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L Luján

Publications and source records attributed to L Luján.

At least 19 recordsLinked to original sources
PubMed2006

Molecular characterization and phylogenetic study of Maedi Visna and Caprine Arthritis Encephalitis viral sequences in sheep and goats from Spain.

Small ruminant lentiviruses (SRLV) are widely spread in many countries, including Spain. However, little is known about the genetic characteristics of Spanish goat and sheep SRLV. In this study, segments from three genomic regions (pol, gag-p25 and LTR) were amplified using DNA isolated from three Spanish autochthonous sheep (one) and goats (two). Animals (one per flock) belonged to distantly located, single-species flocks (goat or sheep). Sequence analysis showed conservation of regions that are putatively relevant to viral survival. Sequences of Spanish goat and sheep SRLV were allocated into phylogenetic trees (phylograms) with known SRLV groups. The phylograms corresponding to the pol, gag-p25 and LTR regions analyzed presented a compatible topology. This showed that Spanish caprine and ovine SRLV sequences belonged to the A or D phylogenetic groups and were closer to sheep SRLV prototypes (A1 group) than to goat SRLV prototypes (B or C groups), according to the current classification [Shah, C., Boni, J., Huder, J.B., Vogt, H.R., Muhlherr, J., Zanoni, R., Miserez, R., Lutz, H., Schupbach, J., 2004a. Phylogenetic analysis and reclassification of caprine and ovine lentiviruses based on 104 new isolates: evidence for regular sheep-to-goat transmission and worldwide propagation through livestock trade. Virology 319 (1), 12-26]. It was not possible to amplify in the three genetic regions the expected fragment in additional Spanish caprine and ovine SRLV proviral DNA sequences with the PCR primers used. This suggests that there is heterogeneity at the primer binding site among Spanish SRLV sequences. It also illustrates the need to develop diagnostic tests that are sensitive in local breeds.

Amino Acid Sequence↗
PubMed2005

Systemic AA-amyloidosis in a European wild boar (Sus scrofa) suffering from generalized tuberculosis.

Summary An adult female wild boar (Sus scrofa) was found moribund in Cabaneros National Park (central Spain). The animal had a markedly emaciated carcass, with body weight of 25.9 kg. At necropsy, most of the parenchymatous organs had widespread variably sized granulomas. Generalized tuberculosis was confirmed by PCR detection of Mycobacterium bovis in the mandibular lymph node. Large amounts of a hyaline, pale eosinophilic material were observed in liver, kidney and intestine. Congo red staining and green birefringence identified amyloid, which was further classified as AA type based on immunohistochemical results. It is speculated that the abundant serum amyloid A derivatives deposited in the tissues as AA-amyloid may be associated with the generalized tuberculosis. This is the first report of amyloidosis in the European wild boar.

Amyloidosis↗
PubMed2004

Ovine pulmonary adenomatosis in Patagonia, Argentina.

An outbreak of pulmonary adenomatosis (OPA) occurred in sheep in Patagonia, Argentina's southernmost region. On the affected farm, nine animals died over a 6-month period with pulmonary lesions of OPA. In all cases, the histology of the lungs was characterized by proliferation of cuboideal and prismatic cells lining the alveoli. Inflammatory exudates and accumulation of alveolar macrophages were marked in most cases, but in six of the cases there was no excess fluid in the airways. The presence of the Jaagsiekte retrovirus was demonstrated in the lungs by immunocytochemistry and PCR. To the best of our knowledge, this is the first report of OPA in Patagonia.

Animals↗
PubMed2003

Clinicopathological features in ovine AA amyloidosis.

This paper describes the clinicopathological findings in sheep with AA amyloidosis. Serum samples from 12 AA amyloid-affected sheep and urine samples from 5 of these ewes were analyzed. In sera, the most important alteration was reflected in hypoalbuminemia, high concentration in beta and gamma-globulins and high levels of serum BUN, phosphorous and potassium. Serum creatinine, cholesterol and calcium concentrations showed no alterations. Urinary analysis showed proteinuria and a high protein/creatinine ratio. In three urine samples, high activities of urinary enzymes gamma-glutamyl transferase (GGT), beta-glucuronidase (GRS) and N-acetyl-beta-D-glucosaminidase (NAG) were observed, their ratios with urinary creatinine being increased for GGT and NAG and decreased for GRS. In conclusion, important alterations in biochemical and urinary parameters were observed in ovine affected by systemic AA amyloidosis. Those related to the activities of urinary enzymes could constitute reliable parameters for assessing renal injury in ovine AA amyloidosis.

Acetylglucosaminidase↗
PubMed2003

Pathology of AA amyloidosis in domestic sheep and goats.

We describe the main pathologic changes in small ruminants affected by AA amyloidosis, together with the partial sequence of the protein involved. Twenty-one sheep and one goat were selected for presenting macroscopic kidney lesions compatible with systemic amyloidosis. Available tissue samples were studied by histologic, immunopathologic, and ultrastructural means. Renal lesions were characterized grossly by pale cortical surfaces with scattered, miliary, whitish-yellow foci and on cut cortical surfaces by straight, whitish-yellow striations. Gangrenous pneumonia was observed in 16 out of 21 affected sheep (76.2%), although other chronic inflammations were also observed. Amyloid was detected in all grossly affected kidneys using Congo red staining, lesions being most remarkable in glomeruli, affecting 95.5% of animals studied. Congophilic deposits were also observed in intertubular interstitium (68.2%) and medulla (57.1%). All amyloid-affected animals presented proximal convoluted tubule lesions, mostly characterized by an increase in diameter and by hyaline granular degeneration that were responsible for the macroscopic appearance of the kidney. Histologically, amyloid was also seen in blood vessels, spleen, liver, lymph nodes, gastrointestinal tract, and adrenal glands. All amyloid deposits demonstrated greenish-yellow birefringence with polarized light, and the antisera prepared against goat amyloid extracts specifically reacted with birefringent congophilic deposits of both sheep and goats. Ultrastructurally, these deposits were formed by masses of straight, nonbranching fibrils located predominantly in the basement membranes of glomerular capillaries and in the mesangium. Partial sequence of the protein in sheep and goats indicated a high degree of homology with the previously reported sequence of sheep Serum Amyloid A.

Amino Acid Sequence↗
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

Early detection of maedi-visna (ovine progressive pneumonia) virus seroconversion in field sheep samples.

The aim of this work was to investigate whether an enzyme-linked immunosorbent assay (ELISA) was useful for early detection of maedi-visna virus (MVV) infection in sheep under field conditions. An ELISA based on p25 recombinant protein and a gp46 synthetic peptide was used. Sequentially obtained serum samples (n = 1,941) were studied for 4 years. ELISA results were compared with those of the agar gel immunodiffusion (AGID) test, and results of both tests were compared with a reference result established using consensus scores for at least 2 of 3 serologic techniques (AGID, ELISA, and western blotting, which was used to resolve result discrepancies between the other 2 techniques). A total of 247 discrepancies were observed between ELISA and AGID. Of these, 131 were due to an earlier detection of 120 sera by the ELISA and 11 sera by AGID. The remaining discrepancies (116) were due to the presence of false reactions in both tests. Fewer false-negative results were found by ELISA than with AGID (6 vs. 69 sera, respectively), whereas the number of false-positive results was virtually the same for ELISA and AGID (21 vs. 20, respectively). In relation to the reference result, ELISA sensitivity and specificity were 97.8% and 98.2%, respectively, whereas values for AGID were 76.3% and 98.3%, respectively. The agreement between ELISA and the reference result was higher than that between AGID and the reference result (K value: 0.96 and 0.77, respectively). A variation in the ELISA signal (based on optical density) was observed during the study period, suggesting different antibody levels throughout the animal's life. The ELISA was useful for detecting MVV-infected sheep in field conditions and has potential for use in control and eradication programs.

Animals↗
PubMed1998

Colorectal sarcoma: analysis of failure patterns.

BACKGROUND AND OBJECTIVES: Colorectal sarcomas (CRS) are rare and their treatment remains controversial, especially for those located in the rectum. The aim of this paper is to evaluate our experience, with special emphasis on the failure pattern after surgical therapy alone or combined with postoperative radiotherapy. MATERIALS AND METHODS: The medical records and histological slides of 13 CRS patients treated between 1986 and 1996 were reviewed retrospectively. RESULTS: The patients included eight males and five females, with a median age of 54 years; nine of their primary tumors were located in the rectum, and four in the colon. The histologies were leiomyosarcoma in nine cases and malignant fibrous histiocytoma in four cases. Surgical treatment consisted of anatomical colectomy (four); local excision (three); abdominoperineal resection (APR)(two); low anterior resection (LAR)(two); LAR en bloc with the prostate (one), and total pelvic exenteration (one). One operative death occurred. The median size of the tumors was 8 cm (range, 5-40). The tumors were graded as low, three, and high, ten. The median follow-up was 24 months. Eight patients in the overall group developed recurrences as follows: local, three; local and distant, three, and distant, two. Five out of nine patients with rectal sarcoma received adjuvant postoperative radiotherapy (PRT). Local recurrence occurred in 20% (1/5) of those who received PRT, and in 100% (3/3) of those who did not. The overall 5-year survival was 40%, and the 5-year survival for patients with low-grade tumors was 66%, as compared with 22% for those with high-grade tumors. CONCLUSIONS: The patterns of failure in CRS are combined in both local and distant sites. However, our results suggest that in rectal sarcoma, the use of surgery + PRT may reduce the local recurrence rate; in selected patients, it may allow for anal sphincter preservation.

Adult↗
PubMed1997

Effect of in vitro maedi-visna virus infection on adherence and phagocytosis of staphylococci by ovine cells.

This work was aimed at studying the effect of maedi-visna virus (MVV) infection in vitro on the ability of sheep cells to adhere to staphylococci (Staphylococcus aureus and Staphylococcus epidermidis), and phagocytose these bacteria. Adherence was studied in sheep choroid plexus cells (SCPC) using an ELISA test and phagocytosis was studied in pulmonary alveolar macrophages (PAM) by chemiluminescence. A 5- and 7-day of in vitro MVV infection resulted in syncytium formation and a significant increased adherence (P < 0.01) of SCPC to bacteria. SCPC endogenous fibronectin was significantly higher (P < 0.01) on days 5 and 7 than on day 0 of MVV infection. A significantly decreased phagocytosis (P < 0.05) was also observed on days 5 and 7 of MVV infection in PAM when compared to MVV-free controls. Comparatively, phagocytosis was highest for S. aureus non-slime producing strains, followed by S. epidermidis, and S. aureus slime producing strains, in that order. Finally, increased expression of both, class I and class II major histocompatibility antigens was also observed in MVV-infected PAM on days 5 and 7, whereas SCPC only demonstrated upregulation of MHC class I. These results, indicative of an alteration of some cell functions in MVV-infected cells, may help to understand interactions between MVV-infected cells and bacteria in simultaneous infections and may provide clues to the possible in vivo interactions of both pathogens.

Animals↗
PubMed1996

Early pulmonary cell response during experimental maedi-visna virus infection.

A model of experimental infection with EV1, a British isolate of maedi-visna virus (MVV), has been developed. Twelve male Texel sheep were allocated to three groups and inoculated by the respiratory route with different inocula. Six of the animals received 10(7.2) tissue culture infective dose (TCID50) of MVV EV1 strain. Two sheep were inoculated with the same dose of heat inactivated MVV EV1 strain. An additional group of four sheep was sham-inoculated with identically prepared virus-free culture media. Experimental infection was followed for 16 weeks. Prior to inoculation, routine haematology, bronchoalveolar lavage (BAL) and flow cytometric analysis of bronchoalveolar lavage fluid (BALF) lymphocytes were performed in all animals to provide baseline parameters. Flow cytometric analysis of BALF lymphocytes and differential BALF cell counts were performed. Precipitating antibodies to MVV developed in all MVV-inoculated animals during the first 4 weeks post-inoculation, while the rest remained seronegative to MVV. MVV-infected animals had significantly decreased (P < 0.05) percentages of macrophages and significantly increased (P < 0.05) percentages of lymphocytes in BALF 4 weeks post-inoculation. Phenotypic changes in BALF T lymphocytes from MVV-inoculated animals, compared with the other two groups, showed significantly decreased (P < 0.05) percentages of CD4+ and gamma delta + T lymphocytes, significantly increased (P < 0.05) percentages of CD8+ lymphocytes and significant inversion (P < 0.05) of the CD4+/CD8+ ratio at different sampling times, but between 2 and 12 weeks post-inoculation. These findings indicate that during experimental MVV-infection an early, short-term cellular reaction occurs in the lung, that is characterised by T lymphocyte phenotypic changes that are very similar, if not identical, to those observed in natural MVV infection.

Animals↗
PubMed1995

Quantitation of transforming growth factor-beta in plasma and pulmonary epithelial lining fluid of sheep experimentally infected with maedi-visna virus.

A model of experimental infection with EV1, a lytic British isolate of maedi-visna virus (MVV), was developed. Ten Texel sheep were allocated to two groups and inoculated by the respiratory route with different inocula. Six of the animals received 10(7.2) TCID50 (tissue culture infective dose) of EV1 strain, while four sheep were sham-inoculated with identically prepared virus-free buffer solution. Experimental infection was followed for 8 weeks post-inoculation (PI), with development of precipitating antibodies to MVV developed in the MVV-inoculated animals during the first 4 weeks PI. Transforming growth factor-beta (TGF-beta) levels, in both bronchoalveolar lavage fluid supernatant and plasma samples, were measured. Concentrations of pulmonary epithelial lining fluid (PELF) TGF-beta were calculated. TGF-beta concentrations in PELF were approximately 165-fold higher than in plasma. No significant differences in the concentrations of plasma or PELF TGF-beta, either within or between groups, were observed.

Animals↗
PubMed1995

In vitro response of lymphocytes from bronchoalveolar lavage fluid and peripheral blood to mitogen stimulation during natural maedi-visna virus infection.

To investigate the effects of maedi-visna virus (MVV) infection on cell-mediated immunity, the in vitro response of bronchoalveolar lavage fluid (BALF) and peripheral blood (BP) lymphocytes (PBL) to exogenous mitogen was analysed. BALF and PBL from control (n = 9) and MVV-infected (n = 7) animals were cultured fro 3 days in the presence and absence of concanavalin A (Con A). Lymphocyte expression of the interleukin-2 receptor (IL-2R) antigen, a parameter of lymphocyte activation, was quantified by dual-colour flow cytometry using the bovine anti-IL-2R monoclonal antibody IL-A111. IL-2R expression by lymphocytes in BALF and PB from control and MVV-infected animals, with and without Con A stimulation, were compared. In the absence of Con A stimulation, the proportion of cultured BALF CD8+ and gamma delta T cells expressing IL-2R was significantly (P < 0.05) lower for MVV-infected animals than for controls. After Con A stimulation the proportion of BALF CD4+ lymphocytes from MVV-infected animals that expressed IL-2R remained significantly (P < 0.05) lower than for controls. Comparisons within group showed that, after Con A stimulation, the proportion of all the T cell subsets in the control group expressing IL-2R, namely CD4+ (P < 0.001), CD8+ (P < 0.001) and gamma delta T cells (P < 0.05), was significantly increased. In the MVV-infected group, this increase was significant (P < 0.05) for CD4+ and CD8+ T cells, but not for gamma delta T cells. In vitro mitogen stimulation of PB T lymphocytes from both control and MVV-infected animals induced a significant elevation in the proportion of all T cell subsets expressing IL-2R when compared to cultured unstimulated control cells. However, there was considerable heterogeneity in the response to Con A of PB T cells from both groups of animals. The expression of IL-2R followed a different pattern to that of BALF lymphocytes, the proportion of unstimulated gamma delta / IL-2R+ T cells from MVV-infected animals being significantly (P < 0.05) higher than that of controls, and the proportion of cultured unstimulated CD8+ / IL-2R+ T cells from MVV-infected animals being significantly (P < 0.05) lower than that from controls. From these studies it can be concluded that the BALF T lymphocyte immune dysfunction observed during natural MVV infection, characterized by impaired IL-2R expression, is maintained under in vitro conditions.

Animals↗
PubMed1995

CD8+ lymphocytes in bronchoalveolar lavage and blood: in vivo indicators of lung pathology caused by maedi-visna virus.

A study to determine the putative relationship between lymphocyte phenotypic alterations in bronchoalveolar lavage fluid and stage of lung pathology in maedi-visna infected sheep has been carried out. Twenty-one ewes (16 Texel and five Scottish blackface) naturally infected by maedi-visna virus and three Oxford controls were used. Animals were killed, lungs were removed, bronchoalveolar lavage was performed and pathological studies were completed. Blood samples were also obtained from 16 animals. Lymphocytes in both bronchoalveolar lavage and peripheral blood were labelled with monoclonal antibodies against the main T lymphocyte subsets (CD4, CD8, CD5 and gamma delta TCR) in order to perform flow cytometric studies. Three aspects of pathology were studied: lymphoid interstitial pneumonia, lymphoid follicular hyperplasia and smooth muscle hyperplasia. Percentages of CD4+, CD5+, gamma delta + T cells and the value for the CD4+ / CD8+ ratio in bronchoalveolar lavage of maedi-visna infected animals were significantly decreased (P < 0.05) when compared to controls, while percentages of CD8+ lymphocytes were increased in bronchoalveolar lavage of infected sheep and they were very close to being significant (P = 0.07) when compared to controls. Lesions were evaluated and simple least-squares regression tests demonstrated that there were several significant correlations between various lymphocyte subsets and pathological parameters studied in this work. However, when a multiple regression test was applied to the data, it was observed that only the CD8+ T cell subset both in bronchoalveolar lavage and in blood was significantly correlated with severity of lung pathology. It is concluded that CD8+ lymphocytes are key cells in the development of the interstitial reaction and the lymphocytic alveolitis observed in maedi-visna infected ewes and that the CD8+ alveolitis is a parallel feature to the intensity of lung lesions. It is further suggested that the percentage of CD8+ lymphocytes in bronchoalveolar lavage and in blood may act as in vivo indicators of lung pathology in maedi-visna infected sheep.

Animals↗
PubMed1994

Exponential analysis of the pressure-volume characteristics of ovine lungs.

Static pressure-volume curves were generated from data obtained from 18 normal anaesthetized adult sheep. Lung volumes were determined by helium dilution. An exponential curve of the form V = Vmax - Ae-KP was fitted to the pressure-volume data from each sheep where P is the static recoil pressure, Vmax represents the volume asymptote, A is the difference between Vmax and the intercept on the volume axis and K defines the slope and hence the shape of the P-V curve. Quality of fit of the data was assessed visually, by means of a sign test and a runs test and by the coefficient of determination (r2). Exponential equations were found to adequately describe the shape of the pressure-volume curve in sheep. The exponent K was not correlated with effective alveolar volume (VAeff) (rs = 0.183; P > 0.05). Static lung compliance was determined over a volume range from the end-expiratory level (VEEL) to VEEL plus 400 ml. Measurements of static lung compliance were significantly correlated with measurements of effective alveolar volume (VAeff) (rs = 0.505; P < 0.025). In the ovine, the exponent K, an index of distensibility, is independent of lung volume and offers a means of assessing lung distensibility in this species.

Air Pressure↗
PubMed1994

Pathophysiologic correlations in lymphoid interstitial pneumonia.

Effective alveolar volume, diffusing capacity for carbon monoxide (DCOsb), volume-corrected diffusing capacity (D/VA), static lung compliance (Cst), and lung distensibility were measured in 16 sheep seropositive for maedi-visna virus (MVV) immediately before they were killed. Lungs were inflation-fixed, and the left lung was randomly sampled for morphometric analysis. The total lung weight, total fixed lung volume, volume densities of tissue (Vvt) and air (Vva), and the alveolar surface density were measured and correlated with the physiologic measurements. The density of surface forces could not account for the variation in the distensibility of the lungs, indicating that tissue-related forces may be important in determining lung distensibility in lymphoid interstitial pneumonia (LIP) associated with MVV infection. Possible sources of tissue-related forces are the contractile tissue associated with lung parenchyma, airways, or vasculature. When DCOsb was corrected for volume, a strong negative correlation with Vvt was noted, indicating that factors distinct from lung-volume reduction are important in limiting gas exchange in LIP associated with MVV infection. More sheep demonstrated abnormal D/VA values than any other physiologic measurement, with reduced values being apparent even in sheep considered clinically normal and with little or no morphometric evidence of lung disease. Measurements of diffusing capacity are thus considered the most sensitive functional index of disease progression.

Animals↗