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Biomedical subjects

R Clavero

Publications and source records attributed to R Clavero.

7 recordsLinked to original sources
PubMed2005

All-optical flip-flop based on an active Mach-Zehnder interferometer with a feedback loop.

A novel architecture for an all-optical flip-flop is validated experimentally. The architecture comprises a single semiconductor optical amplifier-based Mach-Zehnder interferometer with an external feedback loop. The experimental results show optical bistable operation for a latching device with an on-off contrast ratio of 11 dB that employs set and reset pulses of less than 250 pJ, although the energy of these pulses could be greatly reduced by optical integration of the whole device.

Journal Article↗
PubMed1997

[Conversion from +Sandimmune to Neoral in kidney transplant recipients treated with cyclosporine and ketoconazole].

BACKGROUND: Microemulsion cyclosporine is a new pharmaceutical form whose intestinal absorption is more constant, resulting in a better bioavailability. AIM: To assess dose adjustments and variability of blood levels after the conversion of cyclosporine to microemulsion cyclosporine in renal transplant recipients function receiving cyclosporine-ketoconazole. PATIENTS AND METHODS: Thirty four patients with more than one year after the transplantation, with stable renal function and receiving triple immunosuppression were studied. Conventional cyclosporine was changed to the microemulsion form maintaining the same daily dose. Drug serum levels, serum creatinine and blood pressure were measured within two to eight months after the conversion. Doses of microemulsion cyclosporine were adjusted to achieve serum levels of 150 +/- 40 ng/ml. RESULTS: Microemulsion cyclosporine induced a slight initial increase in blood cyclosporine levels. Afterwards, levels were more stable than with conventional cyclosporine (165-185 and 145-210 ng/ml respectively) and the dispersion of values were lower (standard deviations of 70 and 100 ng/ml respectively). Twenty three patients did not require dose adjustments, in four it was reduced and in five it was increased. There were no changes in serum creatinine or blood pressure after the conversion. CONCLUSION: More stable serum levels without adverse reactions were obtained with microemulsion cyclosporine. Doses of cyclosporine need not to be changed during the conversion.

Adolescent↗
PubMed1996

[Acute kidney failure in patients with and without sepsis: prognosis and clinical course].

The purpose of this prospective study was to determine whether the course and prognosis of acute renal failure (ARF) in patients with and without sepsis are different. Two hundred fifty-two (8%) of 3086 consecutive patients admitted to a medical-surgical intensive care unit (ICU) developed ARE. One hundred forty-nine (59%) were septic and 103 (41%) were non-septic. No differences were found between groups regarding the incidence of oliguria, hyperkalemia, hypercatabolism, gastrointestinal bleeding, duration of oligria and renal deficit, severity of axotemia, dialysis requirements and duration of stay in the hospital. There were statistically significant differences between septic and non septic patients with respect of hyponatremia (67.8 vs 54.4%, p < 0.04), respiratory failure (68 vs 54%, p < 0.04), and thrombocytopenia (64 vs 48%, p < 0.02). Mortality in septic patients was higher than in non-septics (56 vs 42.7%, p < 0.009). Factors associated with increased mortality in ARF septic patients were respiratory failure, metabolic acidosis and oliguria while in the non-septics they were hepatic dysfunction, hyperkalemia, respiratory failure and infection acquired during the course of renal failure. We conclude that ARF developing in septic patients has a higher mortality than that of non-septic patients, whereas the incidence of hypercatabolism and oliguria was not different between both groups.

Acute Kidney Injury↗
PubMed1993

[APS-2: comparative study on populations of critical patients in Chile, United States and New Zealand].

Between 1988 and 1991, the Acute Physiologic Score (APS-2) was applied to 1000 critically ill patients admitted to an intensive care unit of a general hospital in Chile. Its predictive capacity was assessed and compared with two series from United States and New Zealand. The mean admission APS-2 in Chilean patients was 12.8 and there was a progressive increase in mortality with elevating scores; no patient with an APS-2 over 30 survived. Admission APS-2 scores in USA and New Zealand were 10.7 and 14.2. Overall mortality in Chilean patients was 28%, compared with 12% in USA and 15% in New Zealand. Within different score ranges, mortality was higher in Chilean patients than those from USA or New Zealand. It is concluded that the assessment of admission APS-2 score underlying diagnosis, physiologic age and previous health status of a patient may help to predict the success of intensive care.

Adult↗
PubMed1985

[Effect of clorgyline and of alpha-methyl-p-tyrosine on the plasma levels of corticosterone in the rat].

The effect of a type A MAO inhibitor, clorgyline, injected alone or with alpha-methyl-p-tyrosine (aMpT) on the plasmatic corticosterone levels estimated at 9 a.m. and 5 p.m. has been studied in male Wistar rats. The clorgyline injected alone produced significant decreases in corticosterone values, especially at 5 p.m., determining a variation lack between the morning and the afternoon levels. When alpha-MpT is associated to IMAO, increases at both points of the day considered in this experiment take place. The amount of NA and 5-HT in the brain was also estimated; clorgyline high increases in Na and 5-HT contents, 5-HT; aMpT reduces the effect of clorgyline, especially as regards content. The results are discussed in relation to this highly specific MAO inhibitor and with the role of these amines as modulators of ACTH secretion. In view of the changes introduced by the aMpT injection, the modifications produced by clorgyline alone are related to NA, but to 5-HT, when the NA synthesis has been interrupted by the tyrosine hydroxylase inhibitor.

Adrenocorticotropic Hormone↗