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Biomedical subjects

R Batista

Publications and source records attributed to R Batista.

10 recordsLinked to original sources
PubMed2004

[Plasma assay of methadone enantiomers with high performance liquid chromatography].

6-Dimethylamino-4,4-diphenylheptane-3-one (methadone) is a synthetic opioid. Presence of an assymetrical carbon in its structure explains existence of two enantiomers. Levogyral enantiomer or R-methadone exhibits an 25 fold superior analgesic activity to the dextrogyral enantiomer S-methadone. In order to run separately a plasma assay of these two enantiomers, a chromatographic chiral separation method coupled with an ultraviolet detection has been performed. It allows selective assay of each enantiomer. This method, although an analytical interference with d-propoxyphene, is sensitive, reproductible, specific and shows a convenient resolution for the analysis of both the stereospecific and racemic forms. This method can be applied for pharmacokinetic study of the drug in patients treated by methadone.

Chromatography, High Pressure Liquid↗
PubMed2004

[Cyclosporine 2% eye drops preparation].

PURPOSE: Cyclosporine administration is very effective in the case of immunological diseases of the cornea, conjunctive or uvea. Moreover, it is widely used in the case of high-risk rejection corneal transplantation. We present a preparation of cyclosporine 2% eye drops. METHODS: Cyclosporine 2% eye drops are prepared following a particular formulation including one part commercially available cyclosporine oral solution (Sandimmun) diluted in four parts of sterile castor oil. Manufacturing procedures maintain the sterile state of the preparation with a laminar airflow hood placed in a particulate controlled room, with pharmacists, technicians and clerical personnel wearing sterile clothes. Physical and chemical monitoring during and after manufacture for each batch guarantees the process and minimizes the risk of batch rejection. Chemical analysis of cyclosporine is conducted using a validated stability-indicating high-performance liquid chromatographic assay (reverse-phase). Blood dosages taken after the first administration at the 24th hour (after administration of the 6th drop) check for systemic integration. RESULTS: Cyclosporine 2% eye drops are fairly stable: 12 months after manufacturing, concentrations result in levels not statistically different from concentrations measured the day of preparation. After a daily regimen of six drops in the eye, cyclosporine 2% eye drops have a very low systemic bioavailability, because the blood concentrations only reach the detection limit of the fluorescence polarization immunoassay used for cyclosporine drug monitoring. This explains the absence of systemic toxicity. CONCLUSION: Cyclosporine 2% eye drops can be available in the hospital pharmacy. The eye drops are stable at room temperature and can be delivered up to 12 months after manufacture. No local adverse effects have been noted, probably in relation with the very low concentration of ethanol in the ocular preparation.

Cyclosporine↗
PubMed2000

Using microwave distillation-solid-phase microextraction--gas chromatography--mass spectrometry for analyzing fish tissue.

A technique for the analysis of the volatile compounds from fish tissue employing microwave distillation-solid-phase microextraction-gas chromatography-mass spectrometry is described. A qualitative listing of 174 compounds observed in the headspace is given, and a quantitative method for the determination of the off-flavor contaminants (2-methylisoborneol and geosmin) is presented. Borneol and decahydro-1-naphthol are used as the surrogate and internal standards, respectively. A linear calibration curve is obtained for 0.1 to 5 ppb with a recovery level of 60% at 2.5 ppb. Comparison of the instrumental method with a human flavor checker showed good agreement.

Animals↗
PubMed1999

Changes in venous histology in chronic hemodialysis patients.

Because most hemodialysis access fails at the venous side, we studied samples of brachial vein obtained during access creation in 15 patients with end-stage renal disease who gave consent. Veins were examined by computer-assisted histomorphometry, and the results correlated with the patients' clinical data. The mean venous medial width was 239 +/- 31 microm, and mean intimal width was 6.0 +/- 0.9 microm. Mean venous medial width was 358 +/- 74 microm and mean venous intimal width was 9.2 +/- 1.2 microm in the 4 patients who had been undergoing dialysis more than 6 months, compared with 196 +/- 23 microm and 4.9 +/- 0.8 microm, respectively, in the 11 patients undergoing dialysis less than 6 months (P < 0.01). The number of months undergoing hemodialysis correlated well with venous medial width (r = 0.79; P < 0.001). Correlation between number of months undergoing dialysis and intimal width did not reach statistical significance. Medial and intimal widths of the 4 patients with diabetes were not significantly different from those of the patients without diabetes. Serum parathyroid hormone level did not correlate with either medial or intimal venous width. We conclude there may be changes in the veins of hemodialysis patients with time that cause thickening of layers, even in veins not directly used for access. This may affect the creation or survival of subsequent vascular accesses.

Adult↗
PubMed1999

Trypanosomicidal kaurane diterpenes from Wedelia paludosa.

The diterpenes ent-kaur-16-en-19-oic acid, ent-kaur-9(11),16(17)-dien-19-oic acid and 3 alpha-angeloiloxy-ent-kaur-16-en-19-oic acid were identified as trypanosomicidal compounds of the ethanolic extract from the aerial parts of Wedelia paludosa D.C. (Asteraceae), showing activity up to the lowest dose of 0.68 mg/mL in the in vitro assay against trypomastigotes of T. cruzi, the causative agent of Chagas' disease (American trypanosomiasis). The other isolates, friedelan-3 beta-ol, ent-kaur-16 alpha-ol-19-oic acid, beta-amyrin acetate and (22-E)-stigmasta-5,22-dien-3 beta-ol, were inactive. This is the first report on the trypanosomicidal activity of ent-kaur-9(11),16(17)-dien-19-oic acid and 3 alpha-angeloiloxy-ent-kaur-16-en-19-oic acids; this effect was already known for ent-kaur-16-en-19-oic acid.

Animals↗
PubMed1995

A seven-iron ferredoxin from the thermoacidophilic archaeon Desulfurolobus ambivalens.

A seven-iron ferredoxin was isolated from aerobically grown cells of the hyperthermoacidophilic archaeon Desulfurolobus ambivalens (DSM 3772). The protein is monomeric, with an apparent molecular mass of 15 kDa and contains 7 iron atoms/molecule. The N-terminal sequence shows a large similarity (70% identity) with that of the ferredoxin isolated from the archaeon Sulfolobus acidocaldarius. The EPR characteristics in both the native (oxidized) and dithionite-reduced states of this protein allowed an unequivocal identification of a [3Fe-4S]1+/0 center, with a reduction potential of -270 +/- 20 mV, at pH 7.5. The protein also contains a [4Fe-4S]2+/1+ center with a very low reduction potential (Eo = -540 mV, pH 7.0), which yields a rhombic EPR spectrum upon reduction with sodium dithionite at high pH. The reduction potentials of both centers are slightly pH dependent between pH 6 and 9. The [3Fe-4S] ferredoxin center is able to accept electrons from pyruvate oxidase and NADH oxidase isolated from D. ambivalens. This ferredoxin is present in large amounts (at least 130 mg/kg wet cells), which allowed the unequivocal observation of oxidized [3Fe-4S] clusters in intact D. ambivalens cells.

Amino Acid Sequence↗
PubMed1991

Glycosaminoglycan polysulfate in the treatment of old age dementias.

1. In a multicenter, placebo-controlled, double-blind clinical trial in 155 elderly patients with cognitive decline, glycosaminoglycan polysulfate was found to be a therapeutically effective agent in the treatment of old age dementias. 2. Treatment with glycosaminoglycan polysulfate in the daily dosage of 600 LRU, administered on the basis of a divided dosage schedule for 12 weeks, was significantly superior to an inactive placebo on several outcome measures including the Wechsler Memory Scale-Russell Revision (Easy Paired Associates Learning and Immediate Visual Reproduction), Mini Mental State Examination, the Sandoz Clinical Assessment Geriatric (Cognitive Dysfunction and Depression), Hachinski Dementia Scale, Brief Psychiatric Rating Scale (Confusion and Depressive Withdrawal) and Global Improvement Scale of the Clinical Global Impression. 3. Adverse effects with glycosaminoglycan polysulfate were few and mild. The drug was equally well tolerated and equally effective in the two major dementias of old age, i.e., primary degenerative and multi-infarct. The number of abnormal laboratory test readings remained essentially unchanged from pre-treatment to post-treatment.

Activities of Daily Living↗
PubMed1983

[A new concept for the training of odontological human resources].

This article describes different aspects, and particularly those of the academic-administrative structure of the Dentistry Program in the Health Sciences Faculty of Universidad Católica "Madre y Maestra," in the Dominican Republic. It presents a general account of the University's approach to the problems of health, and of the events leading up to the establishing of the Program, the basis on which this was done, the theoretical framework in which the curriculum is embedded, and the methodological principles applied. It also gives a detailed description of the curriculum, including the general and specific objectives, the structure and organization, and the modules comprised in each academic year. Finally, the teaching-learning, service, and research activities, and an account of the resources available for the conduct of the Program are reviewed in brief.

Curriculum↗