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1.
J Neurooncol ; 97(2): 233-40, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19806320

RESUMEN

CCAAT/enhancer binding protein (C/EBP) delta is a transcription factor which has been demonstrated to mediate the growth arrest of mammary and prostate cancer cell lines. It is induced by several stimuli including inflammatory cytokines. In this study, C/EBPdelta immunohistochemical expression was assessed in 49 meningiomas of different histotype and grade and correlated with a variety of clinico-pathological data and with the overall and recurrence-free survival of the patients. Positive staining was observed in the nuclei of neoplastic cells in 22 out of the 49 cases analyzed. C/EBPdelta expression was significantly associated with a low histological grade and proliferation index, reflected by low Ki-67 labeling index (LI) and mitotic activity, and with the presence of intra-tumoral inflammatory infiltrate and the absence of necrosis. In addition, the absence of C/EBPdelta was significantly correlated with a shorter disease-free interval. Our findings suggest that C/EBPdelta expression may prevent the development of recurrences by inhibition of neoplastic growth in meningiomas. If further studies confirm its induction by inflammatory mediators, this might be exploited in novel therapies to prevent recurrences in meningiomas.


Asunto(s)
Proteína delta de Unión al Potenciador CCAAT/biosíntesis , Neoplasias Meníngeas/metabolismo , Meningioma/metabolismo , Adulto , Anciano , Anciano de 80 o más Años , Proteína delta de Unión al Potenciador CCAAT/genética , Proliferación Celular , Femenino , Humanos , Inmunohistoquímica , Estimación de Kaplan-Meier , Masculino , Neoplasias Meníngeas/genética , Neoplasias Meníngeas/patología , Meningioma/genética , Meningioma/patología , Persona de Mediana Edad , Adulto Joven
2.
J Exp Bot ; 60(1): 99-105, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19036840

RESUMEN

In spite of the importance of respiration in forest carbon budgets, the mechanisms by which physiological factors control stem respiration are unclear. An experiment was set up in a Eucalyptus globulus plantation in central Portugal with monoculture stands of 5-year-old and 10-year-old trees. CO(2) efflux from stems under shaded and unshaded conditions, as well as the concentration of CO(2) dissolved in sap [CO(2)(*)], stem temperature, and sap flow were measured with the objective of improving our understanding of the factors controlling CO(2) release from stems of E. globulus. CO(2) efflux was consistently higher in 5-year-old, compared with 10-year-old, stems, averaging 3.4 versus 1.3 mumol m(-2) s(-1), respectively. Temperature and [CO(2)(*)] both had important, and similar, influences on the rate of CO(2) efflux from the stems, but neither explained the difference in the magnitude of CO(2) efflux between trees of different age and size. No relationship was found between efflux and sap flow, and efflux was independent of tree volume, suggesting the presence of substantial barriers to the diffusion of CO(2) from the xylem to the atmosphere in this species. The rate of corticular photosynthesis was the same in trees of both ages and only reduced CO(2) efflux by 7%, probably due to the low irradiance at the stem surface below the canopy. The younger trees were growing at a much faster rate than the older trees. The difference between CO(2) efflux from the younger and older stems appears to have resulted from a difference in growth respiration rather than a difference in the rate of diffusion of xylem-transported CO(2).


Asunto(s)
Dióxido de Carbono/metabolismo , Eucalyptus/fisiología , Tallos de la Planta/fisiología , Transporte Biológico , Fotosíntesis , Temperatura , Xilema/metabolismo
3.
J Exp Bot ; 58(8): 2159-68, 2007.
Artículo en Inglés | MEDLINE | ID: mdl-17490994

RESUMEN

Respiration of stems and branches of trees (R(S)) has typically been estimated by measuring radial CO(2) efflux from woody tissue (E(A)) and rates of efflux are often scaled temporally using a temperature relationship (Q(10)). High concentrations of CO(2) in xylem sap ([CO(2)*]) have been shown to affect E(A), and the transport of CO(2) in the xylem stream has been suggested as a mechanism to explain field observations of temperature-independent fluctuations in E(A). Sap velocity and temperature were manipulated in detached branch segments of sycamore (Platanus occidentalis L.) under controlled conditions to quantify these effects. Within individual branches of similar size, E(A) and [CO(2)*] were greater at low sap velocity, while the amount of respired CO(2) transported in sap (transport flux, F(T)) was greater at high sap velocity. E(A) was linearly correlated with [CO(2)*]. In branches of three diameter classes (1, 2, and 3 cm), volume-based E(A), F(T), and R(S) did not differ, but surface-area based CO(2) fluxes increased with diameter class. Regardless of diameter, E(A) accounted for only 30% of respired CO(2) at high sap velocity, while at low sap velocity, E(A) accounted for 71% of respired CO(2). E(A), F(T), and R(S) measured at 5, 20, and 35 degrees C at the same sap velocity showed a typical exponential response to temperature. However, at the lowest temperature, E(A) accounted for only 18% of the CO(2) released from respiring cells compared with 44% at the highest temperature, perhaps due to the effect of temperature on the solubility of CO(2) in water. These results directly demonstrate the transport of respired CO(2) in the xylem stream and may help to explain inconsistencies in stem and branch respiration measurements made in situ.


Asunto(s)
Dióxido de Carbono/metabolismo , Temperatura , Árboles/metabolismo , Transporte Biológico , Árboles/anatomía & histología , Xilema/metabolismo
4.
Histol Histopathol ; 21(10): 1111-4, 2006 10.
Artículo en Inglés | MEDLINE | ID: mdl-16835833

RESUMEN

Müllerianosis is a term used to indicate lesions composed of an admixture of two or three types of müllerian-derivation glands in heterotopic sites. In this report we describe a case of spinal cord müllerianosis which occurred in a 42-year-old woman. The patient had suffered from catamenial lumbago and sciatica of three years duration before undergoing laminectomy of L2-L3 with excision of a polypoid mass that compressed nerve trunks. At histological examination, the lesion was composed of endocervical, endometrial and tubal glands within a smooth muscle nodule. These features were consistent with a diagnosis of müllerianosis. This is a very uncommon form of presentation of müllerianosis that must be correctly identified since patients can benefit from hormonal therapy.


Asunto(s)
Endometriosis/patología , Ependimoma/patología , Tumor Mulleriano Mixto/patología , Conductos Paramesonéfricos/patología , Médula Espinal/patología , Adulto , Endometriosis/diagnóstico , Ependimoma/diagnóstico , Femenino , Humanos , Inmunohistoquímica , Tumor Mulleriano Mixto/diagnóstico
5.
Acta Neuropathol ; 112(5): 617-26, 2006 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16850311

RESUMEN

Caveolin-1 (Cav-1) protein has been documented in several neoplasms with a controversial role in cell proliferation, tumour development and progression. The aim of the present study was to investigate the Cav-1 immunohistochemical expression in human meningiomas. Sixty-two cases, classified as 11 meningothelial (17%), 12 transitional (19%), 5 fibrous (8%), 3 microcystic (5%), 3 secretory (5%), 1 clear cell (2%), 1 chordoid (2%) and 26 (42%) atypical meningiomas, were selected from our pathological files. Clinico-pathological data, including Ki-67 values and survival data were also available. Ten leptomeningeal samples were utilized as normal tissue control. For each case, a polyclonal antibody against Cav-1 was applied and an intensity distribution (ID) score was determined. The Cav-1 immunoexpression was found in 95% of meningiomas with a variable ID score, while only minimal, not uniform, reactivity was noted in non-neoplastic meninges. Of note, higher Cav-1 ID score was significantly correlated with tumour site, Simpson's grade, histological type, higher histologic grade, Ki-67 labelling index > or = 4% and clinical course. Kaplan-Meier curves demonstrated a significantly worse survival in patients with higher Cav-1 ID score, Ki-67 > or = 4% and 2-3 Simpson grade. Multivariate analysis indicated that only Ki-67 was an independent prognostic factor. Increased immunoexpression of the Cav-1 seems to be associated with the biological aggressiveness of meningiomas, reflecting a worse prognosis.


Asunto(s)
Caveolina 1/metabolismo , Neoplasias Meníngeas/metabolismo , Neoplasias Meníngeas/patología , Meningioma/metabolismo , Meningioma/patología , Adulto , Anciano , Anciano de 80 o más Años , Caveolina 1/genética , Proliferación Celular , Progresión de la Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Estimación de Kaplan-Meier , Antígeno Ki-67/metabolismo , Masculino , Neoplasias Meníngeas/genética , Meningioma/genética , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Pronóstico
6.
J Neurosurg Sci ; 49(3): 125-8, 2005 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16288195

RESUMEN

Central neurocytomas are low-grade tumours of neuronal origin, affecting mainly young patients and usually located in the lateral or third ventricle. We report a rare case of central neurocytoma at the fourth ventricle level. Magnetic resonance imaging showed a homogeneously enhancing mass lesion at the fourth ventricle. Gross-total surgical removal was achieved. The histological diagnosis was of central neurocytoma but the lesion showed a fairly elevated Ki-67 index (6%). Given this finding, close neuroimaging monitoring was performed and at the moment the patient is free of recurrence.


Asunto(s)
Neoplasias del Ventrículo Cerebral/patología , Cuarto Ventrículo/patología , Neurocitoma/patología , Adulto , Neoplasias del Ventrículo Cerebral/cirugía , Diagnóstico Diferencial , Ependimoma/patología , Cuarto Ventrículo/cirugía , Humanos , Inmunohistoquímica , Antígeno Ki-67/metabolismo , Imagen por Resonancia Magnética , Masculino , Microscopía Electrónica de Transmisión , Neurocitoma/cirugía
7.
Tree Physiol ; 24(1): 83-90, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14652217

RESUMEN

At the end of the growing season in late July, 20-month-old cork oak (Quercus suber L.) saplings were partially defoliated (63% of leaf area) to evaluate their ability to recover leaf area after defoliation. At 18 and 127 days after defoliation, changes in starch and nitrogen pools were determined in leaves and perennial organs, and variations in photosynthetic carbon uptake were investigated. To determine the role of stored nitrogen in regrowth after defoliation, plant nitrogen was labeled in the previous winter by enriching the nutrient solution with 15N. Plants recovered the lost leaf area in 127 days. Although there was remobilization of starch and nitrogen from leaves and perennial organs, the availability of resources for growth in the following spring was not decreased by defoliation. On the contrary, starch concentration in coarse roots was higher in defoliated saplings than in control saplings, presumably as a result of the higher net CO2 exchange rate in newly developed leaves compared with pre-existing leaves.


Asunto(s)
Fotosíntesis/fisiología , Quercus/fisiología , Árboles/fisiología , Metabolismo de los Hidratos de Carbono , Nitrógeno/metabolismo , Hojas de la Planta/anatomía & histología , Hojas de la Planta/fisiología
8.
Acta Neuropathol ; 103(2): 152-6, 2002 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-11810181

RESUMEN

We report on two children with cerebral gliomas showing extensive lipomatous change of tumor cells. One tumor was a large mass occupying the temporal and occipital lobes of the left hemisphere; the other was a cystic lesion with a mural nodule in the left frontal lobe. Histologically, both tumors were composed of glial cells that contained fat droplets coalescing into a single large droplet, thus resulting in an appearance similar to adipocytes. Immunohistochemistry showed GFAP positivity of tumor cells, which was maintained in the cytoplasmic rim of lipidized cells. Synaptophysin and neurofilaments were negative. Ki-67/Mib1 labeling index was low. Electron microscopy showed intracytoplasmic lipid vacuoles, abundant intermediate filaments and a basal lamina surrounding the cell bodies. Molecular genetic analysis of one tumor revealed no TP53 mutation (exons 4-10), no loss of CDKN2A, and no amplification of EGFR, CDK4 or MDM2. Both patients are alive and well after 3 and 7 years, respectively. However, one of them had to be re-operated on circumscribed local recurrences. Our cases represent a rare variant of low-grade astrocytoma that may be designated as "lipoastrocytoma".


Asunto(s)
Astrocitoma/patología , Neoplasias Encefálicas/patología , Lipomatosis/patología , Factores de Edad , Astrocitoma/genética , Astrocitoma/cirugía , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/cirugía , Niño , Preescolar , Femenino , Humanos , Lipomatosis/genética , Lipomatosis/cirugía
9.
Pathologica ; 93(2): 118-23, 2001 Apr.
Artículo en Italiano | MEDLINE | ID: mdl-11428288

RESUMEN

To further evaluate the role of cytogenetic analysis we studied 19 cases of renal neoplasms. Specific chromosomal aberrations have been demonstrated associated with different histologic types. Particularly, clear cell renal cancers were associated with deletions of the short arm of chromosome 3 and papillary renal cell cancers demonstrated multiple trisomies, and chromophobe cancers and oncocytomas were characterized by loss of whole chromosomes. The utility of cytogenetics as a tool to define the pathological spectrum of renal cell neoplasms is stressed.


Asunto(s)
Carcinoma de Células Renales/genética , Neoplasias Renales/genética , Adulto , Anciano , Aberraciones Cromosómicas/genética , Citogenética , Femenino , Humanos , Cariotipificación , Masculino , Persona de Mediana Edad
10.
Am J Surg Pathol ; 25(3): 401-5, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11224612

RESUMEN

Chordoid glioma is a rare neoplasm occurring in the third ventricle and, as the name implies, having a chordoid appearance. It is currently considered a glial neoplasm of uncertain histogenesis with distinct clinicopathologic features. We report three cases of chordoid glioma with a focus on the ultrastructural appearance. The patients were two men and one woman aged, respectively, 34, 40, and 43 years. Immunohistochemically, all tumors showed strong and diffuse reactivity for glial fibrillary acidic protein and vimentin, whereas immunoreactivity for epithelial membrane antigen and cytokeratin was focal. Ultrastructurally, they showed features of ependymal differentiation for the presence of an apical pole with microvilli and a basal pole characterized, as in normal ependyma, by many hemidesmosomelike structures connecting cell membranes to the underlying basal lamina. Constant features were a submicroscopic cell body zonation (i.e., perinuclear, intermediate, subapical, and apical regions) and the presence of secretory granules. These findings were similar to those described for the secretory ependymal cells of the subcommissural organ, a small structure located in a dorsocaudal region of the third ventricle that undergoes regression after birth in humans. Our observations suggest that chordoid glioma may represent a subtype of ependymoma whose cells resemble the highly specialized ependyma of the subcommissural organ.


Asunto(s)
Neoplasias del Plexo Coroideo/ultraestructura , Glioma/ultraestructura , Tercer Ventrículo/ultraestructura , Adulto , Biomarcadores de Tumor/análisis , Neoplasias del Plexo Coroideo/química , Neoplasias del Plexo Coroideo/clasificación , Desmosomas/ultraestructura , Femenino , Glioma/química , Glioma/clasificación , Hemidesmosomas , Humanos , Técnicas para Inmunoenzimas , Uniones Intercelulares/ultraestructura , Masculino , Microscopía Electrónica , Microvellosidades/ultraestructura , Proteínas de Neoplasias/análisis , Orgánulos/ultraestructura
13.
Pathologica ; 91(1): 18-24, 1999 Feb.
Artículo en Italiano | MEDLINE | ID: mdl-10396946

RESUMEN

INTRODUCTION: Helicobacter pylori is one of the most common causes of human gastritis. Recently, a new agent has been isolated, which also causes a gastritis. It has been initially named Gastrospirillum hominis and renamed Helicobacter heilmannii (Hh). Hh is extremely rare. In spite of the rarity it is important to recognize and diagnose it, as it requires a proper therapy, different from Hp therapy. Clinical presentation and serological results of Hh are superimposable to those of HP. Therefore differential diagnosis resides on histological grounds. PURPOSE of the present paper is to report 14 new cases of Hh gastritis, which constitutes the first italian series. RESULTS: Cases constituted 0.01% of all gastric biopsies seen in the period 1994-1998. Nine patients were male and five were female; age ranged from 32 to 76 years (50 years on average). All patients presented a mild to moderate gastritis. Hh is a spiral bacterium, being about 10 micra in length, localized in single or small groups in the glandular mucus. Two cases were associated with Hp. One case was associated with gastric adenocarcinoma. Two cases were diagnosed during the follow-up of duodenal ulcer. In CONCLUSION, the incidence of Hh gastritis in the present series seems consistent with that from other European countries. In all cases the presence of Hh was associated with features of gastritis. This confirms the pathogenetic role of Hh.


Asunto(s)
Adenocarcinoma/microbiología , Gastritis/microbiología , Infecciones por Helicobacter/microbiología , Helicobacter heilmannii/aislamiento & purificación , Helicobacter/aislamiento & purificación , Neoplasias Gástricas/microbiología , Adenocarcinoma/patología , Adulto , Anciano , Úlcera Duodenal/microbiología , Úlcera Duodenal/patología , Femenino , Gastritis/patología , Helicobacter/clasificación , Infecciones por Helicobacter/patología , Helicobacter heilmannii/clasificación , Humanos , Incidencia , Italia/epidemiología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Tinción con Nitrato de Plata , Neoplasias Gástricas/patología
14.
Surg Neurol ; 51(6): 636-40, 1999 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-10369232

RESUMEN

BACKGROUND: Solitary fibrous tumor (SFT), a mesenchymal neoplasm originally described in the pleura has been more recently reported to arise in a number of other sites, including the meninges. Nowadays immunohistochemistry facilitates the otherwise problematic differential diagnosis with regard to other benign and malignant spindle cell neoplasms of the central nervous system. METHODS: Two recently treated cases of meningeal SFT (one craniospinal, one spinal) are presented and discussed in the light of the present knowledge and a review of the literature. RESULTS: Total resection was followed by complete recovery and both patients are presently asymptomatic and without evidence of disease. The microscopic and immunohistochemical profiles (CD 34, vimentin positive; S-100, EMA negative) were consistent with those of previously reported cases. CONCLUSIONS: The majority of SFTs behave in a benign fashion and do not recur unless subtotally resected. Malignant variants may account for up to 37% of SFTs in other locations but have never been reported to occur in the meninges. Meningeal SFTs are to be considered a new pathological entity. Wider use of immunohistochemical screening should enable the determination of their real incidence; larger series and longer follow-up will provide conclusions about their treatment and prognosis.


Asunto(s)
Fibroma/patología , Hemangiopericitoma/patología , Neoplasias Meníngeas/patología , Meningioma/patología , Adolescente , Diagnóstico Diferencial , Fibroma/cirugía , Hemangiopericitoma/cirugía , Humanos , Masculino , Neoplasias Meníngeas/cirugía , Meningioma/cirugía , Persona de Mediana Edad
15.
Int J Gynecol Pathol ; 17(1): 83-8, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9475198

RESUMEN

A 36-year-old woman presented with intermenstrual spotting and was found to have a cystic mass involving the uterine cervix on a pelvic ultrasound examination. A necrotic and hemorrhagic tumor was excised by hysterectomy and processed for light and electron microscopic investigation and molecular analysis. Microscopic examination revealed a small round cell tumor that immunohistochemical studies (including staining for the highly restricted surface antigen p30/32MIC2) and ultrastructural studies indicated was an extraosseous Ewing's sarcoma (EES)/primitive neuroectodermal tumor (PNET). This diagnosis was established by detection of EWS/ERG fusion transcript through reverse transcription polymerase chain reaction (RT-PCR) with nested primers. Full body computed tomography failed to detect any extrauterine tumor, and the patient is clinically free of disease 18 months after hysterectomy. This case represents the first report of a primary EES/PNET arising in the uterine cervix.


Asunto(s)
Proteínas de Unión al ADN , Tumores Neuroectodérmicos Primitivos/patología , Sarcoma de Ewing/patología , Transactivadores , Factores de Transcripción , Adulto , Biomarcadores de Tumor/metabolismo , Femenino , Humanos , Inmunohistoquímica , Microscopía Electrónica , Tumores Neuroectodérmicos Primitivos/genética , Tumores Neuroectodérmicos Primitivos/metabolismo , Tumores Neuroectodérmicos Primitivos/ultraestructura , Proteínas Oncogénicas/metabolismo , Reacción en Cadena de la Polimerasa , ARN Neoplásico/análisis , Sarcoma de Ewing/genética , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/ultraestructura , Transcripción Genética , Regulador Transcripcional ERG , Translocación Genética
16.
Am J Surg Pathol ; 21(2): 206-12, 1997 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-9042288

RESUMEN

The clinicopathological features of a series of neuronal and mixed neuronal and astrocytic neoplasms of the CNS are described. Patients were aged 5 to 63 years. Six cases were composed predominantly of small round cells with clear cytoplasm resembling central neurocytoma but lacked the characteristic intraventricular location of that tumor. The remaining five cases had similar neurocytomatous features associated with a benign astrocytic component. Ganglion cells and hyalinization vessels were observed in both groups. The growth fraction evaluated with monoclonal antibody Ki67Mib1 was low, ranging from 1 to 1.5%. Immunohistochemical detection of synaptophysin played a crucial role in identifying the neuronal nature of these neoplasms and was instrumental in distinguishing them from oligodendrogliomas, with which they are readily confused. The neuronal nature of the oligodendroglial-like cells was confirmed ultrastructurally in one case. The present cases, together with others reported previously, suggest that neoplasms of the CNS with "neurocytic" components are more frequent than generally assumed and expand the morphologic spectrum of neuronal and mixed neuronal-glial tumors. Except for one patient who died postoperatively, all patients were alive at follow-up ranging from 6 to 80 months.


Asunto(s)
Neoplasias Encefálicas/patología , Ventrículos Cerebrales , Neurocitoma/patología , Oligodendroglioma/patología , Adolescente , Adulto , Neoplasias Encefálicas/química , Neoplasias Encefálicas/terapia , Niño , Preescolar , Diagnóstico Diferencial , Resultado Fatal , Femenino , Proteína Ácida Fibrilar de la Glía/análisis , Humanos , Imagen por Resonancia Magnética , Masculino , Microscopía Electrónica , Persona de Mediana Edad , Neurocitoma/química , Neurocitoma/terapia , Sinaptofisina/análisis
17.
Virchows Arch ; 430(1): 47-51, 1997 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9037315

RESUMEN

Central neurocytoma is a benign, slow-growing neoplasm with favourable prognosis. Biomolecular analysis has failed to demonstrate significant alterations, and no cytogenetic alterations have been reported. In this study we demonstrate chromosome 7 gain in three of nine neurocytomas (33%). Traditional cytogenetic analysis performed in four of the nine cases identified trisomy 7 as the sole chromosomal abnormality in one case. Interphase cytogenetics utilizing fluorescent in situ hybridization (FISH) on cell suspensions from formalin-fixed paraffin-embedded tumour tissue performed in all nine cases detected trisomy 7 in two more cases and tetrasomy in another. Our results suggest that chromosome 7 gain is a feature of neuroectodermal tumorigenesis, possibly conferring growth advantage on the neoplastic cells. FISH on interphase nuclei is a valuable adjunct in the genetic evaluation of rare central nervous system neoplasms with low baseline proliferative activity.


Asunto(s)
Aberraciones Cromosómicas/genética , Cromosomas Humanos Par 7/genética , Citogenética/métodos , Hibridación Fluorescente in Situ/métodos , Neurocitoma/genética , Trisomía/genética , Adulto , Neoplasias del Ventrículo Cerebral/genética , Femenino , Humanos , Masculino
18.
Ultrastruct Pathol ; 20(6): 537-47, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-8940761

RESUMEN

Cells with uniform, small-round nucleus and clear cytoplasm (oligodendroglial-like cell, OLC) are commonly observed in central nervous system (CNS) neoplasm of glial and neuronal lineage, such as oligodendroglioma, clear-cell ependymoma, and central neurocytoma. Immunohistochemistry does not always contribute to the characterization of OLC because of (1) loss of antigen expression; (2) lack of specific markers for oligodendrogliomas; and (3) occasional coexpression of neuronal and glial antigens. An ultrastructural analysis associated with an immunohistochemical study of 20 cases of CNS tumors largely constituted by OLCs has been performed. Neurocytomas (12 cases), medullocytomas (2 cases), cerebral neuroblastoma (1 case), and ganglioglioma (1 case) showed OLCs with ultrastructural features of neuronal differentiation (neuritic processes, dense-core granules, synaptic structures). Oligodendroglioma (3 cases) OLCs were characterized by mitochondrial-rich cytoplasm, and ependymoma (1 case) OLCs showed microrosettes and scattered cilia. The electron microscopic analysis can provide a more precise diagnosis of these OLC-containing tumors despite their uniform morphological appearance.


Asunto(s)
Neoplasias del Sistema Nervioso Central/ultraestructura , Oligodendroglía/ultraestructura , Adulto , Neoplasias del Sistema Nervioso Central/inmunología , Niño , Ependimoma/inmunología , Ependimoma/ultraestructura , Ganglioglioma/inmunología , Ganglioglioma/ultraestructura , Humanos , Inmunohistoquímica , Masculino , Persona de Mediana Edad , Neuroblastoma/inmunología , Neuroblastoma/ultraestructura , Oligodendroglía/inmunología , Oligodendroglioma/inmunología , Oligodendroglioma/ultraestructura
19.
Tree Physiol ; 16(1_2): 115-123, 1996.
Artículo en Inglés | MEDLINE | ID: mdl-14871754

RESUMEN

Daily variations in photoprotective mechanisms were studied in sun and shade leaves of 40-year-old cork oak (Quercus suber L.) trees during early summer in Portugal. Although trees were not severely water stressed because predawn leaf water potentials remained high, photosynthesis and stomatal conductance decreased at midday. The midday depression in gas exchange was not reversed by short-term exposure to "optimal" conditions of temperature, light and vapor pressure deficit. Chlorophyll a fluorescence, maximum photochemical yield of photosystem II and the quantum yield of noncyclic electron transport showed midday depressions, but recovered by the evening. Both short-term changes in the components of the xanthophyll cycle (reversible de-epoxidation of violaxanthin during the day) as well as long-term changes (higher xanthophyll content in sun compared with shade leaves) were detected and may play a role in the dissipation of excess energy at midday. Because the activities of enzymes of the antioxidant system, superoxide dismutase and ascorbate peroxidase, were high enough to cope with the increase in oxygen reactive species likely to arise under the stressful conditions of midday, we conclude that these enzymes may provide an additional mechanism for energy dissipation.

20.
Am J Surg Pathol ; 20(1): 112-7, 1996 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8540602

RESUMEN

We report a case of desmoplastic small-cell tumor occurring in the CNS in relation to the tentorium in a 24-year-old man. Morphologically, the neoplasm had the typical appearance of small, round tumor cells of primitive appearance growing as well-defined nests separated by abundant desmoplastic stroma. The diagnosis was confirmed through the demonstration of immunoreactivity for keratin, desmin, and neuron-specific enolase and the detection by Southern blot analysis of a unique gene resulting from the fusion of the WT1 gene in chromosome 11 and the EWS gene in chromosome 22. This is the first documented instance of the occurrence of this tumor type at a distance from a mesothelial-lined surface.


Asunto(s)
Neoplasias Encefálicas/patología , Adulto , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Clonación Molecular , Humanos , Inmunohistoquímica , Imagen por Resonancia Magnética , Masculino , Sarcoma de Ewing/genética , Tumor de Wilms/genética
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