Biomedical subjects

L Monteagudo

Publications and source records attributed to L Monteagudo.

5 recordsLinked to original sources

PubMed2006

Effect of the quinolone coccidiostat decoquinate on the rearrangement of chromosomes of Eimeria tenella.

The present report concerns our attempts to further study the effect of quinolone coccidiostats on the sporulation of Eimeria tenella oocysts by analyzing the meiotic behaviour of the chromosomes. To that end, synaptonemal complexes were analyzed by TEM applied to intact meiotic chromosomes. These were isolated after disruption of oocysts, which were harvested from decoquinate-medicated and non-medicated (control) birds. In oocysts from control birds, synaptonemal complexes appeared as the 14 bivalents of the normal karyotype. However, in oocysts from medicated birds, our synaptonemal complex analysis revealed a reciprocal translocation, which was observed as an irregular pairing of chromosome axes 5 and 12 resulting in quadrivalent and trivalent configurations. This finding suggests breakage points in chromosomes 5 and 12 and exchange of chromosomal segments. Furthermore, breakpoints in chromosome 12 resulted in telomere deletion. The chromosomal aberrations described in the present study may result in reduced sporulation since chromosomes involved in translocations segregate abnormally during meiosis. In addition, the results reported provide new evidence of the inhibitory effect of quinolones on the sporulation of E. tenella oocysts, since sporocysts were not formed.

Animals↗

PubMed2002

Fetal anasarca (Hydrops foetalis) associated with lymphoid tissue agenesis possibly due to an autosomal recessive gene defect in sheep.

Fourteen hydrops fetalis cases appeared in a sheep flock in the Soria province of Central Spain in two lambing seasons in 2000. There were no previous cases of hydrops fetalis in this flock. Normal delivery could not be completed because fetal weights ranged from 12 to 16 kg and fetuses had massive subcutaneous edema. Five affected pregnant females were studied. The complete lack of lymph nodes in the fetuses was the most outstanding finding, this anomaly likely being the origin of generalized fluid accumulation. Karyotypes were normal. A blind protocol of parentage testing was performed by means of DNA microsatellite analysis, and one of the five existing rams was found to be the only compatible sire of the affected fetuses. This male had been selected from the same flock while the other rams had all been acquired from other farms. The first cases appeared when this ram began breeding, and no cases were observed after replacing it. Male and female fetuses were affected in similar proportions. The existence of a recessive allele affecting normal lymph node embryonic development in this flock is proposed as the most appropriate hypothesis. As a consequence, the use of rams from different farms is indicated as an efficient emergency measure in similar situations, while the affected flock should be excluded from selection programs as long as the anomalous gene remains unidentified.

Animals↗

PubMed2001

Differential secretion of Fas ligand- or APO2 ligand/TNF-related apoptosis-inducing ligand-carrying microvesicles during activation-induced death of human T cells.

Preformed Fas ligand (FasL) and APO2 ligand (APO2L)/TNF-related apoptosis-inducing ligand (TRAIL) are stored in the cytoplasm of the human Jurkat T cell line and of normal human T cell blasts. The rapid release of these molecules in their bioactive form is involved in activation-induced cell death. In this study, we show by confocal microscopy that FasL and APO2L/TRAIL are mainly localized in lysosomal-like compartments in these cells. We show also by immunoelectron microscopy that FasL and APO2L/TRAIL are stored inside cytoplasmic compartments approximately 500 nm in diameter, with characteristics of multivesicular bodies. Most of these compartments share FasL and APO2L/TRAIL, although exclusive APO2L/TRAIL labeling can be also observed in separate compartments. Upon PHA activation, the mobilization of these compartments toward the plasma membrane is evident, resulting in the secretion of the internal microvesicles loaded with FasL and APO2L/TRAIL. In the case of activation with anti-CD59 mAb, the secretion of microvesicles labeled preferentially with APO2L/TRAIL predominates. These data provide the basis of a new and efficient mechanism for the rapid induction of autocrine or paracrine cell death during immune regulation and could modify the interpretation of the role of FasL and APO2L/TRAIL as effector mechanisms in physiological and pathological situations.

Antibodies, Monoclonal↗

PubMed2001

A method for the sequential study of eimerian chromosomes by light and electron microscopy.

In the present study, the authors describe a simple method to isolate chromosomes from eimerian oocysts and to submit them to sequential study by light and electron microscopy. This method includes a reliable and reproducible technique for transferring eimerian chromosomes from slides to grid that fulfills the essential requirements for generalized use in cytogenetics. In addition, this method overcomes the difficulty of the resistance of protozoan oocysts to disruption and permits the release of intact meiotic chromosomes. The observation by the authors of synaptonemal complexes in meiotic chromosomes of different Eimeria species by applying the above-mentioned method to oocysts revealed its importance to future applications.

Animals↗

PubMed1993

Accurate characterization of porcine bivariate flow karyotype by PCR and fluorescence in situ hybridization.

The 19 chromosomal pairs of the swine karyotype are resolved into 18 peaks denoted A to Q and Y by dual-beam flow cytometry. The chromosomal content of six peaks has previously been determined by analyzing male/female differences, karyotypes of animals carrying translocations, and PCR studies of genes with known assignments. For the remaining chromosomes, putative assignments to flow peaks were deduced from comparison of DNA contents, determined by flow cytometry, and chromosomal size. We present here the complete characterization of the pig bivariate flow karyotype using the PARM-PCR technique combined with fluorescence in situ hybridization. Chromosome-specific probes were generated by PCR amplification of 300 sorted chromosomes with primers under nonspecific conditions and used to paint chromosomes by FISH. The chromosomal content of each peak was identified: peaks A (chromosome 1), B (13), C (6), D (2), E (14), F (3), G (7), H (9,4,X), H1 (9), I (15), J (8), K (5), L (10), M (12), N (16), O (11), P (17), Q (18), Y (Y). We were able to characterize perfectly the pig bivariate flow karyotype. Such techniques could be applied to any other species.

Animals↗