The successful use of vancomycin-impregnated cement beads in a patient with vancomycin systemic toxicity: a case report with review of literature.

We report the use of vancomycin laden antibiotic cement beads in a patient with calcaneal osteomyelitis who had prior acute kidney injury (AKI). The patient experienced non-oliguric renal failure after exposure to intravenous vancomycin and recovered well after antibiotic discontinuation and adequate hydration. We are not aware of any similar case report where vancomycin laden antibiotic cement has been used in a patient with AKI to vancomycin.

Resolution of multiple green fluorescent protein color variants and dyes using two-photon microscopy and imaging spectroscopy.

The imaging of living cells and tissues using laser-scanning microscopy is offering dramatic insights into the spatial and temporal controls of biological processes. The availability of genetically encoded labels such as green fluorescent protein (GFP) offers unique opportunities by which to trace cell movements, cell signaling or gene expression dynamically in developing embryos. Two-photon laser scanning microscopy (TPLSM) is ideally suited to imaging cells in vivo due to its deeper tissue penetration and reduced phototoxicity; however, in TPLSM the excitation and emission spectra of GFP and its color variants [e.g., CyanFP (CFP); yellowFP (YFP)] are insufficiently distinct to be uniquely imaged by conventional means. To surmount such difficulties, we have combined the technologies of TPLSM and imaging spectroscopy to unambiguously identify CFP, GFP, YFP, and redFP (RFP) as well as conventional dyes, and have tested the approach in cell lines. In our approach, a liquid crystal tunable filter was used to collect the emission spectrum of each pixel within the TPLSM image. Based on the fluorescent emission spectra, supervised classification and linear unmixing analysis algorithms were used to identify the nature and relative amounts of the fluorescent proteins expressed in the cells. In a most extreme case, we have used the approach to separate GFP and fluorescein, separated by only 7 nm, and appear somewhat indistinguishable by conventional techniques. This approach offers the needed ability to concurrently image multiple colored, spectrally overlapping marker proteins within living cells.

Ablation spectra of the human cornea.

Ablation of human corneal tissue with 193 nm excimer laser energy generates fluorescence in the near ultraviolet and visible regions of the spectrum. The fluorescence spectra from five human corneas were collected during ablation in vitro. We find that the fluorescence spectrum changes continuously as the cornea is ablated from the epithelial surface towards the endothelium. We reduced the dimensionality of the large data set resulting from each cornea by a principal components analysis. The three most significant principal component eigenvectors suffice to describe the observed spectral evolution, and independent analysis of each tissue sample produces a similar set of eigenvectors. The evolution of the calculated eigenvector weighting factors during ablation then corresponds to the observed spectral evolution. In fact, this evolution is qualitatively consistent between corneas. We suggest that this spectral evolution offers promise as a real-time surgical feedback tool.

Consequences of scattering for spectral imaging of turbid biologic tissue.

Spectral imaging permits two-dimensional mapping of the backscattering properties of biological systems. Such mapping requires broadband illumination of the entire area of interest. However, imaging of turbid biological media under these conditions often involves mean photon path lengths that exceed the pixel size. Using a numerical Monte Carlo model, we have studied the effects of photon scattering in a hemoglobin-bearing model system. We find that photon migration and the resulting wavelength-dependent optical coupling between pixels can complicate the analysis of imaging spectroscopy data. In fact, the wavelength dependence of photon trajectories also alters the distribution of photon exit angles at the tissue surface. We therefore find that the finite optical field of view of an imaging spectrometer can affect the measured spectra in the absence of chromatic aberrations.

Unlimited opportunities for environmental interventions with inner-city asthmatics.

The purpose of this study was to identify the asthmatics living in the Lower West Side (LWS) of Buffalo, New York, and then explore the relationship between urban asthmatic and nonasthmatic exposures to many common household aeroallergens. Eight hundred twenty-eight households were visited and 167 asthmatics and 161 nonasthmatics were identified for comparison. Specific self-reported household exposure prevalences were identified for environmental tobacco smoke, sources of molds, household pets, rats, cockroaches, and sources of dust. Sources of molds, pets, and cockroaches were more likely to be found in the homes of asthmatics compared to nonasthmatics (p < 0.05). Other aeroallergens studied, although highly prevalent, were not more likely to be found in either asthmatic or nonasthmatic homes.

Thermal detection of cellular infiltrates in living atherosclerotic plaques: possible implications for plaque rupture and thrombosis.

BACKGROUND: Atherosclerotic lesions are heterogeneous and prognosis cannot easily be predicted, even with intracoronary ultrasound and angioscopy. Serial angiographic and necropsy studies suggest that the risk of plaque rupture correlates only weakly with the degree of stenosis. Most ruptured plaques are characterised by a large pool of cholesterol or necrotic debris and a thin fibrous cap with a dense infiltration of macrophages. The release of matrix-digesting enzymes by these cells is thought to contribute to plaque rupture. Other thromboses are found on non-ruptured but inflamed plaque surfaces. We postulated that both types of thrombotic events may be predicted by heat released by activated macrophages either on the plaque surface or under a thin cap. METHODS: To test the hypothesis, we measured the intimal surface temperatures at 20 sites in each of 50 samples of carotid artery taken at endarterectomy from 48 patients. The living samples were probed with a thermistor (24-gauge needle-tip; accuracy 0.1 degree C; time contrast 0.15 s). The tissues were then fixed and stained. FINDINGS: Plaques showed several regions in which the surface temperatures varied reproducibly by 0.2-0.3 degrees C, but 37% of plaques had substantially warmer regions (0.4-2.2 degrees C). Points with substantially different temperatures could not be distinguished from one another by the naked eye; such points could also be very close to one another (< 1 mm apart). Temperature correlated positively with cell density (r = 0.68, p = 0.0001) and inversely with the distance of the cell clusters from the luminal surface (r = -0.38, p = 0.0006). Most cells were macrophages. Infrared thermographic images also revealed heterogeneity in temperature among the plaques. INTERPRETATION: Living atherosclerotic plaques show thermal heterogeneity, which raises the possibility that an infrared catheter or other techniques that can localise heat or metabolic activity might be able to identify plaques at high risk of rupture or thrombosis.

High-speed spectral imager for imaging transient fluorescence phenomena.

We describe fluorescence spectral imaging results with the microscope computed-tomography imaging spectrometer (muCTIS). This imaging spectrometer is capable of recording spatial and spectral data simultaneously. Consequently, muCTIS can be used to image dynamic phenomena. The results presented consist of proof-of-concept imaging results with static targets composed of 6-mum fluorescing microspheres. Image data were collected with integration times of 16 ms, comparable with video-frame-rate integration times. Conversion of raw data acquired by the muCTIS to spatial and spectral data requires postprocessing. The emission spectra were sampled at 10-nm intervals between 420 and 710 nm. The smallest spatial sampling interval presented is 1.7 mum.