Impact of BK Polyomavirus Plasma Viral Load in Kidney Transplant Outcomes.

BACKGROUND: BK polyomavirus infection (BKVi) is an important cause of kidney transplant (KT) loss, but there is scarce evidence on the impact of BK plasma viral load on graft function and long-term KT survival. METHODS: A retrospective cohort study including all KT recipients with BKVi (BK viremia identified in ≥3 consecutive samples by polymerase chain reaction) in our center from January 2010 to December 2020 was performed. A case-control study (1:2) was performed. We grouped the cases according to their highest peak viral load: low-level viremia (<10,000 copies/mL) and high-level viremia (≥10,000 copies/mL). To identify risk factors for BKVi, a logistic regression analysis was achieved, and a multivariable Cox regression was used to describe risk factors for graft loss. RESULTS: A total of 849 KTs were performed, and 67 presented BKVi (low-level viremia, n = 35 and high-level viremia, n = 26). In logistic regression analysis male sex (odds ratio [OR], 4.226; 95% CI, 1.660-10.758, P = .002), age (OR, 1.047; 95% CI, 1.008-1.088; P = .018), and retransplant (OR, 4.162; 95% CI, 1.018-17.015; P = .047) were predictors of BKVi. Acute rejection was more frequent in the BKVi group (18% vs 4.9%, P = .004), and graft survival was lower in patients with BKVi and high-level viremia (P = .027). In Cox regression analysis, BKVi (hazard ratio, 3.657; 95% CI, 1.146-11.670; P = .029) and specific BKV (BK polyomavirus) high-level viremia (hazard ratio, 1.988; 95% CI, 1.012-3.907; P = .046) were predictors of shorter graft survival. CONCLUSIONS: BKV high-level viremia was associated with BKV nephropathy and poorer graft survival. Additionally, acute rejection is more frequent after BKVi. It is necessary to develop strategies safe and effective for these patients.

Machine Learning based Classification of Local Robotic Surgical Skills in a Training Tasks Set.

During surgical training, it is important for the surgeon develops good motor skills throughout his training. For this reason, various surgical training systems have been developed to enhance these skills. However, one of the great challenges in these training systems is being able to objectively measure the ability and performance of the main surgical tasks, where currently only a global measurement is obtained once the task is completed. In this work, a temporal evaluation scheme is proposed, that is, an evaluation of local surgical performance at different time intervals during the training of typical tasks (knot-tying, needle-passing and suturing). The goal is to automatically classify expert (experience >100 hrs) and non-expert (experience <10 hrs) surgeons according to their performance during training, based on three classifiers: K-Nearest Neighborhood, Random Forest, and Support Vector Machine Unlike other previously reported methods, this work proposes a new evaluation scheme based on segments or time intervals, which can be an indicator of the surgeon's local performance during a robotic surgical task, without the need for direct labeling of the data at the segment level. The classification performance from obtained results was in accuracy 83% to 100%, 88% to 100% of AUC-ROC, and 88% to 100% of F1-Score in the final test between experts and non-experts surgeons, where the Support Vector Machine classifier presented the best performance. These results suggest that this proposed method by time intervals could be used in various surgical trainers to evaluate the local performance of a surgeon during trainingand thus be able to provide a tool for the quantitative visualization of opportunities to improve surgical skills.Clinical relevance- We consider that the proposed method to carry out a local performance evaluation during surgical training can provide useful information in the learning and improvement of surgical skills.

Convolutional Neural Networks for Chagas' Parasite Detection in Histopathological Images.

Chagas disease is a widely spreaded illness caused by the parasite Trypanosoma cruzi (T. cruzi). Most cases go unnoticed until the accumulated myocardial damage affect the patient. The endomyocardium biopsy is a tool to evaluate sustained myocardial damage, but analyzing histopathological images takes a lot of time and its prone to human error, given its subjective nature. The following work presents a deep learning method to detect T. cruzi amastigotes on histopathological images taken from a endomyocardium biopsy during an experimental murine model. A U-Net convolutional neural network architecture was implemented and trained from the ground up. An accuracy of 99.19% and Jaccard index of 49.43% were achieved. The obtained results suggest that the proposed approach can be useful for amastigotes detection in histopathological images.Clinical relevance- The proposed method can be incorporated as automatic detection tool of amastigotes nests, it can be useful for the Chagas disease analysis and diagnosis.

Tortuosidad discreta como medida morfométrica en tumores cerebrales / Discrete tortuosity as a morphometric measure in brain tumors

Resumen: Los tumores cerebrales pueden presentar cambios morfológicos dependiendo de su grado de malignidad. El objetivo de este trabajo es poder detectar y cuantificar estos cambios morfológicos a partir imágenes de resonancia magnética, ya que puede representar una ventaja importante para el diagnóstico no invasivo de los pacientes. Una forma de identificar dichos cambios morfológicos es a través de la medición de su tortuosidad. La tortuosidad discreta es un descriptor que caracteriza curvas bidimensionales, como el contorno de una región. En este trabajo se propone una variante para calcular la tortuosidad de superficies volumétricas. Esta técnica se basa en el uso del código cadena de cambios de pendientes del contorno superficial de un volumen y la denominamos como tortuosidad discreta tridimensional. Este descriptor se utiliza como un índice morfométrico para estudiar la tortuosidad de tumores cerebrales. Para ello se analizan imágenes de resonancia magnética de 20 pacientes con presencia de gliomas de bajo y alto grado de malignidad, considerando cuatro regiones de interés: edema, tumor entero, región activa y necrosis. Como resultado, se muestran los distintos grados de tortuosidad de las diversas regiones, encontrándose solo en algunas de ellas diferencias significativas. Cabe señalar que una desventaja que se tiene presente, es la dependencia de la medición a la utilización de un método robusto de segmentación de las regiones, sin embargo la propuesta de la tortuosidad discreta para superficies volumétricas es satisfactoria.

Abstract: A decision tree based system with heuristic weight factors oriented to diagnosis by Morphological changes in brain tumors may be related to their malignancy. The objective of this work is to be able to detect and quantify these changes in a magnetic resonance imaging, since it can represent an important advantage for the noninvasive diagnosis in patients. One way to identify such morphological changes can be through the measurement of their tortuosity. The discrete tortuosity is a descriptor that characterizes bi-dimensional curves, as the contour of a region. In this work an alternative procedure for calculating the volumetric tortuosity of a surface is proposed. This technique is based in the slope chain code of the surface contour of a volume, and here we call it tridimensional discrete tortuosity. This descriptor is used as a morphometric index to study the tortuosity of brain tumors. For this, magnetic resonance images from 20 patients with low and high malignancy levels were analyzed, considering four regions: edema, whole tumor, enhancing region, and necrotic region. As a result, the tortuosities of the different regions are presented, with significant differences only in some of them. It should be noted that a disadvantage that is present, is the dependence of the measurement to the use of a robust method of segmentation, nevertheless the proposal of the discrete tortuosity for volumetric surfaces is satisfactory.

Time-dependent biodistribution and transgene expression of a recombinant human adenovirus serotype 5-luciferase vector as a surrogate for rAd5-FMDV vaccines in cattle.

Replication-defective recombinant adenovirus 5 (rAd5) vectors carrying foot-and-mouth disease virus (FMDV) transgenes elicit a robust immune response to FMDV challenge in cattle; however mechanistic functions of vaccine function are incompletely understood. Recent efforts addressing critical interactions of rAd5 vectors with components of the bovine immune system have elucidated important aspects of induction of protective immunity against FMDV. In the current study, a rAd5-Luciferase (rAd5-Luc) surrogate vector was utilized for indirect assessment of rAd5-FMDV distribution during the first 48 hours post inoculation (hpi). To compare vector distribution dynamics and time-dependent transgene expression, bovine cells were inoculated in vitro with rAd5-FMDV and rAd5-Luc vectors. Superior transgene expression was detected in cells infected with rAd5-Luc compared to rAd5-FMDV. However, both vectors behaved remarkably similar in demonstrating elevated mRNA transcription at 24 and 48 hpi with peak occurrence of transgene expression at 48 hpi. Injection sites of cattle inoculated with rAd5-Luc contained mononuclear inflammatory infiltrates with hexon and transgene proteins associated with antigen-presenting cells. Luciferase activity, as well as microscopic detection of luciferase antigens, peaked at 24 hpi. Presence of viral mRNA also peaked at 24 hpi but unlike luciferase, remained strongly detected at 48 hpi. Cell-associated luciferase antigens were detected as early as 6 hpi at the cortical interfolicullar areas of local LN, indicating rapid trafficking of antigen-presenting cells to lymphoid tissues. This work provides mechanistic insights on rAd5-mediated immunity in cattle and will contribute to ongoing efforts to enhance rAd5-FMDV vaccine efficacy.

An updated review of simian betaretrovirus (SRV) in macaque hosts.

This review is an updated summary of nearly 30 years of SRV history and provides new and critical findings of original research accomplished in the last 5 years including, but not limited to, the pathogenetic mechanisms underlying the origin of hematopoietic abnormalities observed in infected hosts and proposed new SRV serotypes. Despite major advances in the understanding and control of SRV disease, much more remains to be learned and SRV continues to be an exciting and attractive primate model for comparative studies of the mechanisms of retroviral immunosuppression.

Insulinorresistencia en mujeres obesas afrovenezolanas / Insulin resistance in women obesas afrovenezuelan

Se ha demostrado que los factores genéticos se ven influenciados por la raza, donde las de origen africano presentan tendencia a poseer índice de masa corporal (IMC) elevado con perfil lipídico normal (HDL-c elevado y triglicéridos bajos). El objetivo de este estudio fue analizar el grado de insulino-resistencia utilizando para ello el modelo matemático Homeostasis Model Assessment (HOMA) en 2 pobalciones venezolanas de origen africano. La muestra estuvo conformada por 72 mujeres afrovenezolanas de las poblaciones de Santa María (SM) y San José (SJ), Venezuela, con edades comprendidas entre 36 y 48 años, a las cuales se les realizó historia médica y se les calculó IMC para dividirlas en grupos de mujeres obesas y mujeres no obesas; se determinó glicemia, perfil lipídico y HOMA-IR. Al comparar el grupo de mujeres obesas de las dos poblaciones con las no obesas, no se observó diferencia estadísticamente significativa en la Glicemia (obesas 85,1 ± 3,5 SM y 83 ± 2,9 SJ; no obesas 77,3 ± 2,2 SM y 190,1 ± 9,1 SJ; no obesas 184,4 ± 8.8 SM y 193,4 ± 7,4 mg/dl), Triacilglicéridos (obesas 109,8 ± 16,3 SM y 114,8 ± 21,9 SJ; no obesas 64,9 ± 7,6 SM y 77,5 ± 10,8 SJ mg/dl), LDL-c (obesas 126,6 ± 14,8 SM y 126,9 ± 8,6 Sj; no obesas 115,5 ± 133,6 ± 11,4 SJ mg/dl) y HDL-c séricos (obesas 46,3 ± 4,0 SM y 40,2 ± 3,4 SJ; no obesas 55,5 ± 2,8 SM y 44,1 ± 2,3 SJ mg/dl). Igualmente no hubo diferencia significativa entre el HOMA IR del grupo de mujeres obesas de ambas poblaciones (3,3 ± 0,2 SM y 3,2 ± 0,1 SJ) y el del grupo de no obesas (2,8 ± 0,1 SM y 3,1 ± 0,1 SJ). En conclusión, los grupos de mujeres obesas de las poblaciones de Santa María y San José presentaron HDL-c deprimidas y HOMA IR sobre los límites normales

Disseminated histoplasmosis successfully treated with liposomal amphotericin B following azathioprine therapy in a patient from a nonendemic area.

Histoplasma infections in Europe are rare, and acute disseminated histoplasmosis has been observed only in immunocompromised persons. An unusual case of autochthonous disseminated histoplasmosis in a 22-year-old Spanish man who had been treated with azathioprine and prednisone for 4 weeks before admission is reported. The development of an acute form of the disease may represent an endogenous reactivation of a latent infection as a complication of immunosuppression resulting from the use of these drugs. This case illustrates the potential risk of this opportunistic fungal infection in patients receiving azathioprine therapy, an association that has been rarely described before.