Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
1.
Zygote ; 18(4): 281-91, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20579409

RESUMEN

This work evaluated if an in vitro test, with the combined power of the statistical evaluation of spermatozoa and zona pellucida (ZP) competitive binding ability and a rapid method for accessory sperm counts, could predict the bull fertility. Ten Holstein Friesian bulls of known field fertility (five of high and five of low fertility) were selected. An in vitro heterospermic insemination approach, based on differential staining, was tested on 45 possible pairs of bulls (two batches per bull). Motility and quality (abnormalities and membrane status) seminal characteristics and estimated relative conception rates (ERCR) highlighted only one association between membrane integrity and ERCR (p = 0.007). Differences in ZP binding allowed us to rank bulls into two categories based on low and high binding ability. For eight bulls, this classification reflected the ERCR. Differences between batches were reported for two bulls, in which the effect of heterospermic insemination (the number of sperm binding to ZP from different bulls not in a 1:1 ratio) showed a significant bull-related effect (p < 0.001) in the first batch and no effect (p > 0.05) in the second batch for both bulls. Reduction of the number of oocytes per assay from 25 to 5 had no effect (p > 0.5) on the bulls' ranking. Our results suggest that in vitro competitive binding is a promising approach for estimating bull fertility and support concepts for further implementation, e.g. drastic reduction of oocyte number in a single pair assay and larger scale testing for batches.


Asunto(s)
Bovinos/fisiología , Fertilidad , Espermatozoides/fisiología , Animales , Unión Competitiva , Adhesión Celular , Femenino , Colorantes Fluorescentes , Técnicas In Vitro , Masculino , Análisis de Semen/veterinaria , Recuento de Espermatozoides/veterinaria , Interacciones Espermatozoide-Óvulo/fisiología , Coloración y Etiquetado , Zona Pelúcida/fisiología
2.
AIDS ; 5(12): 1441-6, 1991 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-1814328

RESUMEN

We studied serological aspects of autoimmunity in patients with AIDS, AIDS-related complex (ARC) and in individuals at risk for AIDS. Immunoglobulin (Ig) M, IgG and IgA rheumatoid factors (RF) were quantified by enzyme-linked immunosorbent assay (ELISA), Ig by radial immunodiffusion, and circulating immune complexes (CIC) by the CIC-conglutinin and CIC-complement 1q (C1q) assays. Mean IgM RF levels were normal in AIDS patients, but those of ARC patients were higher and more frequent than the levels defined by agglutination methods. Similar observations were made for intravenous drug users (IVDU) and for both HIV-seropositive and HIV-seronegative homosexual men. Mean IgG RF levels were normal in AIDS and ARC patients but high in homosexual men and, to a lesser degree, in IVDU. IgA RF levels were high in many AIDS and ARC patients, in homosexual men, and in haemophiliac and control groups. The selective increase of the IgA isotype in AIDS was confirmed by the Ig results, which also showed an IgG increase in all groups. IgM were mainly high in people with ARC. CIC were detected in 68% of ARC patients by both methods, and in 55% of AIDS patients by CIC-Clq. A high incidence of positive samples in all at-risk populations, but particularly in seronegative individuals, was observed using CIC-conglutinin. CIC-C1q also revealed larger amounts of CIC in HIV-seronegative individuals, mainly in homosexual men. The study of these humoral aspects of autoimmunity provides useful information on the impairment of B-cells in patients with AIDS and ARC.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Complejo Relacionado con el SIDA/inmunología , Síndrome de Inmunodeficiencia Adquirida/inmunología , Complejo Antígeno-Anticuerpo/sangre , Infecciones por VIH/inmunología , Factor Reumatoide/sangre , Adulto , Enfermedades Autoinmunes/sangre , Niño , Ensayo de Inmunoadsorción Enzimática , VIH-1/inmunología , Humanos , Inmunoglobulinas/sangre , Masculino
3.
Artículo en Inglés | MEDLINE | ID: mdl-18244793

RESUMEN

The success of any reinforcement learning (RL) application is in large part due to the design of an appropriate reinforcement function. A methodological framework to support the design of reinforcement functions has not been defined yet, and this critical and often underestimated activity is left to the ability of the RL application designer. We propose an approach to support reinforcement function design in RL applications concerning learning behaviors for autonomous agents. We define some dimensions along which we can describe reinforcement functions; we consider the distribution of reinforcement values, their coherence and their matching with the designer's perspective. We give hints to define measures that objectively describe the reinforcement function; we discuss the trade-offs that should be considered to improve learning and we introduce the dimensions along which this improvement can be expected. The approach we are presenting is general enough to be adopted in a large number of RL projects. We show how to apply it in the design of learning classifier systems (LCS) applications. We consider a simple, but quite complete case study in evolutionary robotics, and we discuss reinforcement function design issues in this sample context.

4.
Theriogenology ; 79(8): 1171-6, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23523175

RESUMEN

In buffaloes, AI with sexed semen is not fully optimized, and the procedure has only been performed using the approach currently in use for cattle. The objective of the present work was to compare the pregnancy rates in Mediterranean Italian buffalo cows inseminated with sexed frozen-thawed semen at 2, 4, 6, and 8 million sperm per dose, using the Ovsynch protocol and conventional AI at a fixed time. Fresh ejaculates from three buffalo bulls were processed according to Beltsville sperm sorting technology, and packaged in 0.25-mL straws with two total concentrations of 2 and 4 million live sorted sperm per straw. After thawing, semen was evaluated for total motility, forward motility, average path velocity, membrane and DNA integrity, and membrane fluidity. Sorting efficiency was estimated using a real time polymerase chain reaction method developed and validated in our laboratory. The artificial inseminations were conducted during the breeding season on 849 Italian Mediterranean buffalo heifers and cows distributed in 13 farms in northern and central Italy. No significant difference in quality parameters was reported between nonsexed and sexed straws produced with 2 and 4 million sperm. Lower pregnancy rate (P < 0.001) was reported when inseminating doses of sexed semen at 2 million were used (53/170; 31.2%), with respect to conventional nonsexed (78/142; 54.9%), and sexed doses at 4, 6, and 8 million spermatozoa (102/205, 49.8%; 84/175, 48.0%; and 74/157, 47.1%, respectively). No differences were evident using conventional doses and sexed semen with sperm numbers equal or higher than 4 million per dose. Pregnancies were not affected by the sire; 39/82 (47.6%), 120/270 (44.4%), and 151/355 (42.5%), respectively, for the three bulls. Variability in pregnancy rates observed in different herds was not significant. Furthermore, no significant difference was reported between pregnancies obtained with sexed semen in heifers and multiparous, respectively, 179/407 (44.0%) and 131/300 (43.7%). The results of the present work indicate that in Mediterranean Italian buffalo the dose of 4 million represents an optimal compromise when using sexed semen with conventional technologies of insemination, together with estrus synchronization, and the minimum number of spermatozoa per dose. In addition, the real time polymerase chain reaction method was optimized and is now available for estimating sorting efficiency in buffalo.


Asunto(s)
Búfalos/fisiología , Inseminación Artificial/veterinaria , Preservación de Semen/veterinaria , Preselección del Sexo/veterinaria , Espermatozoides/citología , Animales , Bovinos , Separación Celular/métodos , Separación Celular/veterinaria , Criopreservación/veterinaria , Sincronización del Estro/métodos , Femenino , Inseminación Artificial/métodos , Masculino , Embarazo , Índice de Embarazo , Preselección del Sexo/métodos , Recuento de Espermatozoides/veterinaria , Espermatozoides/fisiología
5.
Vet Res Commun ; 34 Suppl 1: S33-6, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20480233

RESUMEN

In dairy cattle breeding, herd reproductive management is the primary focus, affecting a large part of the general costs. A negative association was observed between the level of milk production and fertility. Some studies have shown that a significant percentage of reproductive failure is attributable to semen quality; therefore, if reproduction management is based on artificial insemination, then it is important to assess the fertility level of the sires. In this study, proteomic analysis was used to compare the protein expression profiles from sperm of high- and low-fertility bulls. Comparative proteomic analysis showed that expression of several proteins [nine different two-dimensional electrophoresis (2-DE) spots] is related to fertility level (p

Asunto(s)
Bovinos/fisiología , Fertilidad/fisiología , Perfilación de la Expresión Génica/veterinaria , Proteómica/métodos , Animales , Biomarcadores , Industria Lechera , Regulación de la Expresión Génica/fisiología , Masculino
7.
Evol Comput ; 8(4): 475-93, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11130925

RESUMEN

Holland's Adaptation in Natural and Artificial Systems largely dealt with how systems, comprised of many self-interested entities, can and should adapt as a whole. This seminal book led to the last 25 years of work in genetic algorithms (GAs) and related forms of evolutionary computation (EC). In recent years, the expansion of the Internet, other telecommunications technologies, and other large scale networks have led to a world where large numbers of semi-autonomous software entities (i.e., agents) will be interacting in an open, universal system. This development cast the importance of Holland's legacy in a new light. This paper argues that Holland's fundamental arguments, and the years of developments that have followed, have a direct impact on systems of general network agents, regardless of whether they explicitly exploit EC. However, it also argues that the techniques and theories of EC cannot be directly transferred to the world of general agents (rather than EC-specific) without examination of effects that are embodied in general software agents. This paper introduces a framework for EC interchanges between general-purpose software agents. Preliminary results are shown that illustrate the EC effects of asynchronous actions of agents within this framework. Building on this framework, coevolutionary agents that interact in a simulated producer/consumer economy are introduced. Using these preliminary results as illustrations, areas for future investigation of embodied EC software agents are discussed.


Asunto(s)
Inteligencia Artificial , Evolución Biológica , Algoritmos , Modelos Genéticos , Programas Informáticos
8.
Boll Ist Sieroter Milan ; 69(2): 413-21, 1990 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-2152301

RESUMEN

The behaviour of some serological aspects of autoimmunity was studied in patients with inflammatory bowel disease (IBD) by determining the incidence and levels of serum IgM, IgG and IgA rheumatoid factors (RF) and of circulating immune-complexes (IC) in 67 patients suffering from ulcerative colitis (UC) and 53 from Crohn's disease (CD). Sera from 40 young healthy subjects were included as controls. RF were detected by an enzyme linked immuno-assay (ELISA) and IC by the CIC-conglutinin and the CIC-C1q assays. ELISA detected a higher incidence of IgM RF in both UC and CD groups than the routine agglutination tests, although the mean levels were non significantly higher than in controls. Mean IgG RF levels were significantly above normal in UC and CD patients, the latter showing a greater incidence of elevated values and higher mean levels. IgA RF were significantly elevated only in CD patients; mean values for the UC group were within the normal range. The CIC-conglutinin test did not detect a significant incidence or high mean levels of IC and the CIC-C1q assay turned up a sizeable number of positive samples only in the CD group. Although still only preliminary, these overall findings suggest that RF activity is somehow present in patients with IBD. The greater prevalence of IC in CD patients, together with the patterns of IgG and IgA RF support the concept that this disease possibly involves autoimmune phenomena more than ulcerative colitis.


Asunto(s)
Complejo Antígeno-Anticuerpo/sangre , Colitis Ulcerosa/inmunología , Enfermedad de Crohn/inmunología , Isotipos de Inmunoglobulinas/sangre , Factor Reumatoide/clasificación , Adulto , Niño , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inmunoglobulina A/sangre , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Masculino , Persona de Mediana Edad
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA