Systemic alterations of bovine hemostasis due to Rhipicephalus (Boophilus) microplus infestation.

The tick Rhipicephalus (Boophilus) microplus is a hematophagous ectoparasite that causes considerable economic losses to cattle breeding. Although R. microplus saliva contains several molecules that interfere with the blood coagulation process, so far the systemic alterations in the host hemostatic system have not been described. This study aims to determine if R. microplus infestation induces any disturbance to the host's hemostatic system. To address these questions, six calves were experimentally infested with 20,000 R. microplus larvae and their blood was collected before and 7, 14 and 21 days post-infestation. Collagen and ADP-induced platelet aggregation as well as coagulation (activated partial thromboplastin time and prothrombin time) decreased in infested bovines. Platelet blood count and fibrinogen increased during the course of infestation, probably as a compensatory response. These alterations may play a role in host health status, and show that the host cannot fully counteract the tick anti-hemostatic mechanisms.

Access routes for nutritional therapy.

Enteral nutrition (EN) and total parenteral nutrition (TPN) may provide life-sustaining therapy for surgical patients. The duration of nutritional therapy (enteral or parenteral) implies distinct access routes. We review the main aspects related to access routes for nutrient delivery. The enteral route, whenever feasible, is preferred. For EN lasting less than 6 weeks, nasoenteric tubes are the route of choice. Conversely, enterostomy tubes should be used for longer-term enteral feeding and can be placed surgically or with fluoroscopic and endoscopic assistance. The first choice for patients who will not be submitted to laparotomy is percutaneous endoscopic gastrostomy. Postpyloric access, although not consensual, must be considered when there is a high risk of aspiration. For intravenous delivery of nutrients lasting less than 10 days, the peripheral route can be used. However, because of frequent infusion phlebitis, its role is still in discussion. Central venous catheters (CVCs) for TPN delivery may be (1) nonimplantable, percutaneous, nontunneled-used for a few days to 3 to 4 weeks; (2) partially implantable, percutaneous, tunneled-used for longer periods and permanent access; or (3) totally implantable subcutaneous ports-also used for long-term or permanent access. The subclavian vein is usually the insertion site of choice for central venous catheters. Implantable ports are associated with lower rates of septic complications than percutaneous CVCs. The catheter with the least number of necessary lumens should be applied. Central venous nutrient delivery can also be accomplished through peripherally inserted central catheters, which avoid insertion-related risks.

Remaining small bowel length: association with catheter sepsis in patients receiving home total parenteral nutrition: evidence of bacterial translocation.

Patients with short bowel syndrome (SBS) receiving total parenteral nutrition (TPN) have a high incidence of catheter-related sepsis, one of its major complications. The aim of this study was to correlate the length of remaining small bowel (RSB) with septic episodes related to the central venous catheter in a group of patients with severe SBS with home TPN. The length of the RSB (<50 cm or > or = 50 cm) was related to the frequency of catheter sepsis, time until the first episode, and the agents responsible in eight SBS patients receiving home TPN. There were 13 episodes of catheter infection (0.88 per patient-year). The group with a shorter RSB length (five patients) presented 1.3 to 2.76 infections/year and 2 to 9 months until the first episode, compared to 0 to 0.75 infections/ year (p = 0.0357) and 11 to 65 months until the first episode (p = 0.0332) in the group with the longer RSB. In the first group, the agents isolated were Enterobacteriae (Enterobacter sp., Klebsiella sp., Pseudomonas sp., and Proteus sp.) in eight episodes and Candida sp. in one. In the latter sepsis was caused by Staphylococcus sp. in three episodes and Pseudomonas sp. in one. Therefore patients with remaining small bowel shorter than 50 cm have a higher frequency of catheter-related sepsis, particularly by enteric microorganisms. This might be an evidence of the occurrence of bacterial translocation and its role in the pathogenesis of catheter-related sepsis in patients with an extremely short RSB receiving home TPN.

Postoperative total parenteral nutrition.

Surgical trauma induces complex physiologic changes that lead to catabolism and loss of body cell mass. This reaction is usually mild but can be exacerbated by previous malnutrition and postoperative complications. To avoid severe metabolic distress, nutritional therapy may be prescribed, using the enteral route whenever possible. Postoperative total parenteral nutrition (TPN) is indicated for patients already receiving TPN preoperatively, those severely malnourished prior to major surgery, those unable to eat satisfactorily for 7 days, or patients presenting with severe complications. Postoperative TPN should last for at least 7 days. The total energy requirements are between 30 and 35 kcal/kg/day. About 50% to 70% should be provided in the form of carbohydrates, and 20% to 30% in the form of lipids. The optimal input rates for glucose and lipids are 4 to 5 g/kg/day and 80 mg/kg/hr, respectively. The ideal nitrogen administration is 250 to 300 mg/kg/day, and the optimal calorie/nitrogen ratio is 150 to 200. Some specific amino acids can be added as intravenous dipeptides. An adequate follow-up must include clinical and biochemical parameters. Several trials evaluated the impact of TPN in postoperative patients, but further well designed, controlled clinical trials are still necessary to address a great number of unanswered questions.

[Technical and histological standardization of experimental colitis with trinitrobenzenosulfonic acid (TNBS)]. / Padronização técnica e histológica de colite experimental com ácido trinitrobenzenosulfônico (TNBS).

Attempts to reproduce inflammatory colitis have created many experimental models. Since the pioneer work of Morris et al. (1989), trinitrobenzenosulfonic (TNBS) solutions have been used with different dosages. The aims of this work were standardize the induction of colitis, evaluate the clinical and intestinal effects of different doses and verify the reproducibility of the intestinal inflammatory process. Wistar rats were inoculated endo rectally with 2.5 ml solutions of different concentrations of TNBS and ethanol, and the rats were sacrificed after 14 days. According to the solution concentrations of TNBS (mg) and ethanol (%), six groups of animals were established: Control (saline), 30 mg/30%, 30 mg/40%, 30 mg/50%, 50 mg/10% and 50 mg/30%. Statistical analysis of food ingestion showed no differences between groups (p = 0.247). The 30/50 group presented greater weight loss when compared to 50/10 and 50/30 groups (p = 0.012). Groups 30/50 and 30/40 showed greater degrees of macroscopic lesion than control and 50/10 group (p < 0.05). Histologic lesion was not uniform to all rats regardless of the solution employed. Group 50/10 presented the less severe histologic alterations; on the other hand, 30/40 and 30/50 groups had important changes on mucosal thickness, on vascularization and ulceration. The authors conclude that experimental colitis with TNBS 1) cause intestinal lesions that are not uniform to all animals, although they may be reproduced in many of them; 2) with the same doses of TNBS, the increase in ethanol concentrations leads to a greater inflammatory process, intestinal thickness, vascularization, abscess formation and intestinal ulceration; 3) 50/10 and 50/30 solutions make less severe lesions when compared to 30/40 and 30/50 solutions; 4) 30/50 solution was the best one, as it produces inflammation 90% of the animals, increases in wall thickness in 50%, abscess in 70% and ulceration in 38%.