Search PubMed⌕ Search

Biomedical subjects

A Ribeiro

Publications and source records attributed to A Ribeiro.

At least 91 records · Page 5Linked to original sources
PubMed1989

Sickle cell anemia and mitral valve replacement. Case report.

An 8-year-old black boy with sickle cell disease and severe hemolytic anemia crisis (95% hemoglobin S) also had mitral incompetence due to rheumatic valve disease. A 27 mm monostrut Björk-Shiley valve prosthesis was implanted after partial exchange transfusions had reduced the hemoglobin S to less than 40%. High-flow normothermic perfusion was used during extracorporeal circulation, with care taken to avoid hypoxia and acidosis. Postoperative recovery was uneventful.

Anemia, Sickle Cell↗
PubMed1988

The normal vascularization of the intradural filum terminale in man.

The arterial and venous blood-supply of the intradural filum terminale was studied microscopically in 18 fresh cadavers after removing the dorsolumbar spinal cord in one piece, with the roots and the filum in their dural sheath. The arteries were examined after manual injection of the artery of the lumbar enlargement, while study of the veins was made without injection since their bluish-black color made them easily identifiable. After gross examination, each specimen was fixed and then sectioned at 12 different levels from the medullary conus to the bottom of the dural sac for histologic study. The distribution of the vascularization of the filum terminale appeared constant. A single artery, the artery of the filum, arises from the termination of the anterior spinal axis, either by trifurcation or from the proximal part of one of the 2 branches of the anastomotic ansa of the conus. The artery travels in front of the filum, with rapidly diminishing caliber; rarely, it can be followed into the sacral canal. The vein of the filum travels in front of that structure but behind the artery, as in the cord; its caliber is uniform but varies from subject to subject. It traverses the dura below and is continuous with the anterior spinal vein above. No vessels were found on the dorsal aspect of the filum. While the artery of the filum is of a caliber proportional to that of the filum and appears to be a nutrient vessel, the vein has a caliber unrelated to that of the filum and appears rather as an intradural drainage route continuous with the anterior spinal vein.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗
PubMed1988

Correlation between specific immunosuppression and polyclonal B cell activation induced by a protein secreted by Streptococcus mutans.

The relationship between polyclonal B cell activation and immunosuppressor effects induced by F5'EP-Sm, a non-cytotoxic protein secreted by Streptococcus mutans, was studied in C57BL/6 mice. Mice treated with F5'EP-Sm exhibited a considerable increase in splenic nonspecific Ig plaque-forming cells (PFC) compared with untreated mice. The isotypic pattern of non-specific PFC responses favours IgG2a approximately equal to IgG2b greater than IgG3 greater than IgG1 approximately equal to IgM, when taken as a ratio between treated and untreated animals. When F5'EP-Sm was administered 2 days before immunization with sheep red blood cells (SRBC), the non-specific PFC production was accompanied by an ephemeral increase in specific PFC against SRBC 1 day after immunization, which was quickly replaced by a strong immunosuppression. In contrast, when F5'EP-Sm was injected after priming, there was little or no demonstrable suppression of specific PFC, and the increase of non-specific PFC was much less evident. The kinetic curves representing increase or decrease in relation to controls of specific and non-specific PFC are almost mirror images in each of the isotypes. The in vivo suppressor effect was abrogated in thymectomized mice, although the involvement of the T cell compartment is probably secondary to the B cell mitogen effect, since T-depleted spleen cells proliferate and synthesize non-specific Ig when stimulated in vitro with F5'EP-Sm.

Animals↗
PubMed1986

Ketanserin in the treatment of mild hypertension in elderly patients: preliminary results of a controlled double-blind trial.

Thirty elderly patients (mean age 77.5 years) with mild hypertension were considered for a double-blind trial comparing the effects of ketanserin and propranolol. After 28 days of placebo, a group of 15 patients was given ketanserin at the daily dose of 20 mg twice daily for 15 days and of 40 mg twice daily for the subsequent 75 days, while the other group of 15 patients was given propranolol for 90 days at the dose of 80 mg twice daily. Blood pressure and pulse rate in the supine and standing positions were evaluated every 15 days. After the beginning of treatment with ketanserin there was a gradual but highly significant decrease of the systolic and diastolic blood pressure values. No relevant side-effects or significant biochemical alterations were observed during treatment with ketanserin.

Aged↗
PubMed1985

Thirty-five-day modified red cells and 7-day stored platelet concentrates from triple bags of identical PVC formulation.

There is continuous need for blood components with long shelf life. To this end the 'circle' triple pack has been modified to provide 35-day red cell and 7-day platelet concentrates, in PVC bags of identical formulation and 0.4 mm thick. The plasticizer is a mixture of DEHP and TOTM (CLX Mark II). The primary pack contains 63 ml of CP 277.5 mM glucose. The third pack contains 100 ml of citric acid 2 mM, trisodium citrate 20 mM, NaH2PO4 20 mM, NaCl 123 mM, glucose 40 mM, and adenine 1.26 mM. Plasma is adenine-free. With these modifications both hard- and soft-spun red cells gave satisfactory biochemical and autologous survival indices up to 35 days of storage, the haematocrit not exceeding 60%. Platelet concentrates were acceptable at 7 days of shelf-life.

Adenosine Triphosphate↗
PubMed1982

Survival of transfused platelets collected into new formulation plastic packs.

Platelet concentrates were prepared in plastic packs of polyvinyl chloride with tri(2-ethylhexyl) trimellitate as plasticizer. They were stored, with gentle shaking, at room temperature for periods up to 7 days before labelling with isotope and reinfusing. In vivo survival studies, platelet counts, pH and electron microscopy indicated that platelet concentrates prepared in the new plastic were superior to those prepared in the standard pack currently in use. Oxygen was found to diffuse through the new pack more rapidly than through the standard pack. A shelflife of up to 1 week at room temperature seems possible for platelet concentrates prepared in the new plastic.

Adult↗
PubMed1976

Determination of renin-dependency and sodium-dependency in the three renin sub-groups of essential hypertension.

1. In all three renin sub-groups of essential hypertension, the state of sodium balance determines the degree of participation of the renin-angiotensin system in sustaining high blood pressure. 2. Even the low-renin type can become renin-dependent when sufficient sodium depletion has bee achieved. 3. The main difference between patients of these sub-groups appears to be their variable capacity to become depleted of sodium under standard dietary regimens.

Aldosterone↗
PubMedDate not supplied

Structure of paracrystalline arrays on outer membranes of rat-liver and rat-heart mitochondria.

Crystalline arrays are induced in outer membranes of rat-liver and rat-heart mitochondria by phosphotungstate and silicotungstate. The basic structure of the arrays has been determined by correlation averaging of electron microscopic images of side views of tubular arrays and en face views of planar arrays. The arrays consist of rows of bilobed projecting subunits and are similar (in lattice parameters and projected subunit dimensions) to periodic arrays of ion transport ATPases, e.g., arrays of Ca(2+)-ATPase induced by vanadate in sarcoplasmic reticulum. Hexokinase-labeled colloidal gold particles do not specifically decorate the arrays, suggesting that the hexokinase receptor (VDAC channel) is not a component of the arrays.

Animals↗
PubMedDate not supplied

Simultaneous pancreas-kidney transplantation: five-year results from a single center.

We report the 5-year results of our simultaneous pancreas-kidney transplantation (SPKT) program, started on May 2, 2000. Forty-two SPKT were performed on 42 type I diabetic patients with chronic renal failure. The procedure was performed with enteric diversion and vascular anastomosis to the iliac vessels. Immunosuppressive protocol included antithymocyte globulin, tacrolimus, mycophenolate mofetil, and steroids. The 24 women and 18 men had a mean age of 33.5 +/- 6.3 years and mean 22.8 +/- 14.2 years time of diabetes evolution. Forty patients had been on dialysis for 34.3 +/- 24.1 months, and two were preemptive transplantations. Acute rejection episodes were treated in eight patients (19.1%): in three cases they affected both organs; in two only the kidney was affected; and the other three were pancreas graft rejections. The incidence of postoperative complications requiring re-operation was 42.9%, mostly pancreas graft related. Two patients died, one due to cardiovascular disease; the other was transplant related. Three kidney grafts were lost, and the causes were immunologic, thrombosis, and patient death. Pancreas graft loss occurred in seven patients: thrombosis (n = 3); infection (n = 3); immunologic (n = 1). The patients with surviving grafts were doing well, with normal kidney and pancreas function: serum creatinine = 0.89 +/- 0.15 mg/dL; fasting blood glucose = 79 +/- 16 mg/dL; HbA1c = 4.7 +/- 1.1%. The 1-year patient, kidney, and pancreas survival rates were 97.3%, 94.6%, and 83.8% and 5-year values, 91.7%, 89.2%, and 78.7%, respectively. In conclusion, these results are similar to the most recent UNOS/IPTR reports, leading us to consider our experience with SPKT very positive.

Adult↗
PubMedDate not supplied

Inactivation of viruses in platelet suspensions that retain their in vitro characteristics: comparison of psoralen-ultraviolet A and merocyanine 540-visible light methods.

The ability of two fundamentally different photochemical procedures to inactivate model viruses in platelet suspensions was compared. Merocyanine 540 (MC 540) with visible light was used as an example of an oxygen-dependent chemical-directed at the viral membrane, and aminomethyl trimethyl psoralen (AMT) with ultraviolet A light (UVA) was used as an example of a nucleic acid-directed system. Antiviral conditions in petri dishes were identified and the effects of these procedures on platelet suspensions in plastic storage containers were studied. Concentrations of photochemicals in the 10 to 150 mumol range with 30 to 60 minutes of visible light (MC 540) or 1 to 2 minutes of UVA (AMT) readily inactivated 5 to 6 log10 of vesicular stomatitis virus (VSV) and other model viruses in platelet suspensions, provided the plasma concentration was reduced to about 15 percent by the use of a synthetic platelet storage medium. Extracellular pH, morphology scores, and aggregation response dropped markedly when platelets were treated with MC 540 and visible light. However, treatment with 136 mumol per L of AMT and 1 to 3 minutes of UVA could inactivate 5 log10 of VSV in platelet suspensions with retention of platelet characteristics for 4 days, particularly if oxygen levels were reduced during treatment. These studies demonstrate that AMT-UVA treatment meets the initial requirements for virus inactivation in platelet suspensions.

Blood Platelets↗
PubMedDate not supplied

Physical factors influencing the oviposition of Lutzomyia migonei (Diptera: Psychodidae) in laboratory conditions.

To determine the influence of physical factors on oviposition of Lutzomyia migonei (Diptera: Psychodidae) under laboratory conditions, two sets of experiments were performed. The first test was to determine the influence of the size of pots on oviposition. Gravid flies were placed individually or in groups in different oviposition pots. The number of eggs laid, oviposition time and survival of gravid females were observed. In the second experiment, the influence of irregular surfaces on oviposition was studied. The results suggested that physical space was not an important factor in the oviposition behavior of L. migonei and that the flies showed a preference to oviposit on irregular horizontal surfaces in response to thigmotropic behavior.

Animals↗
PubMedDate not supplied

Development of vegetable extracts by microencapsulation.

The microencapsulation of essential oils offers protection against oxidation and evaporation, and allows the concurrent utilization of several vegetable extracts. Complex coacervation methods have been described for essential oils. Even though microencapsulation involves wrapping the essential oils in shells, some difficulties arise in the process of stabilizing the essential oils: oil may be lost by evaporation and partial dissolution in the water-gelatin phase and this will vary with the type of essential oil being encapsulated. In order to investigate the efficacy of the gelatin-polyphosphate methods we analysed their essential oil microcapsules peppermint and rosemary, in particular their granulometric size distribution, oil content (%) and encapsulation yield (%). In addition the essential oils were analysed by GC before and after microencapsulation so as to investigate the loss of their components during the process.

Capsules↗