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Biomedical subjects

I Navarrete

Publications and source records attributed to I Navarrete.

At least 37 records · Page 2Linked to original sources
PubMed1996

Epidemiological survey of hypodermosis in western Spain.

A serological survey was carried out to establish the prevalence of hypodermosis in Extremadura, a region of western Spain. Direct clinical methods and an enzyme linked immunosorbent assay (ELISA) were used to examine 1668 cattle between February 1992 and March 1993. An overall prevalence of 19.54 per cent was observed by the direct methods, and a prevalence of 42.3 per cent by the ELISA. The sensitivity and specificity of the ELISA for hypodermosis were assessed, and the fluctuation of antibody levels was studied throughout the year and correlated with the age of the host, the intensity of parasitism and the mean larval burden.

Animals↗
PubMed1996

Antigenic cross-reactivity in mice between third-stage larvae of Anisakis simplex and other nematodes.

We used ELISA and immunoblotting to investigate antigenic cross-reactivity in mice between third-stage larvae of Anisakis simplex and five other nematodes: the ascaridoids Ascaris suum, Toxocara canis and Hysterothylacium aduncum, and the nonascaridoids Trichinella spiralis and Trichuris muris. Two sera were raised against each species (including A. simplex, but excluding A. suum), by infection or by immunization with somatic antigens. Serum against A. suum was raised by immunization only. The reactivities of each serum with A. simplex somatic antigens (SA), excretion-secretion antigens (ES), pseudocoelomic fluid antigens (PF) and cuticular antigens (CA) were investigated. The results of ELISA indicated high antigenic cross-reactivity between A. simplex and the remaining ascaridoid nematodes, confirming that there is extensive antigenic similarity within this group of nematode parasites. Immunoblotting again confirmed the high degree of cross-reactivity between the SA of A. simplex and SAs of the other ascaridoids, although several A. simplex SA components in the 11-18 kDA range were only recognized by sera from mice infected with A. simplex. In addition, two A. simplex PF components of 22 and 27 kDA, were recognized only by sera from mice infected with, or immunized with the SA of, A. simplex. Finally, the anti-phosphorylcholine monoclonal antibody BH8 recognized only a small number of A. simplex antigens, indicating that phosphorylcholine epitopes are not significant contributors to the observed cross-reactivity with the other nematodes.

Animals↗
PubMed1996

Experimental trichinellosis in goats.

The susceptibility and distribution of Trichinella spiralis infection in goats were examined in ten autochthonous kids, 2 months old and about 10 kg body weight. The animals were divided into two groups: one experimental group with eight animals, infected with 10,000 T. spiralis 'T1' encysted larvae and a control group with two non-infected animals. All the animals of the experimental group infected by the parasite showed that Trichinella larvae have a special affinity for the tongue, masseters, diaphragm, flexor-extensor muscles, intercostal muscles and myocardium in decreasing order. The ELISA test carried out showed the first increments of optical density (OD) on Day 16 postinfection (p.i), peaking on Days 37-44 p.i. and remaining elevated from this day on, with a slight fall at the end of the experiment (Day 90 p.i.). No alterations were observed in the OD obtained in control animals throughout the experiment. The great muscular establishment of T. spiralis larvae and the sigmoidal evolution of antibody levels confirm the host character of the goat to the parasite.

Animals↗
PubMed1996

Presence of antibodies in the aqueous humour and cerebrospinal fluid during Leishmania infections in dogs. Pathological features at the central nervous system.

In the present paper we show that in dogs, naturally infected with Leishmania infantum, the aqueous humour and the cerebrospinal fluid contain anti-Leishmania IgGs and that the specificity of antigen recognition of these fluids is similar to that of the sera. We also show that in the encephalon and cerebellum of these dogs there is a pathological sponge-like reaction accompanied by neuronal degeneration, mobilization of glial cells together with accumulation of amyloid deposits. The interstitial and intravascular deposition of IgGs and Leishmania antigens in choroid plexus suggest that in these animals there is a failure of the blood-cerebrospinal and ciliary bodies filtration barriers which may allow the transfer of anti-Leishmania IgGs from the blood stream to these fluids. We suggest that the failure of the blood-cerebrospinal barrier and the in situ concentration of anti-Leishmania IgGs and antigens in brain tissues may predispose to the pathological features detected in this compartment.

Animals↗
PubMed1994

Alkyl glycerol monoethers in the marine sponge Desmapsamma anchorata.

1-O-Hexadecylglycerol (chimyl alcohol), 1-O-heptadecylglycerol and 1-O-octadecylglycerol (batyl alcohol) have been identified as the major native constituents of a mixture of free alkyl glycerol ethers isolated from the contained water and the methanolic extract of the sponge Desmapsamma anchorata. Minor components were the free C14, C15, C19, C20 and C21 alkyl glycerol monoethers. The alkyl glycerol monoethers were analyzed and identified by gas chromatography/mass spectrometry of their isopropylidene derivatives. This is the first report on the occurrence of free C15, C19, C20 and C21 alkyl glycerol monoethers in a sponge.

Animals↗
PubMed1993

Genomic organization and expression of two independent gene arrays coding for two antigenic acidic ribosomal proteins of Leishmania.

In the present paper we describe the isolation and characterization of four novel genes of the parasitic protozoan Leishmania infantum. These genes are organized as two independent gene clusters, and they are related by nucleotide sequence to eukaryotic genes encoding acidic ribosomal proteins. Each gene cluster contains two tandemly linked genes coding for identical proteins. Each of the proteins coded by the gene clusters (called LiP and LiP') are highly divergent in sequence, showing the characteristic features of eukaryotic P-proteins from the P2 group. In spite of the sequence conservation of the coding regions of each of the genes in the cluster, the 5'- and 3'-untranslated regions are heterogeneous in sequence. The analysis of the expression of these genes indicates that logarithmic phase promastigotes show increased levels of LiP- and LiP'-specific transcripts compared with stationary phase promastigotes. The steady state RNA levels of the LiP and LiP' genes show a similar dependence of the growth phase of the parasite. Using specific probes for the divergent 3'-untranslated regions of each of the genes, it was found that the abundance of the mature transcripts is different even when the transcripts are derived from the same gene cluster. These findings probably indicate that the 3'-untranslated regions may influence the stability or turnover of the transcripts derived from both LiP and LiP' gene clusters.

Amino Acid Sequence↗
PubMed1993

Dynamics of porcine humoral responses to experimental infections by Spanish Trichinella isolates: comparison of three larval antigens in ELISA.

Five groups of six helminth-free pigs of the Iberian and Landrace x White breeds were each experimentally-infected randomly at a dose of 150 larvae per kg, body weight with one of the five Trichinella isolates, coded as Gm-1, Co-77, Laso, C-76 and Mad-83. These isolates were selected from the two Trichinella species (T. spiralis and T. britovi) so far identified in the Iberian Peninsula. Specific antibodies against the infections were measured on days -14, 0, 6, 16, 20, 27, 34, 49, 63 and 82 post-infection (p.i.), in a comparative indirect ELISA assay using three different antigens prepared from the muscle stage of the parasite. The antigens were a crude saline larval extract (CSLE), excretory-secretory (ES) and surface stripped cetyl-trimethyl ammonium bromide detergent (CTAB) products. Over all, the dynamics of antibody responses were very similar for infections with the five different isolates, although a significant delay in positive and maximum antibody titres was seen in the group infected with C-76, the isolate exhibiting a marked low infectivity to domestic mammals. ELISA with the crude antigen was more sensitive (positive antibody titres appeared between days 6 and 16 p.i.) than with the ES and CTAB preparations (positive titres appeared between days 16 and 20 p.i.). For infections with the C-76 isolate, positive titres appeared between days 16 and 20 p.i. with the CSLE antigen and, on day 27 p.i. with the ES and CTAB antigens. Little cross-reactivity with other common porcine helminth infections appeared only when ELISA was carried out with CSLE and CTAB antigens.

Animals↗
PubMed1992

Molecular characterization of a Leishmania donovani infantum antigen identified as histone H2A.

A Leishmania donovani infantum promastigote cDNA expression library was screened with a serum obtained from a dog naturally infected with this parasite. One of the positive clones obtained revealed nucleotide sequence similarities with the histone H2A genes from various organisms. Northern blot analyses and sequence data of three independently isolated cDNA clones indicated that the Leishmania H2A mRNAs are polyadenylated, as are the basal histone mRNAs of higher eukaryotes and the histone mRNAs of yeast. The analysis of the genomic distribution of the DNA coding for histone H2A suggested that, in L. d. infantum, there are at least four genes coding for the H2A protein. It is likely that there is a simultaneous expression of at least two of the H2A genes since differences in nucleotide sequence between two of the sequenced cDNAs were observed. Affinity-purified antibodies against the beta-galactosidase-fused H2A protein recognize specifically a Leishmania protein band with a molecular mass of 14 kDa.

Amino Acid Sequence↗
PubMed1992

Sarcocystis jorrini sp. nov. from the fallow deer Cervus dama.

Sarcocystis jorrini sp. nov. isolated from the muscle of naturally infected fallow deer (Cervus dama) from the Doñana National Park (Spain) is described by light and electron microscopy. Sarcocysts were macroscopic (2.7 x 1.4 mm) and were found in all striated muscle, including that of the esophagus and the heart. As visualized by light microscopy, the cyst walls were formed by mammilated protrusions surrounded by a coating of connective tissue measuring 10-35 mm in thickness. Electron microscopy revealed that the parasitophorous vacuole was serrated in appearance, with numerous pinocytic vesicles running along its whole length. Villar protrusions were of varying shape and were square, rectangular, or linguiform in cross section. The core of the villi contained small dense granules and microfilaments, which were more abundant in peripheral areas. Ground substance contained larger dense granules clustered around the base of villi. The sarcocyst was surrounded by a secondary cyst wall composed of collagen fibrils and fibrocytes. S. jorrini is the first macroscopically visible sarcocyst of the genus Cervus reported to have a secondary cyst wall.

Animals↗
PubMed1992

Pathological changes in kidneys of dogs with natural Leishmania infection.

A study was made of the nephropathy in canine leishmaniasis produced in ten adult dogs naturally infected with Leishmania infantum. Renal function analyses were performed (uraemia, creatinaemia, plasma proteins, biochemistry and urinary sediment), the humoral immune response (fluorescent antibodies and levels of serum IgG, IgM and IgA) was assessed and histopathological studies were carried out. Correlation of the results showed acute renal insufficiency which was reversible in two animals (endotheliomesangial glomerulonephritis) and irreversible in four cases corresponding to glomerulonephritis in its Type I and Type II proliferative forms; extensive increase in the glomerular basal membrane, proliferation of mesangial cells and growth of the mesangial matrix were observed, as was a widespread incidence of immune complex deposits. Two animals showed chronic renal insufficiency. Lack of renal changes (minimal-changes glomerulonephritis) in two dogs was accounted for in one animal by an almost complete absence of symptoms and in the other by chronic viscerocutaneous symptoms; neither showed more than a slight immunoglobulin response.

Acute Kidney Injury↗
PubMed1992

Changes in the plasma concentrations of lipids and lipoprotein fractions in dogs infected with Leishmania infantum.

A study was made of serum concentrations of cholesterol, phospholipids, triglycerides, cholesterol bound to high-density lipoproteins (HDL), HDL1-cholesterol, HDL2-cholesterol and cholesterol bound to low-density lipoproteins (LDL) in 16 dogs naturally infected with Leishmania infantum (ZMON-1) taken from an endemic focus. Results were compared with those of a control group of ten healthy dogs. Statistically significant increases in cholesterol, triglyceride and LDL-cholesterol levels were observed. There was, however, a statistically significant decrease in HDL-cholesterol level, mainly at the expense of the HDL2-cholesterol subfraction. Cholesterol transport is therefore shown to undergo changes which may be attributed to the consumptive evolution of the disease, immunocomplex deposits in cells, hepatic disorders and interactions between the parasite and the normal cholesterol metabolism of the host.

Animals↗
PubMed1992

Trichinella strain, pig race and other parasitic infections as factors in the reliability of ELISA for the detection of swine trichinellosis.

An enzyme-linked immunosorbent assay (ELISA) using crude worm extracts (CWE) and mixtures of these as antigens of five Spanish isolates (P, C, B1, B2 and W) was developed for detecting homologous and heterologous experimental infections with these isolates between-14 and 82 days post-infection (p.i.) in white and Iberian pigs. A total of 243 pigs (Iberian or cross-bred with this race) with numerous parasitic infections were also screened for the presence of antibodies to a mixture of CWE of C, B1 and B2 isolate. The test showed a specificity of 93.1-98.9% depending on the cut-off values and a maximum sensitivity of 92.8-100% between days 34 and 82 p.i. A low grade of infectivity was shown in the T3 isolates compared to the T1 isolates (P, C, B1 and B2) but high cross-reactions were observed between all the isolates with minor differences between P and W isolates. The highest antibody response was found in P infections and the lowest in pigs infected with the W isolate. A clear association between the presence of several parasitic infections and false positive reactions was not found, but an important relation was shown between high background levels and the Iberian race in experimentally and conventionally raised pigs.

Animals↗
PubMed1991

Histopathological changes in sheep experimentally infected with Babesia ovis.

Histopathological study was made of 12 Merino sheep - five splenectomized and seven intact - experimentally infected with Babesia ovis. Non-purulent encephalitis; initially exudative and subsequently interstitial pneumonia; pericarditis, myocarditis and haemorrhagic endocarditis; centrilobular necrotic hepatitis; hyperplasia of the lymphoreticular system; necrosis and vascular changes in adrenal glands were observed. The kidney was the most severely affected organ, exhibiting acute tubular necrosis typical of kidney shock syndrome. The lesions observed were suggestive of hypovolemic shock culminating in haemorrhagic diathesis owing to consumptive coagulopathy. Additionally, the massive release of catabolites from lysis and necrosis apparently produced endotoxic shock.

Abomasum↗
PubMed1990

Isolation and identification of Babesia ovis in Extremadura (Spain).

A morphological and morphometric comparison was made of a Babesia ovis strain isolated in Extremadura (Spain) and a B. ovis strain from Turkey. Strains were morphologically similar, with a clear predominance of single sub-spherical or anaplasmoid forms. The use of an image analyser to measure B. ovis merozoites revealed significant differences in the long axis, short axis and volume between the two strains. Both strains however behaved in a similar manner in the indirect fluorescent antibody (IFA) test, which suggests a high degree of common antigenicity, despite morphometric differences. Conversely, no cross-reaction was observed between these strains of B. ovis and the other antigens used: B. motasi (The Netherlands), B. motasi (Turkey), B. crassa (Iran) and Theileria ovis (Turkey). B. ovis is therefore considered to be the aetiological agent of babesiosis in the area under study.

Animals↗
PubMed1990

Antibody response and duration of latent infection in sheep following experimental infection with Babesia ovis.

Babesia ovis isolated in Extremadura (Spain) was the subject of a serological study in experimentally inoculated sheep. The first antibody titres, determined by the indirect fluorescent antibody (IFA) test, were observed 7-8 days post infection (p.i.) in all animals except the splenectomized group, in which the only animal that survived showed antibody response 10 days p.i. A faster response following challenge was observed in sheep which were seropositive before inoculation, which suggests the existence of an antigen memory. The highest titres were reached 16-25 days p.i., and subsequently began to fall, reaching minima at the end of the experimental period (330 days p.i.). The chronic carrier state in experimental B. ovis infection had a duration of at least 2 years. Passive transmission of antibodies from experimentally infected mothers to newborn lambs was also detected. Antibody levels were observed for a period not longer than 2 months after birth.

Animals↗
PubMed1989

Hypoglycaemia in experimental canine trichinellosis.

This paper studies changes in serum glucose levels in dogs experimentally infected with Trichinella spiralis, and the histological causes of those changes. Hypoglycaemia is evident in 100% of experimental animals, and can be attributable to three factors: the reduced absorptive capacity of the intestine due to lesions (catarrhal and desquamative enteritis), high glucose consumption by parasites, or histopathological changes in the liver (glycogenic degeneration).

Analysis of Variance↗