Catarina Carvalho

Cerebral coccidioidomycosis after renal transplantation in a non‐endemic area

C. Carvalho, I. Ferreira, S. Gaião, S. Guimarães, R. Costa, J. Santos, S. Sampaio, M. Bustorff, G. Oliveira, M. Pestana. Cerebral coccidioidomycosis after renal transplantation in a non‐endemic area.
Transpl Infect Dis 2010: 12: 151–154. All rights reserved

Plasma and urine renalase levels and activity during the recovery of renal function in kidney transplant recipients

Renalase is a recently described enzyme secreted by the kidney into both plasma and urine, where it was suggested to degrade catecholamines contributing to blood pressure control. While there is a controversy regarding the relationship between renal function and plasma renalase levels, there is virtually no data in humans on plasma renalase activity as well as on both urine renalase levels and activity. We prospectively examined the time course of plasma and urine renalase levels and activity in 26 end-stage renal disease (ESRD) patients receiving a cadaver kidney transplant (cadaver kidney recipients [CKR]) before surgery and during the recovery of renal function up to day 90 post transplant. The relationship with sympathetic and renal dopaminergic activities was also evaluated. The recovery of renal function in CKR closely predicted decreases in plasma renalase levels (r = 0.88; P < 0.0001), urine renalase levels (r = 0.75; P < 0.0001) and urine renalase activity (r = 0.56; P < 0.03), but did not predict changes in plasma renalase activity (r = −0.02; NS). Plasma norepinephrine levels positively correlated with plasma renalase levels (r = 0.64, P < 0.002) as well as with urine renalase levels and activity (r = 0.47 P < 0.02; r = 0.71, P < 0.0005, respectively) and negatively correlated with plasma renalase activity (r = −0.57, P < 0.002). By contrast, plasma epinephrine levels positively correlated with plasma renalase activity (r = 0.67, P < 0.0001) and negatively correlated with plasma renalase levels (r = −0.62, P < 0.003). A significant negative relationship was observed between urine dopamine output and urine renalase levels (r = −0.48; P < 0.03) but not with urine renalase activity (r = −0.33, NS). We conclude that plasma and urine renalase levels closely depend on renal function and sympathetic nervous system activity. It is suggested that epinephrine-mediated activation of circulating renalase may occur in renal transplant recipients with good recovery of renal function. The increase in plasma renalase activity observed in ESRD patients and renal transplant recipients can be explained on the basis of reduced inhibition of the circulating enzyme.

Evolution of bone disease after kidney transplantation: A prospective histomorphometric analysis of trabecular and cortical bone

Post‐transplant bone disease results from multiple factors, including previous bone and mineral metabolism disturbances and effects from transplant‐related medications. Bone biopsy remains the gold‐standard diagnostic tool.

Relationship between everolimus blood concentration assessed using the Innofluor Certican Fluorescence Polarization Immunoassay and the Architect i System sirolimus chemiluminescent microparticle immunoassay.

Everolimus, an immunosuppressive macrolide derivative of sirolimus, has a narrow therapeutic index and variable bioavailability. Assessment of blood concentration of everolimus is necessary to improve immunosuppressive efficacy without increasing potential adverse effects. Recently, Seradyn, Inc (Indianapolis, Indiana) introduced a fluorescence polarization immunoassay (Innofluor Certican Fluorescent Polarization Immunoassay [FPIA]) for quantitation of everolimus blood concentration. This immunoassay has concentration-dependent cross-reactivity with sirolimus, which must be considered in patients recently treated with that drug. In this short-term study, treatment in 53 renal transplant recipients was converted from a sirolimus-based regimen to an everolimus-based regimen. Patients were followed up for 3 months. We investigated whether cross-reactivity with everolimus also occurred with the Abbott Laboratories (Abbott Park, Illinois) Architect i System, a sirolimus chemiluminescent microparticle immunoassay (CMIA) used to quantify sirolimus blood concentration. Quantification of everolimus blood concentration using both the CMIA and the FPIA demonstrated a linear regression: CMIA = 0.73 FPIA +/- 0.77 (r(2) = 0.80; P < .001). A high degree of correlation between the CMIA and FPIA methods (r = 0.90) was confirmed using the Bland-Altman test. We conclude that the Abbott Architect i System sirolimus CMIA should be considered an alternative method for everolimus drug monitoring. The cross-reactions of both the FPIA and CMIA techniques with both sirolimus and everolimus must be considered when converting therapy from one drug to the other. In these conditions, use of an equivalent dosage is of particular importance.

The role of bone biopsy for the diagnosis of renal osteodystrophy: a short overview and future perspectives

Chronic kidney disease (CKD) patients present specific bone and mineral metabolism disturbances, which account for important morbidity and mortality. The term renal osteodystrophy, classically used for the nomination of CKD-associated bone disorder, has been limited to the histologic description of bone lesions, requiring the use of bone biopsy. Biochemical markers and imaging tools do not adequately predict the complex bone changes that are observed in renal osteodystrophy. Parathyroid hormone, which is a universally used biomarker of bone turnover in clinical practice, lacks specificity and sensitivity. Therefore, tetracycline double-labelled transiliac bone biopsy, with bone histology and histomorphometric evaluation, remains the best clinical tool to discriminate bone turnover and to evaluate the other dimensions of renal osteodystrophy. This review will focus on the value of classic bone histomorphometric analysis of trabecular bone in CKD patients and unfold new perspectives of this diagnostic tool, including cortical bone evaluation and bone tissue immunohistochemistry.

Early-onset of disseminated cryptococcal infection in two renal transplant recipients

Cryptococcosis is the third most common invasive fungal infection in organ transplant recipients after candidiasis and aspergillosis. Newly acquired and reactivation of latent infection are the major causes of infection, with typical later-onset and mainly as disseminated infection. The type and intensity of immunosuppression, diabetes mellitus and other co-morbidities as well as uremia seem to be important determinants on clinical presentation and outcome. Moreover, the diagnosis is not always apparent since it usually presents subacutely, as well as mimicking bacterial infections, which may be responsible for a delay in the diagnosis. Thus, a high degree of suspicion and need of invasive procedures for microbiological and histological evaluation are critical for definitive diagnosis and prompt institution of adequate treatment. We report two cases of disseminated cryptococcosis with different presentations and with an early-onset after renal transplantation.

Conversion from sirolimus to everolimus in kidney transplant recipients receiving a calcineurin‐free regimen

Carvalho C, Coentrão L, Bustorff M, Patrício E, Sampaio S, Santos J, Oliveira G, Pestana M. Conversion from sirolimus to everolimus in kidney transplant recipients receiving a calcineurin‐free regimen.
Clin Transplant 2011: 25: E401–E405.

A robust anisotropic edge detection method for carotid ultrasound image processing

Abstract A new approach for robust edge detection on B-mode ultrasound images of the carotid artery is proposed in this paper. The proposed method uses anisotropic Gaussian derivative filters along with non-maximum suppression over the overall artery wall orientation in local regions. The anisotropic filters allow using a wider integration scale along the edges while preserving the edge location precision. They also perform edge continuation, resulting in the connection of isolated edge points along linear segments, which is a valuable feature for the segmentation of the artery wall layers. However, this usually results in false edges being detected near convex contours and isolated points. The use of non-maximum suppression over pooled local orientations is proposed to solve this issue. Experimental results are provided to demonstrate that the proposed edge detector outperforms other common methods in the detection of the lumen-intima and media-adventia layer interfaces of the carotid vessel walls. Additionally, the resulting edges are more continuous and precisely located.

Classification Approach for Measurement of Atherosclerosis Using B-Mode Ultrasound Carotid Images

This paper presents an approach for the detection and delineation of the interfaces at the near and far walls of carotid artery using B-mode ultrasound images. After the delineation the system measures automatically the carotid intima-media thickness (IMT) in order to aid the diagnosis of the atherosclerosis. In this method we start by the measurement, at a pixel level, of local features followed by the selection of the most discriminant ones. The next stage is a classification step which assigns a probability to the pixels to belong to an interface, enabling the detection of the carotid artery interfaces. The final artery boundaries are delineated using a dynamic programming approach. The final measurements of IMT produced by the automatic method proposed in this paper were compared with three manual tracings of experts. It was also compared with an automatic method previously developed. The results show that the two automatic detection methods have similar performance, although with slight improvements in the new method, particularly for the the far wall interface.