sertraline alone. The offspring of LPS-treated dams exhibited anxiety-like behavior and neuroinflammatory biomarker changes during adulthood, which were ameliorated via sertraline + AuNPs treatment. The treatment response was sex-dependent and brain region-specific. These results suggest that AuNPs, which demonstrate potential to bind to other molecules, low toxicity, and reduced inflammation, can be synergistically used with sertraline to improve drug efficacy and safety by decreasing neuroinflammation and sertraline toxicity.


Asunto(s)
Oro , Nanopartículas del Metal , Animales , Ratones , Embarazo , Masculino , Femenino , Oro/metabolismo , Sertralina/farmacología , Enfermedades Neuroinflamatorias , Lipopolisacáridos/farmacología , Células 3T3 NIH , Ansiedad/tratamiento farmacológico
2.
Cell Mol Life Sci ; 79(8): 418, 2022 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-35819535

RESUMEN

Magnesium (Mg2+) is the most prevalent divalent intracellular cation. As co-factor in many enzymatic reactions, Mg2+ is essential for protein synthesis, energy production, and DNA stability. Disturbances in intracellular Mg2+ concentrations, therefore, unequivocally result in delayed cell growth and metabolic defects. To maintain physiological Mg2+ levels, all organisms rely on balanced Mg2+ influx and efflux via Mg2+ channels and transporters. This review compares the structure and the function of prokaryotic Mg2+ transporters and their eukaryotic counterparts. In prokaryotes, cellular Mg2+ homeostasis is orchestrated via the CorA, MgtA/B, MgtE, and CorB/C Mg2+ transporters. For CorA, MgtE, and CorB/C, the motifs that form the selectivity pore are conserved during evolution. These findings suggest that CNNM proteins, the vertebrate orthologues of CorB/C, also have Mg2+ transport capacity. Whereas CorA and CorB/C proteins share the gross quaternary structure and functional properties with their respective orthologues, the MgtE channel only shares the selectivity pore with SLC41 Na+/Mg2+ transporters. In eukaryotes, TRPM6 and TRPM7 Mg2+ channels provide an additional Mg2+ transport mechanism, consisting of a fusion of channel with a kinase. The unique features these TRP channels allow the integration of hormonal, cellular, and transcriptional regulatory pathways that determine their Mg2+ transport capacity. Our review demonstrates that understanding the structure and function of prokaryotic magnesiotropic proteins aids in our basic understanding of Mg2+ transport.


Asunto(s)
Magnesio , Proteínas de Transporte de Membrana , Transporte Biológico , Cationes Bivalentes/metabolismo , Magnesio/metabolismo , Proteínas de Transporte de Membrana/metabolismo , Fosfotransferasas/metabolismo
3.
J Helminthol ; 95: e11, 2021 Mar 02.
Artículo en Inglés | MEDLINE | ID: mdl-33650475

RESUMEN

Probiotics have been shown to reduce the intensity of Toxocara canis infection in mice. However, larval transmission of this nematode also occurs via transplacental and transmammary routes. Thus, the aim of this study was to evaluate the effect of the Saccharomyces boulardii probiotic on the vertical transmission of T. canis in Swiss mice. The mice received 107S. boulardii colony-forming units per gram of food. The supplementation began 15 days before mating and was maintained throughout pregnancy and lactation. The animals were inoculated with 300 T. canis embryonated eggs on the 14th day of pregnancy. The presence of larvae was examined in the organs of the females and their offspring. The examined organs included the following: brain, liver, lungs, heart, kidneys, spleen, eye, skeletal muscle (carcass) and mammary glands of lactating females. There was a 42% (P = 0.041) reduction in the number of larvae transmitted to offspring in the group that received probiotic-supplemented food (GI). Additionally, there was a 50% reduction (P = 0.023) in the number of larvae found in the brains of lactating offspring in the GI group. These results reveal the potential of S. boulardii probiotic use as an auxiliary method of controlling visceral toxocariasis.


Asunto(s)
Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Saccharomyces boulardii , Toxocara canis , Toxocariasis , Animales , Femenino , Lactancia , Larva , Ratones , Embarazo , Probióticos , Toxocariasis/microbiología , Toxocariasis/transmisión
4.
Hum Exp Toxicol ; 36(3): 302-310, 2017 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27198677

RESUMEN

The use of anabolic androgenic steroids (AAS) has grown among practitioners of recreational bodybuilding, with significant contributions of designer steroids, aiming muscle hypertrophy in healthy subjects. The abusive use of AAS in general is associated with adverse effects; one of the most worrisome is cancer development. The aim of this study was to evaluate the effectiveness of the cytokinesis block micronucleus (CBMN) test in human lymphocytes in identifying risk groups for cancer development in users of AAS. Blood was collected from 15 AAS users bodybuilders (G1), 20 non-users bodybuilders (G2) and 20 non-users sedentary (G3). MN analysis was performed on a minimum of 1000 binucleated lymphocytes. The occurrence of MN was significantly higher ( p < 0.05) in individuals of G1 compared to G2 and G3. The results indicate the sensitivity of CBMN in human lymphocytes in the identification of chromosomal damage in consequence of AAS.


Asunto(s)
Anabolizantes/efectos adversos , Pruebas de Micronúcleos , Neoplasias/inducido químicamente , Esteroides/efectos adversos , Levantamiento de Peso , Adulto , Brasil , Humanos , Masculino , Factores de Riesgo , Adulto Joven
5.
Parasitology ; 143(4): 507-17, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-26887285

RESUMEN

Human toxocarosis is a chronic tissue parasitosis most often caused by Toxocara canis. The seroprevalence can reach up to 50%, especially among children and adolescents. The anthelmintics used in the treatment have moderate efficacy. The aim of this study was to evaluate the in vitro and in vivo anthelmintic activity of quinones and their derivatives against T. canis larvae and the cytotoxicity of the larvicidal compounds. The compounds were evaluated at 1 mg mL(-1) concentration in microculture plates containing third stage larvae in an Roswell Park Memorial Institute (RPMI) 1640 environment, incubated at 37 °C in 5% CO2 tension for 48 h. Five naphthoxiranes were selected for the cytotoxicity analysis. The cell viability evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays using murine peritoneal macrophages isolated from C57BL/6 mice revealed that the naphthoxiranes (1 and 3) were less cytotoxic at a concentration of 0.05 mg mL(-1). The efficacy of naphthoxiranes (1 and 3) was examined in murine toxocarosis also. The anthelmintic activity was examined by evaluating the number of larvae in the brain, carcass, liver, lungs, heart, kidneys and eyes. Compound (3) demonstrated anthelmintic activity similar to that of albendazole by decreasing the number of larvae in the organs of mice and thus could form the basis of the development of a new anthelmintic drug.


Asunto(s)
Antihelmínticos/farmacología , Quinonas/farmacología , Toxocara canis/efectos de los fármacos , Toxocariasis/tratamiento farmacológico , Albendazol/farmacología , Albendazol/uso terapéutico , Animales , Antihelmínticos/química , Antihelmínticos/uso terapéutico , Antihelmínticos/toxicidad , Femenino , Larva/efectos de los fármacos , Macrófagos Peritoneales/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Quinonas/química , Quinonas/uso terapéutico , Quinonas/toxicidad , Toxocariasis/parasitología
6.
Arq. bras. med. vet. zootec ; Arq. bras. med. vet. zootec. (Online);67(3): 723-726, May-Jun/2015. graf
Artículo en Inglés | LILACS | ID: lil-753908

RESUMEN

During a research visit for tissue collection at an abattoir located in Pelotas, Brazil, one female genital tract showed both enlarged oviducts. The reproductive tract was collected and analyzed. Occluded uterine tubes and an increase in the organ volume due to the large amount of fluid in the organ lumen were the macroscopic findings. Three samples, corresponding to isthmus, ampulla and infundibulum from each uterine tube and one sample from the endometrium were collected. Samples were fixed in Bouin's solution and processed in light microscopy. Microscopically a decrease in the number of folds and also an increase in the lumen of the organ were observed, mainly in the ampulla and infundibulum. The epithelial lining of the uterine tubes ranged from ciliated to simple squamous. Inflammatory cells were observed between the epithelial cells and in the lamina propria. Hydrosalpinx is difficult to diagnose and can be a cause of infertility in the mare.


Durante uma visita de pesquisa para coleta de tecido em um abatedouro localizado na cidade de Pelotas, Brasil, foi observado um trato genital com aumento do tamanho dos ovidutos. O trato reprodutivo foi coletado e analisado. Os achados macroscópicos observados foram tubas uterinas ocluídas e com aumento do volume do órgão devido à grande quantidade de líquido na luz do órgão. Três amostras, correspondendo a istmo, ampola e infundíbulo, e uma amostra do endométrio foram coletadas. As amostras foram fixadas em solução de Bouin e processadas para microscopia de luz. Microscopicamente foi observada uma diminuição no número de pregas e um aumento do lúmen do órgão, principalmente na ampola e no infundíbulo. O epitélio de revestimento das tubas uterinas variou de cilíndrico ciliado a pavimentoso simples. Células inflamatórias foram observadas entre as células epiteliais e na lâmina própria das tubas uterinas. A hidrossalpinge é difícil de ser diagnosticada e pode ser uma causa de infertilidade na égua.


Asunto(s)
Animales , Femenino , Caballos/anatomía & histología , Enfermedades de las Trompas Uterinas/veterinaria , Enfermedades Urogenitales Femeninas/veterinaria , Microscopía/veterinaria
7.
Gene Ther ; 10(13): 1067-78, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12808437

RESUMEN

Combined injections into experimental tumor nodules of adenovirus encoding IL-12 and certain chemokines are capable to induce immune-mediated complete regressions. In this study, we found that the combination of two adenoviruses, one encoding IL-12 and other MIP3alpha (AdCMVIL-12+AdCMVMIP3alpha) was very successful in treating CT-26-derived colon carcinomas. However, in experimental tumors generated from the pancreatic carcinoma cell line Panc02 such combined treatment induces 50% of macroscopic complete regressions, although local relapses within 1 week are almost constant. We derived cell lines from such relapsing tumors and found that experimental malignancies derived from their inoculum were not amenable to treatment in any case with AdCMVIL-12+AdCMVMIP-3alpha. Importantly, relapsing cell lines were insensitive to in vitro induction of apoptosis by IFNgamma, in clear contrast with the original Panc02 cells. Comparative analyses by cDNA arrays of relapsing cell lines versus wild-type Panc02 were performed revealing an important number of genes (383) whose expression levels were modified more than two-fold. These changes grouped in certain gene ontology categories should harbor the mechanistic explanations of the acquired selective resistance to IFNgamma.


Asunto(s)
Terapia Genética/métodos , Neoplasias Pancreáticas/terapia , Receptores de Quimiocina , Escape del Tumor/genética , Adenoviridae/genética , Animales , Apoptosis , Quimiocina CCL20 , Quimiocinas CC/genética , Neoplasias del Colon/terapia , Femenino , Vectores Genéticos/administración & dosificación , Inmunoterapia/métodos , Interferón gamma/uso terapéutico , Interleucina-12/genética , Proteínas Inflamatorias de Macrófagos/genética , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neoplasias Experimentales/genética , Neoplasias Experimentales/inmunología , Neoplasias Experimentales/terapia , Análisis de Secuencia por Matrices de Oligonucleótidos , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/inmunología , Receptores CCR6 , Receptores de Interferón/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción Genética , Células Tumorales Cultivadas
8.
Alcohol ; 27(3): 163-7, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12163144

RESUMEN

Dietary methionine is mainly metabolized in the liver where it is converted into S-adenosylmethionine (AdoMet), the main biologic methyl donor. This reaction is catalyzed by methionine adenosyltransferase I/III (MAT I/III), the product of MAT1A gene, which is exclusively expressed in this organ. It was first observed that serum methionine levels were elevated in experimental models of liver damage and in liver cirrhosis in human beings. Results of further studies showed that this pathological alteration was due to reduced MAT1A gene expression and MAT I/III enzyme inactivation associated with liver injury. Synthesis of AdoMet is essential to all cells in the organism, but it is in the liver where most of the methylation reactions take place. The central role played by AdoMet in cellular function, together with the observation that AdoMet administration reduces liver damage caused by different agents and improves survival of alcohol-dependent patients with cirrhosis, led us to propose that alterations in methionine metabolism could play a role in the onset of liver disease and not just be a consequence of it. In the present work, we review the recent findings that support this hypothesis and highlight the mechanisms behind the hepatoprotective role of AdoMet.


Asunto(s)
Hígado/fisiología , S-Adenosilmetionina/fisiología , Animales , Humanos , Hepatopatías Alcohólicas/tratamiento farmacológico , Hepatopatías Alcohólicas/fisiopatología , S-Adenosilmetionina/uso terapéutico
10.
J Exp Med ; 190(9): 1329-42, 1999 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-10544204

RESUMEN

The Wiskott-Aldrich syndrome protein (WASp) has been implicated in modulation of lymphocyte activation and cytoskeletal reorganization. To address the mechanisms whereby WASp subserves such functions, we have examined WASp roles in lymphocyte development and activation using mice carrying a WAS null allele (WAS(-)(/)(-)). Enumeration of hemopoietic cells in these animals revealed total numbers of thymocytes, peripheral B and T lymphocytes, and platelets to be significantly diminished relative to wild-type mice. In the thymus, this abnormality was associated with impaired progression from the CD44(-)CD25(+) to the CD44(-)CD25(-) stage of differentiation. WASp-deficient thymocytes and T cells also exhibited impaired proliferation and interleukin (IL)-2 production in response to T cell antigen receptor (TCR) stimulation, but proliferated normally in response to phorbol ester/ionomycin. This defect in TCR signaling was associated with a reduction in TCR-evoked upregulation of the early activation marker CD69 and in TCR-triggered apoptosis. While induction of TCR-zeta, ZAP70, and total protein tyrosine phosphorylation as well as mitogen-activated protein kinase (MAPK) and stress-activated protein/c-Jun NH(2)-terminal kinase (SAPK/JNK) activation appeared normal in TCR-stimulated WAS(-)(/)(-) cells, TCR-evoked increases in intracellular calcium concentration were decreased in WASp-deficient relative to wild-type cells. WAS(-)(/)(-) lymphocytes also manifested a marked reduction in actin polymerization and both antigen receptor capping and endocytosis after TCR stimulation, whereas WAS(-)(/)(-) neutrophils exhibited reduced phagocytic activity. Together, these results provide evidence of roles for WASp in driving lymphocyte development, as well as in the translation of antigen receptor stimulation to proliferative or apoptotic responses, cytokine production, and cytoskeletal rearrangement. The data also reveal a role for WASp in modulating endocytosis and phagocytosis and, accordingly, suggest that the immune deficit conferred by WASp deficiency reflects the disruption of a broad range of cellular behaviors.


Asunto(s)
Activación de Linfocitos/inmunología , Proteínas/genética , Síndrome de Wiskott-Aldrich/inmunología , Actinas/metabolismo , Animales , Linfocitos B/inmunología , Complejo CD3/inmunología , Recuento de Células , Diferenciación Celular , Citoesqueleto/metabolismo , Marcación de Gen , Recubrimiento Inmunológico , Interleucina-2/metabolismo , Ganglios Linfáticos/inmunología , Ratones , Ratones Noqueados , Neutrófilos/inmunología , Fagocitosis/inmunología , Proteínas/inmunología , Receptores de Antígenos de Linfocitos T/metabolismo , Transducción de Señal/inmunología , Bazo/inmunología , Linfocitos T/inmunología , Síndrome de Wiskott-Aldrich/genética , Proteína del Síndrome de Wiskott-Aldrich
11.
FEBS Lett ; 445(2-3): 375-83, 1999 Feb 26.
Artículo en Inglés | MEDLINE | ID: mdl-10094493

RESUMEN

The glycosyl hydrolases are an important group of enzymes that are responsible for cleaving a range of biologically significant carbohydrate compounds. Structural information on these enzymes has provided useful information on their molecular basis for the functional variations, while the characterization of the structural features that account for the high thermostability of proteins is of great scientific and biotechnological interest. To these ends we have determined the crystal structure of the beta-glycosidase from a hyperthermophilic archeon Thermosphaera aggregans. The structure is a (beta/alpha)8 barrel (TIM-barrel), as seen in other glycosyl hydrolase family 1 members, and forms a tetramer. Inspection of the active site and the surrounding area reveals two catalytic glutamate residues consistent with the retaining mechanism and the surrounding polar and aromatic residues consistent with a monosaccharide binding site. Comparison of this structure with its mesophilic counterparts implicates a variety of structural features that could contribute to the thermostability. These include an increased number of surface ion pairs, an increased number of internal water molecules and a decreased surface area upon forming an oligomeric quaternary structure.


Asunto(s)
Desulfurococcaceae/enzimología , Glicósido Hidrolasas/química , Conformación Proteica , Secuencia de Aminoácidos , Secuencia de Bases , Sitios de Unión , Catálisis , Cristalografía por Rayos X , ADN Complementario , Estabilidad de Enzimas , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Relación Estructura-Actividad
12.
J Endod ; 25(9): 627-8, 1999 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10687544

RESUMEN

The microscope may be useful in retreatment to enhance removal of gutta-percha (GP) and to identify deficiencies in the original treatment. This study compared the effectiveness of GP removal with and without a microscope. Forty-five extracted canines were stepback prepared and obturated with GP and Roth's sealer using lateral condensation. Teeth were stored for 17 months in a humidor, then divided into four groups: group 1 (n = 20)--GP removal without aid of the microscope (group 1 criteria for GP removal was lack of GP on final files and on paper points agitated within the chloroform-filled canal); group 2 (n = 20)--GP removal with the microscope. (In addition to group 1 criteria, canals were inspected with the microscope; additional GP was removed when identified. In both groups, GP was removed using a combination of mechanical instrumentation, chloroform solvent, and K-files); group 3 (n = 3)--positive control, canals remained obturated; and group 4 (n = 2)--negative control, canals were neither prepared nor obturated. Teeth were split longitudinally, photographed, then divided into thirds to compare the apical, middle, and cervical thirds. Remnants of GP and sealer on the canal wall were traced with a digitizer, and the remaining mean % GP was analyzed by t test. Group 1 had 8.3% remaining GP, and group 2 had 7.3% remaining GP. There was no significant difference demonstrated between the two experimental groups.


Asunto(s)
Remoción de Dispositivos , Tratamiento del Conducto Radicular/métodos , Gutapercha , Humanos , Microscopía/estadística & datos numéricos , Distribución Aleatoria , Retratamiento , Materiales de Obturación del Conducto Radicular , Cemento de Óxido de Zinc-Eugenol
13.
Artículo en Inglés | MEDLINE | ID: mdl-9798233

RESUMEN

A maxillary permanent central incisor with a history of trauma, apexification, and internal thermocatalytic bleaching sustained a horizontal fracture at the cementoenamel junction, which necessitated extraction of the tooth. After removal, the root apex was examined histologically and by scanning electron microscopy. An apexification "cap" with unusual anatomic character and structure was observed.


Asunto(s)
Ápice del Diente/fisiología , Fracturas de los Dientes/fisiopatología , Raíz del Diente/lesiones , Adulto , Calcificación Fisiológica , Femenino , Humanos , Incisivo/lesiones , Maxilar , Microscopía Electrónica de Rastreo , Ápice del Diente/ultraestructura
14.
J Gerontol B Psychol Sci Soc Sci ; 53(4): P263-72, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9679518

RESUMEN

Young and elderly subjects yielded forced-choice detection thresholds in each of seven sensory tasks: (1) taste of sodium chloride, (2) smell of butanol, (3) cooling, (4) low-frequency vibrotaction, (5) high-frequency vibrotaction, (6) low-frequency hearing, and (7) high-frequency hearing. Average scores across these tasks nearly perfectly separated the 22 elderly from the 15 young subjects. For individual modalities, however, separation between the groups varied from complete (high-frequency touch) to negligible (low-frequency hearing). Scores on the Boston Picture Naming Test and especially the Wechsler Logical Memory Test correlated strongly with average threshold score (Pearson r = .80) and moderately with scores on individual modalities. This sensory-cognitive link is not caused, as might be supposed, by diminishing age-related capacity to handle the detection task, because the very same task resulted in negligible age effect (low-frequency hearing) and large effect (high-frequency hearing) in the same subjects.


Asunto(s)
Envejecimiento/psicología , Umbral Sensorial , Adolescente , Adulto , Anciano , Umbral Auditivo , Cognición , Femenino , Humanos , Masculino , Pruebas Neuropsicológicas , Discriminación de la Altura Tonal , Valores de Referencia , Olfato , Umbral Gustativo , Sensación Térmica , Tacto , Vibración
15.
Eur J Cell Biol ; 74(2): 172-80, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9352222

RESUMEN

An astrocytoma cell line (HTB-14), expressing high amounts of a CD44 variant compared to other astrocytoma lines was shown to bind myelin basic protein to a greater extent than low expressing lines in a concentration-dependent manner. The CD44 variant expressed by HTB-14 cells was determined to migrate in sodium dodecyl sulfate polyacrylamide gel electrophoresis with a molecular mass of 100 kDa compared to that from white matter which had a molecular mass of 80 kDa. The most cationic component of myelin basic protein (MBP), (component 1) bound more avidly than the least cationic isomer (component 8). Internalization of MBP was demonstrated by immunogold electron microscopy and was localized to the perinuclear area with some gold particles in the cytoplasm but not near the plasma membrane. Colocalization with glial fibrillary acid protein suggested an interaction between these two molecules. Binding and internalization of MBP was accompanied by an increase in CD44 as determined by quantitation of gold particles and the measurement of CD44 by sandwich enzyme-linked immunosorbent assay. The implication of these studies for the mechanism of demyelination is discussed.


Asunto(s)
Receptores de Hialuranos/biosíntesis , Proteína Básica de Mielina/metabolismo , Astrocitoma/inmunología , Humanos , Receptores de Hialuranos/aislamiento & purificación , Inmunohistoquímica , Microscopía Electrónica , Unión Proteica/fisiología , Células Tumorales Cultivadas
16.
J Contin Educ Nurs ; 27(2): 85-8, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8698932

RESUMEN

Staff nurses experience time demands that frequently prevent them from attending inservice offerings. The 12 1/2 minute learning session is an innovative approach designed to meet the learning needs of the psychiatric nursing staff in spite of time constraints. The guiding principles for these sessions are: 1) "We learn what we care about," 2) preparation for sessions conveys commitment, and 3) accountability for learning is the individual's responsibility but opportunities for learning are shared. Identified outcomes of these groups are the "earthquake effect" or the shifting of one's footing; opportunity for effective debunking or uncovering of habitual patterns; and "bushfire effect" or contagiousness of enthusiasm.


Asunto(s)
Educación Continua en Enfermería/métodos , Enfermería Psiquiátrica/educación , Enseñanza/métodos , Humanos , Aprendizaje , Factores de Tiempo
17.
Somatosens Mot Res ; 13(1): 1-10, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8725644

RESUMEN

Spatial acuity of touch, like that of vision, tends to decline eventually in nearly everybody's lifetime. This has been revealed by more thorough than customary testing of individual young and elderly subjects. Three kinds of acuity threshold were assessed repeatedly in the index finger. These measured ability to discriminate tactile (1) gaps (by a refined version of two-point threshold), (2) orientation of lines (across vs. along the finger), and (3) length of lines. These acuities relate to prominent discriminatory features of braille, and have been shown earlier to average about 1% larger per annum over the adult life span from about 20 to 80 years. Although there were reliable differences among the elderly subjects in the present experiment, all of them tested consistently worse than the least acute young adult controls. The customary single brief threshold tests heretofore applied are inadequate to capture this ubiquitous but differential individual deficit in advanced age; however, the average of six 15- to 20-min tests spread over 3 days proved more than adequate. The method of repeated threshold testing--applied earlier to olfactory and gustatory sensitivity, and now to tactile acuity--serves to dispel the notion that incidence of sensory loss with aging is highly idiosyncratic.


Asunto(s)
Envejecimiento/psicología , Aprendizaje Discriminativo , Orientación , Umbral Sensorial , Tacto , Adulto , Anciano , Anciano de 80 o más Años , Atención , Femenino , Humanos , Masculino , Persona de Mediana Edad , Psicofísica , Valores de Referencia , Sacarosa , Umbral Gustativo
18.
Chem Senses ; 20(4): 451-9, 1995 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8590030

RESUMEN

Contrary to what has often been said about the subject, decline in taste sensitivity with aging characterizes virtually everybody and is not the artificial result of averaging large losses of a minority with negligible losses of a majority. This assertion is supported by six repeated measures of sucrose thresholds in each of 15 older (over 64 years) and 15 younger (under 27 years) adult subjects. Threshold was determined by a procedure similar to past studies and with the same results: much scatter and considerable overlap between the thresholds of younger and older subjects. A quite contrasting picture emerges, however, when each subject's six threshold determinations are averaged. Averaging shrinks the individual differences among subjects, as well as the over-lap between younger and older subjects. Although virtually all elderly subjects now revealed taste weakness, reliable individual differences in degree of weakness abound among them, suggesting various individual rates of physiological aging. In contrast, young persons exhibit greater uniformity of sensitivity. These findings were brought out by inter-test correlations, which were much higher for the older subjects; i.e. an older subject who tended to score high (low) on one test tended to score high (low) on the other tests. The study confirms the tenuous nature of brief threshold tests as indices of personal sensitivity as found earlier also in olfactory thresholds and in concurrent measurement of two-point touch thresholds in the present study. This revealed correlated losses between repeated taste and touch thresholds from the same 15 older subjects, unrelated to their exact chronological age.


Asunto(s)
Envejecimiento/fisiología , Umbral Gustativo/fisiología , Adulto , Anciano , Anciano de 80 o más Años , Aprendizaje Discriminativo , Humanos , Incidencia , Individualidad , Sensibilidad y Especificidad , Umbral Sensorial/fisiología , Trastornos del Gusto/epidemiología , Trastornos del Gusto/etiología , Tacto/fisiología
19.
J Parenter Sci Technol ; 47(4): 172-6, 1993.
Artículo en Inglés | MEDLINE | ID: mdl-8410563

RESUMEN

An accumulation model for predicting the equilibrium solution concentration of leachables migrating from polymeric containers has been applied to the leaching of several solutes from a blend of a styrene-butadiene-styrene block co-polymer and polypropylene. The model considers three accumulation-limiting mechanisms: total available pool, solute solubility and solute partitioning. Equations relating a solute's solvent-water partition coefficients (Po/w and Ph/w) and its polymer partitioning properties have been developed. With these equations, one can predict leachable accumulation from the container weight, solution volume and the solute's partition coefficients. The maximal accumulation of the leachable in solution will be the lowest value predicted via the three accumulation-limiting mechanisms.


Asunto(s)
Polímeros , Soluciones , Caproatos , Formas de Dosificación , Concentración de Iones de Hidrógeno , Modelos Químicos , Solubilidad
20.
Cell Adhes Commun ; 1(1): 9-20, 1993 May.
Artículo en Inglés | MEDLINE | ID: mdl-7521750

RESUMEN

We have isolated and characterized an antigen from normal human brain called p80, so called because it migrated with an M(r) of 80 kDa on SDS PAGE. The M(r) of 80 kDa consists of a protein of about 55-60 kDa and carbohydrate (20-25 kDa). The carbohydrate is almost entirely of the N-linked type, although a small amount of O-linked carbohydrate was detected. Cross-reactivity with monoclonal antibodies A3D8 and A1G3 showed that p80 could therefore be considered an isoform of the CD44 adhesion molecules. In addition, specific binding to hyaluronate which was not competed for by proteoglycan demonstrated that it involved different sites than the proteoglycan binding sites. We also observed that fucoidan and dextran sulphate increased the binding by 200-250% while chondroitin sulphate C also increased the binding but to a lesser extent. Heparin, heparan sulphate and chondroitin sulphates A and B did not have such an effect. The binding of p80 to hyaluronate was pH dependent with a maximum at pH 6.4. We concluded that p80 was an astrocyte specific adhesion molecule.


Asunto(s)
Astrocitos/metabolismo , Proteínas Portadoras/metabolismo , Ácido Hialurónico/metabolismo , Receptores de Superficie Celular/metabolismo , Receptores Mensajeros de Linfocitos/metabolismo , Encéfalo/metabolismo , Proteínas Portadoras/química , Proteínas Portadoras/inmunología , Moléculas de Adhesión Celular/metabolismo , Humanos , Receptores de Hialuranos , Inmunoquímica , Técnicas In Vitro , Peso Molecular , Esclerosis Múltiple/metabolismo , Oligosacáridos/química , Oligosacáridos/aislamiento & purificación , Unión Proteica , Receptores de Superficie Celular/química , Receptores de Superficie Celular/inmunología , Receptores Mensajeros de Linfocitos/química , Receptores Mensajeros de Linfocitos/inmunología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA