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1.
Colloids Surf B Biointerfaces ; 102: 218-26, 2013 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-23006564

RESUMEN

A low-cost biosorbent hybrid material ready for application was obtained in this work. Yerba mate (Ilex paraguariensis) milling residual dust was used as a polyphenol source by ethanolic extraction. Polyphenols were immobilized within a SiO(2) matrix to form an interpenetrated polymer after glutaraldehyde cross-linking. Pb(II), Cr(III) and Cr(VI) were chosen as model metals for adsorption. The hybrid materials were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and Nitrogen Adsorption Isotherms. Adsorption experimental data were analysed using Langmuir, Freundlich, Dubinin-Radushkevich, Temkin, Redlich-Peterson, Sips and Toth isotherm models along with the evaluation of adsorption energy and standard free energy (ΔG°). The adsorption was observed to be pH dependent. The main mechanism of metal adsorption was found to be a spontaneous charge associated interaction. Electron Spin Resonance (ESR) spectroscopy confirmed that Cr(VI) adsorption was an adsorption-coupled reaction and the adsorbed specie was Cr(V). The hybrid matrix probed its adsorption capacity of Cr(III) in a non-treated tannery wastewater.


Asunto(s)
Ilex paraguariensis/química , Metales Pesados/química , Polifenoles/química , Dióxido de Silicio/química , Adsorción , Cinética , Metales Pesados/aislamiento & purificación , Microscopía Electrónica de Rastreo , Espectroscopía Infrarroja por Transformada de Fourier
2.
Thyroid ; 11(10): 941-6, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11716041

RESUMEN

Conventional cytology cannot discriminate between benign and malignant follicular neoplasms. Our study evaluated the diagnostic role of computer-assisted image analysis in the presurgical assessment of thyroid follicular neoplasms. Fifty-eight patients (14 males, 44 females, age range, 45-75 years) who underwent surgery for cytologic diagnosis of thyroid follicular neoplasm were studied. All patients were first evaluated on clinical grounds and assigned a high/low suspicion of malignancy on the basis of gender, age, and nodule size. Cell image analysis was subsequently performed using a Cytometrica BYK Gulden microscope image processor on Feulgen-stained thyroid cytologic smears. A different population of 50 benign and 50 malignant, histologically evaluated nodules was studied in order to establish image analysis criteria suggestive of thyroid malignancy. Ploidy histogram, proliferation index (PI), nuclear area coefficient of variation (NACV), and anisocariosis ratio (AR) were studied. Thyroid cancer was diagnosed in 16 of 58 follicular neoplasms. Only 7 of these lesions were clinically suspicious (43.7%), whereas 14 of 16 (87.5%) malignant tumors were identified by image analysis. Positive and negative predictive values of image analysis versus clinical evaluation were 46.6% versus 30.4% and 92.8% versus 74.3%, respectively. The distribution of ploidy pattern was different in benign versus malignant follicular neoplasms (chi2 8.25, p = 0.016), malignant lesions showing an increased frequency of heteroclonal aneuploid DNA content (37.5% vs. 7.1%). Increased PI (mean +/- standard deviation (SD) = 11.3 +/- 5.7 vs. 7.1 +/- 6.1; p < 0.01) and NACV (mean +/- SD = 25.28 +/- 1.89 vs. 20.14 0.91; p < 0.01) levels were also observed in malignant follicular neoplasms. In conclusion, computer-assisted image analysis may profitably support clinical evaluation in the assessment of thyroid follicular neoplasms.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/métodos , Ploidias , Neoplasias de la Tiroides/genética , Neoplasias de la Tiroides/patología , Adenoma/diagnóstico , Adenoma/genética , Adenoma/patología , Adulto , Anciano , Aneuploidia , Biopsia con Aguja , Carcinoma Papilar Folicular/diagnóstico , Carcinoma Papilar Folicular/genética , Carcinoma Papilar Folicular/patología , Estudios de Casos y Controles , Núcleo Celular/patología , ADN de Neoplasias/análisis , ADN de Neoplasias/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Índice Mitótico , Valor Predictivo de las Pruebas , Neoplasias de la Tiroides/diagnóstico
3.
Toxicol Appl Pharmacol ; 172(2): 93-7, 2001 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-11298495

RESUMEN

Exposure of a primary culture of glial cells to the classical neurotoxicant trimethyltin (TMT) results in the release of prostaglandin (PG)E(2) and tumor necrosis factor (TNF)-alpha. Prior treatment of glial cells with either the nonspecific inhibitor of cyclooxygenase and lypoxygenase eicosatetraynoic acid (ETYA) or the cyclooxygenase inhibitor indomethacin completely prevented TMT-induced PGE(2) production and TNF-alpha release, suggesting a role for cyclooxygenase metabolites in TMT-induced TNF-alpha release. Exposure of glial cells to increasing concentrations of PGE(2) or other prostanoids did not increase TNF-alpha synthesis, while the presence of exogenous PGE(2) during treatment of glial cells with TMT actually suppressed TNF-alpha release. The activation of arachidonic acid metabolism produces reactive oxygen species (ROS). Scavenging of ROS by means of the antioxidant trolox prevented the TMT-induced release of TNF-alpha from glial cells, while indomethacin was found to suppress ROS formation induced by 1 microM TMT in glial cells. These results suggest that activation of arachidonic acid metabolism causes TNF-alpha release through the production of ROS rather than PGE(2). Indeed, PGE(2) may exert negative feedback on the release of TNF-alpha.


Asunto(s)
Neuroglía/efectos de los fármacos , Neuroglía/metabolismo , Prostaglandina-Endoperóxido Sintasas/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Compuestos de Trimetilestaño/toxicidad , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Ácido Araquidónico/metabolismo , Enfermedades del Sistema Nervioso Central/inducido químicamente , Enfermedades del Sistema Nervioso Central/metabolismo , Dinoprostona/biosíntesis , Activación Enzimática/efectos de los fármacos , Femenino , Neuroglía/citología , Embarazo , Ratas , Estimulación Química , Factor de Necrosis Tumoral alfa/biosíntesis
4.
Neuroimage ; 13(2): 314-27, 2001 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11162272

RESUMEN

Some authors proposed that exact mental calculation is based on linguistic representations and relies on the perisylvian language cortices, while the understanding of proximity relations between numerical quantities implicates the parietal cortex. However, other authors opposed developmental arguments to suggest that number sense emerges from nonspecific visuospatial processing areas in the parietal cortex. Within this debate, the present study aimed at revealing the functional anatomy of the two basic resolution strategies involved in mental calculation, namely arithmetical fact retrieval and actual computation, questioning in particular the respective role of language and/or visuospatial cerebral areas. Regional cerebral blood flow was measured with positron emission tomography while subjects were at rest (Rest), read digits (Read), retrieved simple arithmetic facts from memory (i.e., 2 x 4, Retrieve), and performed mental complex calculation (i.e., 32 x 24, Compute). Compared to Read, Retrieve engaged a left parieto-premotor circuit representing a developmental trace of a finger-counting representation that mediates, by extension, the numerical knowledge in adult. Beside this basic network, Retrieve involved a naming network, including the left anterior insula and the right cerebellar cortex, while it did not engage the perisylvian language areas, which were deactivated as compared to Rest. In addition to this retrieval network, Compute specifically involved two functional networks: a left parieto-frontal network in charge of the holding of the multidigit numbers in visuospatial working memory and a bilateral inferior temporal gyri related to the visual mental imagery resolution strategy. Overall, these results provide strong evidence of the involvement of visuospatial representations in different levels of mental calculation.


Asunto(s)
Encéfalo/fisiología , Procesos Mentales/fisiología , Adulto , Conducta/fisiología , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Circulación Cerebrovascular/fisiología , Humanos , Lenguaje , Masculino , Matemática , Memoria/fisiología , Cintigrafía , Lectura
5.
Nat Neurosci ; 4(1): 103-7, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11135652

RESUMEN

Calculating prodigies are individuals who are exceptional at quickly and accurately solving complex mental calculations. With positron emission tomography (PET), we investigated the neural bases of the cognitive abilities of an expert calculator and a group of non-experts, contrasting complex mental calculation to memory retrieval of arithmetic facts. We demonstrated that calculation expertise was not due to increased activity of processes that exist in non-experts; rather, the expert and the non-experts used different brain areas for calculation. We found that the expert could switch between short-term effort-requiring storage strategies and highly efficient episodic memory encoding and retrieval, a process that was sustained by right prefrontal and medial temporal areas.


Asunto(s)
Aptitud/fisiología , Mapeo Encefálico , Cognición/fisiología , Corteza Prefrontal/fisiología , Lóbulo Temporal/fisiología , Adulto , Velocidad del Flujo Sanguíneo/fisiología , Circulación Cerebrovascular/fisiología , Lateralidad Funcional/fisiología , Giro del Cíngulo/irrigación sanguínea , Giro del Cíngulo/diagnóstico por imagen , Giro del Cíngulo/fisiología , Humanos , Inteligencia/fisiología , Masculino , Matemática , Memoria a Corto Plazo/fisiología , Recuerdo Mental/fisiología , Giro Parahipocampal/irrigación sanguínea , Giro Parahipocampal/diagnóstico por imagen , Giro Parahipocampal/fisiología , Corteza Prefrontal/irrigación sanguínea , Corteza Prefrontal/diagnóstico por imagen , Retención en Psicología/fisiología , Lóbulo Temporal/irrigación sanguínea , Lóbulo Temporal/diagnóstico por imagen , Tomografía Computarizada de Emisión
6.
Cogn Neuropsychol ; 18(3): 275-84, 2001 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-20945215

RESUMEN

Cohen and Dehaene (Cognitive Neuropsychology, 2000, Vol. 17, pp. 563-583) reported the case of a pure alexic patient who preserved some calculation abilities despite severely impaired Arabic numeral reading. They argued that these residual abilities and the general pattern of performance of the patient can be fully explained within their anatomo-functional triple-code model. Here, we show how the lack of specification of the assumed architecture, the failure to provide sufficiently detailed data, and the absence of adequate refutation of alternative accounts make this study unsuitable for constraining theories of numerical cognition.

7.
J Cogn Neurosci ; 12(3): 461-79, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10931772

RESUMEN

Positron emission tomography was used to localize the cerebral networks specifically involved in three basic numerical processes: arabic numeral processing, numerical magnitude comparison, and retrieval of simple addition facts. Relative cerebral blood flow changes were measured while normal volunteers were resting with eyes closed, making physical judgment on nonnumerical characters or arabic digits, comparing, or adding the same digits. Processing arabic digits bilaterally produced a large nonspecific activation of occipito-parietal areas, as well as a specific activation of the right anterior insula. Comparison and simple addition fact retrieval revealed a fronto-parietal network involving mainly the left intraparietal sulcus, the superior parietal lobule and the precentral gyrus. Comparison also activated, but to a lesser extent, the right superior parietal lobe, whereas addition also activated the orbito-frontal areas and the anterior insula in the right hemisphere. Implications for current anatomo-functional models of numerical cognition are drawn.


Asunto(s)
Mapeo Encefálico , Cognición/fisiología , Lóbulo Parietal/anatomía & histología , Lóbulo Parietal/fisiología , Tomografía Computarizada de Emisión , Adulto , Circulación Cerebrovascular , Lóbulo Frontal/irrigación sanguínea , Lóbulo Frontal/fisiología , Humanos , Masculino , Matemática , Pruebas Neuropsicológicas , Lóbulo Occipital/irrigación sanguínea , Lóbulo Occipital/fisiología , Lóbulo Parietal/irrigación sanguínea , Estimulación Luminosa , Tiempo de Reacción/fisiología
8.
Cortex ; 36(3): 377-400, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10921666

RESUMEN

We describe the performance of a brain-damaged subject who suffered from visual agnosia leading to major difficulties in generating and exploiting visual representations from long-term memory. His performance in a physical judgement task in which he was required to answer questions about the visual shapes of Arabic numerals reflected his agnosic problems. However, he showed no impairment in usual number processing and calculation tasks. This case shows that, despite some commonalities in number and object processing, actual numerical processes are not affected by visual agnosia and can be preserved even when fine visual processes are impaired.


Asunto(s)
Agnosia/diagnóstico , Matemática , Agnosia/complicaciones , Cognición/fisiología , Toma de Decisiones , Dislexia/complicaciones , Dislexia/diagnóstico , Humanos , Juicio , Masculino , Trastornos de la Memoria/complicaciones , Trastornos de la Memoria/diagnóstico , Persona de Mediana Edad , Semántica , Índice de Severidad de la Enfermedad
9.
Cortex ; 36(3): 445-54, 2000 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10921671

RESUMEN

It has been shown that some arithmetical problems are stored in the form of individual facts representations (e.g., 3 x 4 = 12) whereas others are solved by general stored rules (e.g., 0 x N = 0). We describe the performance of a brain-damaged subject who presented a mild impairment in arithmetical fact retrieval. Although her performance was almost perfect for rule-based problems in all arithmetical operations, she was severely impaired for 0 + n problems in contrast with her relatively good performance for the corresponding n + 0 problems. This dissociation extends to addition the noncommutability of arithmetical rules described in multiplication.


Asunto(s)
Trastornos del Conocimiento/diagnóstico , Matemática , Afasia/diagnóstico , Afasia/fisiopatología , Encéfalo/diagnóstico por imagen , Encéfalo/fisiopatología , Trastornos del Conocimiento/fisiopatología , Femenino , Humanos , Persona de Mediana Edad , Pruebas Neuropsicológicas , Índice de Severidad de la Enfermedad , Tomografía Computarizada por Rayos X
10.
J Endocrinol Invest ; 22(10): 796-9, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10614530

RESUMEN

We report two patients with incidentally discovered enlarged parathyroid glands while performing neck ultrasonography (US) for thyroid nodules. The parathyroid masses were seen as hypoechoic, homogeneous, oval nodules, separated from the thyroid gland. Both patients were completely asymptomatic, although subclinical evidence of hyperparathyroidism (serum PTH and calcium levels in the upper limit of the normal range, increased ionized serum calcium, osteocalcin, urinary calcium and hydroxyproline) was subsequently found in one patient. An enhanced uptake on sesta-MIBI scinti scan was concordant with the US finding in the two cases. PTH levels in the wash-out from the US-guided fine needle aspiration biopsy, confirmed the parathyroid origin of the lesions. Cytology and immunocytochemistry were, in our cases, unreliable diagnostic procedures. The extensive use of US imaging in thyroid pathology may increase the finding of US incidentally discovered parathyroid adenomas. The early detection of silent parathyroid pathologic findings may extend the natural history of these masses to a preclinical stage. Further investigations are necessary to evaluate the evolution of parathyroid incidentalomas and therefore their clinical significance.


Asunto(s)
Neoplasias de las Paratiroides/diagnóstico por imagen , Glándula Tiroides/diagnóstico por imagen , Calcio/sangre , Calcio/orina , Femenino , Humanos , Hidroxiprolina/sangre , Persona de Mediana Edad , Osteocalcina/sangre , Hormona Paratiroidea/sangre , Ultrasonografía
11.
J Nutr ; 129(12): 2251-7, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10573559

RESUMEN

We investigated the potential beneficial effects of Bifidobacterium animalis on intestinal damage using zinc-deficient (ZD) rats as a model for intestinal alterations. The ZD rats were fed diets containing 1 mg Zn/kg for 20 (ZD(20)) or 40 (ZD(40)) d to induce damage that differed in severity. Subgroups of these rats, the ZD(20) + B and ZD(40) + B groups, received a suspension of B. animalis (3.5 x 10(8) colony forming units) daily for the last 10 d. Another subgroup, the ZD(40) + B + 7 d group, was fed the ZD diet for 7 d after the B. animalis treatment period. Zinc deficiency induced ulcerations, edema, inflammatory cell infiltration and dilatation of blood vessels in duodenum, jejunum and ileum, with increasing severity between 20 and 40 d of zinc deficiency. The mucosa of the ZD(20) + B group was well preserved, and most of the morphologic alterations induced by zinc deficiency were normalized in the ZD(40) + B group. The high fecal concentrations of B. animalis in the ZD(40) + B and ZD(40) + B + 7 d groups indicate that these bifidobacteria survived passage through the gastrointestinal tract and proliferated. Electron microscopy confirmed the elevated numbers of bifidobacteria in cecum. Treatment with B. animalis resulted in greater epithelial cell proliferation and disaccharidase activities in the ZD(40) + B group compared with the ZD(40) group. These findings indicate that B. animalis can protect the intestine from alterations induced by zinc deficiency, suggesting that this bacterium may play a role in intestinal mucosal defense.


Asunto(s)
Bifidobacterium/fisiología , Intestinos/microbiología , Intestinos/patología , Zinc/deficiencia , Animales , Bifidobacterium/crecimiento & desarrollo , Ciego/microbiología , Ciego/ultraestructura , División Celular , Recuento de Colonia Microbiana , Disacaridasas/metabolismo , Mucosa Intestinal/patología , Intestinos/enzimología , Masculino , Microscopía Electrónica , Ratas , Ratas Sprague-Dawley , Zinc/sangre
12.
J Clin Ultrasound ; 27(9): 492-8, 1999.
Artículo en Inglés | MEDLINE | ID: mdl-10525210

RESUMEN

PURPOSE: The aim of our study was to evaluate the incidence of incidentally found parathyroid adenomas (incidentalomas) in patients undergoing sonography of the neck for thyroid disease. METHODS: A total of 1,686 patients (305 men and 1,381 women) underwent sonography of the neck; the mean age was 49.6 +/- 21.7 years. In 38 patients (2.3%; 7 men and 31 women) with a mean age of 48.7 +/- 14.7 years, hypoechoic, homogeneous, oval nodules (mean volume, 1.0 +/- 0. 9 cm(3)) adjacent to the thyroid parenchyma were observed. All these lesions, compatible with the shape of an enlarged parathyroid gland, underwent ultrasound-guided fine-needle aspiration biopsy (FNAB), with measurement of parathyroid hormone (PTH) and thyroglobulin (Tg) levels in the needle washings (FNAB-PTH and FNAB-Tg). Biochemical screening for hyperparathyroidism was also performed. RESULTS: Cytologic examination plus FNAB-PTH/FNAB-Tg measurements revealed the presence of cellular material consistent with parathyroid tissue in 9 patients (24%), thyroid tissue in 22 patients (58%), and lymphoid tissue in 4 patients (11%). A tissue diagnosis was not established in 3 patients (8%). Five of 9 patients with parathyroid enlargement had high serum PTH and calcium levels. CONCLUSIONS: Enlarged parathyroid glands may be incidentally discovered during sonography of the thyroid. In patients with thyroid disease, the positive-predictive value of sonography in the identification of parathyroid tissue was low. Ultrasound-guided FNAB-PTH determination should be carried out when parathyroid adenoma is suspected. The incidental finding of an enlarged parathyroid may or may not be associated with yet undiagnosed hyperparathyroidism.


Asunto(s)
Adenoma/diagnóstico por imagen , Neoplasias de las Paratiroides/diagnóstico por imagen , Adenoma/sangre , Adenoma/patología , Adulto , Biopsia con Aguja , Calcio/sangre , Diagnóstico Diferencial , Femenino , Humanos , Hiperparatiroidismo/sangre , Hiperparatiroidismo/diagnóstico por imagen , Hiperparatiroidismo/patología , Masculino , Persona de Mediana Edad , Hormona Paratiroidea/sangre , Neoplasias de las Paratiroides/sangre , Neoplasias de las Paratiroides/patología , Estudios Retrospectivos , Sensibilidad y Especificidad , Tiroglobulina/sangre , Ultrasonografía
13.
Res Microbiol ; 150(2): 117-27, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10209767

RESUMEN

Seventy strains of Bifidobacterium globosum isolated from gastrointestinal tracts of different animals were studied. Strains were grown at temperatures ranging from 25 to 46.5 degrees C in order to examine changes both in the expression of bifidobacterial outer proteins (BIFOPs) and in their hydrophobic properties. It was observed that the expression of BIFOPs found on the cell-surface changes according to growth temperature, with quantitative and/or qualitative variations. Generally speaking, it was observed that BIFOP expression at low-growth temperature was considerably attenuated, while at medium- and high-growth temperature it increased. Furthermore, at high-growth temperatures, the presence of a new common protein was detected in all the strains studied. Cells from B. globosum strains grown under different temperature conditions were studied in terms of their cellular hydrophobicity properties. At medium-growth temperature, the cell hydrophobicity was strictly correlated with BIFOP expression, while at low and high-growth temperatures, the presence of BIFOP only partially influenced the hydrophobic features.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa/biosíntesis , Bifidobacterium/aislamiento & purificación , Temperatura , Animales , Bifidobacterium/clasificación , Bifidobacterium/metabolismo , Bovinos , Pared Celular/metabolismo , Pollos , Heces/microbiología , Humanos , Técnicas de Inmunoadsorción , Lactante , Conejos , Ratas , Aguas del Alcantarillado/microbiología , Ovinos , Propiedades de Superficie , Porcinos , Agua
14.
Minerva Endocrinol ; 23(2): 57-63, 1998 Jun.
Artículo en Italiano | MEDLINE | ID: mdl-9844356

RESUMEN

BACKGROUND: The efficacy of 6 months therapy with slow-release lanreotide (30 mg i.m. every 10-14 days) in 8 acromegalic patients has been studied. METHODS: These patients had been previously treated (for 62 +/- 5.7 months) with octreotide (100 micrograms t.i.d.) and therefore presented, at the beginning of the study, normal mean GH (3.5 +/- 1.1 ng/ml) and IGF-1 (301.7 +/- 32.9 ng/ml) plasma levels. After a week of wash-out, mean GH (5.5 +/- 1.3 ng/ml) and IGF-1 (523.8 +/- 26.7 ng/ml) plasma levels showed a significant increase (p < 0.01) compared to the values observed during the treatment with octreotide. All 8 acromegalic patients then started the treatment with lanreotide, 30 mg i.m. After 14 days, mean GH plasma levels (4.2 +/- 1.3 ng/ml) did not significantly differ (p = NS) from those observed in the same group of patients during treatment with octreotide, whilst plasma IGF-1 levels (477 +/- 43 ng/ml) were significantly higher (p < 0.05). Four patients, in which mean plasma GH values resulted < 5 ng/ml, continued the therapy with lanreotide every 14 days. In the remaining 4 patients, in which plasma GH values were > 5 ng/ml, lanreotide was administered every 10 days. RESULTS: After 3 months of therapy, 6 out of the 8 patients presented persistent GH levels < 5 ng/ml during the day, with IGF-1 levels comparable to those observed during treatment with octreotide. The other 2 subjects presented plasma GH levels > 5 ng/ml during the day, with increased plasma levels of IGF-1. This latter group of patients was resubmitted treatment with octreotide, 100 micrograms t.i.d. After 6 months of therapy, all 6 patients presented GH and IGF-1 plasma levels comparable to those observed during treatment with octreotide. CONCLUSIONS: These data show that slow-release lanreotide can be a valid therapeutic alternative to octreotide in the medical treatment of acromegalic patients.


Asunto(s)
Acromegalia/tratamiento farmacológico , Antineoplásicos/uso terapéutico , Péptidos Cíclicos/uso terapéutico , Somatostatina/análogos & derivados , Acromegalia/sangre , Adulto , Anciano , Biomarcadores/sangre , Preparaciones de Acción Retardada , Femenino , Hormona del Crecimiento/sangre , Humanos , Masculino , Persona de Mediana Edad , Somatostatina/uso terapéutico
15.
Brain Cogn ; 38(1): 1-16, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9735175

RESUMEN

This study investigated the effects of age on a random generation task. In Experiment 1, young and elderly subjects were asked to generate random strings of letters at 1-, 2-, and 4-s rates. The elderly subjects produced more alphabetical stereotype responses than young subjects, even in the slowest rate condition. Furthermore, as faster rates were imposed, elderly subjects could no longer maintain the pace and missed responses. In Experiment 2, subjects were required to generate letters at the same time that they sorted cards into one, two, four, or eight categories. Age-related differences were observed on most of the measures of randomness (stereotypes, zero-order, and first-order measures). In addition, the number of errors increased with the number of sorting alternatives, especially for elderly subjects. These results suggest the existence of a reduction of the central executive resources, along with a reduced inhibition ability, in the elderly subjects. However, the contribution of a perceptual speed factor is also discussed.


Asunto(s)
Pruebas del Lenguaje , Adulto , Factores de Edad , Anciano , Cognición/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad
16.
Minerva Endocrinol ; 22(4): 107-10, 1997 Dec.
Artículo en Italiano | MEDLINE | ID: mdl-9586418

RESUMEN

In 1990, a 50 year-old man was referred to us for hyperprolactinemia. At 37 years of age the patient had undergone left mastectomy, for a histologically confirmed gynecomastia and, in 1989, he had undergone pituitary adenomectomy, for a PRL secreting macroadenoma (PRL = 3520 ng/ml). Persistently high PRL plasma levels (PRL = 550 ng/ml) showed an incomplete surgical removal of the adenoma and as a consequence, radiotherapy of the pituitary area was performed in 1990. When the patient referred to us, PRL plasma levels were still pathologic and medical therapy with bromocriptine was started. A year later a replacement therapy with cortisone, testosterone, L-thyroxine, was commenced, as the patient presented a post-radiotherapy hypopituitarism. Since the treatment with bromocriptine was unsuccessful, the drug was replaced with cabergoline, but not even the latter was able to normalize PRL plasma levels. In 1996, a nodule of 3 cm in diameter was discovered under his right mammary areola. The nodule biopsy showed a grade II infiltrating ductal breast carcinoma positive to the estrogen and progesterone receptors analysis. A right total mastectomy was performed and the diagnosis was confirmed through histological examination. A case of gynecomastia and breast cancer in a male patient who had been exposed to high PRL plasma levels for several years is reported. In this patient, both elevated PRL plasma levels and a relative hyperestrogenic state may have contributed to originate breast cancer.


Asunto(s)
Neoplasias de la Mama Masculina/complicaciones , Hiperprolactinemia/complicaciones , Adulto , Neoplasias de la Mama Masculina/patología , Humanos , Hiperprolactinemia/patología , Masculino
17.
Cortex ; 30(4): 661-71, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7697989

RESUMEN

We report here the case of a patient (BB), suffering from a precocious evolving dementia with impaired arithmetic performance, who showed specific and theoretical pertinent dissociations in basic mental arithmetic. First, in a task involving production of answers to simple arithmetic problems, a strong dissociation was found among operation: while multiplication was severely impaired, addition was moderately and subtraction only slightly impaired. A second dissociation was found between problems potentially solvable by rules and the others, with the former being better preserved. Finally, in multiplication verification tasks, the rate and distribution of errors among problems were not different from those observed in the multiplication production task. This pattern of performance like the one presented by the patient RG (Dagenbach and McCloskey, 1992), suggests first that stored arithmetical fact representations are segregated by arithmetic operation and second that a distinction has to be drawn between arithmetical rules and arithmetical facts. Last, the parallelism of performance observed here in verification and production tasks suggests that the same deficit(s) is (are) responsible for errors in both tasks.


Asunto(s)
Demencia/psicología , Solución de Problemas/fisiología , Adulto , Femenino , Humanos , Pruebas de Inteligencia , Pruebas del Lenguaje , Matemática , Memoria/fisiología , Desempeño Psicomotor/fisiología
18.
Cognition ; 44(1-2): 159-96, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1511585

RESUMEN

Some people declare that they possess a personal visual representation of numbers: some automatically "see" the numbers they are confronted with in a precise location in a structured mental space, others "associate" specific colours with given numbers. Such visuo-spatial representations of numbers were first described by Galton in 1880 but have since received little attention from psychologists. It is the aim of this article to describe these mental representations and discuss their role in number processing. The authors first review Galton's observations, and then present their own. Finally, they discuss the relevance of these visuo-spatial representations in relation to contemporary debates on number representation and calculation.


Asunto(s)
Formación de Concepto , Imaginación , Matemática , Solución de Problemas , Adulto , Aprendizaje por Asociación , Percepción de Color , Femenino , Percepción de Forma , Humanos , Masculino , Recuerdo Mental , Embarazo
19.
Eur J Clin Pharmacol ; 36(5): 439-42, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2666139

RESUMEN

The magnitude and duration of the antihypertensive effect of slow-release nicardipine (SR-Nicardipine) have been compared with placebo in 36 uncomplicated essential hypertensives (diastolic BP 95 to 115 mm Hg after 1-month placebo washout). According to a double-blind, randomized, cross-over design they received SR-Nicardipine 40 mg b.d. and placebo for 1 month. At the end of each treatment period, blood pressure and heart rate were measured 12 h after the evening dose and 1, 2, 3 and 4 h after the morning dose. SR-Nicardipine significantly reduced systolic (SBP) and diastolic (DBP) blood pressure at each time after dosing. The absolute decrements peaked 4 h after dosing (-18.3 and -11.7 mm Hg, respectively) and more than 90% of the peak effect persisted 12 h after dosing, both for SBP and DBP. The heart rate was slightly increased by SR-Ni-cardipine. Adverse effects monitored with a check-list occurred in 31% of patients during SR-Nicardipine treatment and in 28% on placebo. Thus, SR-Nicardipine 40 mg b.d. has a maintained and significant antihypertensive effect lasting up to 12 h in essential hypertension.


Asunto(s)
Hipertensión/tratamiento farmacológico , Nicardipino/uso terapéutico , Adulto , Anciano , Presión Sanguínea/efectos de los fármacos , Ensayos Clínicos como Asunto , Preparaciones de Acción Retardada , Método Doble Ciego , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Nicardipino/administración & dosificación , Distribución Aleatoria
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