Células-tronco mononucleares autólogas e proteína óssea morfogenética na cicatrização de defeitos tibiais experimentalmente induzidos em cães / Autologue mononuclear stem cells and morphogenetic bone protein in experimentally induced tibial defect healing in dogs

Avaliou-se a utilização de células-tronco mononucleares (CTM) na cicatrização de defeito ósseo experimental como alternativa aos métodos convencionais, analisando-se o tempo de evolução cicatricial e a presença dessas células no tecido neoformado. Foram utilizados 18 cães, separados em três grupos (G) de seis, e de cada animal foram colhidas células da medula óssea (MO), contadas e analisadas para morfometria, por meio da contagem manual e mielograma. Um defeito ósseo tibial foi então criado cirurgicamente, e a lesão tratada com esponja de gelatina embebida em solução fisiológica (G1), esponja de gelatina embebida com aspirado de MO processado (G2) e esponja de gelatina embebida com aspirado de MO processado e proteína óssea morfogenética (rhBMP-2) (G3). A cicatrização foi então avaliada por estudos radiográficos, e a presença de CTM foi identificada por meio de marcadores nanocristais Qtracker, em microscopia com luz fluorescente, uma semana após a intervenção cirúrgica. Entre as células identificadas pelo marcador, foram encontradas células da linhagem óssea. As avaliações radiográficas demonstram crescimento ósseo acelerado nos animais de G2 e G3. Houve diferenças significativas entre o G1 e G3 em todos os tempos estudados, e entre G1 e G2 nos tempos de 30 e 45 dias. A utilização de CTM adultas suplementadas ou não com rhBMP-2 é alternativa favorável ao crescimento ósseo em defeitos experimentais agudos de tíbia de cães.

Mononuclear stem cells (MSC) were experimentally implanted in bone defect, as an alternative to the conventional methods, in order to evaluate the healing speed, and the presence of these cells in the new-born tissue. Bone marrow (BM) was collected from 18 dogs, and then counted and morphometrically analyzed by manual count and myelogram. The dogs were separated in three groups (G) of six animals each. A tibial bone defect was surgically made in each dog and the wound was treated with gelatin sponge and physiologic solution (G1), gelatin sponge and processed BM (G2), and gelatin sponge, processed BM, and rhBMP-2 (G3). The healing was evaluated by radiographic study and the presence of MSC was microscopically identified by Qtracker nanocrystal labeler with a fluorescent light one week after the surgery. Cells from the bone lineage were found among the labeled cells. The radiographic evaluations demonstrated a speed up in bone growth in dogs from G2 and G3, and significant differences were found between G1 and G3 dogs, in all studied periods; and between G1 and G2 animals at 30 and 45 days. The rhBMP-2 supplemented or not-supplemented adult MSC are favorable alternatives to the bone growth in the healing process of acute experimental-induced tibial defects in dogs.

Possible function of IL-6 and TNF as intraadrenal factors in the regulation of adrenal steroid secretion.

Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF alpha) and their mRNAs are present in the human, rat, and bovine adrenal cortex. The release of these cytokines from adrenal cells is regulated by factors that alter adrenal function (e.g., ACTH, angiotensin II, interleukin-1). IL-6 and TNF type 1 receptors are also present on adrenocortical cells. Exposure to IL-6 increases cortisol or corticosterone release from human, bovine, and rat adrenal cells. IL-6 increases basal and ACTH-stimulated aldosterone release, but inhibits angiotensin II-stimulated aldosterone secretion from bovine adrenal cells. IL-6 increases dehydroepiandrosterone (DHEA) release from human cells, but decreases DHEA secretion from bovine cells. TNF alpha inhibits corticosterone release from normal rat adrenal cells or fragments, but increases corticosterone release from cholestatic rat adrenal slices. TNF alpha decreases cortisol release from bovine and fetal human adrenal cells, but increases cortisol release from adult human adrenal cells. TNF alpha inhibits aldosterone secretion from rat and bovine adrenocortical cells. TNF alpha does not affect DHEA secretion from fetal human adrenocortical cells, but inhibits basal and ACTH-stimulated DHEA release from bovine adrenal cell. Because IL-6 and TNF alpha are produced in the adrenal gland and modify adrenal steroid secretion, these cytokines may function as intraadrenal factors in the regulation of adrenal steroid secretion.

Stimulation by interleukin-6 and inhibition by tumor necrosis factor of cortisol release from bovine adrenal zona fasciculata cells through their receptors.

Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) are synthesized and released from adrenal cells. Therefore, the effects of TNF-alpha and IL-6 on cortisol release from bovine zona fasciculata (ZF) cells were investigated. IL-6 (10-1000 pg/mL) significantly increased basal and adrenocorticotropic hormone (ACTH)-stimulated cortisol release in a concentration-dependent manner. This stimulatory effect of IL-6 became apparent at intervals as short as 4 h and continued through 24 h. IL-6 also potentiated the cortisol release stimulated by the adenylyl cyclase activator forskolin. By contrast, TNF-alpha (0.1-10 ng) inhibited basal and ACTH-stimulated cortisol release in a concentration-dependent manner. The inhibitory effects of TNF-alpha on cortisol release were significant at time intervals as short as 4 h and continued through 24 h. TNF-alpha inhibited forskolin-stimulated cortisol release. Binding studies demonstrated that ZF cells have IL-6 receptors (100 receptors/cell, Kd of 7.5 x 10(-11)) and TNF receptors (200 receptors/cell, Kd of 2.4 x 10(-9) M). Immunohistochemical analysis provided evidence that the majority of ZF cells have IL-6 receptors, TNF type 1 receptors, and TNF type 2 receptors. Because IL-6 and TNF-alpha are released from the adrenal cortex and these cytokines modify the release of cortisol from the ZF, IL-6 and TNF-alpha may play a paracrine or autocrine role in the regulation of adrenal function.

Lesäo do plexo braquial após artroplastia total do quadril: relato de caso / Brachial plexus palsy after total hip arthroplasty: a case report

A posiçäo adotada pelo paciente durante o ato operatório é de grande importância, principalmente em se tratando de cirurgias de longa duraçäo e que necessitam de anestesia geral. Os autores relatam um caso raro de lesäo incompleta do plexo braquial em um paciente submetido a uma artroplastia total do quadril (ATQ) devido ao posicionamento inadequado do membro superior durante a cirurgia.