Células-tronco mesenquimais de origem adiposa na fase de proliferação do processo de cicatrização de queimaduras frias / Adipose-derived stem cells in the proliferation phase of the healing process in cold burns

A criocirurgia tem sido utilizada no tratamento de diferentes enfermidades de sistemas e órgãos. Contudo, são relatados efeitos adversos, como cicatrização lenta, cicatrizes extensas, disfunção estética e funcional. As lesões que ocorrem naturalmente pela exposição ao frio extremo, comumente, resultam em gangrena. O presente trabalho teve como objetivo avaliar a influência das células-tronco mesenquimais de origem adiposa (ADSCs) na fase de proliferação da cicatrização de feridas cutâneas. Por meio da aplicação do nitrogênio líquido pela técnica do spray aberto, realizou-se a indução de uma ferida, de aproximadamente 15mm de diâmetro, na região dorsal de cada rato. A ferida recebeu o tratamento de acordo com o grupo ao qual pertencia: 1) aplicação das ADSCs no 15º dia (grupo tratado); 2) aplicação da solução cloreto de sódio 0,9% no 15º dia (grupo sham); 3) nenhuma intervenção até o momento da eutanásia (grupo controle). O grupo tratado com as ADSCs apresentou as maiores taxas de contração média das feridas e obteve diferença estatisticamente significativa em relação ao grupo sham quanto à neovascularização. A terapia com as ADSCs proporcionou uma relevante evolução clínica das feridas, podendo ser constatada ao final do período de avaliação por cicatrizes mais estreitas e compridas.(AU)

Cryosurgery has been used to treat different diseases of systems and organs, although adverse effects have been reported such as delayed wound healing, large scars, esthetical deformation and functional impairment. Injuries caused naturally by the exposure to extreme cold weather conditions mostly result in gangrene. This study aims to evaluate the influence of adipose-derived stem cells (ADSCs) in the proliferation phase on cutaneous wound healing. Through the application of liquid nitrogen by the spraying technique, a 15 millimeter diameter lesion was produced in the dorsal region of each rat. The wound received treatment according to the group it belonged: 1) ADSCs application on the 15th day (treated group); 2) application of 0.9% sodium chloride solution on the 15th day (sham group); 3) no intervention until euthanasia (control group). The group treated with ADSCs showed the highest wound average contraction rate; this group got a significant statistical difference in relation to the sham group when it refers to neovascularization. The ADSCs therapy provides an important clinical evolution of wounds. This was verified at the end of the evaluation period through narrower and longer scars.(AU)

Análises macroscópica e histopatológica do alotransplante parcial de vesícula urinária com células-tronco mesenquimais alogênicas derivadas do tecido adiposo em coelhos / Macroscopic and histopathological analysis of partial urinary bladder allograft using allogenic adipose tissue derived mesenchymal stem cells in rabbits

O número de transplantes de órgãos e tecidos em humanos e animais tem crescido significativamente nos últimos anos, principalmente após o advento de técnicas modernas e mais seguras indutoras de imunossupressão. Objetiva-se com o presente estudo avaliar macro e microscopicamente o alotransplante parcial de bexiga a fresco em coelhos, utilizando como agente imunomodulador células-tronco mesenquimais derivadas do tecido adiposo (ADSC) alogênicas. Foram utilizados 25 coelhos, sendo um deles macho e doador das ADSCs, e os outros 24 eram fêmeas, submetidas a alotransplante parcial de bexiga, tratadas com ciclosporina (GCi) ou células-tronco mesenquimais (GCe). Conclui-se que o GCe teve melhor aceitação histológica do implante em relação ao GCi aos 30 dias de avaliação.(AU)

The number of organ and tissue transplantation in humans and animals has grown significantly recently, especially after the advent of modern and safer techniques of immunosuppression. The objective of this study was to evaluate macro and microscopically partial urinary bladder fresh allograft in rabbits, using as immunomodulatory agent cyclosporine or allogenic adipose tissue derived mesenchymal stem cells (ADSCs). For this purpose, 25 rabbits were used. One male was the donor of ADSCs; 24 females received a partial urinary bladder allograft and were treated with cyclosporine (GCi) or mesenchymal stem cells (GCe). We conclude that the GCe group had better histological acceptance of the implant than GCi group at 30 days evaluation.(AU)

Células-tronco mononucleares associadas ao plasma rico em plaquetas na consolidação de falha óssea no cão. Estudo piloto / Mononuclear stem cells associated with platelet-rich plasma in the consolidation of bone defects in dogs. A pilot study

A padronização de técnicas e o teste da associação do Plasma Rico em Plaquetas (PRP) e das Células-Tronco Mononucleares (CTMs) na consolidação de falhas ósseas corticais, por meio de avaliação clínica, biomecânica, radiológica e histológica, é avaliada em um estudo piloto. Foram utilizados seis cães adultos, fêmeas, sem raça definida, pesando entre 5 e 10kg, separados por sorteio aleatório em seis tratamentos. Foi confeccionada uma falha elíptica de 1,0x0,4cm na cortical medial diafisária da tíbia direita de cada animal, sendo preenchida de acordo com o tratamento proposto. No cão I, a falha foi preenchida com solução fisiológica (SF); no II, com o PRP; no III, com a fração total das células mononucleares (FTCM); no IV, com a fração vascular estromal (FVE); no V, com o PRP associado à FTCM; no VI, com a associação PRP e FVE. Foram realizadas avaliações: clínicas, diariamente; dos graus de claudicação, semanalmente; radiológica e perimetria da coxa, antes, no pós-operatório imediato, aos 7, 14, 21 e 30 dias; biomecânica, antes do procedimento, aos 10, 20 e 30 dias; e biópsias, aos 15 e 30 dias. A FTCM obteve uma contagem e viabilidade média de 2,0x108cél. e 90%, respectivamente, enquanto a FVE obteve 3x106cél. e 50%. O PRP concentrou, em média, sete vezes o número inicial de plaquetas do sangue total, de 250.000 µl-1 plaquetas no sangue total para 1.750.000 µl-1 plaquetas no PRP. Obteve-se padronização adequada de técnicas, possibilitando o teste da associação entre as células-tronco mononucleares (CTMs) e o plasma rico em plaquetas (PRP), assim como seu uso isolado, no reparo de falhas ósseas corticais, indicando a possibilidade de a associação FTCM e PRP ser o melhor tratamento...

The standardization of techniques and tests of the association of Platelet Rich Plasma (PRP) and Mononuclear Stem Cells (MSCs) in the consolidation of cortical bone defects by clinical, biomechanical, radiological, and histological analysis is evaluated in a pilot study. Six adult female dogs of mixed breed, weighing between 5 and 10kg, separated by random draw in six treatments were used. An elliptical failure of 1.0 x0.4cm was done in the medial diaphyseal cortical of the right tibia of each animal, that was filled according with the proposed treatment. In dog I, the failure was filled with saline (S), in dog II with PRP, in dog III with total mononuclear cell fraction (TMCF), in dog IV with stromal vascular fraction (SVF), in dog V with association of PRP and TMCF, and in dog VI with an association of PRP and SVF. Daily clinical evaluation, weekly degrees of lameness, radiological and girth before, immediate postoperative, 7, 14, 21 and 30 days, biomechanics before the procedure, at 10, 20 and 30 days, and biopsies at 15 and 30 days were performed. The TMCF got a count and viability of 2,0x108cells and 90% respectively, while for SVF it was 3x106cells and 50%, respectively. The PRP concentrated on average seven times the original number of platelets from whole blood, platelets from whole blood 250.000 μl-1 to 1.750.000 μl-1 platelets in PRP. This afforded adequate standardization of techniques, enabling the test of association between mononuclear stem cells (MSCs) and platelet-rich plasma(PRP), as well as their separate use to repair cortical bone defects, indicating the possibility of the association between FTCM and PRP to be the best treatment...

Antioxidant and anti-inflammatory effects of quercetin in functional and morphological alterations in streptozotocin-induced diabetic rats.

The aim of this study was to investigate functional and morphological alterations caused by oxidative stress in streptozotocin (STZ)-induced diabetic rats and to evaluate the antioxidant effect of quercetin (QUE) in this disease. One hundred and thirty male Wistar rats, it were randomly distributed in 10 different experimental groups, with ten animals per group: Control Saline (CS), Control Ethanol (CE), Control QUE 5mg/kg (CQ5), Control QUE 25mg/kg (CQ25), Control QUE 50mg/kg (CQ50), Diabetic Saline (DS), Diabetic Ethanol (DE), Diabetic QUE 5mg/kg (DQ5), Diabetic QUE25 mg/kg (DQ25), Diabetic QUE 50mg/kg (DQ50). Therefore, hyperglycemia is directly involved in oxidative stress production, as well as in functional and morphological alterations caused by the excess of free radicals. QUE, specially at the dosage of 50mg/kg, can act as an antioxidant and anti-inflammatory agent, becoming a promising adjuvant in the treatment of diabetes mellitus.

Fração total de células mononucleares intra-articular em cães submetidos à reconstrução do ligamento cruzado / Total fraction of mononuclear intra-articular cells in dogs undergoing cruciate ligament reconstruction

Avaliou-sea ação da fração total de células mononucleares autógenas da medula óssea (FCMO) por aplicação intra-articular, após a correção cirúrgica do ligamento cruzado rompido. Foram utilizados 20 cães, os quais sofreram desmotomia do ligamento cruzado cranial e caudal unilaterais, 21 dias antes do reparo cirúrgico. Dez animais receberam as células autógenas no momento da correção. As avaliações se deram por estudo radiográfico, exames clínicos e biópsias aos 50 e 90 dias pós-operatórios. O grupo que recebeu a FCMO apresentou crescimento ósseo intra-articular ao estudo radiográfico, contudo os 20 animais apresentaram célulasCD34 positivas em suas amostras biopsiadas, indicando haver presença de células-tronco em ambos os grupos. Conclui-se que,para o modelo experimental proposto, não se recomenda o uso da fração total de células mononucleares e que trabalhos experimentais com o uso de células-tronco nas articulações devem evitar modelos cujo foco de lesão mantenha contato direto com a medula óssea.

This study was performed to evaluate the action of the fraction of total mononuclear cells from the bone marrow (FCMO) applied intra-articularly after the surgical repair of an experimentally ruptured cruciate ligament. Twenty dogs which suffered one-sided cruciate desmotomy of the cranial and caudal cruciate ligament 21 days before the correction were used. Ten animals received the FCMO at the time of correction. The assessments were done through X-ray and clinical examinations, and biopsies at 50 and 90 days postoperatively. It was concluded that there was no clinical difference between the two groups until 90 days of evaluation. The group that received FCMO grew intra-articular bone shown on the X-ray study. All twenty animals, however, presented cells marked with CD34 antibodies on their biopsy samples, indicating the presence of stem cells in both groups. It is concluded thatfor theexperimental model, it is not recommended to use the mononuclear cell fraction,andin experimental studies with the use of stem cells in the joints models whose focus of injury keep direct contact with the bone marrow should be avoided.

Alterações oftálmicas associadas à intoxicação experimental por closantel em caprinos / Ophthalmic changes associated with the experimental poisoning by closantel in caprine

Alterações oftálmicas foram experimentalmente induzidas em caprinos após superdosagem com o anti-helmíntico closantel. Foram usados cinco caprinos com sete a oito meses de idade, produtos do cruzamento da raça Saanen com a Pardo Alpino. Os animais mostraram sinais de intoxicação entre quatro e cinco dias após a administração do closantel. Os sinais clínicos caracterizaram-se principalmente por distúrbios neurológicos centrais e cegueira. Ao exame clínico, observaram-se midríase bilateral, perda do reflexo pupilar à luz e cegueira bilateral. À oftalmoscopia indireta, foram observadas degeneração aguda de retina e papiledema. As alterações crônicas mostravam disco óptico acinzentado, atrofia de vasos e da retina. Nos fundos tapetal e não-tapetal notavam-se áreas de despigmentação e lesões irregulares castanho-amareladas. As alterações histológicas consistiam em perda dos neurônios da camada ganglionar e das células da camada nuclear interna e externa da retina. As alterações agudas no nervo óptico e na substância branca do encéfalo foram de degeneração espongiforme. As alterações crônicas do nervo óptico caracterizavam-se por extensa necrose e infiltração de células Gitter.

Ophthalmic alterations were experimentally induced after overdose with the anthelmintic closantel. Five seven to eight- months-old, Saanen x Alpine caprine were used. The animals showed clinical signs of toxicosis four to five days after the administration of closantel. Clinical signs were primarily characterized by central nervous disturbances and blindness. Clinically, bilateral mydriasis, loss of pupillary light reflex, and blindness were observed. At indirect ophthalmoscopic examination, there was acute retinal degeneration and papilledema. Chronic ocular changes consisted of paleness of the optic disc, vascular atrophy, and retinal atrophy. Areas of pigment loss and irregular yellowish-brown foci were present in the tapetal and non-tapetal fundus. Histological alterations consisted of neuronal loss in the ganglion cell layer and depletion of cells in both the outer and inner nuclear layers of the retina. Acute changes of spongy degeneration were noted in the optic nerve and in the cerebral white matter. Chronic lesions in the optic nerve were characterized by extensive necrosis and infiltration by Gitter cells.

Estimulação elétrica neuromuscular em cães com atrofia muscular induzida / Neuromuscular electric stimulation in dogs with induced muscle atrophy

Empregou-se a estimulação elétrica neuromuscular (EENM) de baixa freqüência no músculo quadríceps femoral de cães com atrofia induzida e avaliou-se a ocorrência de ganho de massa nessa musculatura. Foram utilizados oito cães com pesos entre 15 e 30kg, distribuídos aleatoriamente em dois grupos denominados de I ou controle e II ou tratado. A articulação femorotibiopatelar esquerda foi imobilizada por 30 dias pelo método de transfixação percutânea tipo II, com retirada de aparelho de imobilização após esse período. Decorridas 48 horas da remoção, foi realizada a EENM nos cães do grupo II, cinco vezes por semana, com intervalo de 24 horas cada sessão, pelo período de 60 dias. Foram avaliadas a circunferência da coxa, a goniometria do joelho, a análise clínica da marcha, as enzimas creatina-quinase (CK) e aspartato-amino-transferase (AST) e a morfometria das fibras musculares em cortes transversais do músculo vasto lateral colhido mediante biópsia muscular. A EENM foi empregada no músculo quadríceps femoral na freqüência de 50Hz, duração de pulso de 300 milisegundos e relação de tempo on/off de 1:2. Quanto à morfometria das fibras do músculo vasto lateral, no grupo tratado houve aumento significativo (P<0,05) da área transversal aos 90 dias em relação ao dia zero. A EENM de baixa freqüência ocasiona hipertrofia do músculo vasto lateral em cães após a imobilização rígida temporária da articulação do joelho.

Low frequency neuromuscular electrical stimulation (NMES) was used on the femoral quadriceps of dogs with induced muscular atrophy and the occurrence of gain in mass in these muscles was evaluated. Eight dogs from 15 to 30kg were randomly distributed in two groups named I, or control; and II, or treated. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days by percutaneous transfixation type II. After 30 days, the immobilization device was removed. The NMES treatment began 48 hours after the removal of the immobilization device of the dogs of group II, and it was carried out five times per week with an interval of 24 hours between each session, for 60 days. The following parameters were measured: thigh circumference, goniometry of the knee, clinical gait analysis, creatine kinase (CK) and aspartate aminotransferase (AST) enzymes, and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle collected through muscular biopsy. The NMES was applied on the femoral quadriceps at a frequency of 50 Hz, with pulse duration of 300 milliseconds, and the on/off time was at a proportion of 1:2. Regarding the morphometry of the vastus lateralis fibers, a significant increase (P<0.05) in the transversal area of the treated group at 90 days was observed when compared with that identified at the time of immobilization. Thus, it can be concluded that low frequency NMES brings about hypertrophy of the vastus lateralis muscle in dogs after temporary rigid immobilization of the knee joint.

Aspectos histoquímicos e imunoistoquímicos nos neoplasmas do sistema nervoso periférico / Histochemical and immunohistochemical features of peripheral nerve neoplasms

Doze casos de tumores do sistema nervoso periférico, sete schwannomas e cinco neurofibromas foram diagnosticados entre 1964 e 2004, em caninos e bovinos. Histologicamente, as células predominantes nos schwannomas eram fusiformes organizavam-se em paliçada ou em feixes aleatórios. Nos neurofibromas as células neoplásicas eram fusiformes e se originavam da periferia dos nervos formando ninhos e feixes. O tecido conjuntivo era mais abundante nos neurofibromas e os colágenos dos tipos I e III eram os principais constituintes desses neoplasmas. Os neurofibromas foram caracterizados por uma concentração alta e difusa de mastócitos, provavelmente devido à origem das células neoplásicas do perineuro e epineuro. A coloração de AgNOR não se mostrou eficiente como indicador de prognóstico nos neoplasmas analisados. Imunoistoquímicamente houve forte marcação para vimentina (100 por cento) e S100 (100 por cento) em ambos os tipos de tumor. A maioria dos schwannomas (75 por cento) foi positiva para a proteína ácida fibrilar glial; os neurofibromas só apresentaram marcação nas células de Schwann dos fascículos nervosos

A retrospective study of peripheral nerve tumors was made from 1964 to 2004. The tumors summed up 12, being seven schwannomas and five neurofibromas. Schwannomas were composed of spindle-shaped cells either in a palisading pattern or random bundles loosely textured and neurofibromas by spindle cells. The connective tissue components were more prevalent in neurofibromas with a characteristic deployment of collagens type I and III. In AgNOR techniques, both benign and malignant schwannomas and neurofibromas did not show differences. Mast cells stained by toluidine blue were more prevalent in neurofibromas which are rich in reactive endoneurium. Schwannomas (100 percent) and neurofibromas (100 percent) were positive for vimentin and S100 protein, so they prove to be reliable for the diagnosis of peripheral nerve tumors. GFAP marked cells were found in three schwannomas and in Schwann cells within neurofibromas

Cirurgia laparoscópica no diagnóstico de gastrite crônica atrófica seguida de tratamento clínico em cadela: relato de caso / Laparoscopic surgery in the diagnosis of atrophic gastritis in a dog followed by clinical treatment: case report

Descrevem-se o diagnóstico e o tratamento de um caso de gastrite atrófica crônica, em uma cadela sem raça definida, de dois anos de idade. A paciente apresentava como principal sintomatologia vômito crônico. O hemograma, a urinálise e as avaliações bioquímicas séricas não revelaram alterações significativas. Os exames radiológicos e ultra-sonográficos abdominais também não foram sugestivos de alterações. Realizaram-se inspeção da cavidade peritoneal, gastrotomia, gastroscopia, gastrectomia para biopsia e gastrorrafia intracorpórea videolaparoscópicas. Constatou-se ausência de rugosidades estomacais. Ao exame histológico, observou-se atrofia das células principais e parietais da mucosa gástrica. O quadro clínico permitiu o diagnóstico de gastrite crônica atrófica. O animal foi medicado com terapia imunossupressora e apresentou remissão completa dos sinais clínicos

This report describes a case of chronic atrophic gastritis. A two-year-old female mongrel dog showed chronic emesis. The complete blood count serum chemistry and urinalysis values were within the normal limits. Radiographs revealed no alterations. Abdominal evaluation, gastrotomy, gastroscopy, gastrectomy and intracorporeal stomach suture were done by laparoscopic approach. Absence of gastric villous was noticed through laparoscopic biopsy. The microscopic analysis reveled parietal and principal gastric mucosal cells atrophy, which, associated with clinical signs, allowed the chronic atrophic gastritis diagnosis. The animal was treated and clinical signs complete remission was observed

Hipomielinização em cães Weimaraner: relato de caso / Hypomielination in Weimaraner dogs: case report

Três cães, fêmeas, da raça Weimaraner apresentaram tremores corporais rítmicos generalizados a partir da primeira semana de vida. Outros dois cães, machos, da mesma ninhada não apresentaram alterações. Uma fêmea com quatro semanas de idade foi submetida à eutanásia e necropsiada. Macroscopicamente, observou-se no encéfalo pouca demarcação da substância branca em relação à cinzenta. Histologicamente havia acentuada vacuolização de toda a substância branca subcortical. A mielinização no sistema nervoso periférico estava normal. Os sinais clínicos, a idade de ocorrência e as lesões histológicas são compatíveis com a hipomielinogênese congênita descrita em cães

Three female Weimaraner pups had generalized and rhythmic body tremors since the first week of age. The remaining two male littermates were unaffected. One 4-week-old female was euthanatized and necropsied. On gross examination, poor demarcation between the gray and white matter was observed. Microscopically, there was severe hypomyelination of the brain compatible with congenital hypomyelinogenesis reported in dogs

Nódulos fibro-histiocíticos no baço de uma cadela: relato de caso / Splenic fibroistiocytic nodules in a bitch: case report

Descreve-se a ocorrência de múltiplos nódulos fibro-histiocíticos no baço de uma cadela Rottweiler, de sete anos. O diagnóstico foi feito por histopatologia e confirmado por imunoistoquímica positiva para ED1, CD18, vimentina e lisozima. O animal foi sacrificado três meses após o diagnóstico, por severo agravamento dos sinais clínicos.

Multiple fibrohistiocytic nodules in the spleen of a 7-year-old female Rottweiler were reported. The diagnosis was made by histology and immunohistochemistry; cells were positive for ED1, CD18, vimentin and lysozyme. The dog was euthanatized three months after the tumor was diagnosed, due to severe clinical signs.

Acetylcholinesterase activity in rats experimentally demyelinated with ethidium bromide and treated with interferon beta.

The ethidium bromide (EB) demyelinating model was associated with interferon beta (IFN-beta) to evaluate acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC), cerebellum (CB), hypothalamus (HY), pons (PN) and synaptosomes from the CC. Rats were divided into four groups: I control (saline), II (IFN-beta), III (EB) and IV (EB and IFN-beta). After 7, 15 and 30 days rats (n = 6) were sacrificed, and the brain structures were removed for enzymatic assay. AChE activity was found to vary in all the brain structures in accordance with the day studied (7-15-30 days) (P < 0.05). In the group III, there was an inhibition of the AChE activity in the ST, CB, HY, HP and also in synaptosomes of the CC (P < 0.05). It was observed that IFN-beta per se was capable to significantly inhibit (P < 0.05) AChE activity in the ST, HP, HY and synaptosomes of the CC. Our results suggest that one of the mechanisms of action of IFN-beta is through the inhibition of AChE activity, and EB could be considered an inhibitor of AChE activity by interfering with cholinergic neurotransmission in the different brain regions.

Delayed Schwann cell and oligodendrocyte remyelination after ethidium bromide injection in the brainstem of Wistar rats submitted to streptozotocin diabetogenic treatment.

Schwann cell disturbance followed by segmental demyelination in the peripheral nervous system occurs in diabetic patients. Since Schwann cell and oligodendrocyte remyelination in the central nervous system is a well-known event in the ethidium bromide (EB) demyelinating model, the aim of this investigation was to determine the behavior of both cell types after local EB injection into the brainstem of streptozotocin diabetic rats. Adult male Wistar rats received a single intravenous injection of streptozotocin (50 mg/kg) and were submitted 10 days later to a single injection of 10 microL 0.1% (w/v) EB or 0.9% saline solution into the cisterna pontis. Ten microliters of 0.1% EB was also injected into non-diabetic rats. The animals were anesthetized and perfused through the heart 7 to 31 days after EB or saline injection and brainstem sections were collected and processed for light and transmission electron microscopy. The final balance of myelin repair in diabetic and non-diabetic rats at 31 days was compared using a semi-quantitative method. Diabetic rats presented delayed macrophage activity and lesser remyelination compared to non-diabetic rats. Although oligodendrocytes were the major remyelinating cells in the brainstem, Schwann cells invaded EB-induced lesions, first appearing at 11 days in non-diabetic rats and by 15 days in diabetic rats. Results indicate that short-term streptozotocin-induced diabetes hindered both oligodendrocyte and Schwann cell remyelination (mean remyelination scores of 2.57 +/- 0.77 for oligodendrocytes and 0.67 +/- 0.5 for Schwann cells) compared to non-diabetic rats (3.27 +/- 0.85 and 1.38 +/- 0.81, respectively).

Delayed Schwann cell and oligodendrocyte remyelination after ethidium bromide injection in the brainstem of Wistar rats submitted to streptozotocin diabetogenic treatment

Schwann cell disturbance followed by segmental demyelination in the peripheral nervous system occurs in diabetic patients. Since Schwann cell and oligodendrocyte remyelination in the central nervous system is a well-known event in the ethidium bromide (EB) demyelinating model, the aim of this investigation was to determine the behavior of both cell types after local EB injection into the brainstem of streptozotocin diabetic rats. Adult male Wistar rats received a single intravenous injection of streptozotocin (50 mg/kg) and were submitted 10 days later to a single injection of 10 æL 0.1 percent (w/v) EB or 0.9 percent saline solution into the cisterna pontis. Ten microliters of 0.1 percent EB was also injected into non-diabetic rats. The animals were anesthetized and perfused through the heart 7 to 31 days after EB or saline injection and brainstem sections were collected and processed for light and transmission electron microscopy. The final balance of myelin repair in diabetic and non-diabetic rats at 31 days was compared using a semi-quantitative method. Diabetic rats presented delayed macrophage activity and lesser remyelination compared to non-diabetic rats. Although oligodendrocytes were the major remyelinating cells in the brainstem, Schwann cells invaded EB-induced lesions, first appearing at 11 days in non-diabetic rats and by 15 days in diabetic rats. Results indicate that short-term streptozotocin-induced diabetes hindered both oligodendrocyte and Schwann cell remyelination (mean remyelination scores of 2.57 ± 0.77 for oligodendrocytes and 0.67 ± 0.5 for Schwann cells) compared to non-diabetic rats (3.27 ± 0.85 and 1.38 ± 0.81, respectively).

Mastocitoma cutâneo canino: estudo de 45 casos / Canine cutaneous mast cell tumor: study of 45 cases

Quarenta e cinco mastocitomas cutâneos caninos foram graduados histologicamente com o uso de hematoxilina-eosina. Foram empregados os métodos azul de toluidina e região organizadora nucleolar argirofílica (AgNOR) para, respectivamente, evidenciar os grânulos citoplasmáticos e avaliar o índice de proliferação celular. Diversas características histológicas foram observadas, como distribuição das células na pele, tamanho, forma, aspecto de citoplasma e núcleo, quantidade de estroma, presença de eosinófilos e alterações associadas. Com base nessas caracteríscas, 37,8 por cento dos mastocitomas foram classificados como grau I, 51,1 por cento como grau II e 11,1 por cento como grau III. A média geral de AgNOR nos mastocitomas foi de 1,9 (1,2 a 4,3) e as médias para os graus I, II e III foram, respectivamente, de 1,5, 1,85 e 3,25. A técnica de AgNOR mostrou ser de fácil execução, custo acessível e confiável como meio auxiliar para estimar um prognóstico mais objetivo para os mastocitomas.

Reparação microcirúrgica de nervo periférico por meio de sutura, cola de fibrina ou bainha de BioFill® em ratos Wistar / Microsurgical repair of peripheral nerve by means of suture, fibrin glue or BioFill® sheath in Wistar rats

Com o objetivo de comparar três técnicas de neuroanastomose, foram utilizados 54 ratos fêmeas, distribuídos em três grupos de 18 animais, cujos nervos ciáticos direitos foram transeccionados e, em seguida, tratados mediante o emprego das seguintes técnicas: três pontos de sutura epineural, um ponto de sutura epineural associado à bainha de BioFill® e um ponto de sutura epineural com cola de fibrina. A presença do material de sutura foi responsável pelo mau direcionamento das fibras nervosas e formação de neuroma na área da anastomose devido à colisão das fibras nervosas em regeneração com a reação granulomatosa ao fio de sutura. Alterações como degeneração Walleriana, formação de neuroma e proliferação de tecido fibroso foram observadas nos três tratamentos, sendo mais evidentes no grupo que recebeu três pontos de sutura epineural. Os resultados histológicos superiores obtidos com o emprego da bainha de BioFill® e da cola de fibrina comprovaram a eficiência dessas duas técnicas na reparação de nervos periféricos lesados. O uso da bainha de BioFill® oferece vantagens como disponibilidade, simplicidade técnica e baixo custo, tornando-a a melhor alternativa na reparação microcirúrgica do nervo periférico.

Pilocytic astrocytoma in a cat.

A 12-year-old crossbred female cat was presented for necropsy with a history of anorexia, ataxia, convulsions, and blindness. Grossly, a whitish, firm, and well-circumscribed nodule with an irregular surface of approximately 1.5 cm in diameter was observed in the right dorsal, parietal, and occipital lobes of the brain. Histologically, the tumor was composed of neoplastic astrocytes forming irregular interweaving sheets and bundles. These cells were elongated, spindle-shaped, and bipolar, and some had clear cytoplasm and a dense nuclear chromatin pattern. Extensive areas of cartilaginous and osseous metaplasia were observed. By immunohistochemistry, the neoplastic cells were found to be markedly positive for S-100 protein and glial fibrillary acidic protein. On the basis of morphologic and immunohistochemical features, the diagnosis of pilocytic astrocytoma was made.

Ethidium bromide-induced demyelination of the sciatic nerve of adult Wistar rats

Peripheral nerve ultrastructure was assessed after single or multiple local injections of the intercalating dye ethidium bromide. Thirty-four adult Wistar rats of both sexes were divided into five groups and maintained in a controlled environment with rat chow and water ad libitum throughout the experiment. The experimental animals were injected with 1 æl of 0.1 percent ethidium bromide in 0.9 percent saline into the central third of the left sciatic nerve 1 (group 1), 2 (group 2), 4 (group 3), 6 (group 4) or 8 (group 5) times. In groups 2 to 5 the injections were made at 28-day intervals. Control animals received the same amount of 0.9 percent saline. The animals were killed at different times after injection: group 1 at 7 days (2 rats) and 15 days (2 rats); for groups 2, 3, 4 and 5, all rats were killed 10 days after the last injection and the lesions were investigated by light and transmission electron microscopy. In the acute lesions, intoxicated Schwann cells showed a vacuolated cytoplasm and separation of the sheaths from the axon. Myelin sheaths underwent progressive vesiculation and subsequent segmental demyelination. Myelin debris were withdrawn by macrophages and remyelination by Schwann cells was prominent. With the increase in the number of injections collagen fibers also increased in number and progressively enveloped smaller numbers of remyelinated axons composing new fascicles. Wallerian degeneration of fibers apparently not affected by ethidium bromide was more intense in the nerves from groups 4 and 5. The peripheral nerve repairs itself after demyelinating challenges with a profusion of collagen fibers and new fasciculations. This experimental model is valid to mimic recurrent demyelinating neuropathies

Ethidium bromide-induced demyelination of the sciatic nerve of adult Wistar rats.

Peripheral nerve ultrastructure was assessed after single or multiple local injections of the intercalating dye ethidium bromide. Thirty-four adult Wistar rats of both sexes were divided into five groups and maintained in a controlled environment with rat chow and water ad libitum throughout the experiment. The experimental animals were injected with 1 microl of 0.1% ethidium bromide in 0.9% saline into the central third of the left sciatic nerve 1 (group 1), 2 (group 2), 4 (group 3), 6 (group 4) or 8 (group 5) times. In groups 2 to 5 the injections were made at 28-day intervals. Control animals received the same amount of 0.9% saline. The animals were killed at different times after injection: group 1 at 7 days (2 rats) and 15 days (2 rats); for groups 2, 3, 4 and 5, all rats were killed 10 days after the last injection and the lesions were investigated by light and transmission electron microscopy. In the acute lesions, intoxicated Schwann cells showed a vacuolated cytoplasm and separation of the sheaths from the axon. Myelin sheaths underwent progressive vesiculation and subsequent segmental demyelination. Myelin debris were withdrawn by macrophages and remyelination by Schwann cells was prominent. With the increase in the number of injections collagen fibers also increased in number and progressively enveloped smaller numbers of remyelinated axons composing new fascicles. Wallerian degeneration of fibers apparently not affected by ethidium bromide was more intense in the nerves from groups 4 and 5. The peripheral nerve repairs itself after demyelinating challenges with a profusion of collagen fibers and new fasciculations. This experimental model is valid to mimic recurrent demyelinating neuropathies.