Placement of ureteral stents in three rabbits for the treatment of obstructive ureterolithiasis.

Management of ureteral obstruction with stenting is often associated with a lower rate of complications than ureterotomy in domestic carnivores, but this treatment has not been previously evaluated in rabbits. Three rabbits (7, 6 and 10 years old) were diagnosed with unilateral obstructive ureterolithiasis associated with hydronephrosis and hydroureter on abdominal ultrasound. Decreased overall renal function was confirmed in all three cases. Ureteral stents were placed retrogradely via cystotomy without complication in two cases and anterogradely via nephrostomy in the third case. Survival after stent placement was 30, 3 and 8 months, with encrustation of the stent and re-obstruction occurring 18, 1 and 6 months after stent placement in successive cases. Ureteral stenting can be considered for short-term management of ureterolithiasis in rabbits to improve renal function and maintain quality of life. Ultrasound or radiographic monitoring is recommended to detect encrustation of the stent. Studies comparing ureteral stenting to ureterotomy in rabbits are needed to determine the effectiveness of these techniques.

Analysis of air contrast barium enema, computed tomographic colonography, and colonoscopy: prospective comparison.

BACKGROUND: The usefulness of currently available colon imaging tests, including air contrast barium enema (ACBE), computed tomographic colonography (CTC), and colonoscopy, to detect colon polyps and cancers is uncertain. We aimed to assess the sensitivity of these three imaging tests. METHODS: Patients with faecal occult blood, haematochezia, iron-deficiency anaemia, or a family history of colon cancer underwent three separate colon-imaging studies--ACBE, followed 7-14 days later by CTC and colonoscopy on the same day. The primary outcome was detection of colonic polyps and cancers. Outcomes were assessed by building an aggregate view of the colon, taking into account results of all three tests. FINDINGS: 614 patients completed all three imaging tests. When analysed on a per-patient basis, for lesions 10 mm or larger in size (n=63), the sensitivity of ACBE was 48% (95% CI 35-61), CTC 59% (46-71, p=0.1083 for CTC vs ACBE), and colonoscopy 98% (91-100, p<0.0001 for colonoscopy vs CTC). For lesions 6-9 mm in size (n=116), sensitivity was 35% for ACBE (27-45), 51% for CTC (41-60, p=0.0080 for CTC vs ACBE), and 99% for colonoscopy (95-100, p<0.0001 for colonoscopy vs CTC). For lesions of 10 mm or larger in size, the specificity was greater for colonoscopy (0.996) than for either ACBE (0.90) or CTC (0.96) and declined for ACBE and CTC when smaller lesions were considered. INTERPRETATION: Colonoscopy was more sensitive than other tests, as currently undertaken, for detection of colonic polyps and cancers. These data have important implications for diagnostic use of colon imaging tests.

Different mechanisms of uptake of stearic acid and cholesterol into rabbit jejunal brush border membrane vesicles.

The rate of uptake of stearic acid and cholesterol solubilized in taurocholic acid (TC) was examined in rabbit jejunal brush border membrane vesicles (BBMV). For stearic acid (18:0) or cholesterol there was an initial rapid rate of uptake, which reached a plateau within approximately 1 min and remained stable thereafter. At low concentrations of 18:0 and 20 mM, but not 2 mM, TC, there was a curvilinear relationship between the concentration of 18:0 and uptake, whereas the relationship between cholesterol uptake and concentration was linear over a wide range of values. When the concentration of TC was held constant at increasing concentrations of 18:0 or cholesterol, there was a linear increase in the rate of uptake. When the concentration of 18:0 or cholesterol was held constant and the concentration of TC was increased from 2 to 20 mM, the uptake of 18:0 declined, but the rate of uptake of cholesterol increased. When the concentrations of 18:0 plus TC, or cholesterol plus TC, were both increased in unison and their ratio was held constant, their rate of uptake increased. Thus, (i) BBMV may be used to assess the rate of uptake of lipids; (ii) the partitioning of cholesterol from bile acid micelles into the BBMV appears to be by way of "collision" of the cholesterol with the membrane. In contrast, the uptake of 18:0 from the micelle into the membrane vesicles may be by both the collision and the aqueous/dissociation models; and (iii) 18:0 uptake may be mediated by both a concentration-dependent and a concentration-independent component.(ABSTRACT TRUNCATED AT 250 WORDS)

Characterization of lipid intake into rabbit jejunal brush border membrane vesicles.

The absorption of lipids is generally accepted to be mediated by a process of passive diffusion, although some recent data have raised the possibility of a mediated component. Brush border membrane vesicles (BBMV) have been widely used to study nutrient transport, but have only recently been used to examine the uptake of lipids. Using a BBMV technique validated with studies of the uptake of D-glucose, we examined the uptake of linoleic acid into the jejunum of adult rabbits. The uptake of 100 microM linoleic acid was constant between 2 and 20 min, with no overshoot observed at earlier periods. Linoleic acid uptake was suppressed by 88% with 0.6 mM phloridzin and by 58% with 0.2 mM phloretin, but uptake of linoleic acid was unaffected by the absence of sodium, by the presence of a sodium gradient, or by varying the osmolarity of the buffer. Lysis of the BBMV incubated with linoleic acid by the addition of ice-cold deionized water did not alter the amount of linoleic acid associated with the BBMV. The linoleic acid concentration curve was linear up to 160 microM, when carried out under initial rate conditions and in the presence of 2 mM taurocholic acid. These results are compatible with the process of passive uptake of linoleic acid into BBMV of rabbit jejunum, but do not exclude the possible physiological importance of a membrane fatty acid binding protein.

Immunophenotype of lymphoid cells in positive patch tests of allergic contact dermatitis.

The immune phenotype of the infiltrating cells in 13 positive patch tests from 8 cases of contact dermatitis and 1 case of poison ivy was studied. An indirect immunoperoxidase technique was used in conjunction with monoclonal antibodies directed against mature T cells (Leu-1, T11), helper T cells (Leu-3A), suppressor/cytotoxic T cells (Leu-2A), killer and natural killer cells (HNK 1), B cells (B1), Langerhans cells (HLA-DR), and the common acute lymphoblastic leukemia antigen (CALLA), (J5). The majority of infiltrating mononuclear cells were Leu-1+, T11+, Leu-3A+, Leu-2A-, HLA-DR+, T9-, T10-, HNK-, B1-, J5-. Occasional T6+ cells were observed in the epidermis (including spongiotic microvesicles) and also isolated in the dermis and within the dermal mononuclear infiltrates. The phenotype was compared with cutaneous T-cell lymphoma, a disease in which contact allergy and antigenic persistence may play a role.

Self-selection and the obese Zucker rat: the effect of dietary fat dilution.

Adult female lean and obese Zucker rats were allowed to compose their own diets by giving them access to three macronutrient sources. After a baseline period, the fat source was serially diluted. In all, eight concentrations of fat were used. Dilution of the fat source promoted significant increases in the intake of fat by both lean and obese rats. The increased intake of fat was not simply compensatory in nature, but rather represented significant increases in fat consumption. These results suggest that the reported increased appetite for fat of the obese rat is not a unique trait of that genotype. Further, results from this experiment demonstrate that caloric and protein regulation mechanisms may not be controlling the intake of obese and lean rats as precisely as once believed.