Clinical and histopathology characteristics of Castleman disease: a multicenter study of 51 Brazilian patients.

Castleman's disease (CD) is a rare and heterogeneous lymphoproliferative disorder, with limited available clinical information in Brazil. A retrospective study was carried out through information contained in the medical records of 51 patients, between July 1999 and June 2020. Seven patients were excluded, and 44 were analyzed in total. The average age of unicentric CD (UCD) patients was 35 years old and of multicentric CD (MCD) patients was 49 years old (p = 0.013). Regarding gender, there was a predominance of females among patients with UCD (68.4%) and males in patients with MCD (57.9%) (p = 0.103). The most common site of involvement in UCD was the cervical region (36.8%). A total of 73.7% of patients with UCD and 68.4% of patients with MCD presented the histological form hialyne-vascular (HV) (p = 0.499). Most patients with laboratory abnormalities had MCD. A total of 78% of the patients were asymptomatic, with the majority of symptomatic patients with MCD (p = 0.042). Only two of the 27 patients evaluated for the presence of human immunodeficiency virus (HIV) had positive serology. HHV-8 was evaluated in 14 cases, being positive in two. Of the patients with UCD, 94.7% underwent excisional biopsy, against only 41.2% of patients with MCD (p = 0.01). The mean follow-up was 61 months. We observed similarities in the clinical profile between patients in our study and patients described in the literature, such as gender, mean age, B symptoms, visceromegaly, fluid accumulation, and treatment. Unlike the literature, the cervical region was the most affected site, besides the greater association of the HV histological subtype among patients with MCD.

Evaluation of Histological Properties of Human Meniscal Grafts Stored in a Tissue Bank.

Objectives The present paper aims to evaluate and compare the histological features of fresh and frozen menisci stored in a tissue bank for 1 month and for 5 years. Methods The meniscal grafts were subjected to a histological study. A total of 10 menisci were evaluated; 2 were frozen for 5 years, 4 were frozen for 1 month, and 4 were fresh, recently harvested specimens. Histological properties were evaluated in sections stained with hematoxylin and eosin and Masson trichrome methods. Results The menisci frozen for 1 month showed partially preserved collagen fiber structure and no significant hydropic tissue degeneration. The menisci frozen for 5 years presented an evident dissociation of collagen fibers and multiple foci of hydropic degeneration. Discussion Degeneration was much more significant in menisci stored for 5 years, indicating that a long freezing period results in substantial progression of tissue deterioration. This may suggest that the 5-year period, considered the maximum time for graft storage before transplant, is too long. Conclusion Grafts stored for 1 month showed a slight degenerative change in collagen fibers, whereas menisci frozen for 5 years presented significant tissue degeneration.

Evaluation of Histological Properties of Human Meniscal Grafts Stored in a Tissue Bank / Avaliação das propriedades histológicas de enxertos meniscais humanos armazenados em banco de tecido

Abstract Objectives The present paper aims to evaluate and compare the histological features of fresh and frozen menisci stored in a tissue bank for 1 month and for 5 years. Methods The meniscal grafts were subjected to a histological study. A total of 10 menisci were evaluated; 2 were frozen for 5 years, 4 were frozen for 1 month, and 4 were fresh, recently harvested specimens. Histological properties were evaluated in sections stained with hematoxylin and eosin and Masson trichrome methods. Results The menisci frozen for 1 month showed partially preserved collagen fiber structure and no significant hydropic tissue degeneration. The menisci frozen for 5 years presented an evident dissociation of collagen fibers and multiple foci of hydropic degeneration. Discussion Degeneration was much more significant in menisci stored for 5 years, indicating that a long freezing period results in substantial progression of tissue deterioration. This may suggest that the 5-year period, considered the maximum time for graft storage before transplant, is too long. Conclusion Grafts stored for 1 month showed a slight degenerative change in collagen fibers, whereas menisci frozen for 5 years presented significant tissue degeneration.

Resumo Objetivos Avaliar e comparar as características histológicas de meniscos frescos e meniscos congelados armazenados em banco de tecidos por 1 mês e por 5 anos. Métodos Foi feito um estudo histológico com enxertos meniscais. Avaliamos 10 meniscos, sendo 2 que ficaram armazenados sob congelamento por 5 anos, 4 armazenados congelados por 1 mês, e 4 frescos, recém captados. Foram feitos cortes histológicos corados com hematoxilina e eosina e Tricrômico de Masson, para avaliação das propriedades histológicas. Resultados Os meniscos congelados por 1 mês apresentaram preservação parcial da estrutura das fibras colágenas, sem degeneração hidrópica significativa do tecido. Nos meniscos congelados por 5 anos, observamos dissociação evidente das fibras colágenas, com presença de múltiplos focos de degeneração hidrópica. Discussão Encontramos degeneração bem mais significativa nos meniscos armazenados por 5 anos, o que indica que o longo período de congelamento leva à progressão significativa da degeneração do tecido. Isto pode sugerir que o período de 5 anos, considerado período máximo que o enxerto pode permanecer armazenado antes de ser transplantado, é um período muito longo. Conclusão Nos enxertos armazenados por 1 mês, existiu apenas discreta alteração degenerativa das fibras colágenas, enquanto que nos meniscos com 5 anos de congelamento foi observada degeneração significativa do tecido. Tibiais

Expression of the retinoic acid catabolic enzyme CYP26B1 in the human brain to maintain signaling homeostasis.

Retinoic acid (RA) is a potent regulator of gene transcription via its activation of a set of nuclear receptors controlling transcriptional activation. Precise maintenance of where and when RA is generated is essential and achieved by local expression of synthetic and catabolic enzymes. The catabolic enzymes Cyp26a1 and Cyp26b1 have been studied in detail in the embryo, where they limit gradients of RA that form patterns of gene expression, crucial for morphogenesis. This paracrine role of RA has been assumed to occur in most tissues and that the RA synthetic enzymes release RA at a site distant from the catabolic enzymes. In contrast to the embryonic CNS, relatively little is known about RA metabolism in the adult brain. This study investigated the distribution of Cyp26a1 and Cyp26b1 transcripts in the rat brain, identifying several novel regions of expression, including the cerebral cortex for both enzymes and striatum for Cyp26b1. In vivo use of a new and potent inhibitor of the Cyp26 enzymes, ser 2-7, demonstrated a function for endogenous Cyp26 in the brain and that hippocampal RA levels can be raised by ser 2-7, altering the effect of RA on differential patterning of cell proliferation in the hippocampal region of neurogenesis, the subgranular zone. The expression of CYP26A1 and CYP26B1 was also investigated in the adult human brain and colocalization of CYP26A1 and the RA synthetic enzyme RALDH2 indicated a different, autocrine role for RA in human hippocampal neurons. Studies with the SH-SY5Y human neuroblastoma cell line implied that the co-expression of RA synthetic and catabolic enzymes maintains retinoid homeostasis within neurons. This presents a novel view of RA in human neurons as part of an autocrine, intracellular signaling system.