A series of plasmids were constructed to generate RNA complementary to the beta-galactosidase messenger RNA under control of the phage lambda PL promoter. These plasmids generate anti-lacZ mRNA bearing or lacking a synthetic ribosome binding site adjacent to the lambda PL promoter and/or the lacZ ribosome binding site in reverse orientation. Fragments of lacZ DNA from the 5' and/or the 3' region were used in these constructions. When these anti-mRNA molecules were produced in Escherichia coli 294, maximal inhibition of beta-galactosidase synthesis occurred when a functional ribosome binding site was present near the 5' end of the anti-mRNA and the anti-mRNA synthesized was complementary to the 5' region of the mRNA corresponding to the lacZ ribosome binding site and/or the 5'-coding sequence. Anti-mRNAs producing maximal inhibition of beta-galactosidase synthesis exhibited an anti-lacZ mRNA:normal lacZ mRNA ratio of 100:1 or higher. Those showing lower levels of inhibition exhibited much lower anti-lacZ mRNA:normal lacZ mRNA ratios. A functional ribosome binding site at the 5'-end was found to decrease the decay rate of the anti-lacZ mRNAs. In addition, the incorporation of a transcription terminator just downstream of the antisense segment provided for more efficient inhibition of lacZ mRNA translation due to synthesis of smaller and more abundant anti-lacZ mRNAs. The optimal constructions produced undetectable levels of beta-galactosidase synthesis.

Binding Sites↗

PubMedDate not supplied

Comparison of scleral buckling and vitrectomy for retinal detachment resulting from flap tears in superior quadrants.

PURPOSE: To compare the surgical results of vitrectomy and scleral buckling for uncomplicated superior retinal detachment caused by flap tears. METHODS: Included in the study were 225 patients (225 phakic eyes) undergoing primary surgery by three surgeons between January 1990 and December 1996 for superior retinal detachment caused by flap tears (138 eyes by scleral buckling, 87 eyes by vitrectomy); all patients had been followed up for longer than 6 months after surgery. The choice of one of the two procedures was based on each surgeon's preference. The surgical outcome and the rate of complications were retrospectively compared between the two groups of eyes. RESULTS: Initial and final anatomical success rate were 92% and 100% after each procedure. Retinal redetachment after the initial procedure was due to new retinal breaks in 5 eyes, reopening of original breaks in 2 eyes of vitrectomy cases, and due to malpositioned buckle in 11 eyes of scleral buckling cases. Proliferative vitreoretinopathy occurred in 3 eyes of vitrectomy cases. CONCLUSION: Primary vitrectomy was as successful as scleral buckling for treating superior rhegmatogenous retinal detachment. Even though the high incidence of postoperative cataract formation was the major drawback, vitrectomy had some advantages over scleral buckling.

Adult↗

PubMedDate not supplied

The management of retinal detachments associated with choroidal colobomas by vitrectomy with cyanoacrylate retinopexy.

The techniques used and the outcome in eyes treated for retinal detachment associated with choroidal coloboma are described. We reviewed the medical reports on five eyes of five patients with retinal detachment associated with choroidal coloboma who underwent vitrectomy. Retinal breaks were identified at the margin of or within the coloboma and the retina was successfully reattached by vitrectomy and cyanoacrylate retinopexy in four of the five eyes. The remaining one eye, with no visible retinal break both before and during surgery, also underwent cyanoacrylate retinopexy at regions suspected of retinal break, and was successfully reattached. In four eyes (80%) the vision showed improvement and had a visual acuity of 20/100 or better after surgery. None of the eyes required silicone oil tamponade or endophotocoagulation around the disc or at the papillomacular bundle. For the management of retinal detachment associated with choroidal coloboma, cyanoacrylate retinopexy is the method of choice, providing adequate chorioretinal adhesion and satisfactory visual outcome.

Adolescent↗