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Biomedical subjects

B Ortiz

Publications and source records attributed to B Ortiz.

At least 19 recordsLinked to original sources
PubMed2006

CD4+ CD30+ T cells perpetuate IL-5 production in Dermatophagoides pteronyssinus allergic patients.

BACKGROUND: Airway allergic diseases are regulated by interleukin (IL)-5, which causes infiltration of eosinophils into the bronchial epithelium, and by IL-4 which increases serum immunoglobulin E (IgE) production and promotes CD30 expression on Th cells. CD30 generates a costimulatory signal involved in apoptosis or cell proliferation, depending on the microenvironment. Our aims were: (i) to analyze if CD4+ CD30+ T cells from allergic patients proliferate in response to Dermatophagoides pteronyssinus, and (ii) if upon stimulation this cell population produces IL-4 and IL-5. METHODS: Peripheral blood mononuclear cell (PBMC) from 17 allergic rhinitis and mild allergic asthma patients and 12 healthy nonallergic individuals were stimulated with allergen in the presence or absence of anti-IL-4, anti-IL-5 or anti-IL-4Ralpha monoclonal antibodies (mAbs). TdT-mediated dUTP nick end-labeling (TUNEL) assay, 7-aminoactinomycin-D (7-AAD) intercalation, and flow cytometry were used to determine the CD4+ CD30+ blasts percentage, cell proliferation, apoptosis, and intracellular cytokines after 7 culture days. RESULTS: Cell proliferation induced with allergen showed that 90% of the allergen-stimulated blasts were CD4+, 50% of which were CD30+. Allergen-stimulated PBMC showed a progressive increase (mean: from 7% to 23%) of CD4+ CD30+IFN-gamma+ and CD4+ CD30+IL-4+ blasts which diminished (mean: 6%) after 5 culture days. In contrast, CD4+ CD30+IL-5+ blasts showed a continuous progression (from 12% to 24%) that maintained after 7 culture days. The vast majority of CD4+ CD30+ blasts were negative to 7-AAD or TUNEL. Additionally, a significant decrease (34%) was observed in the number of CD4+ CD30+ blasts when IL-4 was neutralized. CONCLUSIONS: These data suggest that specific allergen stimulation of PBMC isolated from allergic patients generates a nonapoptotic CD4+ CD30+ blast subset that produces IL-5.

Adolescent↗
PubMed2001

Diethyl 2-[cyano(toluene-4-sulfinyl)methylene]propanedioate and its Diels-Alder adduct with cyclopentadiene.

The thermal Diels-Alder cycloadditon reaction of diethyl 2-[cyano(toluene-4-sulfinyl)methylene]propanedioate, C(16)H(17)NO(5)S, with cyclopentadiene gave the pure racemates of two of the four possible diastereomers, with a complete pi-facial selectivity and a high (80:20) endo/exo-sulfinyl selectivity. X-ray diffraction studies of diethyl 2-[cyano(toluene-4-sulfinyl)methylene]propanedioate and the major isomer of the cycloaddition product, namely diethyl 3-cyano-3-(toluene-4-sulfinyl)bicyclo[2.2.1]hepta-5-ene-2,2-dicarboxylate, C(21)H(23)NO(5)S, reveal that the conformation of the substituents on the acrylonitrile moiety produces both steric and electronic effects, which affect the stereoselectivity of the reaction.

Journal Article↗
PubMed2000

A search for natural bioactive compounds in Bolivia through a multidisciplinary approach. Part I. Evaluation of the antimalarial activity of plants used by the Chacobo Indians.

Thirty extracts of plants traditionally used by the Chacobos, a native community living in the Amazonian part of Bolivia, were screened in vitro and/or in vivo for antimalarial activity. Two of the four species designated as antimalarial, Geissospermum laeve and Maquira coriacea, displayed rather good activity, corroborating their traditional uses. However, they did show a rather high toxicity in vivo. Among twelve species used to cure symptoms relevant to malaria, five showed good activity: Apuleia leiocarpa, Bauhinia guianensis, Nectandra cuspidata, Sparattanthelium amazonum, Tanaecium jaroba. Two species, Qualea paraensis and Sclerolobium aff. guianense, used to treat scabies, showed interesting antimalarial activity in vivo; three other species (Iryanthera laevis, Prunus amplifolia, Pterocarpus aff. amazonum) used for various medicinal purposes, apparently not related with a Plasmodium infection, also showed antimalarial activity. Finally, one species (Derris amazonica) used as a piscicide displayed good in vitro activity, in the same way as one Annonaceae, Guatteria aff. schomburgkiana, used for construction purposes.

Animals↗
PubMed2000

Isolation of the receptor for Amaranthus leucocarpus lectin from murine naive thymocytes.

From murine medullary thymocytes we purified the receptor for the Amaranthus leucocarpus lectin (ALL) using a complex with the biotin-labeled lectin and avidin-agarose as the affinity matrix. Most ALL(+)thymocytes (83%) are naive cells with the CD4(+)CD8(-)CD45RB(+)phenotype. The receptor for this lectin is a 70 kDa glycoprotein that contains 20% of sugar by mass. It is constituted mainly by aspartic and glutamic acids, serine, proline, and glycine; its glycosidic portion contains mainly O-glycosidically linked glycans with Gal, GalNAc and NeuAc residues as well as one N-glycosidically linked glycan per molecule. Ionic strength chromatography revealed that the ALL-thymocyte receptor (ALLTr) is made up by three isoforms, which possess similar amino acid composition but show slight differences in their sugar composition. The N-terminal amino acid residues are blocked both in the receptor and its purified isoforms. Analyses of the receptor's peptides, obtained by trypsin digestion with MALDI-TOF (matrix assisted laser desorption ionization-time of flight), were compared with the relative values obtained from the NCBInr (Swiss-Prot 10/01/99) database. Our results indicate that the peptides of ALLTr show low homology (<17%) with the human KIIA protein, the Fas-associated death domain protein, and the transforming growth factor-beta type II receptor. Our results suggest that the ALL thymocyte receptor could be considered a novel phenotypic marker specific for naive T cells.

Amino Acids↗
PubMed1999

A comparative study on the purification of the Amaranthus leucocarpus syn. hypocondriacus lectin.

Amaranthus leucocarpus lectin is a homodimeric glycoprotein of 35 kDa per sub-unit, which interacts specifically with N-acetyl-galactosamine. In this work, we compared different glycoproteins that contain Galbeta1-3 GalNAcalpha1-3 Ser/Thr or GalNAcalpha1-3 Ser/Thr in their structure as ligands to purify the A. leucocarpus lectin. From the glycoproteins tested, fetuin was the most potent inhibitor of the hemagglutinating activity and the better ligand for lectin purification; however, the use of desialylated stroma from erythrocytes represented the cheapest method to purify this lectin. O-linked glycans released from the glycoproteins used as affinity matrix and those from different erythrocytes were less inhibitory than parental glycoproteins. The NH2-terminal of the lectin is blocked; moreover, this is the only example of a lectin isolated from this genus to be a glycoprotein. Analysis of the glycoprotein sequences with inhibitory activity for the lectin, showed a different pattern in the O-glycosylation, which confirms that A. leucocarpus lectin recognizes conformation and, probably, distances among O-linked glycans moieties.

Amino Acid Sequence↗
PubMed1998

Dehydroluciferyl-AMP is the main intermediate in the luciferin dependent synthesis of Ap4A catalyzed by firefly luciferase.

It was previously assumed that E x LH2-AMP was the intermediate complex in the synthesis of Ap4A catalyzed by firefly luciferase (EC 1.13.12.7), when luciferin (LH2) was used as cofactor. However, here we show that LH2 is partly transformed, shortly after the onset of the luciferase reaction, to dehydroluciferin (L) with formation of an E x L-AMP complex which is the main intermediate for the synthesis of Ap4A. Formation of three more derivatives of LH2 were also observed, related to the production of light by the enzyme. CoA, a known stimulator of light production, inhibits the synthesis of Ap4A by reacting with the E x L-AMP complex and yielding L-CoA.

Adenosine Monophosphate↗
PubMed1998

[Standardization of the lethal dose 50% of Leptospira interrogans strains used in the control of the leptospirosis cuban vaccine for human use].

The LD50 of strains of L. interrogans used in the potency assay of the Cuban trivalent leptospiral vaccine intended for human use was standardized. The control of the leptospires content of the cultures by means of the adjusting dilution (10 to 12 leptospires per field) was introduced. That was the key of the standardization of the assay, since it guaranteed the reproducibility of the estimate of the LD50 value for each serogroup: 10(5.98) for canicola, 10(5.60) for icterohaemorrhagiae and 10(6.60) for pomona, with the following limits for an interval of 1 log10: 10(4.98)-10(6.98), 10(4.60)-10(6.60) and 10(5.49)-10(7.49), respectively; whereas for a 95% (+/- 2 SD) confidence interval the values were: 10(5.54)-10(6.19); 10(5.33)-10(5.75) and 10(6.35)-10(6.60), respectively. These values were lower than the previous ones, which means ever more reproducibility. The methodology described proved to be satisfactory for the standardization of the LD50 of the challenge strains and it could also be used for evaluating the virulence of other strains of L. interrogans, including those used for the vaccine production.

Cuba↗
PubMed1997

[Socioeconomic determinants and utilization of emergency hospital services].

BACKGROUND: Socioeconomic level is a key determinant for health status. It may also influence on the utilization of hospital emergency services, although the factor responsible for that is not known. The main objective of the present report is to assess whether patients using frequently hospital emergency services have one or more variables related to low socioeconomic level. PATIENTS AND METHODS: A standardized questionnaire was applied to 800 patients randomly selected from those attending the emergency services of a provincial reference hospital. It was gathered information on: income, education level, employment, loneliness, domestic violence, occupational accidents, and life style. Odds ratios (OR) and their 95% confidence intervals (CI) were estimated. Stepwise logistic regression analysis was used to ascertain the independent predictors for attending for than once to the emergency services. RESULTS: In crude analysis, low income and low educational level were significantly related to the use of emergency services (both chi 2 for a trend < 0.05). Alcoholism (OR = 2.3, 95% CI = 1.2-4.7) and domestic violence (OR = 2.6, 95% CI = 0.9-8.1) were also related. Stepwise logistic regression analysis selected income (OR for intermediate level = 1.6, 95% CI = 1.0-2.7, and OR for low level = 2.3, 95% CI = 1.4-3.7) and alcoholism (OR = 2.9, 95% CI = 1.3-6.4) as independent predictors. CONCLUSIONS: Patients with low income and/or alcoholism use emergency hospital services more frequently.

Adult↗
PubMed1997

Use of monoclonal antibodies in diagnosis of paracoccidioidomycosis: new strategies for detection of circulating antigens.

The precise diagnosis of paracoccidioidomycosis, in most cases, is established by direct methods and indirect immunological tests. The latter method is reliant on the identification of the host's humoral responses, which are usually impaired or absent in patients with severe juvenile forms of the disease and in immunocompromised patients. Determining disease activity or assessing treatment responses by measuring antibody levels is difficult, since antibody titer may remain elevated or persist at stationary levels, even in the presence of clinical improvement. Consequently, there is a need for alternative tests aimed at the identification of circulating antigens. A modification of the standard hybridoma production method was used to raise a panel of murine monoclonal antibodies (MAbs) against the yeast form of Paracoccidioides brasiliensis. Of these, MAb PIB, directed against an 87-kDa determinant, was used to develop an inhibition ELISA (inh-ELISA) capable of detecting as little as 5.8 ng of circulating antigen per ml of serum. Sera from 46 patients with paracoccidioidomycosis or other mycoses and sera from healthy individuals were evaluated by the inh-ELISA; overall sensitivity was 80.4% (37 of 46 paracoccidioidomycosis patients tested positive), and specificity compared with that of normal controls from areas of endemicity was 81.4%. The inh-ELISA detected circulating antigen in 100% of patients with the acute form of paracoccidioidomycosis and in 83.3 and 60% of patients with the chronic multifocal and unifocal forms of paracoccidioidomycosis according to the patients' clinical presentation. These results indicate that the inh-ELISA with MAb PIB is effective in the detection of circulating antigen and that this test may be useful for monitoring responses to treatment and establishing disease prognoses.

Antibodies, Fungal↗
PubMed1994

Cloning, sequencing, and expression of RecA proteins from three distantly related thermophilic eubacteria.

Sequences of the recA genes of the highly divergent thermopholic eubacteria Thermus aquaticus (and Thermus thermophilus), Thermotoga maritima, and Aquifex pyrophilus were determined from fragments derived by polymerase chain reaction (PCR) with degenerate primers and from inverse PCR products obtained using unique primers based on the fragment sequences. The source of the PCR products was verified by Southern hybridization. Complete PCR-derived recA genes were cloned into an expression vector regulated by a temperature-sensitive lambda-repressor, and independently derived clones expressing thermostable recA were selected. DNA sequences were verified to be authentic by direct cycle-sequencing of PCR products and/or sequencing of several clones. In contrast to Escherichia coli RecA protein, all the purified thermophilic RecA proteins exhibited single-stranded DNA-dependent ATPase activity optima above 70 degrees C. Phylogenetic analysis of RecA sequences suggested that the thermophilic RecA proteins were at least as different from one another as were Gram-positive organisms, mesophilic Gram-negative organisms, and cyanobacteria. In spite of substantial sequence divergence, interesting characteristics of the thermostable RecA proteins included increased valine content, common amino acid replacements at two highly conserved sites, and an increase in the calculated isoelectric point of approximately a full pH unit.

Adenosine Triphosphate↗
PubMed1993

Specific synthesis of adenosine(5')tetraphospho(5')nucleoside and adenosine(5')oligophospho(5')adenosine (n > 4) catalyzed by firefly luciferase.

Luciferase catalyzes the preferential synthesis of adenosine(5')tetraphospho(5')nucleoside (Ap4N) in the presence of luciferin (LH2), adenosine 5'-[gamma-thio]triphosphate (ATP[gamma S]) and NTP (other than ATP), with very low, or undetectable synthesis of Ap4A or Np4N, because ATP[gamma S] is a good adenylyl donor for the formation of the E-LH2-AMP complex, but a poor adenylyl acceptor from the complex, and NTP, other than ATP, are bad nucleotidyl donors, but good acceptors of the AMP moiety of the E-LH2-AMP complex. Synthesis of the corresponding Ap4N (or Ap5G in the case of p4G were obtained in the presence of ATP[gamma S] and GTP, UTP, CTP, XTP, dTTP, ITP, dGTP, dCTP, dITP, epsilon ATP (epsilon A, N6-ethenoadenosine) or p4G. The yield of synthesis of Ap4N was at least 50% of that theoretically expected. The process can be easily scaled-up, which allows synthesis of at least 1-5 mumol Ap4N. Further evidence for the synthesis of Ap4G from ATP[gamma S] and GTP was obtained by 1H-NMR and 31P-NMR spectroscopy. Synthesis of Ap4N, in yields lower than those above, can also be obtained in the presence of ADP and NTP; synthesis is due to the presence in commercial luciferase of enzymes (adenylate kinase and NDP kinase) that catalyze the synthesis of ATP from ADP and NTP. In the presence of ATP and polyphosphates, luciferase catalyzes the synthesis of a variety of compounds of adenosine 5'-polyphosphates (pnA; n = 3-20 and ApnA; n = 4-16). In the presence of P3 or P4, preferential synthesis of p4A and Ap5A or p5A and Ap6A were obtained, respectively, showing that both polyphosphates accept the adenylyl moiety of the E-LH2-AMP complex. Polyphosphates of chain length 5, 15 and 35 elicited the synthesis of a variety of PnA and ApnA. Ap4A is also split by luciferase in the presence of P3 or P4 (but not in the presence of P5) yielding preferential synthesis of p4A and Ap5A, or p5A and Ap6A, respectively.

Adenosine Diphosphate↗
PubMed1992

Gender influences the in vitro renin release responses to dopamine and adrenergic receptor blockade in the summer-active ground squirrel Spermophilus lateralis.

1. 10(-4) M Dopamine stimulated and 10(-7) M inhibited in vitro resting renin release (RR) only in the female animals. 2. Alpha- or beta-adrenergic blockade prevented the stimulation but not the inhibition of RR by dopamine in the female animals. 3. Membrane receptor mechanisms mediating these changes do not involve alterations in tissue cyclic AMP content. 4. The sensitivity of the juxtaglomerular cells to dopamine challenge is gender dependent during summer activity.

Adrenergic Antagonists↗
PubMedDate not supplied

[S100 protein as tumoral marker in melanoma patients. Comparative study with sentinel node biopsy and whole body FDG-PET].

PURPOSE: Analyze the significance of serum S100 as tumor marker and study it in the sentinel node biopsy and in the whole body FDG-PET studies. MATERIAL AND METHODS: 332 melanoma patients diagnosed of cutaneous melanoma were included (41 untreated and 291 previously treated). Serum levels were measured by an immunoradiometric assay. Cut-off value was 0.2 microg/l. RESULTS: In the 41 untreated patients, the S100 mean values were: mean 0.36 microg/l, median 0.29 microg/l, with 56.1% of positivities. Serum mean values in stage III and IV were significantly higher than stage I and II (0.489 microg/l vs 0.209 microg/l) (p < 0.05). The mean serum value of S100 in treated patients and without evidence of disease was 0.14 microg/l and the median 0.13 microg/l. Sensitivity and specificity for detection of recurrence or metastases in the follow-up were 76.2% and 88.6%, respectively. There is a correlation of 91.3% between S100 and FDG-PET studies (23 patients). S100 does not provide information on the sentinel lymph node biopsy. CONCLUSIONS: S100 is not useful to diagnose melanoma in its early stages but it is a good tumor marker for the follow-up and monitoring of melanoma patients.

Adolescent↗