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Biomedical subjects

C Bravo

Publications and source records attributed to C Bravo.

At least 19 recordsLinked to original sources
PubMed2003

Blood cyclosporine C0 and C2 concentrations and cytomegalovirus infections following lung transplantation.

The aim of this study was to determine whether cyclosporine levels predose (C0) and at two hours postdose (C2) were higher among patients presenting with cytomegalovirus (CMV) infection or disease. Between days 40 and 365 posttransplantation serial C0 and C2 levels were measured in 15 lung transplant recipients. Nine developed 13 episodes of CMV infection or disease. Both C0 and C2 levels were higher during CMV infection or disease episodes. Eleven of the 13 CMV episodes (84%) displayed C0 >220 ng/mL and none had C0 <200 ng/mL. For C2, 11 of 13 CMV episodes (84%) showed C2 >1200 ng/mL and none had C2 <1000 ng/mL. Among determinations that did not coincide with a CMV episode, 7 of 21 (33%) showed C0 >220 and 9 of 21 (42%) showed C2 >1200, respectively (P<.05). In conclusion, cyclosporine blood levels are higher among patients presenting with CMV infection or disease.

Adult↗
PubMed2001

Nebulized amphotericin B prophylaxis for Aspergillus infection in lung transplantation: study of risk factors.

BACKGROUND: Aspergillus infection remains a major cause of morbidity and mortality after lung transplantation. Therefore, some strategies have been attempted, one of which is nebulized amphotericin B (nAB); however, the efficacy of this prophylaxis has not been shown clearly. The aim is to study whether nAB can protect against Aspergillus infection in lung transplant recipients. PATIENTS AND METHODS: A study of risk factors was conducted in 55 consecutive lung allograft recipients. Twenty-three potential risk factors were analyzed. In 44 (80%) patients, nAB was indicated as prophylaxis. Multivariate analysis using logistic regression was performed. RESULTS: Eighteen of the 55 patients (33%) developed infection due to Aspergillus spp. Multivariate analysis showed nAB to be a preventive factor (odds ratio: 0.13; 95% confidence interval [CI] 0.02-0.69; p < 0.05) and cytomegalovirus (CMV) disease was an independent risk factor for developing Aspergillus infection (odds ratio: 5.1; 95% CI 1.35-19.17; p < 0.05). Only 1 patient required withdrawal of the prophylaxis owing to bronchospasm. nAB was well-tolerated in the remaining patients with only a few, mild, easily controlled side effects. CONCLUSIONS: The present results show that nAB prophylaxis may be efficient and safe in preventing Aspergillus infection in lung-transplanted patients, and CMV disease increases the probability of Aspergillus infection.

Adolescent↗
PubMed2001

Metabolic changes induced by cold stress in rat liver mitochondria.

The mechanisms involved in the metabolic changes induced by cold stress in isolated rat liver mitochondria were studied. Respiration, ATP synthesis, and membrane potential as well as the contents of several metabolites were determined in liver mitochondria from cold-exposed rats. At different times of cold exposure, the force-flux relationships showed net variation in flux (enhanced respiration, diminished ATP synthesis) with no associated variation in force (H+ gradient); this suggested that decoupling rather than classical uncoupling was involved in the effects of cold stress. The flux control coefficient of the H+ leak on basal respiration was slightly increased by 380 h of cold exposure. Cold stress also induced a diminution in total membrane fatty acids, Zn2+, Fe3+, ATP, and ADP/O ratios; the content of cytochromes c + c1 and b oscillated. The contents of Ca2+, Na+, Pi, and cytochromes a + a3 were not affected, whereas matrix ADP, AMP, K+, and Mg2+ were markedly increased. Basal and oleic acid-stimulated respiration of mitochondria from cold-stressed rats was inhibited by GDP, carboxyatractyloside, or albumin. These agents did not affect basal respiration in control mitochondria. Western blot analysis showed enhanced expression of a protein of about 35 kDa, presumably the uncoupling protein 2, induced by long-term cold exposure. The overall data suggest that cold stress promoted decoupling of oxidative phosphorylation, and hence, changes in several matrix metabolites, by increasing free fatty acids and the UCP2 content.

Adenine Nucleotides↗
PubMed2001

[Ocular blood flow and characteristics of retinal detachment].

PURPOSE: To determine if ocular blood flow (OBF) changes in retinal detachment (RD) are related with its characteristics (extension, macular involvement, PVR or duration). METHODS: 60 patients with unilateral rhegmatogenous RD and 20 < > patients were selected. Color Doppler Ultrasound was used to measure OBF velocities in the ophthalmic artery (OA), central retinal artery (CRA) and vein (CRV) and posterior ciliary arteries (PCA) of both eyes of each patient. The IOP and RD characteristics were considered. In each case the paired Student's T test (OBF) and Wilcoxon test (IOP) were used for the statistical analysis (p<5%). RESULTS: Peak systolic (PS) and end diastolic (ED) velocities of OA, PS of CRA and PS and ED of PCA were decreased in the RD eyes compared to the normal ones (p<0.05). The PS and ED rates of OA and PS of CRA were also decreased (p<0.05) in the other eyes compared to the normal ones. Both the decrease in velocity and in the IOP were related with 2 or more quadrants of RD (p<0.05), macula detachment (p<0.05), PVR >/=C(2) (p<0.05) and duration of >/=15 days (p<0.05). CONCLUSION: RD correlates with decreased ocular blood flow velocities and IOP in both the RD as well as in the other eye. The worse the characteristics of the RD, the lower the velocities and the IOP

Aged↗
PubMed2000

[Lymphangioleiomyomatosis: study of 15 patients].

BACKGROUND: Lymphangioleiomyomatosis (LAM) is an uncommon disease of not well-known evolution. We describe the clinical features and follow-up of a group of patients diagnosed of LAM in a hospital pulmonary transplantation programme. PATIENTS AND METHODS: 15 women (mean age: 43, range: 36-52) diagnosed of LAM, 9 at the Hospital Vall d'Hebron and 6 referred from other hospitals, for preoperative evolution of lung transplantation, were retrospectively studied. RESULTS: Dyspnea appeared in all cases and it was the main symptom. Pleural problems in the early evolution of the disease were also very frequent (12 out of 15 patients). For this reason, pleurodesis was performed in 7 patients and pleurectomy in 2 (one of them bilateral). Thoracic CT scan showed very characteristic cystic images and abdominal CT proved the presence of extrathoracic associated angiomyolipomas in one case. In two patients, LAM was diagnosed after studying the explanted lung. These two patients had been previously misdiagnosed of emphysema and pulmonary haemosiderosis. Survival since the beginning of symptoms was 82 and 49%, 5 and 10 years later, respectively. Six out of eight patients who underwent lung transplantation had a long postoperative survival. CONCLUSIONS: LAM seems to be as infrequent in Catalunya as in other countries, even if some cases could be misdiagnosed. Lung transplantation is useful in the advanced stages of the disease and, in our experience, it has improved respiratory insufficiency in half of the patients.

Adult↗
PubMed2000

Isoniazid prophylaxis in lung transplantation.

The incidence of tuberculous disease (TD) is higher in lung-transplant patients than in the general population. During a 7-year period, we included 61 patients who underwent lung transplantation in a prospective isoniazid prophylaxis protocol. Isoniazid was prescribed to infected and anergic patients not previously treated when added to the waiting list. Six of 61 patients (10%) developed tuberculosis. We observed no differences in tuberculous disease incidence between infected-anergic and non-infected patients. In our tuberculous-endemic area, isoniazid prophylaxis is safe and offers protection from TD to infected and anergic patients who must be enrolled in a lung transplantation program.

Adolescent↗
PubMed2000

[Safety and efficacy of celiprolol in hypertensive patients with chronic obstructive lung disease].

BACKGROUND: Third generation beta blockers have an intrinsic simpatico-mimetic activity and are cardioselective. Therefore, they should not have adverse bronchial effects and could even have a slight bronchodilator activity. AIM: To test the efficacy and safety of celiprolol in hypertensive patients with chronic obstructive lung disease. PATIENTS AND METHODS: Uncomplicated hypertensive patients with chronic obstructive lung disease received celiprolol during 12 weeks. They were subjected to monthly clinical assessment and ventilatory function was measured on the basal period and at the end of the trial. RESULTS: During the study period, blood pressure fell significantly from 179 +/- 6/112 +/- 8 to 161 +/- 4.7/98 +/- 1.6 mmHg. No changes were observed in forced expiratory volume in 1 s or in forced expiratory flow between 25 and 75% of the vital capacity. No subjective changes in respiratory function were reported during the trial. CONCLUSIONS: No changes in ventilatory function were observed in these patients with chronic obstructive lung disease, treated with celiprolol during 12 weeks.

Adrenergic beta-Antagonists↗
PubMed2000

Woven vascular microsurgical prostheses in our experimental practice.

The authors have been concerned for six years with the development of woven microsurgical prostheses in experiments on laboratory rats, beagle dogs and domestic white pigs. In rats, in 224 experiments employing 38 types of prostheses with an inner diameter of 2 mm, a reliable prosthesis was selected, described as No. 36, with a 100% patency after insertion of a 1 cm long portion into a defect in the abdominal aorta in 40 experiments. The follow-up of this type of prosthesis lasted 12 months. In large animals this type of prosthesis was implanted into a defect of the radial artery and cephalic vein in dogs and into the femoral artery and the artery of a vascular pedicle of groin and lateral thigh flap. These experiments on large animals are not yet complete and will be the subject of a separate paper.

Animals↗
PubMed1999

[Reimplantation lesion in the postoperative period of lung transplantation. Incidence, predictive factors, prognosis and outcome. The Lung Transplantation Group of Vall d'Hebron University General Hospital].

BACKGROUND: Reimplantation disease (RD) is a postoperative complication in lung transplantation. It is defined as hypoxemia (PaO2/FiO2 ratio < 150 mmHg), radiologic infiltrates and decrease of lung compliance. The aim of the study was to analyze the incidence, predictive factors, prognosis and outcome of the patients with RD. PATIENTS AND METHOD: 49 patients submitted to lung transplantation (June 1991-December 1996) were admitted in our intensive care unit (ICU). Donor and recipient conditions, surgical parameters and outcome in ICU were analyzed. Mann-Whitney, Kruskall-Wallis, Fisher, Pearson and ANOVA-Friedman tests were used for statistical analysis according to the different variables. RESULTS: 49% of the patients (29/49) developed RD, which was influenced neither by lung disease, nor by the kind of transplantation or by ischemia time. All patients with a long surgical time developed RD, versus only 41% in those where surgery was undertaken in a shorter period of time, OR: 2.8 (1.5-5.7; p = 0.0016). The patients with RD improved showing a PaO2/FiO2 ratio of 176 and 235 mmHg at 24 and 48 h respectively (ANOVA, p < 0.00001). The patients with RD needed 14 days of mechanical ventilation versus 7 days in those without RD (p = 0.013). There were no statistically significant differences in stay and mortality in ICU. CONCLUSIONS: RD is a common complication in the postoperative phase of lung transplantation. It is present in almost all the patients with long surgical time. Almost all of them improve, with the same survival but a longer period of mechanical ventilation.

APACHE↗
PubMed1999

Inhibition and uncoupling of oxidative phosphorylation by nonsteroidal anti-inflammatory drugs: study in mitochondria, submitochondrial particles, cells, and whole heart.

The effects of the anti-inflammatory drugs diclofenac, piroxicam, indomethacin, naproxen, nabumetone, nimesulide, and meloxicam on mitochondrial respiration, ATP synthesis, and membrane potential were determined. Except for nabumetone and naproxen, the other drugs stimulated basal and uncoupled respiration, inhibited ATP synthesis, and collapsed membrane potential in mitochondria incubated in the presence of either glutamate + malate or succinate. Plots of membrane potential versus ATP synthesis (or respiration) showed proportional variations in both parameters, induced by different concentrations of nimesulide, meloxicam, piroxicam, or indomethacin, but not by diclofenac. The activity of the adenine nucleotide translocase was blocked by diclofenac and nimesulide; diclofenac also slightly inhibited mitochondrial ATPase activity. Naproxen did not affect any of the mitochondrial parameters measured. Nabumetone inhibited respiration, ATP synthesis, and membrane potential in the presence of glutamate + malate, but not with succinate. NADH oxidation in submitochondrial particles also was inhibited by nabumetone. Nabumetone inhibited O2 uptake in intact cells and in whole heart, whereas the other five drugs stimulated respiration. These observations revealed that in situ mitochondria are an accessible target. Except for diclofenac, a negative inotropic effect on cardiac contractility was induced by the drugs. The data indicated that nimesulide, meloxicam, piroxicam, and indomethacin behaved as mitochondrial uncouplers, whereas nabumetone exerted a specific inhibition of site 1 of the respiratory chain. Diclofenac was an uncoupler too, but it also affected the adenine nucleotide translocase and the H+-ATPase.

Adenosine Triphosphate↗
PubMed1999

Preregistration study on the safety and contraceptive efficacy of a progesterone-releasing vaginal ring in Chilean nursing women.

The contraceptive efficacy and safety of a progesterone-releasing vaginal ring (PVR) manufactured in Chile were compared to that of the Copper T 380A IUD (T-Cu) in nursing women enrolled at three Chilean clinics. A total of 285 volunteers chose to use the PVR and 262 the T-Cu. Plasma progesterone levels attained with the ring decreased from 25 to 14 nmol/L from month 1 to month 3 of use. Ring replacement was scheduled every 3 months. Volunteers continued in the study until weaning or completing the continuous use of four PVRs. No pregnancies occurred in 2320 and 2183 woman-months of exposure with the PVR and the T-Cu, respectively. Lower continuation rates in the first 6 months because of problems with use and a longer lactational amenorrhea were observed in the PVR than in the T-Cu group. Breast-feeding performance and infant growth were similar in both groups. These results confirm the high efficacy and safety of the PVR for nursing women and have led to the registration of the PVR by Chilean health authorities.

Adult↗
PubMed1999

A Y form of hammerhead ribozyme trapped by photo-cross-links retains full cleavage activity.

The conformation in solution of a small bipartite I-III hammerhead ribozyme has been deduced from the photo-crosslinks formed between cleavable ribo-deoxysubstrates appropriately substituted with the probe deoxy-4-thiouridine and ribozyme residues. The ribozyme-substrate complex is able to adopt a Y-like structure with stems I and II in close proximity in the presence of 400 mM Na+ only. Indeed, a cross-link joining stem I (1.6) to loop II (AL2.4) forms in significant amount under these conditions. This cross-linked complex furthermore elicits, upon Mg2+ addition, a catalytic activity similar to that exhibited by the complexes cross-linked at the distal ends of either stem I or stem III or of the non-substituted bipartite complex. This shows that the reaction mechanism is fully compatible with a strong structural constraint between stems I and II and that sodium ions at high concentration (400 mM) are able to promote a proper folding of hammerhead ribozymes. None of the multiple cross-links formed within the ribozyme core (probe in position 16.1 or 1.1) was found catalytically active. The cross-link patterns nevertheless indicate a higher flexibility of the core in Na+ than in Mg2+. While most of the cross-links can be accommodated by the Y solution structure, some of them (16.1 to U4 and 2.1) definitely can not, suggesting that additional alternative inactive conformations exist in solution.

Buffers↗
PubMed1999

Determining and understanding the control of flux. An illustration in submitochondrial particles of how to validate schemes of metabolic control.

Two complementary methods were used to determine how the rate of respiration and that of ATP hydrolysis were controlled in rat liver submitochondrial particles. In the first, 'direct control analysis' method, respiration was titrated with malonate, antimycin or cyanide at 20, 30 and 37 degrees C, to determine the flux control exerted by succinate dehydrogenase, cytochrome bc1 complex and cytochrome c oxidase, respectively. Together, the three respiratory complexes only controlled the flux by about 50%, leaving the other 50% of flux control to the H+ leak. In the second, 'elasticity based' method, the elasticity coefficients of the respiratory chain or the H+-ATPase and the H+ leak towards the H+ gradient were determined. Then, the flux control coefficients were calculated using the connectivity and summation laws of metabolic control theory. The correspondence between the flux control coefficients determined in the two ways validated the two methods. This allowed us to use the second method to analyse what was the kinetic origin of the observed distribution of control. Control of ATP hydrolysis by the ATPase decreased with increasing ATPase activity; hence, the control exerted by the H+ leak increased with increasing ATPase activity, due to a diminishing elasticity towards the H+ gradient. Reverse electron transport was mainly controlled by the ATPase; the sum of flux control coefficients of succinate dehydrogenase, NADH-CoQ oxidoreductase, and H+-ATPase yielded a value greater than one, indicating that the H+ leak exerted a significant negative control on this pathway.

Adenosine Triphosphatases↗
PubMed1998

Functional and aesthetic consequences in the forearm after harvesting the Chinese flap.

We have evaluated the donor site after harvesting the chinese flap in 40 patients operated at the Clinic of Plastic and Aesthetic Surgery of Brno between 1989 and 1994. We conclude that: 1--The hand function is not oustandly altered after harvesting the flap, but in our study 11 patients (27.5%) indicated that they have some limitation or impairment of their hand function. 2--Tolerance to forearm deformity is considerable, but it depends on degree of the defect for which the flap is transferred: 25 patients (62.5%) would like to elect a different flap. 3--It is necessary to think about cosmetic consequences of the chinese flap and consider other possibilities of the flap choice. Secondary defect may be for the patient a problem even several years after operation.

Adolescent↗