D.V. Will

Combined multiplanar optical coherence tomography and confocal scanning ophthalmoscopy

We demonstrate the clinical application of a multiplanar imaging system that simultaneously acquires en face (C-scan) optical coherence tomography (OCT) and the corresponding confocal ophthalmoscopic images, along with cross-sectional (B-scan) OCT at specifiable locations on the confocal image. The advantages of the simultaneous OCT and confocal acquisition as well as the challenges of interpreting the C-scan OCT images are discussed. Variations in tissue inclination with respect to the coherence wave surface alter the sampling of structures within the depth of the retina, producing novel slice orientations that are often challenging to interpret. We have evaluated for the first time the utility of C-scan OCT for a variety of pathologies, including melanocytoma, diabetic retinopathy, choroidal neovascular membrane, and macular pucker. Several remarkable new aspects of clinical anatomy were revealed using this new technique. The versatility of selective capture of C-scan OCT images and B-scan OCT images at precise points on the confocal image affords the clinician a more complete and interactive tool for 3-D imaging of retinal pathology.

Native fluorescence and excitation spectroscopic changes in Bacillus subtilis and Staphylococcus aureus bacteria subjected to conditions of starvation

Fluorescence emission and excitation spectra were measured over a 7-day period for Bacillus subtilis (Bs), a spore-forming, and Staphylococcus aureus (Sa), a nonspore-forming bacteria subjected to conditions of starvation. Initially, the Bs fluorescence was predominantly due to the amino acid tryptophan. Later, a fluorescence band with an emission peak at 410 nm and excitation peak at 345 m, from dipicolinic acid, appeared. Dipicolinic acid is produced during spore formation and serves as a spectral signature for detection of spores. The intensity of the 410-nm band continued to increase over the next 3 days. The Sa fluorescence was predominantly from tryptophan and did not change over time. In 6 of the 17 Bs specimens studied, an additional band appeared with a weak emission peak at 460 cm and excitation peaks at 250, 270, and 400 nm. The addition of beta-hydroxybutyric acid to the Bs or the Sa cultures resulted in a two-order of magnitude increase in the 460-nm emission. The addition of Fe2+ quenched the 460 emission, indicating that a source of the 460-nm emission was a siderophore produced by the bacteria. We demonstrate that optical spectroscopy-based instrumentation can detect bacterial spores in real time.

Combined Baerveldt glaucoma implant and scleral buckling surgery for patients with retinal detachment and coexisting glaucoma.

Purpose:To report on the usefulness of combined Baerveldt glaucoma implantation (BGI) and scleral buckling surgery for patients with glaucoma requiring a scleral buckle for retinal detachment repair. Methods:Retrospective, consecutive, noncomparative, and interventional case series of 30 eyes (30 patients) that underwent simultaneous scleral buckle and BGI surgery, using a staged (group 1, n=21 patients) or nonstaged (group 2, n=9 patients) approach to BGI implantation. Successful intraocular pressure (IOP) control was defined as 6 mm Hg⩽IOP⩽18 mm Hg. Results:Although not statistically significant, mean best corrected visual acuity (LogMAR) improved from 2.0 before surgery to 1.7 after surgery (P=0.13) with a mean follow-up of 27.7 months. Of the 21 patients in group 1, only 13 (62%) required second-stage tube insertion at a mean of 7.0±8.0 months (range, 1 to 24 mo) postoperatively. For these eyes combined with group 2 eyes, mean IOP was reduced from 31.1±10.8 to 12.7±6.0 mm Hg (P<0.0001), and the mean number of glaucoma medications was reduced from 2.9±1.4 to 1.2±1.3 (P<0.001). Life table rates of successful IOP control were 90% and 80% at 12 and 24 months, respectively. Conclusions:Combined scleral buckle and BGI is an effective technique for managing coexisting glaucoma and retinal detachment and provides the clinician with a useful surgical option while minimizing surgical risk.

In situ changes in native fluorescence from Bacillus subtilis during endospore formation

Native fluorescence emission and excitation spectra were used to monitor changes in Bacillus subtilis (Bs) and Staphylococcus aureus (Sa) subjected to starvation conditions. Initially, the fluorescence spectra from the Bs and Sa was dominated by tryptophan emission. After the second day, a fluorescence band with an emission peak at 410 nm and an excitation peak at 345 nm appeared in the Bs. This emission is from dipicolinic acid, a major constituent of bacterial endospores. The dipicolinic acid intensity increased steadily during the next 2 to 4 days as the number of Bs forming spores increased. No dipicolinic acid signal was observed in the (non-spore forming) Sa. The addition of β-hydroxybutyric acid to either the Bs or Sa resulted in the emergence of a third band with very strong fluorescence emission maximum at 460 nm and with excitation maxima at 250, 270 and 400 nm. This 460 nm emission was quenched with the addition of Fe2+, indicating that the source of this emission is a siderophore produced by the bacteria.