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DIALNET OAI Articles (759,804 recursos)
Dialnet (Difusión de Alertas en la Red) es una plataforma de recursos y servicios documentales, cuyo objetivo fundamental se centra en mejorar la visibilidad y el acceso a la literatura científica hispana a través de Internet.

Ciencias biológicas

Mostrando recursos 1 - 20 de 2,495

1. ¿Es la «ingeniería genética natural» un desafío para la Teoría Sintética? - Diéguez Lucena, Antonio Javier

2. ¿Invasoras o invitadas? - Moreno Ostos, E.

3. Georgiy Frantsevich Gause - Blanco Martín, José María; Aledo, Juan Carlos

4. Respuesta al déficit hídrico de la vid: maneras de adaptarse a la sequía al incrementar la eficiencia en el uso del agua - Cretazzo, Enrico
Climate change represents a serious threat for the future of viticulture. The temperature increase, due to a major atmospheric CO2 concentration, leads to a higher environmental evapotranspiration demand that is a major hydric deficit for plants. All that may be impossible, or at least unprofitable, cultivating grapevine in the Mediterranean area along this century. Therefore, the optimization of water use is necessary in order to avoid, or at least delay, this scenario. On one hand, researchers are constantly looking for technological advances in irrigation management. On the other hand, a deep understanding of vine physiological processes and related molecular pathways is necessary, because they depend both...

5. Notación científica para científicos - Claros Díaz, Manuel Gonzalo

6. Nanotecnología inspirada en la naturaleza: celdas solares sensibilizadas con colorante - Sánchez De Armas, Rocío; Gutiérrez-Beltrán, Emilio
The conversion of solar energy into electricity is one of the best solutions to solve both the problems of global warming and energy shortage. Inspired by the natural photosynthesis, researchers have developed artificial devices, called solar cells, to perform similar photochemical reactions. Dye Sensitized Solar Cells (DSSC), based on an organic or inorganic dye supported on a semiconductor, are one of the most promising type of solar cell. Although this technology has a strong potential for producing a clean energy matrix, it still remains a great challenge to develop a cheap and stable system with high efficiency. Here, we present a brief description on the design...

7. Role of Smad1 in diabetic nephropathy:: Molecular mechanisms and implications as a diagnostic marker - Abe, Hideharu; Matsubara, Takeshi; Arai, Hidenori; Doi, Toshio
Diabetic nephropathy (DN) is the leading cause of chronic kidney failure. Moreover, DN is associated with elevated cardiovascular morbidity and mortality. DN is characterized by progressive expansion of the mesangial matrix and thickening of the glomerular basement membrane, resulting in the obliteration of glomerular capillaries. Advanced glycation endproducts (AGEs) produced as the result of hyperglycemia are known to stimulate the production of extracellular matrix (ECM) proteins, resulting in glomerulosclerosis. Exposure of cultured mesangial cells to AGEs results in a receptor-mediated upregulation of mRNA and protein secretion of type IV collagen (Col4), which is a major component of ECM. Here we...

8. Microglia - insights into immune system structure, function, and reactivity in the central nervous system - Wirenfeldt, Martin; Babcock, Alicia A.; Vinters, Harry V.
Microglia are essential cellular components of a well-functioning central nervous system (CNS). The development and establishment of the microglial population differs from the other major cell populations in the CNS i.e. neurons and macroglia (astrocytes and oligodendrocytes). This different ontogeny gives microglia unique properties. In recent years detailed studies of the microglial population have been greatly facilitated by the use of bone marrow (BM) chimeric animals. Experimental BM transplants have provided the opportunity to trace and investigate how BM cells migrate into the CNS and settle to become microglia. Furthermore various functional properties of microglia in the normal and pathological...

9. DNA repair mechanisms in mammalian germ cells - Ozturk, Saffet; Demir, Necdet
Mammalian germ cells encounter several types of DNA damage. This damage is almost completely repaired in a short period of time to provide the maintenance of genomic integrity. The main repair mechanisms operating in mammalian germline cells are: nucleotide excision repair (NER), base excision repair (BER), mismatch repair (MMR), DNA double strand break repair (DSBR), and post replication repair (PRR). Currently, there are relatively few publications that summarize basic information and new findings on DNA repair mechanisms used in mammalian germ cells. In the present article, we review the studies that discuss repair mechanisms operating in the female and male...

10. Quantitative analysis of vessels with smooth muscle layer in astrocytic tumors:: correlation with histological grade and prognostic significance - Sato, Shinya; Sato, Yuichiro; Hatakeyama, Kinta; Marutsuka, Kousuke; Yamashita, Atsushi; Takeshima, Hideo; Asada, Yujiro
Angiogenesis plays an important role in the progression of astrocytic tumors and its evaluation is a major prognostic factor. Although the form of proliferating vessels ranges from fine capillaries to well-developed vascular structures with a smooth muscle layer, the characteristics of vascular smooth muscle cells (SMCs) are not understood in detail. We therefore examined the density, size and shape of tumor vessels, as well as CD34-immunoreactive (CD34-Vs) or a-smooth muscle actin-immunoreactive (SMA-Vs) vessels in 46 primary astrocytomas (grade II diffuse astrocytomas, n=11, grade III anaplastic astrocytomas, n=15, grade IV glioblastomas, n=20) and in normal brain tissues from 10 autopsies. We...

11. Genetic alterations in pulmonary epithelioid hemangioendothelioma and epithelioid angiosarcoma - Cao, Y.; Zou, S.-M.; Zhang, K.-T.; Lu, N.; Liu, Y.; Feng, L.; Wen, P.; Han, N.-J.; Lin, Dong-Mei
Epithelioid hemangioendothelioma (EHE) is a low-to-intermediate-grade vascular tumor that occurs in many organs, and epithelioid angiosarcoma (EA) is a subtype of angiosarcoma that is associated with high-grade malignancy. These two types of tumors have different forms of biological behavior. Pulmonary epithelioid hemangioendothelioma (PEH) and epithelioid angiosarcoma (PEA) are both very rare, and genetic studies on them are extremely limited. We examined and compared the cytogenetic characteristics of these two types of lung tumors in two patients utilizing the Array-Comparative Genomic Hybridization (Array-CGH) method. Considerable differences in the cytogenetic characteristics were observed between the two types of tumors. Small fragment gains (<10...

12. Decorin and biglycan expression:: its relation with endothelial heterogeneity - Calabrese, Graciela C.; Gazzaniga, Silvina; Oberkersch, Roxana; Wainstok, Rosa
Decorin and biglycan proteoglycans play important roles in the organization of the extracellular matrix, and in the regulation of cell adhesion and migration. Given morphological and functional endothelial heterogeneity, information is needed regarding whether endothelial cells (ECs) from different vascular beds possess different profiles of proteoglycan constituents of the basement membranes. Here, we report that endothelia from different murine organs and EC lines derived thereof produce and secrete different patterns of proteoglycans. A faint colocalization between decorin and PECAM/CD31 was found on tissue sections from mouse heart, lung and kidney by immunofluorescence. Three EC lines derived from these organs produced decorin...

13. Neonatal thymulin gene therapy in nude mice:: Effects on the morphology of the pituitary corticotrope population - Martines, Eliana; Reggiani, Paula; Schwerdt, José I.; Goya, Rodolfo G.; Cónsole, Gloria
The integrity of the thymus during early life is necessary for a proper maturation of the neuroendocrine system, including the adrenal axis. The thymic metallopeptide thymulin seems to be a central physiologic mediator of thymus-pituitary communication. Furthermore, neonatal thymulin gene therapy has been shown to prevent the typical alterations of gonadotrophic cell number and morphology and serum gonadotropin levels in nude female mice. In the present study we assessed the impact of athymia and the effect of neonatal thymulin gene therapy on the corticotropic cell population in nude mice. The effect of thymulin administration to adult nudes on their hypothalamic...

14. The primary cilium:: A relevant characteristic in interstitial cells of rat duodenum enteric plexus - Junquera Escribano, Concepción; Cantarero Carmona, I.; Luesma Bartolomé, Mª José; Soriano-Navarro, Mario; Martínez Ciriano, Carmen; Castiella Muruzabal, Tomás; García-Verdugo, José Manuel
Studies in vitro have permitted the identification of enteric neural progenitor cells. Now the question arises as to where these progenitor cells are located in vivo. The purpose of this paper is to identify possible candidate cells by means of transmission electron microscopy (TEM). We have located three interstitial cellular types around the rat duodenum myenteric plexus. Type I cells have been identified as Interstitial Cells of Cajal (ICCs). These cells present well defined ultrastructural characteristics, including the triple connexion IC- nervous trunk- blood vessels. Type II cells show characteristics of immature cells, emphasizing the presence of a single cilium with...

15. Overexpression of Aquaporin-1 in lung adenocarcinomas and pleural mesotheliomas - López-Campos Bodineau, José Luis; Sánchez Silva, Rocío; Gómez Izquierdo, L.; Márquez Martín, Eduardo; Ortega Ruiz, Francisco; Cejudo, Pilar; Toledo Aral, Juan José; Echevarría, Miriam; Barrot Cortés, Emilia
Aquaporin-1 (AQP1) is the main water channel responsible for water transport through many epithelia and endothelia. The latest evidence pointed toward an important role of this protein also in gas permeation, angiogenesis, cell proliferation and migration. In the present work we studied the expression of AQP1 by immunohistochemical staining of 92 lung biopsies from patients diagnosed with a pleuro-pulmonary tumor (71 lung and 21 pleural neoplasms). AQP1 expression was analyzed comparing the results among the different histological patterns and against 9 control cases (5 parenchyma and 4 healthy pleura). Clear staining of AQP1 was detected in 39 of the 92...

16. Transcription factor snail1 expression and poor survival in pharyngeal squamous cell carcinoma - Jouppila-Mättö, Anna; Tuhkanen, Hanna; Soini, Y.; Pukkila, Matti; Närkiö-Mäkelä, Mervi; Sironen, Reijo; Virtanen, Ismo; Mannermaa, Arto; Kosma, Velli-Matti
Snail1, a key regulator of epithelial-mesenchymal transition (EMT), plays an important role in tumour progression. Previous studies of snail1 have mainly focused on the epithelial tumour cells. The objective of this study was to evaluate the expression of snail1 protein in endothelial cells, stromal myofibroblasts and malignant epithelial cells of pharyngeal squamous cell carcinomas (PSCC), as well as its relation to clinicopathological features and survival. One hundred and ten tissue microarray samples were analyzed for snail1 expression using immunohistochemistry. In endothelial cells snail1 expression was observed in 51 (48%) of 107 cases and it predicted reduced disease specific survival (DSS)...

17. Alterations in the dynamics of inflammation, proliferation and apoptosis in subcutaneous implants of lupus-prone mice - Campos, Paula P.; Vasconcelos, Anilton C.; Ferreira, Mônica A. N. D.; Andrade, Silvia P.
Wound repair is a complex process that involves inflammation, proliferation, extracellular matrix deposition/remodeling and apoptosis. Autoimmune diseases profoundly affect the healing process. We have used histological parameters to characterize the recruitment of mast cells and the proliferative activity and apoptosis in the fibrovascular tissue induced by subcutaneous polyether-polyurethane sponge implants in lupus-prone New Zealand White (NZW) and in control Balb/c mouse strains at days 10 and 21 post implantation. Fibrovascular tissue infiltration (hematoxylin and eosin staining), mast cell number (Dominici staining) and cellular proliferation (AgNOR staining) peaked early (day 10) but collagen deposition (picrosirius red staining) and apoptosis remained high...

18. The use of slaughterhouse-obtained small intestinal tissue as control material in histological studies should be applied with prudence - De Ceulaer, K.; Van Ginneken, C.; Delesalle, C.; Van Brantegem, L.; Deprez, P.; Weyns, A.
This study aimed to evaluate the reliability of slaughterhouse-obtained small intestinal tissue as control material in equine colic research where molecular stress responses in small intestinal tissue are investigated. For this purpose, small intestinal samples from colic horses were collected during surgery or immediately after euthanasia at the oral border of strangulation resection sites and routinely processed for histopathology (i.c. rinsed with 4°C Krebs� solution, fixated overnight with 4% neutral buffered formaldehyde (FH) at room temperature). Control samples consisted of pieces of mid-jejunum, collected at the slaughterhouse and routinely processed for histopathology under 4 different conditions. The 4 conditions differed...

19. Alterations in diet consistency and variation in Hypoxia Inducible Factor-1? expression in condylar chondrocytes - Kaklamanos, Eleftherios G.; Papamitsou, Theodora; Sioga, Antonia; Economou, Louise
Objective. To investigate the expression of HIF-1? during the postnatal development of the mandibular condyle under normal and soft consistency diet conditions. Materials and Methods. Forty eight Wistar-Furth rats, aged 21 days, were divided into two groups, each being fed with either normal or soft consistency diet. Three animals from each group were sacrificed after 3, 7, 10 days (initial period), 14, 17 days (intermediate period), and 21, 24 and 28 days (final period) after the start of the experiment. Immediately after sacrifice, the mandible was excised surgically, fixed, demineralised and embedded in paraffin. Six µm thick sections were obtained,...

20. Efecto del ácido indolbutírico y tipo de estacas en el enraizamiento de copoazú en cámaras de subirrigación - Abanto, Carlos; Cardoso Chagas, Pollyana; Alves Chagas, Edvan; Rengifo Pérez, Christian Paolo; Pérez Flores, Wendy Mishell; Rosello Tamani, Elias; Villacorta Tuesta, Leonidas; Jaymes Vásquez, Milena
El trabajo fue realizado en el área de propagación vegetativa de la estación experimental del IIAP Pucallpa con el objetivo de determinar el efecto del Ácido Indolbutírico y tipo de estacas en el enraizamiento de Theobroma grandiflorum, en cámaras de subirrigación. El estudio se realizó mediante un Diseño Completamente al Azar (DCA), con arreglo factorial 2A x 5B, con 3 repeticiones y 10 estacas por unidad experimental. El factor A fue constituido por dos niveles: estacas semileñosas (apicales) y estacas leñosas (medias) y el factor B por cinco dosis de AIB: 0 ppm, 1000ppm, 3000ppm, 6000 ppm y 9000 ppm...

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