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L Robledo

Publications and source records attributed to L Robledo.

10 recordsLinked to original sources
PubMed2001

Determination of the redox properties of human NADPH-cytochrome P450 reductase.

Midpoint reduction potentials for the flavin cofactors in human NADPH-cytochrome P450 oxidoreductase were determined by anaerobic redox titration of the diflavin (FAD and FMN) enzyme and by separate titrations of its isolated FAD/NADPH and FMN domains. Flavin reduction potentials are similar in the isolated domains (FAD domain E(1) [oxidized/semiquinone] = -286 +/- 6 mV, E(2) [semiquinone/reduced] = -371 +/- 7 mV; FMN domain E(1) = -43 +/- 7 mV, E(2) = -280 +/- 8 mV) and the soluble diflavin reductase (E(1) [FMN] = -66 +/- 8 mV, E(2) [FMN] = -269 +/- 10 mV; E(1) [FAD] = -283 +/- 5 mV, E(2) [FAD] = -382 +/- 8 mV). The lack of perturbation of the individual flavin potentials in the FAD and FMN domains indicates that the flavins are located in discrete environments and that these environments are not significantly disrupted by genetic dissection of the domains. Each flavin titrates through a blue semiquinone state, with the FMN semiquinone being most intense due to larger separation (approximately 200 mV) of its two couples. Both the FMN domain and the soluble reductase are purified in partially reduced, colored form from the Escherichia coli expression system, either as a green reductase or a gray-blue FMN domain. In both cases, large amounts of the higher potential FMN are in the semiquinone form. The redox properties of human cytochrome P450 reductase (CPR) are similar to those reported for rabbit CPR and the reductase domain of neuronal nitric oxide synthase. However, they differ markedly from those of yeast and bacterial CPRs, pointing to an important evolutionary difference in electronic regulation of these enzymes.

Electron Transport↗
PubMed2000

Encephalitis due to a free-living amoeba (Balamuthia mandrillaris): case report with literature review.

BACKGROUND: Amebic infections can spread to the central nervous system with a lengthy but usually fatal course. A typical case is presented to raise awareness of this increasingly reported infectious process that may have a more favorable outcome if diagnosed in its early stages. CASE DESCRIPTION: A 38-year-old male presented with an ulcerating 10 x 8 cm mass on his thigh and smaller skin nodules. In less than 6 months seizures developed due to granulomatous lesions of the brain. Biopsies/excisions of the thigh lesion, a subcutaneous nodule, and a brain lesion were performed. He failed to respond to broad spectrum antibiotics and antineoplastic agents, and died within 6 weeks of the initial MRI scan of the brain. Rare amebic trophozoites were appreciated in the biopsy specimens on post-mortem review, and Balamuthia mandrillaris confirmed as the infecting agent on immunofluorescence studies. CONCLUSIONS: Granulomatous amebic encephalitis is a parasitic infection with a lengthy clinical course before rapid deterioration due to extensive brain lesions is noted. Either early treatment with antimicrobials or-in rare cases-excision of the brain lesion(s) may offer the chance of a cure.

Adult↗
PubMed1999

Potentiometric analysis of the flavin cofactors of neuronal nitric oxide synthase.

Midpoint reduction potentials for the flavin cofactors in the reductase domain of rat neuronal nitric oxide synthase (nNOS) in calmodulin (CaM)-free and -bound forms have been determined by direct anaerobic titration. In the CaM-free form, the FMN potentials are -49 +/- 5 mV (oxidized/semiquinone) -274 +/- 5 mV (semiquinone/reduced). The corresponding FAD potentials are -232 +/- 7, and -280 +/- 6 mV. The data indicate that each flavin can exist as a blue (neutral) semiquinone. The accumulation of blue semiquinone on the FMN is considerably higher than seen on the FAD due to the much larger separation (225 mV) of its two potentials (cf. 48 mV for FAD). For the CaM-bound form of the protein, the midpoint potentials are essentially identical: there is a small alteration in the FMN oxidized/semiquinone potential (-30 +/- 4 mV); the other three potentials are unaffected. The heme midpoint potentials for nNOS [-239 mV, L-Arg-free; -220 mV, L-Arg-bound; Presta, A., Weber-Main, A. M., Stankovich, M. T., and Stuehr, D. J. (1998) J. Am. Chem. Soc. 120, 9460-9465] are poised such that electron transfer from flavin domain is thermodynamically feasible. Clearly, CaM binding is necessary in eliciting conformational changes that enhance flavin to flavin and flavin to heme electron transfers rather than causing a change in the driving force.

Animals↗
PubMed1999

Hispanic mothers' knowledge and care of their children with respiratory illnesses: a pilot study.

This pilot study was designed to identify Hispanic mothers' knowledge and health practices regarding caring for their children with respiratory illnesses. Using an interview guide, the researchers identified the mothers' perceptions of their children's health, the etiology and symptoms of asthma and other respiratory illnesses, health practices, folk illnesses, services sought and language barriers when using health services. The findings suggest that Hispanic mothers have limited knowledge of respiratory illnesses and use culturally related practices when caring for their sick children. Implications for pediatric nursing practice are discussed, and strategies to improve care for Hispanic families are presented.

Adult↗
PubMed1995

Influence of the hydrophobicity of lipase isoenzymes from Candida rugosa on its hydrolytic activity in reverse micelles.

Two isoenzymes of Candida rugosa lipase, having the same mol.wt., size and similar aminoacid sequence, were studied in reverse micelles of AOT. The results demonstrated the relevance of lipase hydrophobicity in reactions in anionic micelles. This is a key factor in mitigating the inhibition effect of charged micelles. The more hydrophobic isolipase A was a better biocatalyst for hydrolytic processes in these systems. Its alpha-helix content increased from 31% to 49% of the total structure in reverse micelles. A fluorescence study indicated a more apolar environment for the more hydrophobic isolipase A. Emission spectra of this isolipase in the AOT systems were blue shifted. At omega 0 values where each isolipase presented its maximum activity, a decrease of the emission intensity of Trp was found. An enzyme and substrate dependence of optimal omega 0 is reported. The different interaction of isolipases A and B with the micellar system produced an opposite omega 0 dependence to their stabilities. The more hydrophobic lipase A had higher stability at higher droplet sizes.

Candida↗
PubMedDate not supplied

Listening to Hispanic mothers: guidelines for teaching.

Teaching Hispanic mothers in a culturally sensitive way to care for their children is a challenge to pediatric nurses. Pediatric nurses must be familiar with customs and the folk medicine practiced by Hispanic mothers. It is very important that the pediatric nurse listens to the voices of Hispanic mothers to determine their health practices, and those that may have been used in their children. Familiarity with folk medicine and health practices will facilitate an appropriate treatment plan and will help to determine whether the mothers' practices are dangerous or beneficial for the child. Pediatric nurses should assess for concurrent use of home remedies and conventional medications to determine if there are any known interactive effects. Finally, increasing the number of pediatric nurses who are fluent in Spanish will enable the voices of Hispanic mothers to be better heard, which in turn, will improve the health status of Hispanic children.

Adult↗