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C Romero

Publications and source records attributed to C Romero.

At least 55 records · Page 3Linked to original sources
PubMed1998

Metal coordination of azurin in the unfolded state.

1H NMR data applied to the paramagnetic cobalt(II) derivative of azurin from Pseudomonas aeruginosa have made it possible to show that the metal ion is bound to the protein in the unfolded state. The relaxation data as well as the low magnetic anisotropy of the metal ion indicate that the cobalt ion is tetrahedral in the unfolded form. The cobalt ligands have been identified as the residues Gly45, His46, Cys112 and His117. Met121 is not coordinated in the unfolded state. In this state, the metal ion is not constrained to adopt a bipyramidal geometry, as imposed by the protein when it is folded. This is clear confirmation of the rack-induced bonding mechanism previously proposed for the metal ion in azurin.

Azurin↗
PubMed1998

Antiretroviral effect and safety of abacavir alone and in combination with zidovudine in HIV-infected adults. Abacavir Phase 2 Clinical Team.

OBJECTIVES: To evaluate, over 12 weeks, the antiretroviral activity and safety of abacavir, used alone and in combination with zidovudine (ZDV), as treatment for HIV-1-infected subjects who had limited or no antiretroviral treatment. DESIGN: Seventy-nine HIV-1-infected subjects, with CD4 cell counts 200-500 x 10(6)/l and <12 weeks of previous treatment with ZDV were enrolled in a multicenter study. Subjects were randomly assigned to one of four cohorts receiving abacavir monotherapy for the first 4 weeks (200, 400, or 600 mg every 8 h daily, or 300 mg every 12 h daily) and, thereafter, combination therapy of abacavir with 600 mg ZDV or ZDV placebo, administered in a double-blind manner for an additional 8 weeks. METHODS: Antiretroviral activity was assessed by measuring changes in plasma HIV-1 RNA levels and CD4+ cell counts. Safety was assessed by monitoring clinical adverse events and laboratory abnormalities during the 12-week period and for 4 weeks post-treatment. RESULTS: Treatment with abacavir, alone or in combination with ZDV, produced marked decreases in plasma HIV-1 RNA loads and increases in CD4+ cell counts in all groups. At week 4, median plasma HIV-1 RNA loads decreased by 1.11-1.77 log10 copies/ml and median CD4+ cell counts increased by 63-111 x 10(6)/l in all groups. At week 12, median HIV-1 RNA loads decreased by 1.02-2.24 log10 copies/ml (abacavir monotherapy) and by 1.81-2.01 log10 copies/ml (abacavir-ZDV); median CD4+ cell counts increased by 79-195 x 10(6)/l (abacavir monotherapy) and by 93-142 x 10(6)/l (abacavir-ZDV). At week 12, the percentage of subjects who had plasma HIV-1 RNA levels below 400 and 40 copies/ml were 28 and 11%, respectively (abacavir monotherapy) and 69 and 22%, respectively (abacavir-ZDV). Eight subjects (10%) discontinued the study prematurely because of adverse events; nausea (n = 4) and hypersensitivity (n = 3) were the most common reasons for withdrawal. There were no deaths among the study subjects. CONCLUSIONS: In HIV-infected subjects who have received little or no prior antiretroviral therapy, treatment with abacavir alone or in combination with ZDV is well tolerated and resulted in sustained improvements in key immunologic and virologic efficacy parameters through 12 weeks.

Acquired Immunodeficiency Syndrome↗
PubMed1998

[Bacterial endocarditis in the aortic valve of a three month old infant. Correction with an aortic homograft].

We report the case of a three-month-old infant with an infective endocarditis of the aortic valve, showing perforation of two valve leaflets and a perivalvular abscess. The patient was operated on using a cryopreservated homograft with anastomosis of both coronary arteries. The outcome is good two years after surgery. This is the youngest patient operated on using this technique in our country.

Aortic Valve↗
PubMed1998

A reliability study of the Spanish version of the social behaviour schedule (SBS) in a population of adults with learning disabilities.

The reliability of the Spanish version of the Social Behaviour Schedule (SBS) was tested in a vocational setting on a sample of 64 subjects with learning disabilities. Test-retest assessment showed a good percentage of agreement (80%) and adequate kappa values for most SBS items. The overall percentage of agreement of inter-rater reliability was 85% and kappa values were moderate to nearly perfect for 52% of items. Inter-informant analyses produced poorer results, with an average agreement of 43% and inadequate kappa values on 42% of items. The intraclass correlation coefficient (ICC) was 0.64 for test-retest, 0.76 for inter-rater assessment and 0.94 for inter-informant assessment. The Spearman correlation coefficient was adequate on the test-retest and inter-rater analyses, but not on inter-informant analysis. This low inter-informant agreement could be attributed to environmental factors which alter the reliability of reports from different informants in community settings with high levels of normalization. In such environments, an interview with a key informant may not suffice, and both a careful review of the clinical record and a direct interview with subjects may enhance the reliability of the information attained.

Adult↗
PubMed1998

Evaluation of the relatedness of Brucella spp. and Ochrobactrum anthropi and description of Ochrobactrum intermedium sp. nov., a new species with a closer relationship to Brucella spp.

The relatedness of Brucella spp. and Ochrobactrum anthropi was studied by protein profiling, Western blot, immunoelectrophoresis and 16S rRNA analysis. Whole-cell and soluble proteins of brucellae and O. anthropi showed serological cross-reactivities quantitatively and qualitatively more intense than those existing with similar extracts of Agrobacterium spp. Numerical analysis of Western blot profiles of whole-cell extracts showed that O. anthropi LMG 3301 was closer to Brucella spp. than to O. anthropi LMG 3331T, a result not obtained by protein profiling. These differences were not observed by Western blot with soluble fractions, and immunoelectrophoretic analyses suggested that this was due to destruction of conformational epitopes in Western blot procedures with the subsequent simplification of antigenic profile. Analysis of the 16S rRNA sequences of strains previously used in the species definition confirmed that strain LMG 3301, and also LMG 3306, were closer to the brucellae, and that LMG 3331T was in a separate cluster. The LMG 3301 and the LMG 3331T clusters could also be separated by their different colistin sensitivity and by PCR with 16S rRNA Brucella primers, and both methods showed strains of both clusters among clinical isolates classified as O. anthropi by conventional tests. These results and those of previous DNA-DNA hybridization studies [Holmes, B., Popoff, M., Kiredjian, M. & Kersters, K. (1988). Int J Syst Bacteriol 38, 406-416] show that the LMG 3301 cluster and related clinical isolates should be given a new species status for which the name Ochrobactrum intermedium sp. nov. is proposed (type strain is LMG 3301T=NCTC 12171T = CNS 2-75T).

Animals↗
PubMed1997

Transport of long-chain native fatty acids across lipid bilayer membranes indicates that transbilayer flip-flop is rate limiting.

Evidence from a number of laboratories suggests that membrane proteins may meditate the transport of physiologic fatty acids (FA) across cell membranes. However, studies using lipid membranes indicate that FA are capable of spontaneous flip-flip, raising the possibility that rapid transport through the lipid phase obviates the need for a transport protein. Determining the rate-limiting steps for transport of FA across lipid membranes, therefore, is central to understanding FA transport across cell membranes. The transport of long-chain FA across lipid membranes, from the aqueous compartment on one side of the lipid bilayer to the aqueous phase on the other side, has not been measured previously. In this study, we have used the fluorescent probe ADIFAB to monitor the time course of FA movement from the outer to the inner aqueous compartments and from the lipid membrane to the outer aqueous compartment of lipid vesicles. These two measurements, together with measurements of the lipid:aqueous partition coefficients, allowed the determination of the rate constants for binding (kon), flip-flop (kff), and dissociation (koff) for the transport of long-chain natural FA across lipid vesicles. These rates were determined using large unilamellar vesicles (LUV) of approximately 1000 A diameter, prepared by extrusion and giant unilamellar vesicles (GUV), prepared by detergent dialysis, that are >/=2000 A diameter. The results of these studies for vesicles composed of egg phosphatidylcholine (EPC) and cholesterol reveal kff values that range from 3 to 15 s-1 for LUV and from 0.1 to 1.0 s-1 for GUV, depending upon temperature and FA type. For these same vesicles, dissociation rate constants range from 4 to 40 s-1 for LUV and from 0.3 to 2.5 s-1 for GUV. In all instances, the rate constant for flip-flop is smaller than koff, and because the rate of binding is greater than the rate of transport, we conclude that flip-flop is the rate-limiting step for transport. These results demonstrate that (1) kff and koff are smaller for GUV than for LUV, (2) the rate constants increase with FA type according to oleate (18:1) < palmitate (16:0) < linoleate (18:2), and (3) the barrier for flip-flop has a significant enthalpic component. Comparison of the flip-flop rates determined for GUV with values estimated from previously reported metabolic rates for cardiac myocytes, raises the possibility that flip-flop across the lipid phase alone may not be able to support metabolic requirements.

Biological Transport↗
PubMed1997

Nasal mucociliary transport and ciliary ultrastructure in cystic fibrosis. A comparative study with healthy volunteers.

Cystic fibrosis (CF) is a deadly hereditary disease that produces an abnormally thick, viscous and abundant secretion in the respiratory tract. This secretion in turn leads to the development of recurrent respiratory infections and irreversible lung damage. We have studied nasal mucociliary transport by means of an isotopic technique in 12 patients with CF and in 12 healthy volunteers. Nasal mucociliary transport was repeated at 12-18 months in the patients. In five randomly selected patients ciliary ultrastructure was studied. The velocity of nasal mucociliary transport was significantly slower than in healthy persons (P < 0.001) and no significant differences were observed in both studies (P < 0.05). No significant differences were either observed in the CF group between the homo- and heterozygotes (P < 0.5), or in those six patients infected by Pseudomonas aeruginosa (P < 0.05). Ciliary ultrastructure was normal in one patient. In another patient the sample showed no cilia, while the remaining three exhibited changes similar to those observed in chronic respiratory infections: supernumerary peripheral tubules, ciliary disorientation and ciliary complexes.

Adolescent↗
PubMed1997

[Intravenous leiomyomatosis with cardiac extension].

Intravenous leiomyomatosis is a very rare uterine neoplasm, characterized by histological benignity. In some cases, it could extend through the ovaric or iliac veins up to the vena cava and the right chambers of the heart. We report a patient with symptoms of right heart failure, who was diagnosed by transesophagic echocardiography of intravenous leiomyomatosis with extension to the right ventricle. Complete excision was achieved employing simultaneous sternotomy and laparotomy with echocardiographic intraoperative monitorization.

Echocardiography↗
PubMed1997

[The placement of a Wiktor stent for the treatment of vasospastic angina: a case report].

A 46-year-old male with a fixed stenosis in the mid-segment of the left anterior descending artery underwent balloon angioplasty. The procedure included the placement of two Wiktor stents because of severe dissection. Five months later he complained of Prinzmetal angina with ST elevation in the anterior wall. A metilergobasine test during the coronary arteriogram showed a discrete, severe spasm on the proximal segment of the left anterior descending artery. Because of a lack of symptomatic improvement with high-dose nitrates and calcium blockers, a Wiktor coronary stent was successfully implanted in the proximal left anterior descending artery, resulting in complete relief of the angina.

Angina Pectoris, Variant↗
PubMed1997

Mechanisms of transmission of Aujeszky's disease virus originating from feral swine in the USA.

To understand the possible mechanisms of transmission of Aujeszky's disease virus (pseudorabies or PRV) from a feral pig reservoir, intranasal infections were initiated in domestic pigs and in pigs from a herd derived from captured feral pigs. Virus strains originating from feral pigs and from domestic pigs were compared. Similar shedding patterns were obtained in both feral-derived and domestic pigs, however, virus strains from feral pigs were markedly attenuated. Virus could be isolated after acute infection from nasal secretions, tonsils and occasionally from genital organs. In studies of transmission of PRV by cannibalism, either latently infected or acutely infected tissue was fed to both domestic and feral-derived pigs. In two similar experiments, latently infected tissue did not transmit virus, but tissues from acutely infected pigs did transmit infection. Cannibalism was observed typically in both types of pigs older than 6 weeks of age. It was concluded that transmission of PRV originating from feral pigs can occur by several mechanisms including the respiratory route and by cannibalism of pigs that die of acute infection. Transmission of PRV from feral swine may, however, result in sub-clinical infection.

Animals↗
PubMed1995

Effect of Escherichia coli lipopolysaccharide on surfactant secretion in primary cultures of rat type II pneumocytes.

The purpose of this study is to evaluate the effect of the Escherichia coli lipopolysaccharide on the secretion of phosphatidylcholine, the principal component of pulmonary surfactant, in primary cultures of rat alveolar type II pneumocytes. Lipopolysaccharide stimulated phosphatidylcholine secretion in a time- and dose-dependent manner. At a concentration of 200 micrograms/ml, lipopolysaccharide stimulated the release of phosphatidylcholine 4-fold over the basal secretory rate, and the concentration producing half the maximal response was 20 micrograms/ml. The stimulatory effect of lipopolysaccharide on phosphatidylcholine secretion was additive to that of the protein kinase C activator TPA, which is a potent stimulator of surfactant secretion. Lipopolysaccharide did not activate protein kinase C, which suggests that stimulation of phosphatidylcholine secretion by the endotoxin was through a mechanism independent of protein kinase C activation.

Animals↗