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Biomedical subjects

T Aguilar

Publications and source records attributed to T Aguilar.

11 recordsLinked to original sources
PubMed2001

[A new species of Euphyllia (Scleractinia: Caryophylliidae) in the limestones of Barra Honda, Costa Rica].

A new species of scleractinian coral is described: Euphyllia donatoi. This is the first report of this genus from Central America. The outcrop is located on the north-west of Costa Rica. It consists of large colonies (1.2 m high by 0.5 m in diameter), from a patch reef which had a dendroid habit. They are part of a very distintive facies in a micritic limestones of the Barra Honda Formation (Paleogene). The finding is important because these are the only macrofossils found in Barra Honda Formation. The growth took place under unstable ecological conditions resulting in a low diversity autocthonous community. It probably developed in very shallow water with a high sedimentation rate.

Animals↗
PubMed1997

Activation of HIV-1 coreceptor (CXCR4) mediates myelosuppression.

Chemokines are cytokines that activate and induce the migration of leukocytes. Stroma-derived factor-1 (SDF-1) is a novel chemokine that blocks the entry of T-tropic HIV-1 mediated by fusin/CXCR4/LESTR (leukocyte-derived seven-transmembrane domain receptor). In this work we demonstrate that SDF-1 triggers increases in intracellular calcium and inhibits the proliferation of myeloid progenitor cell line 32D. By contrast, SDF-1 neither triggers a calcium response nor affects the proliferation of the myeloid progenitor cell line 32D-GR that is deficient in CXCR4. Responsiveness to SDF-1 was rescued by transfection of 32D-GR cells with a cDNA encoding the human CXCR4. The data indicate that SDF-1 induces myelosuppression by activation of CXCR4. The constitutive production of SDF-1 by bone marrow stromal cells argues for a major role of SDF-1 on the regulation of myelopoiesis.

Animals↗
PubMed1997

Effects of Plasmodium berghei infection on arteether metabolism and disposition.

Arteether (AE) is primarily deethylated to dihydroqinghaosu (DQHS) in rats and humans. Conversion of AE to DQHS was impaired in microsomes from rats infected with Plasmodium berghei. The Km for AE was 175.1 +/- 49.1 and 124.4 +/- 115.1 mumol/l, and Vmax was 2.24 +/- 0.45 and 1.22 +/- 0.67 nmol AE formed/mg protein/min in control and infected microsomes (p < 0.05), respectively. Calculated intrinsic clearance (CLint = initial Vmax/Km) for AE was only 4% lower in infected microsomes. Apparent pharmacokinetic parameter estimates for AE using the isolated perfused rat liver demonstrated no differences (p > 0.05) in volume of distribution, clearance, and half-life between normal and infected animals. Malaria infection resulted in decreased biliary excretion of free AE and DQHS. The majority of AE is eliminated via biliary excretion of conjugated DQHS, which is approximately 500-fold higher than free DQHS and 75-fold higher than free AE on a molar basis.

Animals↗
PubMed1991

Prediction of neurodevelopmental outcome in infants with and without bronchopulmonary dysplasia.

In a group of 236 very low birth weight (VLBW) surviving infants, 60 had developed bronchopulmonary dysplasia (BPD) in the nursery. When compared with the 176 infants without BPD, infants with BPD were smaller, more immature, with lower one- and five-minute Apgar scores. Infants with BPD had a greater incidence of cardio-pulmonary and central nervous system (CNS) complications in the nursery. On follow-up, 25 (42%) of these infants were abnormal developmentally compared to 7% of infants without BPD (p less than .001). When comparisons were made within the group of infants with BPD, very few differences were found in maternal or infant risk factors between the normal and abnormal infants. The infants with BPD who had poor outcome more often had seizures and severe intraventricular hemorrhage (IVH). The infants with BPD who had good outcome were more often small for gestational age (SGA) and resuscitated with intubation at birth. They had apnea in the nursery more frequently than did abnormal infants with BPD. We conclude that VLBW infants with BPD are at greater risk for poor neurodevelopmental outcome than those without BPD. The risk for the infant with BPD relates to CNS complications rather than to chronic lung disease.

Aging↗
PubMed1989

Maternal factors associated with delivery of infants with birthweight less than 2000 grams in a low socioeconomic population.

Women of low socioeconomic status (SES) are known to have a higher incidence of low birthweight (LBW) infants who are a major source of neonatal mortality and morbidity. SES, however, does not define a homogeneous population. If prenatal programs could be oriented specifically toward women of higher risk within the low SES population, they should be more effective. Within our uniformly low SES population, we compared mothers who had given birth to infants weighing less than 2000 g with mothers of infants weighing over 3000 g in order to identify factors associated with a LBW birth. We found medical factors, including hypertension and infection during pregnancy, demographic factors, including race, marital status, and lack of prenatal care, and lifestyle factors, including drug and alcohol abuse, to be more common among women giving birth to infants weighing less than 2000 g. These factors can be used to develop more effective intervention programs for low SES populations.

Adolescent↗
PubMed1986

Polysaccharide surface antigens expressed by nonmucoid isolates of Pseudomonas aeruginosa from cystic fibrosis patients.

We tested nonmucoid Pseudomonas aeruginosa isolates obtained from cystic fibrosis (CF) patients for the expression of lipopolysaccharide (LPS) serotype antigens, serum sensitivity, and production of mucoid exopolysaccharide (MEP). When all nonmucoid isolates were compared with a set of random mucoid isolates, 20 of 52 (38%) nonmucoid isolates were typable and serum resistant, compared with 13 of 51 (24%) mucoid isolates (P = 0.16 by chi-square analysis). However, nonmucoid strains from CF patients colonized only with nonmucoid strains were more frequently typable and serum resistant (67%) than were nonmucoid isolates from patients cocolonized with mucoid strains (31%) (P = 0.012, Fisher exact test). An inhibition enzyme-linked immunosorbent assay done with bacterial extracts, a direct-whole-cell enzyme-linked immunosorbent assay done with affinity-purified antibody to MEP, and immune electron microscopy all demonstrated production of MEP by all nonmucoid P. aeruginosa isolates tested, including nonmucoid revertants of mucoid strains. No other bacterial species tested positive in these assays. These findings suggest that MEP is produced by all P. aeruginosa isolates obtained from CF patients, that the initial colonizing nonmucoid strains produce a smooth LPS, and that once LPS-rough, mucoid strains appear in the sputum, the predominant LPS phenotype is rough regardless of colony morphology.

Antigens, Bacterial↗
PubMed1983

Facilitating "flow" through therapeutic recreation services.

The rationale and means for facilitating flow for disabled individuals in situational and community recreation settings is discussed. The flow model and arousal model are discussed and implications of leadership aimed at facilitating flow are delineated. Specific principles discussed are: attracting attention, arranging complexity to provide optimal challenge, narrowing the stimulus field, minimizing extrinsic rewards, arranging for immediate feedback, and minimizing the individual's awareness of and focusing on the outcomes of involvements.

Awareness↗
PubMed1974

Evolution of L-1, 2-propanediol catabolism in Escherichia coli by recruitment of enzymes for L-fucose and L-lactate metabolism.

A mutant strain of Escherichia coli capable of growth on l-1,2-propanediol was isolated previously. The mutant is characterized by constitutive production of a propanediol:nicotinamide adenenine dinucleotide (NAD) oxidoreductase which is essential for the new growth property. In the present study, it is shown that phage P1 cotransduces the genetic locus conferring this property and the genes for the utilization of l-fucose. A further indication of a relationship between these two growth properties is provided by the observation that wild-type E. coli excretes propanediol during fermentation of l-fucose. Under these conditions, a propanediol dehydrogenase (lactaldehyde reductase) is induced. This enzyme migrates on diethylaminoethyl-cellulose with the propanediol dehydrogenase produced constitutively by the mutant strain. A key event in the establishment of the ability to grow on propanediol is evidently a shift in the expression and function of propanediol dehydrogenase; an enzyme catalyzing formation of a reduced fermentation product anaerobically in wild-type cells functions aerobically to oxidize this same product in the mutant. l-Lactaldehyde, which is thus derived from propanediol, is converted to l-lactate by another dehydrogenase (l-lactaldehyde:NAD oxidoreductase) which is constitutively produced by both wild-type and mutant cells. The normal function of this enzyme is not yet established. l-Lactate is converted to pyruvate by an inducible NAD-independent l-lactate dehydrogenase. Thus, the carbons of propanediol are brought into the central metabolic network of the cell.

Aerobiosis↗
PubMedDate not supplied

Intrauterine growth curves of weight, length, and head circumference for a predominantly Hispanic infant population.

The purpose of this study was to develop intrauterine growth curves in a predominantly Hispanic population of low socioeconomic status near sea level and to compare them with published intrauterine growth curves. Infants born at Los Angeles County-University of Southern California Medical Center provided the study population. Gestational age was determined by maternal history and confirmed by Ballard clinical assessment in 6,100 infants. Growth curves were developed for weight, length, and head circumference from 24 through 44 weeks gestation. The intrauterine curves were similar to those developed from white non-Hispanic births in California and from white middle class infants born in Portland, OR. The Los Angeles curves differed from other curves developed in Denver, CO, where the infants were significantly smaller from the 34th week of gestation. The authors found no adverse effects on intrauterine growth by race or socioeconomic status. The curves presented in this paper are more appropriate than the Denver curves for white populations born near sea level regardless of socioeconomic status.

Body Height↗