PubMed Health⌕ Search

Biomedical subjects

Scott Larson

Publications and source records attributed to Scott Larson.

7 recordsLinked to original sources
PubMed2007

Collagen shields as a drug delivery system for the fourth-generation fluoroquinolones.

PURPOSE: To evaluate the penetration of commercially available gatifloxacin and moxifloxacin into the anterior chamber of a rabbit eye using collagen shields presoaked in the antibiotics as a drug delivery system. METHODS: Collagen shields, presoaked for 10 min in commercially available solutions of gatifloxacin (diluted intravenous Tequin) or moxifloxacin (Vigamox) with the same concentration, were placed on the surface of each of the corneas of 12 rabbits for a total of 24 eyes (12 in each group). Aqueous humor samples were taken 3 and 6 h later. RESULTS: The concentrations of both antibiotics were high after 3 h (3.1 +/- 1.3 microg/ml for moxifloxacin and 2.3 +/- 0.8 microg/ml for gatifloxacin, p = 0.22). The concentration of gatifloxacin after 6 h was statistically significantly higher than for moxifloxacin (0.76 +/- 0.33 microg/ml vs. 0.29 + 0.14 microg/ml, respectively, p = 0.03). CONCLUSION: Our results suggest that collagen shields can be effective as a drug delivery system for the fourth-generation fluoroquinolones with a longer effect for gatifloxacin.

Animals↗
PubMed2006

A large single-center experience with treatment of patients with crotalid envenomations: outcomes with and evolution of antivenin therapy.

BACKGROUND: Antivenin (crotalid) polyvalent (ACP; Antivenin Crotalidae Polyvalent; Wyeth, Melville, NY) is associated with frequent allergic reactions. Allergic reactions are fewer with ovine Fab antivenin (FabAV). This study describes the management of crotalid envenomations in patients treated with FabAV or ACP, and without antivenin. METHODS: We performed a retrospective chart review of crotalid envenomations over 10 years. Demographic data, hematologic profiles, details of antivenin administration, and in-hospital morbidity and mortality were collected. RESULTS: There were no mortalities and a single amputation. Fewer fasciotomies were performed in the FabAV (9%) group versus the ACP group (24%). Mean hospital stay was 3.4 days. No allergic reactions were associated with FabAV. Fourteen of 211 reactions were associated with ACP (P < .001). Coagulopathy was frequent. CONCLUSIONS: FabAV represents an improvement in management of crotalid envenomations because of reduced allergic reactions. Serious morbidity and mortality is rare. Coagulopathy is frequent but bleeding is not. Limb salvage is high. Surgical debridement and ACP are contraindicated when FabAV is available.

Adolescent↗
PubMed2006

Hydrophilic acrylic intraocular lens as a drug-delivery system: Pilot study.

PURPOSE: To evaluate the ability of a hydrophilic acrylic intraocular lens (IOL) to serve as a drug-delivery system for commercially available gatifloxacin and moxifloxacin. SETTING: David J. Apple, MD, Laboratories for Ophthalmic Devices Research, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. METHODS: Hydrophilic acrylic IOLs (C-flex, Rayner Ltd.), presoaked for 24 hours in commercially available solutions of gatifloxacin (Zymar) or moxifloxacin (Vigamox), were implanted in the capsular bag of 6 rabbits for a total of 12 eyes (6 in each group). Aqueous humor samples were taken 2, 4, and 6 hours after implantation. One rabbit served as a control and had nonpresoaked C-flex IOLs implanted. At the end of the operation, 1 drop of Vigamox was applied to the right eye and 1 drop of Zymar was applied to the left eye of the control rabbit. RESULTS: High concentrations of both antibiotics were found in all the samples of the eyes implanted with the presoaked IOLs. The concentrations of the antibiotics decreased over time, but even the 6-hour sample concentrations were markedly higher than the concentrations found in the control rabbit after 4 hours. CONCLUSION: The results suggest that the Rayner C-flex IOL can be effective as a drug-delivery system for fourth-generation fluoroquinolones.

Acrylic Resins↗
PubMed2006

Hydrophilic acrylic intraocular lens as a drug-delivery system for fourth-generation fluoroquinolones.

PURPOSE: To evaluate the ability and safety of a hydrophilic acrylic intraocular lens (IOL) as a drug-delivery system for commercially available gatifloxacin and moxifloxacin. SETTING: David J. Apple, MD, Laboratories for Ophthalmic Research, John A. Moran Eye Center, Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, USA. METHODS: Thirty rabbits were divided into 2 similar groups. In Group A (15 rabbits, 30 eyes), hydrophilic acrylic IOLs (C-flex, Rayner Intraocular Lenses, Ltd.) presoaked for 24 hours in commercially available solutions of gatifloxacin 3 mg/mL or moxifloxacin 5 mg/mL were implanted after evacuation of the crystalline lens. Group B (15 rabbits, 30 eyes) had topical preoperative and postoperative cataract prophylaxis with gatifloxacin 3 mg/mL or moxifloxacin 5 mg/mL; IOLs that were not presoaked were also implanted after evacuation of the crystalline lenses. In both groups, aqueous humor samples were taken 4, 8, or 12 hours after IOL implantation (5 eyes at each time point) to determine the antibiotic concentrations. Clinical examinations were performed 24 hours postoperatively. RESULTS: The antibiotic concentrations in Group A (presoaked IOLs) were statistically significantly higher than those in Group B (topical) for both antibiotics in all postoperative samples except moxifloxacin at 12 hours. In both groups, there was no statistically significant difference between the concentrations of the 2 antibiotics. No eye showed signs of clinical toxicity. CONCLUSION: Results show the C-flex IOL is a safe and effective drug-delivery system for fourth-generation fluoroquinolones.

Acrylic Resins↗
PubMed2006

Intraocular concentrations of gatifloxacin and moxifloxacin in the anterior chamber via diffusion through the cornea using collagen shields.

PURPOSE: To evaluate the penetration of gatifloxacin and moxifloxacin into the anterior chamber, and any adverse reaction to the cornea, using collagen shields presoaked in oversaturated solutions of the antibiotics. METHODS: Collagen shields, presoaked for 10 minutes in an oversaturated solution of gatifloxacin or moxifloxacin, were placed on the surface of each of the corneas of 15 rabbits for a total of 30 eyes (15 in each group). The antibiotics were prepared by dissolving the powder form of the antibiotics in a solution until no further particulate could be further dissolved. Aqueous humor samples were taken 3.5 and 6 hours later. RESULTS: The initial concentrations of gatifloxacin and moxifloxacin were 5.43 +/- 0.16 mg/mL and 3.14 +/- 0.22 mg/mL, respectively. The average concentration of gatifloxacin in the anterior chamber was higher than that of moxifloxacin at the 3.5-hour sample (6.32 +/- 2.67 microg/mL versus 3.55 +/- 3.5 microg/mL, P = 0.0034). The concentrations of both antibiotics, although decreased, remained relatively high at the 6-hour sample (1.39 +/- 1.13 microg/mL versus 0.816 +/- 0.6 microg/mL at 6 hours, respectively, P = 0.22). No obvious clinical or histologic signs of toxicity were noticed in either group. CONCLUSION: Gatifloxacin and moxifloxacin showed good penetration into the anterior chamber with no obvious adverse reaction to the cornea. The concentrations in the anterior chamber exceeded the minimal inhibitory concentration (MIC) 90 of most organisms responsible for postoperative endophthalmitis (POE).

Animals↗
PubMed2005

Middle-aged children of Alzheimer parents, a pilot study: stable neurocognitive performance at 20-year follow-up.

The objective of this pilot study on a convenience sample of 25 offspring of Alzheimer patients (mean age 61.5 +/- 8.8 years; range, 50-82) was the early detection of neurocognitive decline. This preliminary report appears to be the first one dealing with 20-year follow-up of neurocognitive data of Alzheimer's disease (AD) children. Digit symbol (Wechsler Adult Intelligence Scale) was the only of 11 neurocognitive measures with a significant decline. And that decline between first and last testing (mean = 19.98 +/- 0.30 years) was on raw scores, not scaled scores. Neither parents' age at onset of AD nor autopsy confirmation or offspring APOE-e4 status influenced neurocognitive results. More robust data than currently available are needed to confirm the findings of this first pilot study and to determine both the trajectory of neurocognitive decline in AD and the risks of developing AD faced by children whose parent had the disease.

Aged↗