The effect of chewing sugar-free gum on plaque regrowth at smooth and occlusal surfaces.

BACKGROUND AND AIM: Chewing gum has the potential to provide oral health benefits including plaque control. The aim of this study was to determine the effects of chewing sugar free gum on plaque regrowth at buccal, lingual and occlusal surfaces of teeth. METHOD AND MATERIALS: 11 healthy and dentally-fit dental hygiene students participated in this randomised, single-blind crossover 4-day plaque regrowth study. From a zero plaque score on day 1, subjects suspended oral hygiene measures and either chewed gum or did not chew gum over 4 days. Gum chewing was one piece chewed for 30 min 4 x per day. On day 4, subjects were scored for plaque after disclosing from buccal, lingual and unrestored occlusal surfaces. RESULTS: There was no significant difference in smooth surface plaque scores between the treatments but significantly less plaque accumulated (44%) at occlusal surfaces during gum chewing compared to no gum chewing. CONCLUSION: Chewing gum can reduce plaque accumulation at sites of predilection for caries but has little or no effect at sites of predilection for gingivitis.

Phase 1 trial of transforming growth factor beta 2 in chronic progressive MS.

Transforming growth factor (TGF)-beta2 is a pleiotropic cytokine associated with remissions in multiple sclerosis (MS) and amelioration of allergic encephalomyelitis. We assessed the safety of TGF-beta2 in an open-label trial of 11 patients with secondary progressive (SP) MS. Five patients had a reversible decline in the glomerular filtration rate. There was no change in expanded disability status scale or MRI lesions during treatment. Systemic TGF-beta2 may be associated with reversible nephrotoxicity, and further investigation of its therapeutic potential in MS should be performed with caution.

Reoperation after failed macular hole surgery.

PURPOSE: The authors determined the anatomic and visual success rates of vitrectomy in patients who have failed previous macular hole surgery. METHODS: Standardized Early Treatment Diabetic Retinopathy Study (ETDRS)-style best-corrected visual acuity was measured in each patient pre- and postoperatively. Surgery was performed at two centers using a standardized protocol, as previously reported, using 1330 ng bovine-derived transforming growth factor-beta 2 (TGF-beta 2) and 16% perfluoropropane internal gas tamponade. Endpoint analyses were conducted for anatomic closure of the hole, visual improvement of three or more ETDRS lines, and final visual acuity of > or = 20/63 and > or = 20/40. RESULTS: Forty-eight failing macular hole surgery were reoperated. The anatomic results showed closure of the hole in 40 (83%) cases at the end of the mean follow-up interval of 7.4 months. The visual acuity improved in greater than or equal to three lines in 52%, was > or = 20/63 in 54%, and was > or = 20/40 in 25% of reoperated eyes. The only factor associated with a better final visual acuity was preoperative visual acuity better than 20/80. Nuclear sclerosis leading to cataract extraction was observed in 13 (30%) of 43 initially phakic eyes. CONCLUSIONS: Macular hole closure was induced in this subset of reoperated patients. Visual improvement occurred often, although in a lower percentage than has been reported for primary surgical eyes. Repeat vitrectomy should be considered in patients with persistent macular hole after failure of primary surgery.

Distribution of iatrogenic retinal breaks in macular hole surgery.

BACKGROUND: Intraoperative peripheral iatrogenic retinal breaks can be a serious complication of vitreous surgery. This study was undertaken to determine whether vitreous surgical techniques used for macular hole surgery were associated with a different incidence or distribution of retinal breaks. METHODS: The authors prospectively evaluated a series of 181 consecutive eyes undergoing macular hole surgery. Contemporaneous reporting of intraoperative and postoperative retinal breaks and postoperative retinal detachments was performed. Comparison was made to historic controls of two case series of patients undergoing vitreous surgery for other indications. RESULTS: Of 181 eyes, 10 (5.5%) had 15 intraoperative retinal breaks. Of the 15 breaks, 3 (20%) were in the quadrant near the surgeon's right-hand sclerotomy, 9 (60%) were in the two inferior quadrants, and 11 (73%) were in the two temporal quadrants. By comparison to previously reported case series, tears in our series were less likely to be near the right-hand sclerotomy (P = 0.00055) and more likely to occur in the two inferior retinal quadrants (P = 0.00015) and two temporal retinal quadrants (P = 0.0042). Two patients (1.1%) of 181 had postoperative retinal detachments. CONCLUSIONS: Patients undergoing vitreous surgery for macular hole have a similar incidence but different location of iatrogenic retinal breaks when compared with patients undergoing pars plana vitrectomy for other indications. These breaks are not distributed near sclerotomy sites and tend to be in the inferior and temporal retina. This establishes the need for greater intraoperative surveillance in these areas.

Safety and effect of transforming growth factor-beta(2) for treatment of venous stasis ulcers.

Transforming growth factor-beta(2) promotes healing in a variety of animal models and exhibits clinical effects thought to be mediated by connective tissue formation. Two clinical trials were conducted to evaluate the safety and effect of transforming growth factor-beta(2) purified from bovine bone and delivered topically to venous stasis ulcers three times per week for up to 6 weeks by means of a lyophilized collagen vehicle. The first was an open-label trial comparing transforming growth factor-beta(2) purified from bovine bone (0.5 microg/cm(2)) with a placebo consisting of lyophilized collagen vehicle-without active drug. After no safety issues arose in that trial, a prospectively randomized, closed-label, observer-blinded, three-armed trial was conducted to compare bovine transforming growth factor-beta(2) (2.5 microg/cm(2)) with the collagen matrix placebo vehicle and with a standard dressing. Standardized elastic compression was applied to all test extremities. The rate of reduction of ulcer area as measured by planimetry was the primary measure of effect. No serious safety-related events occurred in either trial. Clinical evaluation suggested that improvement in the quality and quantity of granulation tissue appeared to precede epithelialization of ulcers treated with bovine transforming growth factor-beta(2). In both studies, treatment with bovine transforming growth factor-beta(2) appeared to have a positive effect on the rate of ulcer closure, whereas ulcers in the control groups continued to exhibit impaired healing. In the open-label study, the mean rate of closure of ulcers treated with bovine transforming growth factor-beta(2) was significantly greater than that of ulcers treated with placebo. There was likewise enhanced reduction in ulcer area in the ulcers treated with bovine transforming growth factor-beta(2) in the second trial. However, because of a higher variability in patient response and a greater placebo effect, the difference was not significant. The placebo was not worse than the standard care arm, thereby showing that the vehicle is not injurious to healing. The combined results of the two trials suggest that, at doses of 0.5 to 2.5 microg/cm(2), bovine transforming growth factor-beta(2) is safe as a topically applied agent in a collagen matrix vehicle and can have a positive effect on closure of venous stasis ulcers. Large multicenter trials appear to be indicated to evaluate fully the potential utility of transforming growth factor-beta(2) in accelerating closure of chronic dermal ulcers.

Effects of intraocular bubble duration in the treatment of macular holes by vitrectomy and transforming growth factor-beta 2.

PURPOSE: To compare the effect of a long-acting (16% perfluoropropane [C3F8]) versus a short-acting (air) intraocular gas tamponade on visual outcome and macular hole closure rate after vitrectomy and intravitreal instillation of transforming growth factor-beta 2 (TGF-beta 2) on the macula. METHODS: Vitrectomy with removal of the posterior hyaloid fluid-gas exchange with instillation of TGF-beta 2 was performed in 15 eyes treated with air and 37 eyes treated with 16% C3F8 using identical surgical techniques (mean follow-up, 5.6 months). RESULTS: The macular hole was closed successfully in 36 (97%) of 37 eyes treated with 16% C3F8 and in 8 (53.3%) of 15 eyes treated with air (P = 0.00007). The visual acuity improved by a mean of 3.1 lines on the Early Treatment of Diabetic Retinopathy Study chart for eyes treated with 16% C3F8 and 1.3 lines for eyes treated with air (P = 0.003). CONCLUSIONS: A longer duration intraocular gas tamponade from 16% C3F8 gives a much higher rate of successful closure of macular holes and improved visual acuity using vitrectomy and TGF-beta 2 than does air.

The effect of pars plana vitrectomy and transforming growth factor-beta 2 without epiretinal membrane peeling on full-thickness macular holes.

PURPOSE: Surgical techniques for the treatment of macular holes generally include removal of the overlying cortical vitreous and/or epiretinal membranes. The authors demonstrate that by using vitrectomy, posterior hyaloid removal, fluid-gas exchange, and transforming growth factor-beta 2 (TGF-beta 2), a growth factor that modulates the wound healing process, epiretinal membrane peeling can be avoided and the surgical procedure thereby simplified without compromising results. METHODS: A total of 24 eyes of 24 patients with stage 2, 3, or 4 full-thickness macular holes were treated. Of 24 patients, 1 was lost to follow-up after suffering a stroke; the remaining 23 (17 females and 6 males) (age range, 11-81 years; mean, 64 years) were followed for 5 to 16 months (mean, 12 months). Preoperative best-corrected visual acuity ranged from 20/50 to 20/400 (mean, 20/125). A standardized vitrectomy was performed with posterior hyaloid removal and, after a near-complete fluid-air exchange, 0.1 ml of a solution containing 1330 ng of TGF-beta 2 was instilled over the macular hole. No attempts were made to peel epiretinal membranes or drain fluid from the macular hole. RESULTS: Of 23 eyes, 22 (96%) had resolution of the surrounding subretinal fluid and flattening of the macular hole (1 patient required a second procedure, in which visual improvement of 20/30 was achieved); 11 (48%) had visual acuities of 20/40 or better, 19 (85%) had visual acuities of 20/60 or better, and 19 (85%) showed an improvement in visual acuity of at least two lines (mean, 3.8 lines). The authors saw no retinal pigment epithelial mottling. CONCLUSION: The authors' results demonstrate that treatment of macular holes using vitrectomy, fluid-gas exchange, and the instillation of a solution containing TGF-beta 2, without epiretinal membrane peeling, maintains efficacy while simplifying surgery.

Transforming growth factor-beta 2 significantly enhances the ability to flatten the rim of subretinal fluid surrounding macular holes. Preliminary anatomic results of a multicenter prospective randomized study.

Previous studies of treatment of full-thickness macular holes have effected resolution of the surrounding subretinal fluid cuff in 58%-71% of cases. An initial report has found 330 ng and 1,330 ng transforming growth factor-beta 2 to be successful in effecting resolution of the surrounding subretinal fluid cuff in 100% of cases. A randomized, masked, controlled, prospective, multicenter study of 90 patients with full-thickness macular holes was performed to assess the efficacy of the local application of TGF-beta 2 at the time of vitrectomy surgery. Eligibility criteria included: (1) best corrected visual acuity of 20/80 or worse; (2) duration of macular hole for less than 1 year; and (3) absence of other ocular disorders that might interfere with vision. Patients were evenly randomized to receive placebo, 660 ng transforming growth factor-beta 2, or 1,330 ng transforming growth factor-beta 2. The treatment assignment was unmasked at the examination 3 months after treatment only if the macular hole failed to close. If the initial treatment had been placebo, patients were offered crossover to 1,330 ng transforming growth factor-beta 2 during a reoperation. It can be deduced that resolution of the subretinal fluid cuff occurred in 16 of 30 placebo-treated eyes, 53 of 58 eyes treated with transforming growth factor-beta 2, and in 9 of 13 cases (69%) initially treated with placebo that subsequently underwent repeat surgery under the crossover option.(ABSTRACT TRUNCATED AT 250 WORDS)

A rapid method for the extraction and purification of DNA from human leukocytes.

A rapid method for the extraction and purification of DNA from human leukocytes was developed. Crude nucleic acids were obtained by sodium dodecylsulfate (SDS) lysis and potassium acetate precipitation of other cellular material, and the DNA was purified by ribonuclease digestion, diethylaminoethyl (DEAE) cellulose chromatography and ethanol precipitation. DNA obtained by this method is biologically active as reflected by its ability to act as substrate for various nucleases and T4 DNA ligase. The yield was sufficiently high that DNA from less than 1 ml of blood could be used for a number of reactions.

Clastogenic activity of caffeic acid and its relationship to hydrogen peroxide generated during autooxidation.

Caffeic acid is a clastogenic cinnamic acid found in a conjugated form in a variety of foods. The possibility that the biological activity of caffeic acid is due to hydrogen peroxide generated during its autooxidation in solution was investigated using chromosome aberrations in Chinese hamster ovary cells as a test system. Freshly prepared caffeic acid at pH 7.00 contained only traces of hydrogen peroxide, as assayed by the molybdate-catalyzed release of I-3. Such solutions exhibited clastogenic activity which could not be accounted for by the level of hydrogen peroxide present, and which was not significantly diminished by the addition of catalase or horseradish peroxidase. 3-day-old solutions of caffeic acid exhibited higher levels of hydrogen peroxide, and increased biological activity. In such solutions, the clastogenic activity was catalase-sensitive and could be entirely accounted for by the level of hydrogen peroxide present.