Experimental ileal J-pouch construction

Abstract

Endorectal ileal pouch-anal anastomosis has become the surgical alternative of choice for patients requiring colectomy for ulcerative colitis or familial polyposis coli. The optimal method of ileal pouch construction has not been determined. In this study, a canine preparation was used to compare the immediate results of three different techniques of ileal J-pouch construction. The three methods studied were two-layer hand-suturing (HS), stapling through enterotomies placed laterally on the ileal limbs (LS), and stapling via an apically placed enterotomy (AS). All three techniques resulted in watertight reservoirs. Ease of construction was scored significantly differently among the pouch variations (AS greater than LS greater than HS). Construction time was significantly less for both of the stapled reservoirs than for the HS pouch. Capacity of the AS pouch was significantly greater than the HS reservoir. This study suggests that stapling the ileal J-pouch through a single apical enterotomy should be the preferred technique during colectomy, mucosal proctectomy, and ileal pouch-anal anastomosis.

Synthesis of a cyclic monomer of perdeuterated poly(ethylmethylsiloxane)

“…The following reaction of protonated/deuterated dichloroethylmethylsilane with zinc oxide [10][11][12] resulted in a mixture of cyclic protonated/deuterated (mainly EM3 and 2,4,6,8-tetraethyl-2, 4,6,8-tetramethylcyclotetrasiloxane) and oligomeric protonated/deuterated ethylmethylsiloxanes [reaction step (8)]. The zinc ions were precipitated with sodium carbonate to avoid polymerization during the following fractional distillation under reduced pressure, isolating the cyclotrisiloxane.…”

“…EM3 can be prepared by the condensation reaction of commercially available protonated dichloroethylmethylsilane with zinc oxide. This method has already been applied to symmetrically substituted dichlorodialkylsilanes [10], to dichlorodiphenylsilane [ 11 ], and to dichloromethylphenylsilane [ 12]. To our knowledge, no synthetic pathway of 2,4,6-tri(pentadeuteroethyl)-2,4,6-tri(trideuteromethyl)cyclotrisiloxane (hereafter called EMrd24) starting from perdeuterated ethanol and methanol exists in the literature.…”

Synthesis of poly(methylphenylsiloxane) rich in syndiotacticity by Rh-catalysed stereoselective cross-dehydrocoupling polymerization of optically active 1,3-dimethyl-1,3-diphenyldisiloxane derivatives

“…It was reported that the ring-opening polymerization of cis-D Ph 3 gave stereoregular poly(methylphenylsiloxane) (PMPS), which exhibited a small degree of crystallinity and slight dependence of T g on tacticity. 4,5 However, assignment of the triad signals of PMPS in 1 H NMR is not unambiguously established. Ballauff and co-workers 4 Bresler et al 9 and Llorente et al 13 suggested that the peak of syndiotactic triad should appear at higher ®eld than that of isotactic triad (I = 0.19, H = 0.14, S = 0.09 ppm), whereas a contra- dictory assignment was suggested by Baratova et al 7,8 (S = 0.13, H = 0.08, I = 0.03 ppm).…”

“…Apparently, the effect of the stereoregularity on T g was not signi®cant, in contrast to the case of PMPS rich in isotacticity. 4,5 However, because T g also depends on the molecular weight together with the tacticity of the polymers, no concrete conclusion can be drawn. In addition, it seems necessary to prepare pure syndiotactic PMPS with high molecular weight to conclude studies on the effect of stereoregularity on the physical properties.…”