Indomethacin-induced reduction in neonatal piglet mesenteric blood flow is blunted by dopexamine.

BACKGROUND: Dopexamine is a specific dopaminergic and beta2-adrenergic agonist. Using newborn piglets, we have previously shown that (1) dopexamine increases cardiac output and mesenteric blood flow; (2) indomethacin reduces mesenteric blood flow. METHODS: Ultrasonic blood flow probes were placed around the ascending aorta, cranial mesenteric artery, and a renal artery of 0 to 2-day-old and 2-week-old piglets. Animals of each age were grouped (5 to 8 animals per group) and subjected to one of three experimental protocols: (1) 0.4 mg/kg indomethacin infusion, (2) 10 microg/kg/min dopexamine infusion begun 10 minutes before indomethacin, or (3) no treatment. RESULTS: Control animals demonstrated no significant alterations in mesenteric blood flow. Compared with baseline, indomethacin produced significant (P< .05, analysis of variance) declines in cranial mesenteric artery blood flow in 0 to 2-day old (37.2+/-5.7 mL/min v 17.9+/-3.7 mL/min at 90 min), and 2-week-old (80.2+/-12.5 mL/min v 29.7+/-5.7 mL/min at 90 minutes) piglets. In both animal groups treated with dopexamine before indomethacin, the decreases in cranial mesenteric artery blood flow were eliminated (38.4+/-7.6 mL/min at baseline v 36.5+/-6.8 mL/min at 90 minutes in 0 to 2 day olds; 79.9+/-10.0 mL/min at baseline v 77.5+/-14.7 mL/min in 2 week olds). Indomethacin-induced declines in renal blood flow were similarly abrogated by dopexamine. CONCLUSION: Dopexamine may prove of clinical benefit when a neonate is considered a candidate for indomethacin therapy.

Utility of the biofragmentable anastomotic ring in traumatic small bowel injury.

OBJECTIVE: To evaluate the use of the 25 mm Biofragmentable Anastomotic Ring (BAR) in traumatic small bowel injury. METHODS: In a one year prospective, nonrandomized study, 18 patients (x age = 25 yrs) with penetrating small bowel injury had 25 BAR devices placed to restore intestinal continuity. Using one-way analysis of variance, this group was compared to 63 historical controls (x age = 27 yrs) with small bowel trauma who had either sutured or stapled anastomoses (SSA), with regard to Penetrating Abdominal Trauma Index (PATI) score, time until return of bowel function, and postoperative morbidity. RESULTS: PATI scores for the two groups were not significantly different (P = 0.099). No deaths in the SSA group (n = 8) or in the BAR group (n = 1) were related to the anastomotic technique. There was no significant difference (P = 0.991) in the rate of post-operative intestinal obstruction between BAR (n = 3) and SSA (n = 8) groups; none of the BAR patients required re-operation. The average length of time for return of bowel function was not significantly different (P = 0.197) between BAR (4.3 days) and SSA (5.8 days) groups. CONCLUSIONS: The 25 mm BAR may be used in the repair of traumatic small bowel injury, based upon comparable outcomes when compared with sutured and stapled anastomoses.

Antimicrobial alternatives for calf diarrhea: enteric responses to Escherichia coli, deferoxamine, or gallium in neonatal calves.

Intestinal malabsorption or transferable resistance in enteric bacteria are potentially serious complications of routine oral administrations of antibiotics. On the basis of reports on antimicrobial effects of host iron sequestration and on synthetic iron chelators or competitors in vitro, 2 iron antagonists were studied for their potential as alternative antimicrobials for Escherichia coli diarrhea. Deferoxamine, a fungal iron chelator used to treat acute iron intoxication, and elemental gallium, a competitive inhibitor of iron activity in metabolic enzyme systems, were examined for their effects on enteric morphology and function in neonatal calves. Twelve male calves were allotted to 4 groups: (1) given nonpathogenic E coli (control); (2) given enterotoxigenic B44 E coli; (3) given deferoxamine (50 mg/kg, twice a day); and (4) given gallium (4 mg/kg, twice a day). Calves were studied for 8 days, including the conduct of oral glucose and lactose tolerance tests on days 1, 3, and 7. By day 7, according to oral glucose and lactose tolerance tests, peak plasma glucose concentrations in all calves of groups 2, 3, and 4 were lower than those values in controls. The frequency of diarrhea was significant in all treated calves, and disease was most severe in the deferoxamine-treated calves. Quantitative cultural examination on day 8 showed significant numerical increases of jejunal and ileal E coli and ileal lactobacilli in deferoxamine-treated calves (group 3) and of ileal streptococci in gallium-treated calves (group 4) and showed jejunal and ileal overgrowths of Saccharomyces yeast in deferoxamine-treated calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Diarrhea and malabsorption in calves associated with therapeutic doses of antibiotics: absorptive and clinical changes.

Of 28 healthy, nondiarrheal, colostrum-fed neonatal calves, 22 developed diarrhea after they were given (orally) for 3 to 5 days maximally recommended doses of chloramphenicol, neomycin, ampicillin, or tetracycline. Ampicillin-, neomycin-, or tetracycline-treated calves had significantly (P less than 0.05) decreased and delayed glucose absorption during oral glucose tolerance tests. Chloramphenicol-treated calves had significantly (P less than 0.05) higher base-line plasma glucose concentrations during the non-test period and had no significant increase in blood glucose concentrations during the tolerance tests compared with those in control calves.

Malabsorption due to selected oral antibiotics.

This article represents an overview of recent research conducted on antibiotic-induced malabsorption in calves. The authors feel strongly that this work identifies a serious and ill-defined problem in the management of neonatal calves. Too often the solution utilized by veterinarian and stockmen for controlling neonatal diarrhea has been to administer oral antibiotics. In many cases, this has been done on the basis of antibiotic sensitivity testing, an approach that seems appropriate. Unfortunately, little consideration has been given to the relative sensitivity of the neonatal intestinal mucosa, with its very rapid turnover, to the potentially detrimental effects of oral antimicrobial therapy. The data that we have collected over the past 3 years conclusively demonstrate that high levels of four commonly used oral antibiotics, especially neomycin and chloramphenicol but also tetracycline and ampicillin, can cause a malabsorption diarrhea in normal calves. This action is not due to viral agents or overgrowth of resistant microbes but is the result of direct modification of the intestinal mucosa. Extrapolation of these data to different dose levels may not be accurate. Oral antibiotics may be of value in treating neonatal enteritis. Conversely, there can be too much of a good thing, and many cases of chronic diarrhea following use of oral antibiotics may be the result of an overenthusiastic and prolonged dosage regimen. Be cautious!

Pathologic changes associated with induced small intestinal strangulation obstruction and nonstrangulating infarction in horses.

Arteriovenous (ischemic strangulation obstruction, ISO) or venous (hemorrhagic strangulation obstruction, HSO) occlusions were created in the jejunum of 5 anesthetized horses and were left in situ for 1-, 2-, or 3-hour intervals. Segments were evaluated grossly for color, thickness, and motility. The horses were euthanatized, and the degree of mucosal slough, edema, congestion, and hemorrhage was determined histologically. Segments subjected to ISO became dark, but did not contain edema or hemorrhage. Segments subjected to HSO were characterized by progressive congestion, edema, and hemorrhage especially in the mucosal layer. Histologically, the mucosal epithelium was affected approximately equally by ISO or HSO, although more gross changes were evident in segments subjected to HSO.

Evaluation of fluorescein dye as an indicator of small intestinal viability in the horse.

In 6 horses, 2 types of ischemic lesions were created in small intestinal segments by selective ligation of vessels and intestinal wall for 1, 2, or 3 hours. After confirming the ischemia by IV injection of sodium fluorescein, the ligatures were released. Five minutes later, the fluorescent patterns were documented photographically. Observed patterns ranged from normal (identical to that observed in unaffected bowel) to a patchy distribution of non-fluorescence (indicating incomplete perfusion). None of the experimental segments was normal when reevaluated 1 month later. The typical appearance included fibrosis, adhesions, and thickening of the bowel wall. It was concluded that IV injection of fluorescein can be used to indicate perfusion of the intestine, but that this is not the only criterion for determining clinical outcome in cases of intestinal ischemia in horses.

Pancreatic beta cell tumor in a ferret.

A ferret with clinical and laboratory signs of hypoglycemia was found at surgery to have a beta cell tumor of the pancreas. There had been recurrent episodes of weakness, ataxia, dehydration, and hypothermia. A fasting blood glucose content was 43 mg/dl and the amended insulin/glucose ratio was 362.5. The tumor was removed, yet hypoglycemia persisted postoperatively. Clinical signs related to hypoglycemia did not recur following application of medical treatment and frequent feedings. The histologic appearance of the tumor closely resembles that which has been seen in other species.

Hypothyroidism: an early sign of vitamin A deficiency in chickens.

The effect of a marginal vitamin A deficiency on thyroid function was investigated in chicks gaining weight. This study examined the hypothesis that hypothyroidism is one of the earliest manifestations of hypovitaminosis A in chicks. Day-old Leghorn cockerels were fed vitamin A-adequate and deficient diets. Blood vitamin A levels were reduced in the deficient chicks by 3 weeks of age. Body weight gains were less in the 5-, 6-, 7- and 8-week-old A-deficient chicks than in controls. Compared to controls, vitamin A-deficient chicks were characterized by thyroid follicle hypertrophy by 4 weeks, heavier thyroids as a percent of body weight at 5 weeks, less serum thyroxine (T4) at 7 weeks and lower serum triiodothyronine (T3) and T4 at 8 weeks. These results indicate that one of the earliest signs of vitamin A deficiency in chicks is hypothyroidism.

Clinicopathologic findings in dogs and cats with ethylene glycol intoxication.

Clinicopathologic findings were retrospectively evaluated in 26 cats and 24 dogs with ethylene glycol intoxication. Common clinical signs were ataxia, depression, vomiting, and hypothermia. Characteristic alterations in the hemogram and serum chemical profile included neutrophilia, lymphopenia, azotemia, hyperphosphatemia, hypocalcemia, hyperglycemia, and decreased whole blood bicarbonate. Common urinalysis findings included isosthenuria, proteinuria, glucosuria, hematuria, calcium oxalate and hippurate crystalluria, and the presence of renal epithelial cells, white blood cells, and granular and cellular casts in the urine sediment. The high death rate (78%) was attributed to delays in presentation, diagnosis, and therapy.

Evaluation of laparoscopy for obtaining renal biopsy specimens from dogs and cats.

Laparoscopic direction of renal biopsy was evaluated in 37 dogs and 1 cat suspected of having renal disease. Specimens adequate for morphologic diagnosis were obtained in 37 cases (97%). Eleven of the 38 animals were necropsied and the biopsy diagnosis was confirmed in 10 of the cases (91%). Excessive pericapsular hemorrhage and severe hematuria developed in 1 dog. Three dogs (8%) had macroscopic hematuria for 24 hours after biopsy.