Laryngeal office-based procedures: A safe approach

PURPOSE

Laryngeal surgeries using a flexible nasopharyngoscope equipped with an operative channel has gained popularity, with gradual increase in the variety of interventional office-based procedures, under local anesthesia. The purpose of this study is to analyze the tolerance of such procedures.

MATERIALS AND METHODS

Retrospective cohort study. 337 cases were performed during 2 years. We collected the following data: type of pathology, type of procedure and modalities of anesthesia, adverse events.

RESULTS

19 % of the visits were for the purpose of Biopsy, 65 % for an injection, and Trublue Laser was utilized in 12 % of the procedures. Regarding the pathologies, 27 % were vocal fold paralysis, 18 % leukoplakia or another suspicious lesion, 15 % recurrent respiratory papillomatosis, 13 % neuromuscular disorder, 9 % vocal fold scarring, 7 % vocal cord atrophy and 6 % had an inflammatory presentation. Side effects were documented in 26 visits (7.7 %) and were minor in almost all the encounters: they included strong reflexive cough, deep throat pain, discomfort, gag reflex, anxiety, vagal discomfort, malaise, hypersalivation, nose pain, labile hypertension. More severe side effects were very rare and included septal wound and epistaxis, erythematous rash, dyspnea, and transient dysarthria. 13 procedures were either aborted, or canceled at initial steps, due to inability of the patient to tolerate the procedure and were rescheduled for general anesthesia. 97 % of the cases were released home after 1 h of surveillance.

CONCLUSION

Office-based flexible interventional laryngoscopy under local anesthesia is a safe and well-tolerated procedure, with abundance of various interventions feasible on ambulatory, office-based setup.

Room temperature direct band gap emission characteristics of surfactant mediated grown compressively strained Ge films

Compressively strained Ge films have been grown on relaxed Si_0.45Ge_0.55 virtual substrates using molecular beam epitaxy in the presence of Sb as a surfactant. Structural characterization has shown that films grown in the presence of surfactant exhibit very smooth surfaces with a relatively higher strain value in comparison to those grown without any surfactant. The variation of strain with increasing Ge layer thickness was analyzed using Raman spectroscopy. The strain is found to be reduced with increasing film thickness due to the onset of island nucleation following Stranski-Krastanov growth mechanism. No phonon assisted direct band gap photoluminescence from compressively strained Ge films grown on relaxed Si_0.45Ge_0.55 has been achieved up to room temperature. Excitation power and temperature dependent photoluminescence have been studied in details to investigate the origin of different emission sub-bands.

Enhancement of photoluminescence intensity of erbium doped silica containing Ge nanocrystals: distance dependent interactions

Photo-physical processes in Er-doped silica glass matrix containing Ge nanocrystals prepared by the sol-gel method are presented in this article. Strong photoluminescence at 1.54 μm, important for fiber optics telecommunication systems, is observed from the different sol-gel derived glasses at room temperature. We demonstrate that Ge nanocrystals act as strong sensitizers for Er(3+) ions emission and the effective Er excitation cross section increases by almost four orders of magnitude with respect to the one without Ge nanocrystals. Rate equations are considered to demonstrate the sensitization of erbium luminescence by Ge nanocrystals. Analyzing the erbium effective excitation cross section, extracted from the flux dependent rise and decay times, a Dexter type of short range energy transfer from a Ge nanocrystal to erbium ion is established.

Cyclodextrin-enhanced degradation of toluene and p-toluic acid by Pseudomonas putida

Degradation of an immiscible aromatic solvent, toluene, and a water-soluble aromatic compound, p-toluic acid, by a Pseudomonas putida strain in the presence of beta-cyclodextrin (beta-CD) was investigated. The ability of CDs to interact with hydrophobic organics and form inclusion compounds was exploited in this study to remove or alleviate the toxicities of substrates and consequently to enable or enhance degradation. Liquid toluene was found to be highly toxic to P. putida. However, this phase toxicity was removed when crystalline beta-CD-complexed toluene was provided as the substrate. The latter was fully degraded at a concentration of up to 10 g/liter. Degradation of toluene vapors was enhanced in the presence of beta-CD as a result of reduced molecular toxicity and facilitated absorption of the gaseous substrate. Similarly, beta-CD alleviated the inhibitory effect of p-toluic acid on P. putida. This protective effect of CD was remarkably more prominent when the microbial culture was shock loaded with an otherwise toxic dose of p-toluic acid (1.8 g/liter).

Bacterial toxicity of cyclodextrins: luminuous Escherichia coli as a model

The effect of various concentrations of natural and chemically modified cyclodextrins on the luminescence of an Escherichia coli suspension was investigated. All cyclodextrins were found to reduce, albeit to a varying degree, the luminescence level of the bacterial cells, thus suggesting a direct interaction between the cyclodextrins and cells. The inhibitory concentrations IC20 and IC50 of the various cyclodextrins were determined and taken to represent their toxicity effects upon the bacterial cells. Among the natural cyclodextrins, gamma- and alpha-CD interfered minimally with the bacterial luminescence and consequently were essentially non-toxic. The following descending order of toxicity was observed: beta-CD >> alpha-CD > gamma-CD. Among the chemically modified cyclodextrins, Dimeb was clearly toxic while Trimeb and the hydroxylated derivatives (hydroxypropyl-alpha-CD, HPACD; -beta-CD, HPBCD; -gamma-CD, HPGCD) were essentially non-toxic. The following descending order of toxicity was observed: Dimeb >> HPBCD > Trimeb > HPACD > HPGCD.

Cyclodextrins as carriers of cholesterol and fatty acids in cultivation of mycoplasmas

The design of fully or partly defined media for mycoplasma cultivation involves the need to provide the essential lipids, cholesterol and long-chain fatty acids, in an assimilable and nontoxic form. This study introduces cyclodextrins (CDs) as carriers of these lipids, thus suggesting alternatives to serum or bovine serum albumin (BSA). The effects of beta-CD and two forms of chemically modified beta-CD, dimethyl-beta-CD (Dimeb) and hydroxypropyl-beta-CD (Hyprob), on the growth of Mycoplasma capricolum and Acholeplasma laidlawii were investigated in a basal medium as well as in serum- and BSA-supplemented media. beta-CD was found to inhibit the growth of the sterol-requiring M. capricolum in both serum and BSA media, but it stimulated the growth of the sterol-independent A. laidlawii. Inhibition by beta-CD was explained by its capacity to form a water-insoluble CD-cholesterol complex, thus rendering it unavailable to the cells. Dimeb, despite its strong complexing ability for lipids, was found to be toxic to all mycoplasma species in both liquid cultures and agar diffusion susceptibility tests. In sharp contrast to beta-CD and Dimeb, Hyprob (with a degree of substitution of 4.2) added at 5 and 10 mM to a basal medium supplemented with lipids permitted growth of M. capricolum. Comparison of growth curves in the two conventional serum and BSA media with those in two Hyprob media revealed comparable growth and growth rates.

Biomass axial distribution in airlift bioreactor with yeast and plant cells

This study was aimed at determining the degree of biomass homogeneity in the various parts of an internal loop airlift bioreactor, thus verifying the assumption, often made in bioreactor studies, of a well-mixed liquid-biomass system. Following characterization of the hydrodynamics of the vessel with water, the axial biomass distribution in the riser and downcomer was determined for plant and yeast cell suspensions of 5.8, 8.5, and 12.5 g DW/L Phaseolus vulgaris and of 30 and 46 g DW/L Saccharomyces cerevisiae. The airlift bioreactor with a surface ratio A(D)/A(D) of 1.04 and aspect ratio of 4.95 was investigated under various aeration rates. The yeast cells were found to be distributed practically uniformly throughout the vessel at the aeration rates of 0.1-1.45 vvm. However, in the case of the denser and cluster-forming plant cells, a clear trend of a gradual bio-mass accumulation in the downcomer, a slightly lower but uniform biomass loading in the riser, and a slightly higher biomass concentration in the gas-liquid separator was observed at the lower aeration rates of 0.1-0.61 vvm. In the case of powderized calcium carbonate (55 g/L) often used in fermentations of organic acids, a slight trend of a gradual accumulation of solids towards the bottom parts in both the downcomer and riser was observed. A better representative sampling location, in terms of solids and biomass loading, seems to be in the middle part of the vessel. It is suggested that airlift bioreactors with higher aspect ratios (>5) may be prone to a more significant inhomogeneity of solids (biomass and particles).

A new cyclodextrin-agar medium for surface cultivation of microbes on lipophilic substrates

Inclusion of cyclodextrins into an agar gel enabled a homogeneous incorporation of water-immiscible lipophilic organic liquids and solids as substrates for surface microbial growth or conversion. Surface cultivation of Candida lipolytica and C. tropicalis was demonstrated in alpha- and beta-cyclodextrin/hexadecane-agar media.