Geraldo Eleno Silveira Alves

Salmonella enterica Serovar Typhi Conceals the Invasion-Associated Type Three Secretion System from the Innate Immune System by Gene Regulation

Delivery of microbial products into the mammalian cell cytosol by bacterial secretion systems is a strong stimulus for triggering pro-inflammatory host responses. Here we show that Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever, tightly regulates expression of the invasion-associated type III secretion system (T3SS-1) and thus fails to activate these innate immune signaling pathways. The S. Typhi regulatory protein TviA rapidly repressed T3SS-1 expression, thereby preventing RAC1-dependent, RIP2-dependent activation of NF-κB in epithelial cells. Heterologous expression of TviA in S. enterica serovar Typhimurium (S. Typhimurium) suppressed T3SS-1-dependent inflammatory responses generated early after infection in animal models of gastroenteritis. These results suggest that S. Typhi reduces intestinal inflammation by limiting the induction of pathogen-induced processes through regulation of virulence gene expression.

Experimental ischemia and reperfusion in equine small colon

The effects of ischemia and reperfusion were studied in the small colon of 12 horses. Under general anesthesia, arterial pressure and arterial hemoglobin oxygen saturation values were maintained constant and within the normal physiological range. After celiotomy, the small colon was exposed and three segments were demarcated. Total arterial venous ischemia was induced in two segments during 90 (group A) and 180 (group B) minutes. The third segment was the control group. Full-thickness biopsy specimens, for histopathology, were obtained at the end of the ischemia periods and at 90 (groups A and B) and 180 minutes (group A) of reperfusion. The mucosa and the submucosa were evaluated by semiquantitative morphological assessment such as epithelial detachment, edema and hemorrhage, and by quantitative morphological assessment such as percentual depth of mucosal loss (ML) and mucosal crypt:interstitium ratio (C:I). After ischemia, lesions such as ML, C:I, epithelial detachment and mucosal edema were more intense in group B when compared to group A. In both groups after reperfusion there were significant increases in ML, C:I, epithelial detachment and submucosal edema. The results showed aggravation of the mucosal lesions in the reperfusion period in equine small colon, and the model was considered adequate for experimental purposes.

Hemogasometria em eqüinos com compactação experimental do cólon maior tratados com sene, fluidoterapia enteral e parenteral

The blood acid-base status was studied in equines when induced large colon impaction was followed by applying an isotonic polionic enteral solution, or sene associated with intravenous fluid therapy, or fluid therapy alone. The blood samples were collected in twenty animals, four groups (E8, RL, SE, and C) of five animals each. Animals of the treated groups had experimentally induced colon impactions. Equines in group E8 received isotonic polionic enteral solution (8 mL kg -1 h -1 48

Tratamento da compactação experimental do cólon maior em eqüinos: resultados de laboratório e exames bioquímicos

The effects of isotonic polionic enteral solution, sene plus intravenous (IV) fluid therapy or fluid therapy IV only for the large colon impaction treatment in horses were evaluated. Twenty animals were divided in four groups. Animals of the treated groups had experimentally induced colon impactions. Group C (control) was not treated; group E8 received isotonic polionic enteral solution (8ml/kg/hour/48 hours); group SE received sene (20mg/kg, two doses with 24 hours interval) and ringer lactate IV (10ml/kg/hour/12 hour, during two days), and group RL received ringer lactate IV (16ml/kg/hour/12hour, during two days) only. Animals in the E8 group had hypernatremia, hypercloremia and hyperglycemia. Animals of the SE group had higher concentration of urea, creatinine, osmolality and plasmatic lactate. Ringer lactate IV only, group RL, did not cause alteration in the electrolytic equilibrium. In conclusion, intravenous fluid therapy with Ringer solution alone was the most efficient treatment for biochemical correction in horses with large colon impaction. Fluid therapy was also efficient in minor degree. Sene treatment associated with intravenous fluid therapy had the poorest results among the protocols to normalize biochemical variables.

Efeito do ultra-som terapêutico em tendinite experimental de eqüinos: estudo clínico, ultra-sonográfico e histopatológico de dois protocolos

In order to evaluate two therapeutic ultrasound protocols for treatment of injuries of the superficial digital flexor tendon (SDFT) a study was performed in 18 horses. In each horse, a 0.25% solution of collagenase was injected in the middle of the left SDFT. The horses were randomly and equally divided into three groups. Horses from Group A were treated with therapeutic ultrasound of 3 MHz frequency and 1 W/cm2 intensity on continuous mode for six minutes; horses from Group B were treated with the same frequency, intensity, and time, but on pulsed mode; Group C was kept as controls. The treatment began 48 hours after the collagenase injection, totaling eight sessions. The horses were clinically evaluated for 40 days. Ultrasonographic images were evaluated weekly to score the severity rate (SR), which was based on echogenicity and cross sectional area of the lesion in the tendon. The induced lesion resulted on an average increase of 1.5cm in the shin circumference, pain response to digital pressure ranging from low to high and lameness ranging from grade 1 to 3. Regression of clinical signs were detected on average in nine days in Group A, 12 days in Group B, and 21 days in Group C. Decreases of the SR after 40 days were 42.5, 57.7 and 34.1% in groups A, B and C, respectively. Histological evaluation demonstrated intense neovascularization and fibroblastic activity on treated groups (A and B), when compared to the controls. These results suggest that UST is effective in reducing clinical signs of tendinitis.

Efeito da hidrocortisona sobre a lesão de reperfusão e reparação da mucosa após isquemia venosa experimental no jejuno de eqüinos

In order to evaluate the effect of hydrocortisone sodium succinate (HSS) for treatment of intestinal ischemia-reperfusion, 12 halothane-anesthetized horses were subjected to both venous and arteriovenous ischemia of the jejunum. After one hour of ischemia, HSS (4.0 mg/kg/IV) was administered to six animals (T group). The other six horses received saline (NT group). Biopsy specimens were obtained after one and two hours of ischemia, and one, two and 12 hours after reperfusion. These samples were evaluated to assess the degree of mucosal damage and infiltration of neutrophils, hemorrhage, and edema. The scores for neutrophil infiltration, edema and hemorrhage did not differ between T and NT groups in both models of ischemia. However, in the jejunum subjected to venous ischemia, the scores for mucosal lesion increased significantly (P<0.05) after two hours of reperfusion only in the NT group, indicating that HSS prevented reperfusion injury. The scores for mucosal damage were equivalent after 12 hours of reperfusion following arteriovenous ischemia in T and NT groups. In contrast, mucosal lesion due to venous ischemia were more severe in the NT group (P<0.01), indicating that intestinal repair was stimulated by HSS. These results indicate that HSS may be used as an adjuvant for treatment of intestinal isquemia and reperfusion lesions in the horse.

Sistemas osso-implante ex vivo utilizando haste intramedular polimérica para imobilização de fraturas femorais em bovinos jovens

The development of new devices using available and low cost materials may be an useful alternative for the treatment of long bone fractures in large animals. The aim of this study was to evaluate the mechanical strength of young bovine femur with diaphyseal fracture fixed with different polymeric intramedullary nails. Bending and compression tests using a universal machine were carried out in 4 distinct groups of 6 femurs from young calves. In one of the groups bones were intact while in the other three fractured bones were fixed using an intramedullary nail made of polypropylene, polyacetal or polyamide (one for each group). Considering bending and compression tests together, none of the used polymers offered strength to the fractured bones similar to the intact ones. The agreement of this findings with those from previous published in vivo results indicates that the employed ex vivo methods for mechanical assays may be useful in the search of stronger materials to be used in development of new devices.

Considerações sobre a obtenção e o uso do plasma rico em plaquetas e das células mesenquimais indiferenciadas em enxertos ósseos

The rich platelet plasma (RPP) and indiferenciate mesenchimal cells (IMCs), or stem cells, have been widely studied because of their high potential of osteoinduction in bone grafts. However, the utilization of RPP and IMCs must be done following correct methodology of isolation and use. The inappropriate methodology can be a determinant factor of its efficacy on bone grafts and can explain some controversial results of its utilization in bone grafts.

Influência das pontas excessivas de esmalte dentário na digestibilidade e nutrientes de dietas de eqüinos

Para avaliar a influencia das pontas excessivas de esmalte dentario na digestibilidade dos nutrientes de dietas de equinos, utilizaram-se 13 animais alimentados com capim-elefante (Pennisetum purpureum) e racao comercial. Foram analisadas materia seca, proteina bruta, energia bruta, fibra em detergente neutro, fibra em detergente acido, hemicelulose e celulose nas fezes antes e duas semanas apos o desgaste corretivo das pontas excessivas de esmalte. A digestibilidade aumentou (P<0,001) em todas as variaveis estudadas apos o desgaste corretivo.

Características celulares e bioquímicas do líquido peritoneal de eqüinos submetidos à peritonite experimental

O objetivo deste trabalho foi estudar caracteristicas citologicas e bioquimicas do liquido peritoneal de equinos utilizando-se 60 animais sem raca definida, divididos aleatoriamente em dois grupos, tratado e controle, submetidos a um modelo experimental de peritonite, utilizando-se a laparotomia mediana. O grupo-tratado recebeu tratamento transcirurgico com antibioticos e antinflamatorios. No periodo pos-operatorio ambos os grupos receberam o mesmo tratamento. Foram colhidas amostras de liquido peritoneal 24h antes da cirurgia e, posteriormente, ate 120h, sendo realizadas avaliacoes macroscopicas, citologicas e bioquimicas. As caracteristicas citologicas e bioquimicas mostraram alteracoes que refletiram o estado das superficies mesoteliais, assim como forneceram resposta a terapia aplicada. A terapia induziu uma resposta inflamatoria menos intensa, caracterizada por menores concentracoes de proteina total e fibrinogenio, bem como atividade fagocitica mais acentuada. Tambem foram verificadas modificacoes quantitativas e qualitativas 12h apos a inducao de peritonite. O tempo de observacao das modificacoes celulares e bioquimicas deve ser superior a 120h apos a inducao de peritonite para se obter informacoes completas sobre as caracteristicas estudadas.