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Biomedical subjects

R Brito

Publications and source records attributed to R Brito.

16 recordsLinked to original sources
PubMed2000

Growth, metabolic rate, and digestive enzyme activity in the white shrimp Litopenaeus setiferus early postlarvae fed different diets.

Growth rate, soluble-protein content, oxygen consumption, ammonia excretion, and digestive-enzyme activity were studied in Litopenaeus setiferus early postlarvae under four feeding regimens that included combinations of freshly hatched Artemia nauplii, microparticulate commercial diet, and algae. Growth and of postlarvae fed a mixed diet were significantly higher. Artificial diet used alone caused the lowest growth, lowest soluble-protein content, higher ammonia excretion, lowest O:N ratio, and higher proteolytic and amylase activities. The artificial diet stimulated proteolytic activity and ammonia excretion of postlarvae, apparently in response to some deficiency in protein composition of the diet. Based on results in growth, soluble-protein content, enzymatic activity, and metabolic substrate, we determined that partial substitution of Artemia nauplii by artificial diet, with or without addition of algae when rearing early postlarval stages, will benefit the growth and nutritional state of L. setiferus postlarvae.

Journal Article↗
PubMed1999

Oral fluoropoyrimidines.

Protracted intravenous infusions of fluorouracil (5-FU) in the treatment of colorectal cancer have been associated with a reduction in toxicity and enhanced clinical activity compared with bolus 5-FU schedules. However, these protracted infusions require portable infusion pumps and central venous lines, which are associated with complications of venous thrombosis, infection, and line slippage. An effective oral 5-FU formulation could provide a more convenient protracted treatment method with fewer complications. Because of its inconsistent and erratic absorption, the use of oral 5-FU was abandoned decades ago. The inconsistent absorption of oral 5-FU may be attributed to varying levels of dihydropyrimidine dehydrogenase (DPD) in the gastrointestinal tract. Two methods have been used to circumvent 5-FU's metabolism by DPD in the gastrointestinal tract. First, DPD may be inactivated, allowing for reliable, consistent absorption of 5-FU. Second, 5-FU prodrugs can be administered, being absorbed as intact molecules via the gastrointestinal tract and subsequently converted to 5-FU. The oral fluoropyrimidines discussed here are capable of providing prolonged 5-FU exposure with a reduced incidence of toxicity.

Animals↗
PubMed1998

The oral fluorouracil prodrugs.

Discussed herein are selected oral fluorinated pyrimidines that are converted to 5-fluorouracil (5-FU) in vivo to exert antitumor activity. These agents include capecitabine (Xeloda), tegafur-uracil (UFT) plus leucovorin (Orzel), and S-1 (BMS247616). These agents offer the convenience of an orally administered therapy with potentially fewer toxic effects than conventional bolus regimens of 5-FU plus leucovorin. These oral agents provide prolonged 5-FU exposure at lower peak concentrations than observed with bolus intravenous administration of 5-FU and may confer pharmacoeconomic advantages by reducing administration costs and toxicity-related hospitalizations. These regimens also have the potential for improved therapeutic activity by achieving higher 5-FU concentrations in the tumor or by biochemically modulating 5-FU. Phase III trials in patients with advanced colorectal carcinomas are comparing the antitumor activity of these agents with that of intravenous 5-FU plus leucovorin.

Administration, Oral↗
PubMed1979

Neurofibrillary changes in the cerebral cortex of a patient with subacute sclerosing panencephalitis (SSPE).

Biopsy fragments from the frontal cortex of one patient with SSPE were studied with ultrastructural methods. Special attention was given to the presence of neurofibrillary tangles observed in all cortical layers. These tangles were composed either of filaments with a diameter of 10 -- 12 nm or of paired helical filaments 22 -- 24 nm at their widest and periodically reduced to 10 nm about every 80 nm. These tangles were observed in all cortical layers, while those formed by single filaments were only visualized in layer 3. The simultaneous appearance of both types of tangles in the same patient suggests that they may be chemically related, which is in keeping with recent chemical data concerning the nature of the neurofilament protein subunit.

Adolescent↗
PubMedDate not supplied

[Exercise test: abnormal ST segments restricted to recovery phase].

PURPOSE: To determine the incidence of atherosclerotic coronary artery disease (CAD) and or myocardial ischemia in patients (pt) with abnormal ST segments restrict to recovery phase (RRAST) of exercise testing (ET). MATERIAL AND METHOD: Retrospective study in 19 non consecutive pt with RRAST, related to coronary arteriography or exercise planar scyntillography (18 men, 58 +/- 9 years, 18 asymptomatic). RESULTS: RRAST corresponded to ST segment depression from 1 to 4 mm, with T inversion during early recovery (2 pt); late (14 pt) or both (4 pt). It was documented CAD (14 pt and 9) with artery-by-pass surgery); hypertensive myocardiopathy with normal coronary (3 pt), and mitral prolapse valve (1 pt). In 13 pt with coronary arteriography or exercise scyntillography, within the first 6 months from exercise testing, myocardial ischemia was confirmed in 8 pt in 3 pt, successive exercise testing showed RRAST reproductive in 2 cases. CONCLUSION: The authors report the high incidence of CAD and or transitory hypoperfusion during myocardial scyntillography in symptomatic men with middle age with RRAST during exercise testing.

Adult↗
PubMedDate not supplied

[Obtaining antibodies and development of an immunoassay for the detection of Escherichia coli proteins in preparations of human recombinant gamma interferon].

The present paper refers to the obtainment of polyspecific antisera directed against Escherichia coli host strain used to produce recombinant human gamma interferon (rec. hum. gamma IFN). The antisera were obtained by the cascade immunization method. The animals (n = 3) were initially immunized with an E. coli protein preparation (EcPp) of the host strain obtained from a blank run which assures the absence of the rec. hum. gamma IFN protein. Afterwards, consecutive immunizations were carried out with the less immunogenic proteins. To obtain those proteins, EcPp is passed through a column containing antibodies purified from previous inoculations coupled to a gel matrix. In this way, the proteins that have not been recognized by the immune system in that moment (e.g. do not have their corresponding antibodies coupled to the column) are separated an used to reimmunize the animals. The analyses of the antisera by Western blotting show a progressive recognition of the host strain proteins by the antisera with the progression of the cascade method. The recognition is evident through all the molecular weight range. Those antisera were used as quality control of the recombinant protein, by quantification of the host strain protein contaminants using a multiantigenic ELISA. The detection limit of that system was 3.125 ng/mL and the quantification limit 6.25 ng/mL.

Animals↗