PubMed Health⌕ Search

Biomedical subjects

A Olmo

Publications and source records attributed to A Olmo.

At least 19 recordsLinked to original sources
PubMed1999

IgG western blot as a confirmatory test in early syphilis.

Sensitivity and specificity of IgG detection by Western blotting performed with a lysate of Treponema pallidum whole cells were compared with those of the most common assays used in the laboratory diagnosis of syphilis, i.e. fluorescent treponemal antibody absorption test (FTA-ABS) and treponemal haemagglutination assay (TPHA). Thirty-five serum samples obtained from twenty-one patients with a clinical diagnosis of early syphilis, based on the presence of typical chancre or skin or mucous membrane lesions, were studied. In addition, thirty blood samples from donors, ten sera positive for Borrelia burgdorferi and five positive for Leptospira interrogans were tested as controls. The clinical diagnosis was the reference method used to compare the performance of the serological tests. Western blotting performed with a sensitivity and specificity of 100%, whereas the corresponding sensitivity and specificity for FTA-ABS were 88.5% and 98%, respectively. The performance of TPHA showed a sensitivity of 86% and a specificity of 100%.

Adult↗
PubMed1999

Comparative in-vitro activity of moxifloxacin, minocycline and azithromycin against Chlamydia spp.

The in-vitro activity of moxifloxacin, a new 8-methoxyquinolone, was compared with minocycline and azithromycin against 40 strains of Chlamydia trachomatis, Chlamydia pneumoniae and Chlamydia psittaci. Both the MIC and the MBC of moxifloxacin ranged from 0.03 to 0.125 mg/L. MICs of minocycline ranged from 0.015 to 0.06 mg/L and MBCs between 0.03 and 0.25 mg/L. MICs of azithromycin ranged from 0.03 to 0.125 mg/L and the MBCs between 0.06 and 0.5 mg/L. MBC values of moxifloxacin were the same as MICs in 32 (80%) of 40 strains tested, whereas those of minocycline and azithromycin were two to four times higher than their MICs. These data confirm those previously obtained indicating that quinolones kill chlamydial strains at concentrations equivalent to their MICs.

Anti-Bacterial Agents↗
PubMed1999

Specific antibodies reactive with the 22-kilodalton major outer surface protein of Borrelia anserina Ni-NL protect chicks from infection.

An outer surface lipoprotein of 22 kDa was identified in the avian pathogen Borrelia anserina Ni-NL by using antibody preparations reactive with bacterial surface-exposed proteins. Amino acid sequence analysis of the 22-kDa protein demonstrated 90% identity with VmpA of B. turicatae, suggesting that the protein belongs to the family of 20-kDa outer surface proteins of the genus Borrelia. All of the 60 chicks intramuscularly treated with antibodies specifically reacting with the 22-kDa protein and infected with strain Ni-NL were completely protected from infection, since no spirochetemia was detected, and from death. Control chicks were treated with immune sera raised against apathogenic strain B. anserina Es, which expresses a prominent 20-kDa polypeptide that is also a member of the Vmp family but does not cross-react immunologically with the 22-kDa protein of the Ni-NL strain. These animals, infected with B. anserina Ni-NL, showed a high degree of spirochetemia 10 days after infection, and all died between 14 and 21 days after infection. The results showed that the 22-kDa surface protein of B. anserina Ni-NL is a determinant of the pathogenic potential of the strain and also confirmed that only strain-specific antibodies are protective against B. anserina infection.

Amino Acid Sequence↗
PubMed1997

Karyotypic Variability in Ribosomal DNA Subchromosome Size among Colpodid Ciliates, a Possible Tool To Differentiate Colpodid Species.

Pulsed-field gel electrophoresis has been applied to analyze the karyotypic variability among colpodid ciliates. The 18S ribosomal gene was found at different locations in the electrophoretic pattern, and these size variations in the ribosomal DNA subchromosomal molecule seem to be species specific. This could potentially be a useful new tool with which to differentiate colpodid ciliates.

Journal Article↗
PubMed1997

Vitamin D metabolite-mediated hypercalcemia in Wegener's granulomatosis.

Hypercalcemia may occur during the course of various granuloma-forming diseases. Herein we describe a patient who had symptomatic hypercalcemia as a prominent sign of Wegener's granulomatosis. We observed a direct correlation between the serum levels of 1,25-dihydroxyvitamin D [1,25(OH)2D] and both the serum and the urinary calcium levels. Administration of prednisone and cyclophosphamide led to a substantial decrease in the levels of calcium and serum 1,25(OH)2D, but the serum levels of 25-hydroxyvitamin D remained unchanged. Two months after admission of the patient, the levels of calcium and 1,25(OH)2D increased; after we increased the dose of cyclophosphamide, these levels decreased (the dose of corticosteroids was not changed). We suggest that the excessive synthesis of 1,25(OH)2D was inhibited by a direct or indirect action not only of prednisone but also of cyclophosphamide on the 1 alpha-hydroxylation of 25-hydroxyvitamin D in the activated macrophage of Wegener granulomas. Furthermore, in view of this case and two other recently reported cases, we believe that Wegener's granulomatosis must be definitively added to the list of granulomatous diseases that are responsible for 1,25(OH)2D-mediated hypercalcemia.

Calcium↗
PubMed1997

Chronic cyclosporin A nephrotoxicity, P-glycoprotein overexpression, and relationships with intrarenal angiotensin II deposits.

P-glycoprotein (P-gp) expels hydrophobic substances from the cell, including chemotherapeutic agents and immunosuppressants such as cyclosporin A (CsA) and FK506. Exposure of cultured renal tubular cells to CsA induces P-gp overexpression in cell membranes. Angiotensin II has recently been implicated as the principal factor responsible for progression of interstitial fibrosis induced by CsA. To investigate the in vivo relationships between histological lesions, P-gp overexpression, and intrarenal angiotensin II deposits, we developed a model of chronic CsA toxicity in Sprague-Dawley rats treated with 25 mg/kg/day CsA for 28 and 56 days and fed either a standard maintenance diet or a low-salt diet. Immunohistochemical methods were used to study the expression of P-gp in renal tubular cells and the appearance of intrarenal angiotensin II deposits. Rats treated with CsA developed chronic nephrotoxicity lesions that were more evident in the group fed the low-salt diet. Treatment with CsA induced overexpression of P-gp in tubular cells of the kidney that increased with time. We found that immunohistochemical expression of P-gp was slightly more severe in rats fed a low-salt diet. Intrarenal deposits of angiotensin II were more evident in rats treated with CsA; these deposits also increased with time. This finding was also more relevant in rats given the low-salt diet. The up-regulation of P-gp was inversely related to the incidence of hyaline arteriopathy (r = -0.65; P < 0.05), periglomerular (r = -0.58; P < 0.05) and peritubular fibrosis (r = -0.63; P < 0.05), and intrarenal angiotensin H deposits in animals with severe signs of nephrotoxicity (r = -0.65; P < 0.05). These results support the hypothesis that the role of P-gp as a detoxicant in renal cells may be related to mechanisms that control the cytoplasmic removal of both toxic metabolites from CsA and those originating from the catabolism of signal transduction proteins (methylcysteine esters), which are produced as a result of ras activation in presence of angiotensin II.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Co-existence of circular and multiple linear amplicons in methotrexate-resistant Leishmania.

Circular and linear amplicons were analyzed in detail in Leishmania tropica cells resistant to methotrexate (MTX). Both types of elements presented sequences related to the H locus and coexisted in resistant cells. The linear amplicons appeared first during the selection process (at 10 microM MTX) and varied with regard to size and structure in cells exposed to increasing concentrations of drug. The circular element was evident at higher concentrations (50 microMs) but was the major amplified DNA in cells resistant to 1000 microM MTX while the level of amplification of the linear elements remained low. The extrachromosomal DNAs were unstable in the absence of drug and their disappearance coincided with an increase in sensitivity to MTX. Mapping of the minichromosomes and the circular element showed that they were all constituted by inverted duplications. The circular amplicon contained an inverted repeat derived from the H locus that encompassed the pteridine reductase gene (PTR1) responsible for MTX resistance. The amplified segment in the linear amplicons was longer and included the pgpB and pgpC genes that encode P-glycoproteins of unknown function previously characterized in different Leishmania species.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Amplification of the H locus in Leishmania infantum.

We have selected for a Leishmania infantum cell line resistant to high levels of methotrexate (MTX). The resulting cells were 1233-fold more resistant than wild-type and contained amplified H-region circles. Homologous genes to the antifolate resistant ltdh gene and to the P-glycoprotein ltpgpA gene of Leishmania tarentolae were observed to be contained within the amplicon. In order to invoke additional mechanisms of resistance, we examined possible variations in MTX accumulation. Resistance was not correlated with a decreased uptake of MTX. On the contrary, the resistant line presented a 3-fold increase in the steady-state accumulation of drug with regard to the wild-type line. Northern blot analysis using gene specific probes, showed that the ltdh probe and the ltpgpA probe recognized single transcripts of 1 kb and 5 kb respectively which were both overexpressed only approx. 5-fold in resistant cells. We propose that amplification of the antifolate resistance gene, homologue to the ltdh gene of L. tarentolae, is apparently the only mechanism involved in resistance to the cytotoxic drug MTX in L. infantum resistant to 1000 microM of MTX.

Animals↗
PubMed1994

Isolation and characterization of a mutant dihydrofolate reductase-thymidylate synthase from methotrexate-resistant Leishmania cells.

The MTX-resistant Leishmania major promastigote cell line D7BR1000 displays extrachromosomal amplified R-region DNA, which contains the gene for dihydrofolate reductase-thymidylate synthase (DHFR-TS) (Garvey, E. P., and Santi, D. V. (1986) Science 233, 535-540). Now we report that these methotrexate (MTX)-resistant cells also possessed a structurally altered DHFR-TS. We have performed the cloning, expression, and characterization of the altered DHFR-TS gene. The DNA sequence of the altered DHFR-TS gene revealed a single base change in position 158 which resulted in the substitution of a methionine in position 53 of DHFR for an arginine. Steady-state measurements of the purified recombinant enzyme indicated that the mutation did not cause significant modifications in the Km for DHFR or TS substrates but lowered the kcat by 4-fold. Of greater interest, there was a modification in the effect on MTX inhibition of DHFR. The initial inhibition complex appeared to have been unaffected by the alteration, but the subsequent slow-binding step of inhibition in the wild-type enzyme is absent in the altered enzyme. Consequently, the overall Ki for MTX was 30-fold greater for the mutant than for the wild-type enzyme. Transfection of L. major with the mutant DHFR-TS gene gives parasites that are capable of growing in medium containing 10 mM methotrexate, showing that the altered DHFR gene is in itself capable of conferring MTX resistance in Leishmania.

Animals↗
PubMed1994

Cloning and expression of the dihydrofolate reductase-thymidylate synthase gene from Trypanosoma cruzi.

We have cloned, sequenced and expressed the Trypanosoma cruzi gene encoding the bifunctional protein dihydrofolate reductase-thymidylate synthase (DHFR-TS). The strategy followed for the isolation of positive clones from a genomic library was based on the construction of a probe by the amplification of highly conserved sequences of the TS domain by the polymerase chain reaction. Translation of the open reading frame of 1563 bp yields a polypeptide of 521 amino acids with a molecular mass of 58829 Da. For heterologous expression of T. cruzi DHFR-TS in Escherichia coli, the entire coding sequence was amplified by polymerase chain reaction and cloned into the plasmid vector pKK223.3. The presence of catalytically active DHFR-TS was demonstrated by complementation of the Thy- E. coli strain chi 2913 and the DHFR- Thy- E. coli strain PA414. The gene is expressed as an active protein which constitutes approximately 2% of the total cell soluble protein. Recombinant bifunctional enzyme and the DHFR domain have been purified by methotrexate-Sepharose chromatography to yield 1-2 mg of active DHFR-TS per litre of culture. Southern and electrophoretic analyses using the coding sequence as probe indicated that the T. cruzi enzyme is encoded by a single copy gene which maps to two bands of approximately 990 kb and 1047 kb. It appears that T. cruzi is diploid for the DHFR-TS gene which is located on two different-sized homologous chromosomes.

Amino Acid Sequence↗
PubMed1994

[Primary meningioma of the nasal cavity].

Meningiomas are benign tumors developed from aracnoid meningeal cells. Its primary extracranial and extravertebral onset is a rarity, arising more frequently in the scalp and orbit. Its beginning in nasal fosae is considered exceptional. Diagnosis will be based on cranial CTY scan and histology of the whole tumour once extirpated. A case of advanced primary nasal meningioma is reported. The AA. emphasize the difficulties in presurgical diagnosis in this type of growths.

Diagnosis, Differential↗
PubMed1993

[The laryngeal involvement in Kaposi's sarcoma in the acquired immunodeficiency syndrome].

Kaposi's sarcoma (KS) is a malignant vascular neoplasm characterized, in its classical form, by a slow evolutive course, beginning in the lower extremities. Lately have been reported more and more cases of this entity associated with the acquired immunodeficiency syndrome (AIDS), running much more aggressively. In ENT-pathology are not uncommon this kind of neoplasm in the oral cavity and oropharynx. However at larynx's level such descriptions till now had been sporadic. The AA. present a KS case sitting in the epiglottis of an AIDS patient. They emphasize the importance of a throughout ENT-examination of these patients and also remark the necessity of performing various and deep biopsies in order to gain a diagnosis that can be relied on. Finally, they review the updated management alternatives for this sort of pathology.

Acquired Immunodeficiency Syndrome↗