Basilic vein transposition: what is the optimal technique?

OBJECTIVES: To compare the outcome of the one-stage basilic vein transposition (BVT) fistula with a modified, two-stage technique. DESIGN: Retrospective case-controlled study, performed in an academic centre. MATERIAL: A total of 173 candidates for BVT fistula (87 males, mean age 61 years). METHODS: In one-stage BVT, the basilic vein is mobilised through a single incision, placed inside an anterolateral arm tunnel and anastomosed with the brachial artery. In two-stage procedures, the fistula-arterial anastomosis is created first, followed by the second stage, after fistula maturation several weeks later, when the basilic vein is mobilised through two skip incisions, transected near the anastomosis, placed inside an anterolateral arm tunnel and reanastomosed. Morbidity and fistula maturation rate were the main outcome measures. RESULTS: In one-stage BVT (n=76), the incidence of venous hypertension, wound haematomas and all complications (17%, 13% and 43%, respectively) was significantly higher than in two-stage procedures (n=98) (4%, p=0.004, 3%, p=0.012 and 11%, p<0.001, respectively). Time (68 days) to fistula use was significantly decreased in one-stage BVT than in two-stage procedures (132 days, p<0.001) but failure to mature rate was equivalent (15% vs. 18%, p=0.49). CONCLUSIONS: Our results indicate that the two-stage BVT fistula through two skip-arm incisions is superior to the established one-stage procedure in terms of less morbidity but at the cost of a second operation and longer time to access use. Further research comparing these two techniques is necessary. Until this issue is resolved, an individualised approach is suggested.

The effects of prenatal methylazoxymethanol acetate (MAM) on holeboard exploration and shuttle avoidance performance in rats.

Forty pregnant rats were given an IP injection of either 0, 14, 22, or 30 mg/kg of MAM on day 15 of gestation. One animal of each sex from each litter was tested between 80 and 90 days of age in a holeboard mounted on a stabilimeter. An additional animal of each sex from each litter was tested between 110 and 120 days of age in a two-way shuttle avoidance task. In the holeboard task, prenatal treatment with MAM resulted in an increased frequency of dipping which was accompanied by an increased number of transitions between holes, rather than stereotypy. Altered patterns of exploratory behavior over the course of the test session were also evident in MAM treated offspring as compared to controls. The 22 mg/kg group tended to show less of a decrease in their activity levels over the course of the session than the other groups. In the shuttle avoidance task, prenatal treatment with MAM resulted in a facilitation of avoidance performance as compared to controls. In addition, increased activity (as measured by intertrial interval crossings) was evident in MAM treated offspring, while escape latencies were equivalent across the groups. However, the pattern of results suggest that the facilitated avoidance performance cannot be accounted for by the increased activity. These results are discussed in terms of various hypothesis which may account for the behavioral deficits shown by MAM treated offspring.

Pervasive hyperactivity and long-term learning impairments in rats with induced micrencephaly from prenatal exposure to methylazoxymethanol.

Pregnant Long-Evans rats were given a single i.p. injection of 30 mg/kg of methylazoxymethanol (MAM) acetate or saline on day 14 of gestation (vaginal plug = day 0). All litters were reduced to 8 at birth and were reared by their biological dams. Between 49-192 days of age all offspring were examined on open-field, figure-8 (at two different ages), and hole-board tests of activity, as well as passive avoidance and Biel water maze tests of learning (also at two different ages). The MAM offspring showed no increase in mortality, but weighed less than controls, a difference that remained relatively constant throughout the experiment. At 204-215 days of age the MAM offspring were confirmed to be micrencephalic, a known effect of this drug at this dose and exposure period. On all tests of activity the MAM offspring were markedly hyperactive. The female progeny also exhibited a pronounced impairment of normal activity habituation patterns. The MAM males, however, showed a marked impairment of passive avoidance performance, while the females did not. At 2 months of age the MAM offspring also showed a pronounced deficit in learning a water maze. This maze deficit had not abated when tested again at 6 months of age. The MAM induced brain and behavioral abnormalities provide a potentially useful animal model of congenital micrencephaly and associated mental retardation.

Intellectual deficit associated with transplacentally induced microcephaly in the rat.

Fischer rats injected with methylazoxymethanol late in pregnancy produce young with considerably reduced cerebral hemispheres. They appear normal otherwise. As adults these animals make many more errors in the Hebb-Williams maze than do control animals.