Dietary calcium and bone health.
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Adolescent↗
Biomedical subjects
J Dominguez
Publications and source records attributed to J Dominguez.
Intestinal leiomyomas: angiographic imaging.
A retrospective angiographic study was done on 19 patients with solitary leiomyomas of the small bowel, one patient with multiple leiomyomas, and two patients with leiomyosarcomas. All patients had gastrointestinal bleeding but no small bowel obstruction. Selective mesenteric angiography was the main diagnostic procedure. Tumoral hypervascularity and dense capillary staining within a well-circumscribed mass were present in all patients. Prominent and irregular feeding arteries were seen in 19 cases and prominent draining veins in 20. Contrast extravasation indicating the site of active bleeding was shown in two patients.
Adult↗
Localization of African swine fever viral antigen, swine IgM, IgG and C1q in lung and liver tissues of experimentally infected pigs.
An immunohistological study was carried out on lungs and livers of pigs experimentally infected with two different African swine fever virus (ASFV) isolates. ASFV antigen, swine immunoglobulins (IgM and IgG) and (Clq) complement were demonstrated in both organs at different stages of infection. The ASFV antigen was mainly found in mononuclear phagocytic system (MPS) cells. Immunoglobulins and complement were observed in plasma, infected and non-infected phagocytic cells and cell debris. These findings suggest the presence, in acute infection, of immune complexes which may be involved in immunopathogenic mechanisms.
African Swine Fever↗
Detection of African horsesickness virus in infected spleens by a sandwich ELISA using two monoclonal antibodies specific for VP7.
A sandwich enzyme-linked immunsorbent assay (ELISA) for rapid detection of African horsesickness virus (AHSV) in infected spleens or cell culture supernatant was developed. This method uses two monoclonal antibodies (MAbs) which recognize two non-overlapping epitopes of the major core protein (VP7) to coat the solid phase, and one labeled with biotin as second antibody. This ELISA was evaluated for its ability to detect AHSV in infected spleens resulting in a sensitivity of 97.4% and a specificity of 100% compared with virus isolation in cell culture, and can be used for the detection of the nine different AHSV serotypes.
African Horse Sickness↗
Role of protein kinase C in the regulation of prostaglandin synthesis in human endothelium.
The present study specifically addresses the role of protein kinase C (PKC) activation in human endothelial cell Ca2+ mobilization, a response that is functionally coupled to the production of the potent arachidonate (AA) metabolite, prostacyclin (PGI2). Phorbol 12-myristate 13-acetate (PMA), alpha-thrombin, and sodium fluoride (NaF), a direct G-protein activator, produced a rapid and time-dependent translocation of PKC from the cytosol to the membrane. Activation of PKC by brief pretreatment of human umbilical vein endothelial cell (HUVEC) monolayers with PMA resulted in the inhibition of NaF-induced inositol phosphate increases and attenuation of both alpha-thrombin- and NaF-activated increases in intracellular Ca2+ (Ca2+i). Ca2+ mobilization induced by ionophore A23187 was not affected by PKC preactivation, suggesting PKC-dependent negative feedback inhibition of phosphatidylinositol (PI)-specific phospholipase C (PLC). Agonist-stimulated AA release and PGI2 synthesis in PMA-pretreated cultured human endothelial cells, however, was potentiated, and the enhanced PGI2 synthesis produced by A23187, NaF, and alpha-thrombin was dependent upon the dose of PMA. Treatment of HUVEC monolayers with an intracellular Ca2+ chelator, 1,2-bis(2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid-acetoxymethylester (BAPTA-AM), dramatically reduced alpha-thrombin-, NaF-, and A23187-induced PGI2 synthesis, demonstrating the importance of Ca2+i availability in PGI2 synthesis. BAPTA pretreatment did not inhibit PMA-induced PKC activation, and BAPTA-mediated inhibition of agonist-stimulated PGI2 synthesis was partially attenuated by prior PMA pretreatment. Staurosporine, a potent PKC inhibitor, at concentrations that inhibited PKC-induced phosphorylation of histone-1, augmented both alpha-thrombin- and NaF-induced production of inositol phosphates but markedly inhibited alpha-thrombin-, NaF-, and A23187-induced PGI2 synthesis. The downregulation of PKC activity by prolonged PMA treatment (18 h) produced similar inhibition of PGI2 synthesis by these agonists (approximately 50% inhibition). These studies indicate that the integrated phospholipase A2 and PLC activities are under complex regulation by factors that include both PKC activation and [Ca2+i]. PKC exerts dual effects on prostaglandin synthesis via negative regulation of Gp-coupled PI-specific PLC and positive feedback regulation of AA release and PGI2 synthesis. PKC is thus a critical determinant in the regulation of human endothelial cell prostaglandin synthesis by both receptor-mediated and G-protein-dependent cellular activation.
Aequorin↗
Gp-regulated phosphoinositide hydrolysis in turkey and human erythrocytes exposed to fluoride ion: relationship to calcium influx.
Previous studies have demonstrated that although both mammalian and avian erythrocytes express an inducible inositol bisphosphate-specific phospholipase C, only the latter possess the guanine nucleotide-binding protein (Gp) that regulates this activity. In confirmation of previous reports, turkey erythrocyte plasma membranes responded to guanosine 5'-0-(3-thio)triphosphate (GTP-gamma-S) and fluoroaluminates with hydrolysis of phosphoinositides, release of inositol phosphates, and generation of diacylglycerol, whereas human erythrocyte plasma membranes exhibited no such changes when incubated with known activators of guanine nucleotide regulatory proteins. We next contrasted responses of intact turkey and human erythrocytes to fluoroaluminates to develop a model to investigate the cellular effects of Gp activation. When turkey erythrocytes were exposed to fluoroaluminates, cellular levels of diacylglycerol and phosphatidic acid rapidly increased as phosphoinositides were hydrolyzed. The alterations in the lipid composition of turkey erythrocytes effected by fluoroaluminates were remarkable; phosphatidic acid levels increased over 30-fold, whereas levels of polyphosphoinositides were decreased to less than 10% of those present before stimulation. In contrast, fluoroaluminates caused only minor alterations in the diacylglycerol and phospholipid content of intact human erythrocytes. To define the role of inositol-specific phospholipase C activation in the transmembrane conveyance of extracellular Ca++, we compared the influx of extracellular Ca++ in human and turkey erythrocytes exposed to fluoroaluminates. Fluoroaluminates initiated a sustained influx of extracellular 45Ca++ into turkey, but not human, erythrocytes. These results provide strong support for the hypothesis that Gp activation results in an influx of calcium into stimulated cells. Moreover, the data demonstrate that comparison of responses of human and turkey erythrocytes to fluoroaluminates provides a well-defined method for investigating the mechanisms and consequences of Gp activation in intact cells.
Animals↗
Clinical and ultrastructural analysis of failures in chemonucleolysis.
A series of 12 patients with failed chemonucleolysis were analyzed to determine the various causes of such failures. The ultrastructural findings observed in laminectomy specimens did not account for the failure in the enzyme treatment. The findings suggested deficient cellular nutrition secondary to enzymatic histolysis of the nucleus pulposus.
Chymopapain↗
MAP-1 and MAP-2 binding sites at the C-terminus of beta-tubulin. Studies with synthetic tubulin peptides.
The interaction of microtubule-associated proteins MAP-1 and MAP-2 with different peptides containing sequences covering the C-terminal region of beta-tubulin isoforms has been analyzed. Our results indicate that MAP-1 and MAP-2 bind to a common sequence within the variable C-terminal region of the different beta-tubulin isoforms, while MAP-2 also interacts with the subdomain beta (422-434) of the constant region, in agreement with previous results (Maccioni, R.B., Rivas, C., & Vera, J.C. (1988) EMBO J. 7, 1957-1963). The productive interaction of MAP-2 with the latter domain appears to be involved in the assembly of microtubules.
Amino Acid Sequence↗
Inhibitory effects of phospholipase D on chondrogenesis in vitro.
Mesenchymal cells from the wing buds of stage 24 chick embryos undergo differentiation to cartilage when plated at high density. Treatment of these cultures with phospholipase D resulted in inhibition of chondrogenesis. Phospholipase D treatment (which produces phosphatidic acid from membrane phospholipids) was found to affect cell proliferation and to dramatically increase intracellular free calcium levels and inositol phosphate production. Intracellular free Ca2+, mobilized as a result of phosphatidylinositol phosphate hydrolysis, may therefore inhibit chondrogenesis in embryonic mesenchymal cells.
Animals↗
Sodium fluoride induces phosphoinositide hydrolysis, Ca2+ mobilization, and prostacyclin synthesis in cultured human endothelium: further evidence for regulation by a pertussis toxin-insensitive guanine nucleotide-binding protein.
The role of guanine nucleotide-binding proteins in the induction of prostacyclin synthesis by stimulated endothelial cells is incompletely understood. We report that sodium fluoride (NaF), a potent activator of cellular guanine nucleotide-binding proteins, affected time- and concentration-dependent generation of prostacyclin (PGI2) by cultured human umbilical vein endothelial cells without evidence of cellular toxicity detected by 51Cr or lactate dehydrogenase release. PGI2 synthesis by NaF-stimulated endothelial cells was associated with increases in arachidonate release, phosphoinositide hydrolysis, generation of inositol phosphates, and accumulation of diacylglycerol. These responses to NaF, as well as alpha-thrombin-mediated responses, were not dependent upon the availability of extracellular free Ca2+ but were associated with the mobilization of stored intracellular Ca2+ detected by the luminescence of the photoprotein aequorin. Neither PGI2 synthesis nor Ca2+ responses following alpha-thrombin or NaF stimulation were inhibited by pretreatment of cells with the islet activating protein from Bordetella pertussis but were significantly attenuated by the G protein inhibitor GDP beta S in permeabilized cells. Our results are compatible with a model wherein NaF directly activates a phosphoinositidase-linked guanine nucleotide regulatory protein, Gp, in human umbilical vein endothelial cell monolayers. This activation results in phosphoinositide hydrolysis, Ca2+ mobilization, arachidonate release, and subsequent functional activation, assessed by PGI2 release. Biologically relevant agonists such as alpha-thrombin may exert their influence on arachidonate metabolism, in part, by promoting receptor-dependent activation of this G protein.
Adenosine Diphosphate Ribose↗
Unique amino acid substitutions in the capsid proteins of foot-and-mouth disease virus from a persistent infection in cell culture.
Maintenance of a persistent foot-and-mouth disease virus (FMDV) infection in BHK-21 cells involves a coevolution of cells and virus (J. C. de la Torre, E. Martínez-Salas, J. Díez, A. Villaverde, F. Gebauer, E. Rocha, M. Dávila, and E. Domingo, J. Virol. 62:2050-2058, 1988). The resident FMDV undergoes a number of phenotypic changes, including a gradual decrease in virion stability. Here we report the nucleotide sequence of the P1 genomic segment of the virus rescued after 100 passages of the carrier cells (R100). Only 5 of 15 mutations in P1 of R100 were silent. Nine amino acid substitutions were fixed on the viral capsid during persistence, and three of the variant amino acids are not represented in the corresponding position of any picornavirus sequenced to date. Cysteine at position 7 of VP3, that provides disulfide bridges at the FMDV fivefold axis, was substituted by valine, as determined by RNA, cDNA, and protein sequencing. The modified virus shows high buoyant density in cesium chloride and depicts the same sensitivity to photoinactivation by intercalating dyes as the parental FMDV C-S8c1. Amino acid substitutions fixed in VP1 resulted in altered antigenicity, as revealed by reactivity with monoclonal antibodies. In addition to defining at the molecular level the alterations the FMDV capsid underwent during persistence, the results show that positions which are highly invariant in an RNA genome may change when viral replication occurs in a modified environment.
Amino Acid Sequence↗
Prospective, controlled, randomized non-blind comparison of intravenous/oral ciprofloxacin with intravenous ceftazidime in the treatment of skin or soft-tissue infections.
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Administration, Oral↗
A discrete repeated sequence defines a tubulin binding domain on microtubule-associated protein tau.
The protein domain responsible for the interaction of tau with tubulin has been identified. Biophysical studies indicated that the synthetic peptide Val187-Gly204 (VRSKIG-STENLKHQPGGG) from the repetitive sequence on tau binds to two sites on the tubulin heterodimer and to one site on each of the microtubule-associated protein-interacting C-terminal tubulin peptides alpha(430-441) and beta(422-434). The binding data showed a relatively stronger interaction of Val187-Gly204 with beta(422-434) as compared to that with alpha(430-441). The interaction of this tau peptide with either alpha or beta tubulin peptides appears to be associated with conformational changes in both the tau and the tubulin peptides. The beta tubulin peptide also appears to induce a structural change of tau fragment Val218-Gly235. Interestingly, tau peptides Val187-Gly204 and Val218-Gly235 induced tubulin self-assembly in a cold-reversible fashion, and incorporated into the assembled polymers. The specificity of the interaction of the tau peptide was supported by the competition of tau protein for the interaction with the tubulin polymer. In addition, the tau peptide appears to contain the principal antigenic determinant(s) recognized by anti-idiotypic antibodies that react with the tubulin binding domains on microtubule-associated proteins. The present findings together with the demonstration of the presence of multiple sites for the binding of the alpha(430-441) and beta(422-434) tubulin fragments to tau, and the existence of repetitive sequences on tau, strongly support the hypothesis that the region of tau defined by the repetitive sequences is involved in its interaction with tubulin.
Amino Acid Sequence↗
[Reconstructive surgery using a massive prosthesis in loosening of a hip prosthesis].
Thirteen cases with loosening of THR treated by a massive prosthesis are reviewed. In previous years, with more conservative surgery, the loss of bone stock was most important. The results after a long follow-up were satisfactory. This was a desperate procedure during a period without a bone-bank. Despite the major problems with failure of this procedure, the author still recommends it in elderly patients who need early mobilization or when the use of a bank-bone is not possible.
Adult↗
Influence of air pollution on extrinsic childhood asthma.
A crossed comparative study was done with 248 extrinsic asthmatic children living either in polluted or non-polluted areas (mean emission per year of sedimentary material greater than or less than 300 mg/m2/day, respectively) to establish the influence of air pollution on childhood extrinsic asthma. The mean number of wheezing crises per year was significantly higher for the children living in polluted areas (10.4 versus 7.69). In addition, incidence of severe asthma (types II, III, and IV) in children living in polluted areas was markedly increased whereas the slight form of asthma (type I) was more frequent in children living in non-polluted areas. No correlation, however, between the wheezing episodes and levels of atmospheric contaminants (fumes and SO2) was detected when a group of 84 extrinsic asthmatic children living in polluted areas was studied longitudinally for a year. The data indicate that air pollution, as an isolated agent, plays a transient role in the appearance of wheezing episodes in subjects with extrinsic asthma. Results also suggest that the air pollution may potentiate wheezing episodes via alternative mechanisms.
Air Pollution↗
Regulatory effects of S-100 protein and parvalbumin on protein kinases and phosphoprotein phosphatases from brain and skeletal muscle.
In the eluted fractions of histone-treated crude extracts separated by Sephadex G-200 filtration, multiple protein kinase (PK) activities, including three from brain and two from skeletal muscle, were augmented by both S-100 protein and parvalbumin on the phosphorylation of endogenous substrates. One additional PK activity suppressed by both S-100 and parvalbumin was also found in muscle. In comparison, phosphoprotein phosphatases (PPase), which were also prepared by the same procedure of initial step of histone-treatment followed by the steps of Bio-Gel P-6DG for brain and DNA-cellulose for muscle, were all activated by S-100 while inhibited by parvalbumin and phosphatidylserine.
Animals↗
Occupational asthma caused by cellulase.
Inhalation of enzyme dusts can cause occupational asthma, and the list of enzymes able to induce asthma is increasing. We report two patients with asthma induced by occupational exposure to cellulase powder derived from Aspergillus niger. A type I hypersensitivity to this enzyme was demonstrated by means of skin test reactivity, positive passive transfer test, positive reverse enzyme immunoassay for specific IgE, and immediate bronchial provocation test response to cellulase dust. Skin tests with an A. niger extract were positive. Cross-reactivity between cellulase dust and an entire A. niger extract was also demonstrated.
Adult↗
Meningitis due to a glucose-negative, maltose-negative strain of Neisseria meningitidis.
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Child, Preschool↗