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ABSTRACT The objective of this study was to understand how the shares’ volatility affects the portfolios’ dynamics formed using the model of pairs trading in the Brazilian stock market. This article distinguished itself by bringing new evidence about the effects of volatility in the pairs trading model not covered by previous studies, expanding the sample size analyzed in the Brazilian stock market. The chosen theme’s relevance is that investors can use pairs trading or long-short models to build their portfolios. The use of cointegration concepts probabilistically contributes to portfolios’ formation weakly correlated to the market indexes with superior performance. This article impacts the area by contributing new evidence for better use of the model in the analysis of investments. From January 2016 to December 2018, the 90 most liquid assets of Bolsa, Brasil, Balcão (B3) were analyzed, totaling 5,927,400 possible pairs. The Augmented Dickey-Fuller test and subsequent backtesting of the pairs in the proposed period were used to evaluate the cointegration criteria. Statistical analysis was performed by parametric and non-parametric tests and Pearson and Spearman correlation analyses. The results found indicated that the formation of portfolios by pairs trading with dependent assets with the criterion of higher levels of volatility (20 periods) presented a superior performance. These findings can be justified by a better risk and return ratio for the portfolio, measured by the Sharpe Index of the returns obtained concerning the portfolio’s volatility, compared to a portfolio formation based on a random selection of the pairs. In addition, the results also showed a low correlation of returns concerning the market index. Therefore, the application of the statistical cointegration analysis methodology alone does not guarantee results that are different from the market average.

Abstract: Background: The intestinal mucosa plays an important role in the mechanical barrier against pathogens. During Toxoplasma gondii infection, however, the parasites invade the epithelial cells of the small intestine and initiate a local immune response. In the submucosal plexus, this response promotes an imbalance of neurotransmitters and induces neuroplasticity, which can change the integrity of the epithelium and its secretory function. This study evaluated the submucosal neurons throughout acute T. gondii infection and the relationship between possible alterations and the epithelial and immune defense cells of the mucosa. Methods: Forty Wistar rats were randomly assigned to 8 groups (n = 5): 1 control group, uninfected, and 7 groups infected with an inoculation of 5000 sporulated T. gondii oocysts (ME‐49 strain, genotype II). Segments of the ileum were collected for standard histological processing, histochemical techniques, and immunofluorescence. Key Results: The infection caused progressive neuronal loss in the submucosal general population and changed the proportion of VIPergic neurons throughout the infection periods. These changes may be related to the observed reduction in goblet cells that secret sialomucins and increase in intraepithelial lymphocytes after 24 hours, and the increase in immune cells in the lamina propria after 10 days of infection. The submucosa also presented fibrogenesis, characterizing injury and tissue repair. Conclusions and Inferences: The acute T. gondii infection in the ileum of rats changes the proportion of VIPergic neurons and the epithelial cells, which can compromise the mucosal defense during infection. [ABSTRACT FROM AUTHOR]

The objective of this study was to understand how the shares' volatility affects the portfolios' dynamics formed using the model of pairs trading in the Brazilian stock market. This article distinguished itself by bringing new evidence about the effects of volatility in the pairs trading model not covered by previous studies, expanding the sample size analyzed in the Brazilian stock market. The chosen theme's relevance is that investors can use pairs trading or long-short models to build their portfolios. The use of cointegration concepts probabilistically contributes to portfolios' formation weakly correlated to the market indexes with superior performance. This article impacts the area by contributing new evidence for better use of the model in the analysis of investments. From January 2016 to December 2018, the 90 most liquid assets of Bolsa, Brasil, Balcão (B3) were analyzed, totaling 5,927,400 possible pairs. The Augmented Dickey-Fuller test and subsequent backtesting of the pairs in the proposed period were used to evaluate the cointegration criteria. Statistical analysis was performed by parametric and non-parametric tests and Pearson and Spearman correlation analyses. The results found indicated that the formation of portfolios by pairs trading with dependent assets with the criterion of higher levels of volatility (20 periods) presented a superior performance. These findings can be justified by a better risk and return ratio for the portfolio, measured by the Sharpe Index of the returns obtained concerning the portfolio's volatility, compared to a portfolio formation based on a random selection of the pairs. In addition, the results also showed a low correlation of returns concerning the market index. Therefore, the application of the statistical cointegration analysis methodology alone does not guarantee results that are different from the market average. [ABSTRACT FROM AUTHOR]

Background: Urinary sediment is a noninvasive laboratory test that can be performed by an automated analyzer or manually by trained personnel. Manual examination remains the diagnostic standard because it excels at differentiating isomorphic from dysmorphic red blood cells and identifying other urinary particles such as renal tubular epithelial cells (RTECs), lipids, crystals, and the composition of casts. This study aimed to investigate the prevalence of a complete profile of urinary sediment particles and its associations with histologic lesions on kidney biopsy, regardless of diagnosis., Methods: This was a single-center, observational retrospective study of 131 patients who had contemporary manual urinary sediment evaluation and kidney biopsy. A comprehensive set of urinary particles and histologic lesions were quantified, and their associations were analyzed., Results: In our samples, we found an elevated frequency of findings suggestive of proliferative kidney disease and a low frequency of particles evoking urologic damage. The association of histologic lesions and urinary particles was explored with a multivariate model. We identified urinary sediment characteristics that independently correlated with the presence of some histologic lesions: urinary lipids with mesangial expansion (OR=2.86; 95% confidence interval [95% CI], 1.3 to 6.3), mesangial hypercellularity (OR=2.44; 95% CI, 1.06 to 5.58), and wire loops and/or hyaline deposits (OR=2.89; 95% CI, 1.13 to 7.73); Urinary renal tubular epithelial cells with endocapillary hypercellularity (OR=3.17; 95% CI, 1.36 to 7.39), neutrophils and/or karyorrhexis (OR=4.51; 95% CI, 1.61 to 12.61), fibrinoid necrosis (OR=4.35; 95% CI, 1.48 to 12.74), cellular/fibrocellular crescents (OR=5.27; 95% CI, 1.95 to 14.26), and acute tubular necrosis (OR=2.31; 95% CI, 1.08 to 4.97)., Conclusions: In a population of patients submitted to kidney biopsy, we found that the presence of some urinary particles (renal tubular epithelial cells, lipids, and dysmorphic erythrocytes), which are seldom reported by automated analyzers, is associated with active proliferative histologic lesions. In this regard, manual urinary sediment evaluation may help to shape the indications for performing a kidney biopsy., (Copyright © 2022 by the American Society of Nephrology.)

Background: Kidney disease is a rare manifestation of ankylosing spondylitis (AS) and its pathological alterations remain poorly described. The aim of this study was to investigate the clinical presentation and pathological alterations on kidney biopsy of AS patients and review and discuss the current literature on the issue., Methods: We retrospectively studied the clinical presentation and kidney pathological alterations of 15 Caucasian AS patients submitted to kidney biopsy between October 1985 and March 2021., Results: Patients were predominantly male (66.7%) with median age at the time of kideney biopsy of 47 years [IQR 34 - 62]. Median serum creatinine at presentation was 1.3 mg/dL [IQR 0.9 - 3] and most patients also had either proteinuria (85.7%) and/or hematuria (42.8%). The most common indication for kidney biopsy was nephrotic syndrome (33.3%), followed by acute or rapidly progressive kidney injury (20%) and chronic kidney disease of unknown etiology (20%). Chronic interstitial nephritis (CIN) (n=3) and AA amyloidosis (n=3) were the most common diagnosis. Others included IgA nephropathy (IgAN) (n=2), focal segmental glomerulosclerosis (n=2), membranous nephropathy (n=1), and immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN)(n=1)., Conclusions: We present one of the largest series of biopsy-proven kidney disease in Caucasian AS patients. We found a lower prevalence of IgAN than previously reported in Asian cohorts. We found a higher prevalence of CIN and a lower prevalence of AA amyloidosis than that described in previous series of Caucasian patients. We also present the first case of AS-associated IC-MPGN.

Bullous pemphigoid is an autoimmune bullous cutaneous disease. We report the case of a 60 year-old male patient whose kidney allograft failed and was on hemodialysis for the previous 16 months. After tapering immunosuppressive medication, he presented simultaneous bullous eruption and kidney allograft intolerance syndrome. Investigation showed a positive BP180 anti-basement membrane zone antibody and skin biopsy was consistent with bullous pemphigoid. The patient was treated with corticotherapy and bullous pemphigoid resolved. The development of new onset diabetes and concerns over long term immunosuppression, halted the decision to continue corticotherapy and the patient underwent graft nephrectomy, with resolution of the kidney allograft intolerance syndrome without recurrence of the bullous disease. The occurrence of bullous pemphigoid in patients with failed renal allograft is rare, with only eleven cases reported in literature. This case illustrates how graft nephrectomy can provide a definitive cure to bullous pemphigoid in this setting., (Copyright © 2021 Société francophone de néphrologie, dialyse et transplantation. Published by Elsevier Masson SAS. All rights reserved.)

We report a 63-year-old man with well-controlled type 2 diabetes mellitus and hypertension, who presented with new onset nephrotic proteinuria and rapid deterioration in renal function. The atypical clinical presentation prompted us to consider a non-diabetic and non-hypertensive cause and to perform a renal biopsy. A diagnosis of fibrillarglomerulonephritis (FGn) was made based on electronic microscopy. Proteinuria remained in nephrotic range despite treatment with prednisolone, and renal function deteriorated. We suggest that other causes of proteinuria should be considered in patients with diabetes who present with the nephrotic syndrome when there is no other evidence of microvascular disease. We review the spectrum of fibrillar glomerulopathies including FGn, primary and secondary amyloidosis and immunotactoid glomerulonephritis., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The intestinal mucosa plays an important role in the mechanical barrier against pathogens. During Toxoplasma gondii infection, however, the parasites invade the epithelial cells of the small intestine and initiate a local immune response. In the submucosal plexus, this response promotes an imbalance of neurotransmitters and induces neuroplasticity, which can change the integrity of the epithelium and its secretory function. This study evaluated the submucosal neurons throughout acute T. gondii infection and the relationship between possible alterations and the epithelial and immune defense cells of the mucosa., Methods: Forty Wistar rats were randomly assigned to 8 groups (n = 5): 1 control group, uninfected, and 7 groups infected with an inoculation of 5000 sporulated T. gondii oocysts (ME-49 strain, genotype II). Segments of the ileum were collected for standard histological processing, histochemical techniques, and immunofluorescence., Key Results: The infection caused progressive neuronal loss in the submucosal general population and changed the proportion of VIPergic neurons throughout the infection periods. These changes may be related to the observed reduction in goblet cells that secret sialomucins and increase in intraepithelial lymphocytes after 24 hours, and the increase in immune cells in the lamina propria after 10 days of infection. The submucosa also presented fibrogenesis, characterizing injury and tissue repair., Conclusions and Inferences: The acute T. gondii infection in the ileum of rats changes the proportion of VIPergic neurons and the epithelial cells, which can compromise the mucosal defense during infection., (© 2017 John Wiley & Sons Ltd.)

Anticoagulant-related nephropathy is a type of acute kidney injury caused by overcoagulation. We describe a case of an 84-year-old man with arterial hypertension, coronary heart disease and atrial fibrillation treated with acenocoumarol, who presented with haematoproteinuria and acute kidney injury during a phase of excessive anticoagulation. In addition to IgA nephropathy, renal biopsy also revealed acute tubular necrosis, red blood cell casts and positive iron staining in tubular cells. After this acute episode, renal function improved and proteinuria decreased below the nephrotic range., (2017 BMJ Publishing Group Ltd.)

Toxoplasmosis is a widely distributed disease caused by the protozoan Toxoplasma gondii that is mainly transmitted orally. Once ingested, the parasite crosses the intestinal barrier to reach the blood and lymph systems to migrate to other regions of the host. The objective of this study was to evaluate the changes in the myenteric plexus and the jejunal wall of Wistar rats caused by oral infection with T. gondii oocysts (ME-49 strain). Inocula of 10, 100, 500 and 5000 oocysts were used. The total population of myenteric neurons and the most metabolically active subpopulation (NADH-diaphorase positive - NADH-dp) exhibited a decrease proportional to the dose of T. gondii. There was also a quantitative increase in the subpopulation of NADPH-diaphorase-positive (NADPH-dp) myenteric neurons, indicating greater expression of the NOS enzyme. Neuronal atrophy was observed, and morphological and morphometric alterations such as jejunal atrophy were found in the infected groups. Hypertrophy of the external muscle with the presence of inflammatory foci was observed in the group infected with 5000 oocysts. The changes observed in the infected groups were proportional to the number of oocysts inoculated., (Copyright © 2015 Elsevier Inc. All rights reserved.)