Mast cells in the pathophysiology of Duchenne muscular dystrophy in Golden Retriever dogs / O papel dos mastócitos na patogênese da distrofia muscular de Duchenne em cães Golden Retriever

The Golden Retriever muscular dystrophy (GRMD) is one of the best models of Duchenne muscular dystrophy (DMD), with similar genotypic and phenotypic manifestations. Progressive proliferation of connective tissue in the endomysium of the muscle fibers occurs in parallel with the clinical course of the disease in GRMD animals. Previous studies suggest a relationship between mast cells and the deposition of fibrous tissue due to the release of mediators that recruit fibroblasts. The aim of this study was to evaluate the presence of mast cells and their relationship with muscle injury and fibrosis in GRMD dogs of different ages. Samples of muscle groups from six GRMD and four control dogs, aged 2 to 8 months, were collected and analyzed. The samples were processed and stained with HE, toluidine blue, and Azan trichrome. Our results showed that there was a significant increase in infiltration of mast cells in all muscle groups of GRMD dogs compared to the control group. The average number of mast cells, as well as the deposition of fibrous tissue, decreased with age in GRMD dogs. In the control group, all muscle types showed a significant increase in the amount of collagenous tissue. This suggests increased mast cell degranulation occurred in younger GRMD dogs, resulting in increased interstitial space and fibrous tissue in muscle, which then gradually decreased over time as the dogs aged. However, further studies are needed to clarify the role of mast cells in the pathogenesis of fibrosis.(AU)

O cão Golden Retriever distrófico (Golden Retriever muscular dystrophy - GRMD) é um dos melhores modelos da distrofia muscular de Duchenne (DMD), com manifestações genotípicas e fenotípicas similares. A proliferação progressiva de tecido conjuntivo no endomísio das fibras musculares ocorre paralelamente ao curso clínico da doença em animais GRMD. Estudos anteriores sugerem uma relação entre os mastócitos e a deposição de tecido fibroso devido à liberação de mediadores que recrutam fibroblastos. O objetivo deste estudo foi avaliar a presença de mastócitos e sua relação com a lesão muscular e fibrose em cães GRMD de diferentes idades. Amostras de grupos musculares de seis GRMD e quatro controles, com idade entre 2 a 8 meses, foram coletadas e analisadas. As amostras foram processadas e coradas com HE, azul de toluidina e tricrômico de Azan. Nossos resultados mostraram que houve um aumento significativo na infiltração de mastócitos em todos os grupos musculares de cães GRMD em comparação com o grupo controle. O número médio de mastócitos, assim como a deposição de tecido fibroso, diminuiu com a idade em cães GRMD. No grupo controle, todos os tipos musculares mostraram um aumento significativo na quantidade de tecido colágeno. Isto sugere o aumento da degranulação de mastócitos em cães GRMD mais jovens, resultando em aumento do espaço intersticial e tecido fibroso no músculo, que então gradualmente diminuiu com o tempo à medida que os cães envelheceram. No entanto, mais estudos são necessários para esclarecer o papel dos mastócitos na patogênese da fibrose.(AU)

Role of neuroendocrine modulation and biochemistry in the sepsis in Piaractus mesopotamicus.

Sepsis is a systemic process with multifactorial pathophysiology that affects most animal species. It is responsible for high rates of morbidity and mortality. This work aimed to study the biochemical and neuroendocrine changes of the sepsis process in Piaractus mesopotamicus after Aeromonas hydrophila inoculation analyzing changes in blood leukocyte and differences in neuroendocrine-biochemical modulation using RNA-seq. Fish showed hypercortisolemia, inhibition of glucose absorption, followed by hypocortisolemia and then hyperglycemia. Thyroid hormones (T3 and T4) showed immediate decrease in serum and T4 increased 6 h post-inoculation (HPI). Sepsis-induced hormonal alterations triggered changes in the metabolic pathways increasing protein and lipid catabolism, use of transient anaerobic glycolysis and liver injury. A reference transcriptome was constructed based on blood leukocytes from P. mesopotamicus. The assembly resulted in total 266,272 contigs with a N50 of 2786 bp. There was a reorganization of plasma membrane of leukocytes at the beginning of the septic process with increased expression of neuroendocrine receptors and with continuous flow of neurotransmitters, hormones and solutes with compensatory regulation at 6 HPI. Three and nine HPI seemed to be critical, the expression of a number of transcription factors was increased, including the modulatory DEGs related to glucocorticoid and thyroid hormones induced and suppressed (FDR < 0.05). Neuroendocrine modulation can regulate leukocytes and biochemical parameters of peripheral blood, being important sources for the study of the pathophysiology of sepsis. These finding highlights the importance of further studies focusing on biochemical-neuroendocrine changes in blood leukocytes and systemic sepsis.

Morphological, microbiological and ultrastructural aspects of sepsis by Aeromonas hydrophila in Piaractus mesopotamicus.

Aeromonas bacteria can cause an infection characterized by septicemia and is one of the most common pathogens in tropical fish. This disease is responsible for high morbidity and mortality rates, causing considerable losses in aquaculture. Thus, the understanding of its pathophysiology is crucial to develop control strategies of this bacterial infection in farmed fish. This study aimed to characterize early pathological aspects of acute sepsis in pacu (Piaractus mesopotamicus) experimentally infected with Aeromonas hydrophila. A total of 160 juvenile pacus were inoculated intraperitoneally with A. hydrophila (1.78 x 109 CFU/mL) and at 0 (control), 1, 3, 6, and 9 hours post-inoculation (hpi), animals were anesthetized and samples were collected for microbiological, light microscopy and transmission electron microscopy (TEM) analyzes. The results showed the occurrence of hemodynamic alterations, such as hemorrhage and congestion, which were observed mainly after 6 and 9 hpi. It was possible to re-isolate Aeromonas at all sampling times except in control group. However, just after 9 hpi it was possible to find the bacteria in all fish and tissues. Light microscopy analyses revealed a degenerative process, necrosis and vascular damage mainly at 6 and 9 hpi. According to the ultrastructural examination, areas of cellular death were identified in all examined tissues, especially at 6 and 9 hpi. However, the most severe, related to necrosis, were observed after 6 and 9 hpi. The findings suggested that this bacterium spreads in the first hpi through the fish organs, mainly affecting spleen, liver and kidney, causing irreversible lesions at the molecular level.

Hematological and immune changes in Piaractus mesopotamicus in the sepsis induced by Aeromonas hydrophila.

The pathogenesis of sepsis involves complex systems and multiple interrelationships between the host and pathogen producing high mortality rates in various animal species. In this study, hematological disturbances, innate immunity and survival during the septic process in Piaractus mesopotamicus inoculated with Aeromonas hydrophila were studied. For this aim, fish blood samples were taken from control and infected groups 1, 3, 6, and 9 h post-inoculation (HPI). Leukogram showed reduction in the number of leukocytes and thrombocytes, followed by cessation of leukocyte chemotaxis 6 HPI and severe morphological changes in leukocytes and erythrocytes. At 3 HPI production of reactive oxygen species increased and at 6 HPI decreased. There was no change in serum lysozyme concentration and lytic activity of the complement system, despite the progressive increase in serum lytic activity and bacterial agglutination. Finally, the changes in clinical signs due to aeromonosis and increasing septicemia resulted in a reduction in survival to 57.14% after 36 HPI. It was possible concluded that these hematological and immune are crucial event in the worsening of sepsis in P. mesopotamicus, and these findings are utility for diagnosing and understanding the pathophysiology sepsis in pacu induced by A. hydrophila.

Evaluation of potential changes in liver and lung tissue of rats in an ischemia-reperfusion injury model (modified pringle maneuver).

In surgical procedures involving the liver, such as transplantation, resection, and trauma, a temporary occlusion of hepatic vessels may be required. This study was designed to analyze the lesions promoted by ischemia and reperfusion injury of the hepatic pedicle, in the liver and lung, using histopathological and immunohistochemical techniques. In total, 39 Wistar rats were divided into four groups: control group (C n = 3) and ischemia groups subjected to 10, 20, and 30 minutes of hepatic pedicle clamping (I10, n = 12; I20, n = 12; I30, n = 12). Each ischemia group was subdivided into four subgroups of reperfusion (R15, n = 3; R30, n = 3; R60, n = 3; R120, n = 3), after 15, 30, 60, and 120 minutes of reperfusion, respectively. Significant differences were observed in the liver parenchyma (P < 0.05) between the values of microvesicles and hydropic degeneration at different times of ischemia and reperfusion. However, the values of vascular congestion, necrosis, and pyknotic nuclei showed no significant differences (P > 0.05). In the lung parenchyma, a significant difference was observed (P < 0.05) between the values of alveolar septal wall thickening and inflammatory infiltration at different times of ischemia and reperfusion. However, there was no significant difference (P < 0.05) between the values of vascular congestion, bronchial epithelial degeneration, interstitial edema, and hemorrhage. The positive immunoreactivity of caspase-3 protein in the liver parenchyma (indication of ongoing apoptosis), showed no significant differences (P > 0.05) at different times of ischemia and reperfusion. In the pulmonary parenchyma, the immunoreactivity was not specific, and was not quantified. This study demonstrated that the longer the duration of ischemia and reperfusion, the greater are the morphological lesions found in the hepatic and pulmonary parenchyma.

Acute aerocystitis in Nile tilapia bred in net cages and supplemented with chromium carbochelate and Saccharomyces cerevisiae.

Oreochromis niloticus bred in net cages were supplemented with cell wall of Saccharomyces cerevisiae (Sc) (0.3%) or chromium carbochelate (Cr) (18 mg/kg of feed) or in association (Sc + Cr), for 90 days. After this period, acute inflammation was induced in the swim bladder by inoculation of 3 × 10(8) CFU of inactivated Streptococcus agalactiae, and another group received 0.65% saline solution (control). Twelve, 24, and 48 h after stimulation, the inflammation was evaluated through total and differential counting of accumulated cells, and through leukocyte respiratory burst in the blood, cortisolemia, glycemia and serum lysozyme concentration. The results showed that there were greater total numbers of cells in the exudate of fish inoculated with inactivated bacterium than in those injected with saline solution, with predominance of lymphocytes, thrombocytes, macrophages and granulocytes. Tilapia supplemented with Cr presented increased total numbers of cells with significant accumulation of lymphocytes and reductions in cortisolemia and glycemia, but the different treatments did not have any influence on leukocyte respiratory burst or serum lysozyme concentration. Tilapia supplemented with Sc and the Cr + Sc association did not present significant changes to the variables evaluated, despite higher accumulation of lymphocytes in the inflammatory exudate from fish treated with Sc. The results indicate that tilapia bred in net cages and supplemented with Cr presented higher total accumulation of cells at the inflammatory focus, thus indicating an increase in the inflammatory response induced by the bacterium, probably due to the reduction in cortisolemia and higher glucose consumption. Thus, supplementation with Cr had beneficial action, which facilitated development of acute inflammation induced by the bacterium, but did not affect neither leukocyte respiratory burst in the blood nor serum lysozyme concentration.

Lectinhistoquímica del granuloma inducido por el bacilo de Calmette Guérin en Piaractus mesopotamicus / Lectinhistochemical staining of granuloma induced by bacillus Calmette-Guerin in Piaractus mesopotamicus

Objetive. This study was conducted to evaluate, by means of lectinhistochemistry (LHC), the expression of carbohydrates in granulomas induced by the bacillus Calmette-Guerin (BCG) in muscle tissue of Piaractus mesopotamicus after 33 days. Material and methods. Histological sections with 3 μm thick were incubated with the following lectins :WGA (Wheat germ agglutinin), DBA (Dolichos biflorus agglutinin) and HPA (Helix pomatia agglutinin), and the results were evaluated by light microscopy. Results. Acid fast bacilli were stained by Ziehl Neelsen (ZN) and strong labeled by WGA in the cytoplasm of macrophages. Labeling with DBA was intense in fibroblasts and weak in macrophages. On the other hand, HPA binding was stronger in macrophages, especially in those that were in close contact with epithelioid cells, without evidence of binding to fibroblasts. The epithelioid cells were not labeled by the used lectins, but they were identified by Hematoxilin-Eosin (HE). The lectins labeled specific type saccharides in glycoproteins, as N-acetylglucosamine present in bacilli and macrophages, as well as N-acetyl-galactosamine in macrophages. The control group showed no inflammation or lectin binding. Conclusions. This technique may be useful in identifying receptors for WGA, DBA and the HPA lectins in epithelioid granuloma induced by BCG in P. mesopotamicus.

El presente estudio fue realizado para evaluar por medio de lectinhistoquímica (LHC), la expresión de carbohidratos en granulomas inducidos por el bacilo de Calmette-Guérin (BCG) en músculo de Piaractus mesopotamicus después de 33 días. Materiales y métodos. Cortes histológicos de 3 µm de grosor fueron incubados con las siguientes lectinas: WGA (Wheat germ aglutinin), DBA (Dolichos biflorus agglutin) y HPA (Helix pomatia agglutinin), y los resultados evaluados por medio de microscopia de luz. Resultados. Bacilos ácido resistentes fueron identificados por la tinción de Ziehl Neelsen(ZN). Se observó un marcaje intenso con WGA en el citoplasma de macrófagos. El marcaje con DBA fue intenso en fibroblastos y débil en macrófagos. Con la lectina HPA el marcaje fue intenso en macrófagos, principalmente en los que estaban en estrecho contacto con las células epitelióides, externamente se observó marcaje débil en fibroblastos. Las células epitelióides no fueron marcadas por las lectinas, pero fueron identificadas con la tinción de Hematoxilina-Eosina (HE). Las lectinas tuvieron un tipo de marcaje específico en algunos monosacáridos, como N-acetilglucosamina presente en los bacilos y en macrófagos, y N-acetilgalactosamina en macrófagos. En el grupo control no fue observada inflamación así como tampoco marcaje con las lectinas. Conclusiones. Esta técnica resultó eficiente en la identificación de receptores para las lectinas WGA, DBA y HPA en el granuloma epitelióide inducido por BCG en P. mesopotamicus.

Efeitos benéficos de probióticos no intestino de juvenis de Tilápia-do-Nilo / Beneficial effects of probiotics on the intestine of juvenile Nile tilapia

Os objetivos deste trabalho foram os de avaliar o percentual de sobrevivência, a microbiota instestinal, a integridade da mucosa, e a qualidade da carcaça de juvenis de Tilápias-do-Nilo, Oreochromis niloticus, após 80 dias de alimentação com dieta contendo aditivo probiótico (Bacillus cereus 4,0x10(8) UFCg-1 e Bacillus subtilis 4,0x10(8) UFCg-1), na proporção de 4g/kg de ração peletizada. O delineamento experimental foi inteiramente casualizado com dois tratamentos, sendo um grupo controle e outro alimentado com dieta adicionada de probiótico. Foram realizados os cálculos do percentual de sobrevivência relativa, análise da microbiota intestinal por cultura microbiológica, análise histomorfométrica da mucosa intestinal e análise químico-bromatológica da carcaça dos peixes. Os resultados demonstraram que as tilápias do grupo tratado apresentaram percentual de sobrevivência relativa maior (P<0,05) que o do grupo controle e colonização intestinal por B. cereus e B. subtilis com maior (P<0,05) número de unidades formadoras de colônia em relação ao grupo controle. A análise histomorfométrica demonstrou que o grupo alimentado com aditivo probiótico apresentou vilosidades mais altas e mais largas, além de maior número de células caliciformes que o observado no grupo controle (P<0,05). Em relação à qualidade de carcaça os resultados demonstraram que houve interferência positiva (P<0,05) do probiótico no grupo tratado em relação ao controle quanto aos teores de proteína e extrato etéreo. Estes resultados permitem inferir que a suplementação com probiótico, como testado neste estudo, induziu a colonização intestinal por bactérias benéficas e promoveu maior percentual de sobrevivência relativa, diminuiu a descamação da mucosa, e favoreceu o aumento do número de células caliciformes.

The aim of this study was to evaluate the survival rate, the intestinal microbiota, the mucosal integrity, and the carcass quality of juvenile Nile Tilapia, Oreochromis niloticus, after 80 days being fed on a diet containing probiotic additive (Bacillus cereus 4.0x10(8) CFUg-1 and Bacillus subtilis 4.0x10(8) CFUg-1), at the ratio of 4g/kg of pelleted feed. The completely randomized design with two treatments was used: one control group and one group fed on the mentioned diet. The evaluation of survival rate, the intestinal microbiota analysis by microbiological culture, histomorphometrical analysis of intestinal mucosa and chemical analysis of carcass was performed. The results showed that tilapias from the treated group had higher relative survival rate (P<0.05) than the control group, higher number of colony-forming units (P<0.05) regarding intestinal colonization by B. cereus and B. subtilis, and higher rates of intestinal mucosal integrity (P<0.05), evaluated by histomorphometry. As for the latter, the group being fed on feed with probiotic additive was observed to have higher and larger villi, besides having a higher number of goblet cells than the control group. Concerning the carcass quality, the results showed that there was positive interference (P<0.05) of the probiotic on the treated group in comparison to the control group as in regard to levels of protein and ether extract. These results allow the inference that the supplementation with probiotic, as tested in this experiment, led to the intestinal colonization by beneficial bacteria and resulted in higher relative survival rate, decreased the mucosal desquamation and helped in the increase of the number of goblet cells.

Acute aerocystitis in Piaractus mesopotamicus: participation of eicosanoids and pro-inflammatory cytokines.

A total of 360 pacus (Piaractus mesopotamicus) were used to study vascular permeability (VP) and inflammatory cell component (CC) in induced aerocystitis in P. mesopotamicus through inoculation of inactivated Aeromonas hydrophila, and the effect of steroidal and nonsteroidal anti-inflammatory drugs. It was observed that after inoculation of A. hydrophila, the maximum VP occurred 180 min post-stimulus (MPS). Pretreatment with anti-inflammatory drugs inhibited VP, and the inhibitory effect of dexamethasone was seen earlier than the effects caused by meloxicam and indomethacin. Inoculation of the bacterium caused a gradual increase in the accumulation of cells, which reached a maximum 24 h post-stimulus (HPS). Pretreatment with dexamethasone, indomethacin and meloxicam reduced the accumulation of lymphocytes, thrombocytes, granulocytes and macrophages. There was no significant difference between the different doses of the drugs tested. The results suggest that eicosanoids and pro-inflammatory cytokines participate in chemical mediation in acute inflammation in pacus.

Myxosporidiosis in intensively-reared Piaractus mesopotamicus: Histopathological diagnosis by means of Ziehl-Neelsen staining / Mixosporidiose em Piaractus mesopotamicus de criação intensiva: diagnóstico histopatológico pela coloração Ziehl-Neelsen

Samples of different organs from intensively-reared Piaractus mesopotamicus were collected and processed using routine histological techniques in order to produce thin sections for staining with hematoxylin-eosin and with the Ziehl-Neelsen method. Through examination under an optical microscope, myxosporidians of the genera Henneguya sp. and Myxobolus sp. were identified, respectivelyin the gills and kidneys of P. mesopotamicus. Plasmodia with immature spores of Henneguya sp. were located along the secondary lamellae, with total length of 30.45±4.84µm and width of 3.52±0.33µm. Spores of Myxobolus sp. were located in the kidneys, with total length of 8.94±0.82µm and width of 5.59±0.39µm. Histopathological analysis of the gills showed plasmodia containing spores of Henneguya sp., at intralamellar and intravascular localities, at different stages of development. Spores of Myxobolus sp. were identified in the kidneys, in the peritubular region and in the interstices and glomerulus, surrounded by melanomacrophages. Focal hemorrhage was recorded in a few cases. Ziehl-Neelsen staining allowed to identify particular features of the spores and facilitated biometry and enabled classification in comparison with hematoxylin-eosin, thus demonstrating its usefulness for histopathological diagnosis of the parasitosis.

Amostras de diferentes órgãos de Piaractus mesopotamicus mantidos em criação intensiva foram coletadas e processadas mediante as técnicas histológicas usuais para obtenção de cortes que foram corados com hematoxilina-eosina e pelo método de Ziehl-Neelsen. Ao exame em microscopia de luz foi possível identificar mixosporídeos dos gêneros Henneguya sp. e Myxobolus sp. em brânquia e rim de P. mesopotamicus respectivamente. Plasmódios com esporos imaturos de Henneguya sp. foram localizados ao longo das lamelas secundárias e mensurados (comprimento total 30,45±4,84µm e largura 3,52±0,33µm) e no rim esporos de Myxobolus sp. (comprimento total 8,94±0,82µm e largura 5,59±0,39µm). Na análise histopatológica das brânquias observaram-se plasmódios contendo esporos de Henneguya sp., com localização intralamelar e intravascular, em diferentes estágios de desenvolvimento. No rim identificaram-se esporos de Myxobolus sp., na região peritubular e no interstício e glomérulo, circundados por melanomacrófagos. Em poucos casos foi registrada hemorragia focal. O uso da coloração de Ziehl-Neelsen permitiu identificar particularidades dos esporos, facilitou sua biometria e classificação em comparação com a hematoxilina-eosina, demonstrando sua utilidade no diagnóstico histopatológico da referida parasitose.

Histopatologia de fígado, rim e baço de piaractus mesopotamicus, prochilodus lineatus e pseudoplatystoma fasciatum parasitados por myxosporídios, capturados no Rio Aquidauana, Mato Grosso do Sul, Brasil / Histopathology of liver, kidney and spleen of Piaractus mesopotamicus, Prochilodus lineatus and Pseudoplatystoma fasciatum infected by myxosporean parasite, caugth in Aquidauana River, Mato Grosso do Sul, Brazil

Histological analysis of kidney, spleen and liver of Piaractus mesopotamicus, Prochilodus lineatus and Pseudoplatystoma fasciatum, infected by myxosporean, caugth in Aquidauana river, MS, was studied. After necropsy, samples of liver, previous kidney and spleen were fixed in 10 percent buffered formalin and processed followed histological routine methods. Sections of 5 μm were stained with hematoxylin and eosin. Myxobolusporofilus, M. colossomatis and were found in P. lineatus, in P. mesopotamicus respectively and Myxobolus spp. Were also found in all three species of fish. Myxosporideans cysts in the liver and spleen of P mesopotamicus were also related. Up to 50 percent of P mesopotamicus and P lineatus liver samples showed diffuse hepatodistrofy. Liver sections also showed concentric hialin structures in over 80 percent of samples and esteatosis in 50 percent of them. In P mesopotamicus kidney, 95.23 percent of them showed tissue changes consisted of 60 percent with diffuse moderate nefrodistrofy and congestion of glomerular sinusoids. In P lineatus kidney, 20 percent of the samples showed tissues changes. No heavy damage was observed in the fish spleen.

Este estudo descreveu a histopatologia de rim, baço e fígado de Piaractus mesopotamicus, Prochilodus lineatus e Pseudoplatystoma fasciatum, parasitados por mixosporídios, capturados no Rio Aquidauana, MS. Após necropsia, amostras do fígado, rim cefálico e baço foram colhidas, fixadas em formalina a 10 por cento tamponada e processadas de acordo com a rotina histológica. Os cortes foram feitos à espessura de 5 μm e corados com hematoxilina-eosina. Foram encontrados Myxobolus porofilus em P. lineatus, M. colossomatis em P. mesopotamicus e Myxobolus spp. nas três espécies de hospedeiros. Cistos de mixosporídios no exame histopatológico foram vistos no fígado e baço de P. mesopotamicus. Mais de 50 por cento das amostras de fígado de P mesopotamicus e P lineatus apresentou hepatodistrofia difusa. Mais de 80 por cento das amostras de fígado de P. fasciatum apresentou formações hialinas concêntricas e esteatose em 50 por cento das amostras. Em 95,23 por cento das amostras de rins de P. mesopotamicus, foram observadas alterações teciduais, e em mais de 60 por cento dos casos nefrodistrofia difusa moderada e congestão de sinusóides glomerulares. Alterações teciduais nas amostras de rins de P. lineatus foram observadas em menos de 20 por cento da amostra. No baço dos peixes ora examinados não foram encontradas lesões dignas de relato.

[Histopathology of liver, kidney and spleen of Piaractus mesopotamicus, Prochilodus lineatus and Pseudoplatystoma fasciatum infected by myxosporean parasite, caugth in Aquidauana River, State of Mato Grosso do Sul, Brazil]. / Histopatologia de fígado, rim e baço de Piaractus mesopotamicus, Prochilodus lineatus e Pseudoplatystoma fasciatum parasitados por myxoporídios, capturados no rio Aquidauna, Mato Grosso do Sul, Brasil.

Histological analysis of kidney, spleen and liver of Piaractus mesopotamicus, Prochilodus lineatus and Pseudoplatystoma fasciatum, infected by myxosporean, caugth in Aquidauana river, MS, was studied. After necropsy, samples of liver, previous kidney and spleen were fixed in 10% buffered formalin and processed followed histological routine methods. Sections of 5microm were stained with hematoxylin and eosin. Myxobolus porofilus, M. colossomatis and were found in P. lineatus, in P. mesopotamicus respectively and Myxobolus spp. Were also found in all three species of fish. Myxosporideans cysts in the liver and spleen of P. mesopotamicus were also related. Up to 50% of P. mesopotamicus and P. lineatus liver samples showed diffuse hepatodistrofy. Liver sections also showed concentric hialin structures in over 80% of samples and esteatosis in 50% of them. In P. mesopotamicus kidney, 95.23% of them showed tissue changes consisted of 60% with diffuse moderate nefrodistrofy and congestion of glomerular sinusoids. In P. lineatus kidney, 20% of the samples showed tissues changes. No heavy damage was observed in the fish spleen.

[Effects of parasitism on gill structure of Leporinus macrocephalus Garavello and Britsk, 1988 (Anastomidae) and Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes:Characidae)]. / Efeitos do parasitismo sobre a estrutura branquial de Leporinus macrocephalus Garavello e Britsk, 1988 (Anastomidae) e Piaractus mesopotamicus Holmberg, 1887 (Osteichthyes:Characidae).

This work described the lesions caused in different species of fish by gill parasites from fee-fishing at Guariba, State of São Paulo. The research was developed from april, 1997 to march to 1999, seeking to verified the kind tissues lesions from fish. Of these, forty and seven were Leporinus macrocephalus and fifty and five Piaractus mesopotamicus. About 87.2% of the L. macrocephalus, and 58.1% of the P. mesopotamicus were sponged by several species of parasites. The parasite most abundant in L. macrocephalus was Piscinoodinium pillulare, while monogenean, Trichodina sp and myxosporidian infected P. mesopotamicus. Severe gill lesions have been observed in L. macrocephalus and P. mesopotamicus caused by monogenean, P. pillulare e Trichodina sp. parasitism, such as intersticial hemorrhage, sub-epithelium edema, inflammation, epitelial hiperplasy in filaments and lamina, proliferation of mucosal cells and laminar fusion.

Presença de cartilagem em tendöes flexores: revisäo do padräo histológico

Foi realizado estudo do padräo histológico vascular de tendöes flexores profundos da pata dianteira de cäes. Observou-se que os tendöes näo possuem padräo vascular e histológico uniforme em toda sua extensäo, fato que contraria os conceitos classicos. Nas áreas tendinosas sinoviais observaram-se áreas avasculares que estavam em correspondência com a presença de tecido cartilagionoso nas faces volares e no interior dos tendöes. Nestas áreas foram observados ainda células com características de condrócitos no interior de feixes de fibras colágenas e tecido cartilaginoso nos septos conjutivos, que ainda näo foram descritos. Com base nos achados os autores sugerem revisäo no conceito do padräo histológico dos tendöes flexores da mäo humana, bem como dos modelos experimentais utilizados atualmente