Simultaneous liver and renal transplantation in a pediatric patient with type I hyperoxaluria.
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Child↗
Biomedical subjects
J Ortega
Publications and source records attributed to J Ortega.
Induction with basiliximab reduces acute rejection in pediatric liver transplant patients treated with tacrolimus and steroids.
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Adrenal Cortex Hormones↗
Pathological and immunohistochemical study of the liver and hepatic lymph nodes of sheep chronically reinfected with Fasciola hepatica, with or without triclabendazole treatment.
Hepatic lesions and changes in the hepatic lymph nodes were examined in groups of sheep infected, and sometimes reinfected, with metacercariae of Fasciola hepatica, with or without treatment with triclabendazole (TCBZ). Hepatic damage was more severe in sheep given small repeated ("trickle") infections than in those given two larger, spaced doses. Inflammatory infiltrates of eosinophils, CD3+ T cells, CD79 alpha+ B cells and IgG+ plasma cells, and the presence of granulomata, were particularly marked in trickle-infected groups, suggesting that the host response to certain fluke or egg antigens causes severe hepatic damage. TCBZ administration induced the elimination of flukes and healing of the majority of hepatic lesions but did not prevent severe hepatic damage produced by later infections.
Animals↗
Structural normalization of the lymphoid tissue in asymptomatic HIV-infected patients after 48 weeks of potent antiretroviral therapy.
BACKGROUND: The hallmark of HIV infection is the involution and destruction of lymphoid tissue. However, very little information exists on the effect of highly active antiretroviral therapy (HAART) on lymphoid tissue structure. OBJECTIVE: To evaluate the effect of a HAART regimen after 48 weeks on the architecture and cell regeneration of tonsil lymphoid tissue in HIV-infected patients with CD4 T cell counts > or = 500/microl. METHODS: From June 1997 to February 1998 all asymptomatic HIV-infected patients with CD4 T cell counts > or = 500/microl seen at our unit were offered quadruple antiretroviral therapy. Tonsil biopsies were obtained at baseline and at 48 weeks. Tonsil tissue sections were examined to evaluate structural and immunohistochemical changes by two blinded and independent pathologists. Cell numbers were counted for selected markers in T-dependent zones. RESULTS: Eleven patients were evaluable, six were excluded because of insufficient or inadequate sampling in at least one of the biopsies. Cellular depletion, plasma cell accumulation and prominent vessels were observed in all cases; three excluded patients with evaluable baseline biopsies showed similar tissue lesions. Follow-up biopsies demonstrated some degree of improvement in all patients. Germinal centres appeared in seven cases that were not seen at baseline. CD4 cell counts increased and CD8 cell counts decreased significantly in lymphoid tissue. An increase in CD45RA+ cells was observed; however, the proportion of CD45+Ki67+ cells did not differ between baseline and 48 weeks. CONCLUSION: This study shows an unexpected range of moderate to severe lymphoid tissue lesions in mildly immunosuppressed HIV-infected patients, which was partly restored after 48 weeks of HAART.
Adult↗
Lysine 188 substitutions convert the pattern of proteasome activation by REGgamma to that of REGs alpha and beta.
11S REGs (PA28s) are multimeric rings that bind proteasomes and stimulate peptide hydrolysis. Whereas REGalpha activates proteasomal hydrolysis of peptides with hydrophobic, acidic or basic residues in the P1 position, REGgamma only activates cleavage after basic residues. We have isolated REGgamma mutants capable of activating the hydrolysis of fluorogenic peptides diagnostic for all three active proteasome beta subunits. The most robust REGgamma specificity mutants involve substitution of Glu or Asp for Lys188. REGgamma(K188E/D) variants are virtually identical to REGalpha in proteasome activation but assemble into less stable heptamers/hexamers. Based on the REGalpha crystal structure, Lys188 of REGgamma faces the aqueous channel through the heptamer, raising the possibility that REG channels function as substrate-selective gates. However, covalent modification of proteasome chymotrypsin-like subunits by 125I-YL3-VS demonstrates that REGgamma(K188E)'s activation of all three proteasome active sites is not due to relaxed gating. We propose that decreased stability of REGgamma(K188E) heptamers allows them to change conformation upon proteasome binding, thus relieving inhibition of the CT and PGPH sites normally imposed by the wild-type REGgamma molecule.
Amino Acid Sequence↗
Gyrotropy problem in nonhomogeneous media: The case of short-pitch chiral-smectic-C liquid crystals and incommensurate structures.
The question about the existence of macroscopic models for gyrotropy in inhomogeneous materials is examined. We have carried out a detailed polarimetric study on a short-pitch chiral-smectic-C liquid crystal, which has been taken as an example of an inhomogeneous optical medium. In accordance to the theoretical predictions, we have found that, as a first approximation, the inhomogeneous liquid crystal can be modeled as a homogeneous uniaxial medium with huge optical activity in a direction perpendicular to the optic axis. However, some deviations have been determined in the precise values of the optical activity predicted by the theory. These discrepancies have been attributed to higher-order gyration-like effects, which are usually negligible and have not been considered in previous theoretical approaches. The agreement improves when these higher-order effects are incorporated. In the light of the above results, the theory is applied to the case of incommensurate structures. The origin of gyrotropy in these materials is clarified, and it is shown that this quantity can be described by a usual macroscopic tensor. If the incommensurate structure has an inversion center we deduce that all gyration effects rigorously vanish, contrary to the opinion maintained by several authors.
Journal Article↗
Surface soft phonon and the sqrt[3] x sqrt[3] <--> 3x3 phase transition in Sn/Ge(111) and Sn/Si(111).
Density functional theory calculations show that the reversible Sn/Ge(111) sqrt[3]xsqrt[3]<-->3x3 phase transition can be described in terms of a surface soft phonon. The isovalent Sn/Si(111) case does not display this transition since the sqrt[3]xsqrt[3] phase is the stable structure at low temperature, although it presents a partial softening of the 3x3 surface phonon. The rather flat energy surfaces for the atomic motion associated with this phonon mode in both cases explain the experimental similarities found at room temperature between these systems. The driving force underlying the sqrt[3]xsqrt[3]<-->3x3 phase transition is shown to be associated with the electronic energy gain due to the Sn dangling bond rehybridization.
Journal Article↗
Comparison of outcomes of unrelated bone marrow and umbilical cord blood transplants in children with acute leukemia.
In order to compare the outcomes of unrelated umbilical cord blood transplants (UCBTs) or bone marrow transplants, 541 children with acute leukemia (AL) transplanted with umbilical cord blood (n = 99), T-cell-depleted unrelated bone marrow transplants (T-UBMT) (n = 180), or nonmanipulated (UBMT) (n = 262), were analyzed in a retrospective multicenter study. Comparisons were performed after adjustment for patient, disease, and transplant variables. The major difference between the 3 groups was the higher number in the UCBT group of HLA mismatches (defined by serology for class I and molecular typing for DRB1). The donor was HLA mismatched in 92% of UCBTs, in 18% of UBMTs, and in 43% of T-UBMTs (P <.001). Other significant differences were observed in pretransplant disease characteristics, preparative regimens, graft-versus-host disease (GVHD) prophylaxis, and number of cells infused. Nonadjusted estimates of 2-year survival and event-free survival rates were 49% and 43%, respectively, in the UBMT group, 41% and 37% in the T-UBMT group, and 35% and 31% in the UCBT group. After adjustment, differences in outcomes appeared in the first 100 days after the transplantation. Compared with UBMT recipients, UCBT recipients had delayed hematopoietic recovery (Hazard ratio [HR] = 0.37; 95% confidence interval [95CI]: 0.27-0.52; P <.001), increased 100 day transplant-related mortality (HR = 2.13; 95CI: 1.20-3.76; P <.01) and decreased acute graft-versus-host disease (aGVHD) (HR = 0.50; 95CI: 0.34-0.73; P <.001). T-UBMT recipients had decreased aGVHD (HR = 0.25; 95CI: 0.17-0.36; P <.0001) and increased risk of relapse (HR = 1.96; 95CI: 1.11-3.45; P =.02). After day 100 posttransplant, the 3 groups achieved similar results in terms of relapse. Chronic GVHD was decreased after T-UBMT (HR = 0.21; 95CI: 0.11-0.37; P <.0001) and UCBT (HR = 0.24; 95CI: 0.01-0.66; P =.002), and overall mortality was higher in T-UBMT recipients (HR = 1.39; 95CI: 0.97-1.99; P <.07). In conclusion, the use of UCBT, as a source of hematopoietic stem cells, is a reasonable option for children with AL lacking an acceptably matched unrelated marrow donor.
Analysis of Variance↗
Functional domains of the ClpA and ClpX molecular chaperones identified by limited proteolysis and deletion analysis.
Escherichia coli ClpA and ClpX are ATP-dependent protein unfoldases that each interact with the protease, ClpP, to promote specific protein degradation. We have used limited proteolysis and deletion analysis to probe the conformations of ClpA and ClpX and their interactions with ClpP and substrates. ATP gamma S binding stabilized ClpA and ClpX such that that cleavage by lysylendopeptidase C occurred at only two sites. Both proteins were cleaved within in a loop preceding an alpha-helix-rich C-terminal domain. Although the loop varies in size and composition in Clp ATPases, cleavage occurred within and around a conserved triad, IG(F/L). Binding of ClpP blocked this cleavage, and prior cleavage at this site rendered both ClpA and ClpX defective in binding and activating ClpP, suggesting that this site is involved in interactions with ClpP. ClpA was also cut at a site near the junction of the two ATPase domains, whereas the second cleavage site in ClpX lay between its N-terminal and ATPase domains. ClpP did not block cleavage at these other sites. The N-terminal domain of ClpX dissociated upon cleavage, and the remaining ClpXDeltaN remained as a hexamer, associated with ClpP, and expressed ATPase, chaperone, and proteolytic activity. A truncated mutant of ClpA lacking its N-terminal 153 amino acids also formed a hexamer, associated with ClpP, and expressed these activities. We propose that the N-terminal domains of ClpX and ClpA lie on the outside ring surface of the holoenzyme complexes where they contribute to substrate binding or perform a gating function affecting substrate access to other binding sites and that a loop on the opposite face of the ATPase rings stabilizes interactions with ClpP and is involved in promoting ClpP proteolytic activity.
ATPases Associated with Diverse Cellular Activitie↗
Sonographic findings in brucellar hepatic abscess.
Brucellar hepatic abscesses are rare; to our knowledge, only 41 cases have been described in the literature. We report the case of a 29-year-old Spanish woman who was hospitalized because of fever, weakness, and weight loss. Abdominal sonography showed a hypoechoic lesion with central calcification. Brucella spp. were not isolated from an aspirate of the liver or blood cultures. The diagnosis was based on the association of characteristic sonographic features (central calcification and peripheral necrotic areas) and positive Brucella agglutination tests. The patient improved rapidly with antibiotic treatment.
Adult↗
[Yield of transthoracic echocardiography with high frequency transducer in the study of the anterior descending coronary artery].
INTRODUCTION AND OBJECTIVES: This study was performed to evaluate the feasibility and utility of a transthoracic high frequency transducer to detect and measure the left anterior descending coronary artery flow in patients with lesions in this artery or anterior myocardial infarction. MATERIALS AND METHODS: We studied 11 subjects with lesions greater than 75% and another 10 with anterior myocardial infarction. We compared the results with a control group of 18 subjects. An ATL HDI 5000 ultrasound unit with a 5-8 MHz transducer was used to identify the left anterior descending in the anterior interventricular sulcus from an apical four chamber window. We considered that left anterior descending was detected when a diastolic predominant flow pattern was obtained with pulse Doppler. RESULTS: Left anterior descending was detected in 37/39 of cases (94.4%). Patients with coronary lesions showed a decrease in the limit of significance in the diastolic/systolic peak velocity ratios: 2.5 (SD 0.7) vs 1.8 (SD 0.3) with a p = 0.024. Patients with anterior myocardial infarction obtained lower diastolic/systolic peak velocity ratios than controls: 2.5 (SD 0.7) vs 1.4 (SD 0.3) with a p = 0.001. CONCLUSIONS: Left anterior descending coronary artery flow can be assessed by transthoracic high frequency echocardiography in greater than 90% of the cases. Patients with coronary lesions and those with anterior myocardial infarction have a decreased diastolic/systolic peak velocity ratio.
Aged↗
[Diagnosis of apical hypertrophic cardiomyopathy using contrast echocardiography].
Apical hypertrophic cardiomyopathy is a disease with clear electrocardiographic and echocardiographic characteristics. However, poor visualization of apical endocardial border is a limiting factor to diagnose apical hypertrophic cardiomyopathy by echocardiography. We present a case report of a patient with a characteristic electrocardiogram but poor apical endocardial border delineation. A contrast-enhanced echocardiography was performed to confirm the diagnosis of apical hypertrophic cardiomyopathy. We discuss the role of echocardiographic image enhancement with contrast to diagnose apical hypertrophic cardiomyopathy.
Aged↗
Lack of efficacy of atenolol for the prevention of neurally mediated syncope in a highly symptomatic population: a prospective, double-blind, randomized and placebo-controlled study.
OBJECTIVES: This study was designed to evaluate the efficacy of atenolol for the long-term management of patients with vasovagal syncope. The primary hypothesis was that atenolol is not superior to placebo for the treatment of vasovagal syncope. BACKGROUND: There is no definitive well-controlled analysis of the efficacy of beta-adrenergic blocking agents in patients with recurrent vasovagal syncope. METHODS: This is a prospective, randomized, double-blind, placebo-controlled study. Fifty patients with recurrent vasovagal syncope were included (at least two episodes in the last year). A baseline tilt test was performed. Twenty patients (40%) had a positive tilt test. Intravenous atenolol prevented a second positive tilt in five patients. The patients were randomized to receive either atenolol or a placebo (26 patients atenolol 50 mg/day, 24 patients placebo). The follow-up procedure lasted one year. The primary end point of the study was the time to first recurrence of syncope. RESULTS: In the intention-to-treat analysis, the group treated with atenolol had a similar number of patients with recurrent syncopal episodes as the placebo group. The Kaplan-Meier actuarial estimates of time to first syncopal recurrence showed that the probability of remaining free of syncope drops similarly in both groups and that there was no statistical difference between both curves (patients treated with atenolol vs. the placebo) with a log-rank test p value of 0.4517. CONCLUSIONS: The recurrence of neurocardiogenic syncope in highly symptomatic patients treated with atenolol is similar to that of patients treated with placebo.
Adolescent↗
Three-dimensional reconstruction of a recombinant influenza virus ribonucleoprotein particle.
A three-dimensional structural model of an influenza virus ribonucleoprotein particle reconstituted in vivo from recombinant proteins and a model genomic vRNA has been generated by electron microscopy. It shows a circular shape and contains nine nucleoprotein monomers, two of which are connected with the polymerase complex. The nucleoprotein monomers show a curvature that may be responsible for the formation of helical structures in the full-size viral ribonucleoproteins. The monomers show distinct contact boundaries at the two sides of the particle, suggesting that the genomic RNA may be located in association with the nucleoprotein at the base of the ribonucleoprotein complex. Sections of the three-dimensional model show a trilobular morphology in the polymerase complex that is consistent with the presence of its three subunits.
Image Processing, Computer-Assisted↗
[Reimplantation edema in the transplanted lung. Reperfusion-ischemia or hydrostatic edema?].
The development of non cardiogenic pulmonary edema or pulmonary reimplantation response after lung transplantation has been well described. The cause is ischemic vascular injury of the allograft, results in increased permeability of the lung after reperfusion, in turn leading to interstitial and alveolar edema. We report two cases of pulmonary reimplantation response after bilateral sequential lung transplantation. Massive pink frothy fluid was noted in the orifice of the double-lumen endobronchial tube. Blood and endobronchial fluid samples were collected for protein electrophoresis. We conclude that, in spite of the severity of reimplantation response, this complication can be resolved early when the cause is mainly hydrostatic.
Blood Proteins↗
[Comparative study of reduced-size and whole liver transplantation in children].
It is difficult to find adequate donors for many children with low weight. In order to increase the pool size of donors and decrease mortality on the waiting list, several reduction techniques have been developed in the last years (reduced, segmental and split liver). The aim of this study is to compare morbility and mortality in our serie between children who received a full-size liver and those who received a partial one. We retrospectively compared 27 cases of reduced-size liver transplants (RLTx) with 102 cases of full-size liver transplants (FLTx) performed between june of 1985 and february of 2000. Mean age in RLTx was 38.1 months (range 6-144) vs 70.8 months (range 5-192) in FLTx. Mean weight was 11.9 k (range 5.8-30) in RLTx vs 20.48 k (range 4.4-68) in FLTx. Mean donor/recipient body ratio was 4.88 in RLTx and 2.03 in FLTx. The indication of transplantation was urgent in 14 patients (51.8%) from the RLTx group and in 12 (11.7%) from the FLTx one. The requirements of transfusions during surgery was greater in the RLTx (177 cc/kg of RBC transfusions vs 124 cc in FLTx). There was no differences between both groups regarding other postoperative complications (portal thrombosis, need of reintervention and biliary complications). Arterial thrombosis was observed only in FLTx (12 cases). Graft survival at 3 months was 49% for the RLTx and 73% for the FLTx. It was 43% and 67%, respectively, at 1 year, and 43% and 53% at 5 years after liver transplantation (p = 0.06). If we consider only elective transplants, survival was 72% for RLTx and 75% for the FLTx at 3 months. Although survival is lower in the RLTx group, the difference is not significant. If we consider only the elective transplants, survival is almost the same in both groups. The reduction techniques are a good method to decrease mortality in the waiting list without increasing post-transplant morbidity and mortality.
Child↗
Second-harmonic generation studies in the B2 and B4 phases of a banana-shaped liquid crystal.
Second-harmonic generation (SHG) measurements have been performed in the B2 phase of the achiral banana-shaped molecule with n=12 alkoxy end chains (P-12-O-PIMB). A quantitative value of the nonlinear efficiency has been obtained from SHG curves at oblique incidences, taking into account that the signal is generated by a random orientation of different domains. In the B4 phase, circular dichroism, optical absorption and SHG studies have been carried out. It has been found that there are no simple helical arrangements giving rise to selective reflection in the visible region of the spectrum. In addition, some unusual features of the SHG behavior are pointed out. It is concluded that the phase is intrinsically inactive for the SHG process. The detected signal is due to the presence of some birefringent inclusions that are created at the B2 to B4 transition and slowly disappear while the sample is maintained within the B4 phase. A structural model for these inclusions is presented.
Journal Article↗
Analysis of risk factors following pediatric liver transplantation.
Several recipient, donor and operation factors as well as postoperative complications related to patient survival after liver transplantation (LT) in children were studied by univariate and multivariate analyses. In a 13-year period, 103 patients under 15 years of age underwent 120 LT; the mean age was 63 months and 36% were under 2 years of age. Indications for LT were cholestatic disease in 68 (56%), metabolic diseases in 18 (14%), fulminant hepatic failure in 8 (7.5%), cirrhosis in 7 (5.8%), and retransplants in 17 (14%). Whole liver was transplanted in 79% of cases and partial liver in 21%. Actuarial survival at 1, 5, and 10 years was 70%, 61%, and 57%, respectively. United Network of Organ Sharing (UNOS) I recipients (RR = 2.7), primary non-function (PNF) (RR = 13.9), and hepatic artery thrombosis (HAT) (RR = 3.8) were independent factors for lower patient survival in multivariate analysis. Thus, in our experience, postoperative mortality as a consequence of the patient's condition before transplantation, or complications such as PNF or HAT, are the major causes of decreased survival in pediatric LT.
Adolescent↗