Evaluation of the Pentax-AWS(®) and the Macintosh laryngoscope in difficult intubation: a manikin study.

BACKGROUND: The Pentax-AWS (AWS(®)), a new video laryngoscope, has been shown to be useful in cases of difficult intubation. We hypothesized that the AWS(®) would be more useful in the settings of a narrow upper airway than the Macintosh laryngoscope. We compared each device in simulated scenarios of representative difficulty of tracheal intubation using a manikin. The primary endpoint was the rate of successful intubation. METHODS: With each device, 23 anesthesiologists performed tracheal intubation in a SimMan(®) manikin in the following scenarios: (1) normal airway, (2) tongue edema, (3) cervical spine rigidity, (4) pharyngeal obstruction, (5) jaw trismus, (6) tongue edema with pharyngeal obstruction. The intubation time and success rate were measured. Each participant was asked to rate the difficulty of intubation (1=very easy; 5=very difficult). RESULTS: In the scenarios of tongue edema and tongue edema with pharyngeal obstruction, the AWS(®) yielded a higher success rate (100% vs. 34.8%; P<0.001, 65.2% vs. 21.7%; P=0.006), a shorter intubation time [14.6 (7.0) vs. 33.4 (13.0) s; P<0.001, 24.5 (12.0) vs. 37.6 (11.9); P=0.047; mean (standard deviation)], and a lower difficulty score [2 (1-4) vs. 5 (1-5); P<0.001, 4 (2-5) vs. 5 (3-5); P<0.001; median (range)], compared with the Macintosh laryngoscope. CONCLUSION: The AWS(®) has an advantage over the Macintosh laryngoscope in simulated tongue edema and tongue edema with pharyngeal obstruction. Further studies in a clinical setting are necessary to confirm these findings.

Experimental and simulation analysis of community structure of nitrifying bacteria in a membrane-aerated biofilm.

Until now, only few attempts have been made to assess biofilm models simulating microenvironments in a biofilm. As a first step, we compare the microenvironment observed in a membrane aerated biofilm (MAB) to that derived from a two-dimensional computational model with individual ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) embedded in a continuum EPS matrix. Gradients of oxygen were determined by means of microelectrodes. The change in nitrifying bacterial populations with the biofilm depth was quantified using fluorescence in situ hybridization (FISH) in combination with a confocal laser scanning microscopy (CLSM). Microelectrode measurements revealed that oxic and anoxic or anaerobic regions exist within the MAB. The oxygen profile predicted by the model showed good agreement with that obtained by microelectrode measurements. The oxic part of the biofilm was dominated by NSO190 probe-hybridized AOB, which formed relatively large clusters of cells directly on the membrane surface, and by the NOB belonging to genus Nitrobacter sp. On the other hand, NOB belonging to genus Nitrospira sp. were abundant at the oxic-anoxic interface. The model prediction regarding AOB and Nitrobacter sp. distribution was consistent with the experimental counterpart. Measurements of AOB cluster size distribution showed that colonies are slightly larger adjacent to the membrane than at the inner part of the biofilm. The sizes predicted by the current model are larger than those obtained in the experiment, leading to the arguments that some factors not contained in the model would affect the cluster size.

Surface glycopeptide change triggered by contact between normal cells from rat liver and their simian virus 40-transformed cells from the same virus.

Surface glycopeptide changes triggered by mixed culture of normal cells from rat liver cell line WIRL-3 and simian virus 40-transformed cells from the same line were studied. In addition, biologic responses of the normal cells and the transformed cells to three kinds of surface glycopeptides derived from the normal cells, the transformed cells, and these cells in mixed culture were investigated. Surface glycopeptide derived from the mixed culture showed a quantitative increase and a qualitative change in the glycopeptide structure, not detected in the surface glycopeptide of normal cells and transformed cells cultured separately. The surface glycopeptide changes observed in the mixed culture were mainly ascribable to normal cells responding to transformed cells, and a surface glycopeptide change in normal cells induced a qualitative surface glycopeptide change in transformed cells. Differences in biologic response of normal cells and transformed cells to the above three surface glycopeptides were investigated with the use of inhibition of [3H]thymidine uptake of the cells by the three different surface glycopeptide preparations. The inhibition rates of uptake in normal cells were 30% by all three surface glycopeptides (200 microgram/ml culture medium); inhibition rates in transformed cells were 65% by mixed-culture surface glycopeptide, 50% by normal cell-surface glycopeptide, and 35% by transformed cell-surface glycopeptide.

Ligation errors in DNA computing.

DNA computing is a novel method of computing proposed by Adleman (1994), in which the data is encoded in the sequences of oligonucleotides. Massively parallel reactions between oligonucleotides are expected to make it possible to solve huge problems. In this study, reliability of the ligation process employed in the DNA computing is tested by estimating the error rate at which wrong oligonucleotides are ligated. Ligation of wrong oligonucleotides would result in a wrong answer in the DNA computing. The dependence of the error rate on the number of mismatches between oligonucleotides and on the combination of bases is investigated.

Identification of the gene encoding a NAD(P)H-flavin oxidoreductase coupling with dibenzothiophene (DBT)-desulfurizing enzymes from the DBT-nondesulfurizing bacterium Paenibacillus polymyxa A-1.

The gene encoding NAD(P)H-flavin oxidoreductase (flavin reductase), which couples efficiently with dibenzothiophene (DBT)-desulfurizing monooxygenases of Rhodococci, was cloned from a DBT-non-desulfurizing bacterium Paenibacillus polymyxa A-1 in Escherichia coli, and designated as flv. Cell-free extracts from the recombinant exhibited a flavin reductase activity about forty times higher than that of the E. coli carrying the vector DNA only. Nucleotide sequence analysis reveals that the gene product consists of 208 amino acids and showed about 27%, 32% and 21% identity in amino acid sequence with FRase I, the major flavin reductase of Vibrio fischeri, the NADH dehydrogenase of Thermus thermophilus and several members of the nitroreductase family, respectively. The coexpression of flv with two kinds of desulfurizing genes, dszABC and tdsABC, in E. coli enhanced the rate of DBT degradation by about 10 and 5 times as high as in the case without flv, respectively.

Microbial ecology of nitrifying bacteria in wastewater treatment process examined by fluorescence in situ hybridization.

The microbial ecology of nitrifying bacteria in various types of wastewater treatment processes and the dynamic response of the microbial ecology in biofilms were investigated using fluorescence in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. Nitrifying bacteria were found to exhibit various organizational forms under different conditions of substrate composition and concentration. Ammonia-oxidizing bacteria were dominant in ammonia-rich inorganic wastewater, while heterotrophic bacteria and ammonia-oxidizing bacteria were localized at different positions in the biofilm in organic wastewater. The dynamics of the microbial ecology in the biofilm with regard to the spatial distribution of ammonia-oxidizing bacteria and heterotrophic bacteria caused by a gradual change in substrate composition was successfully monitored by FISH analysis.

Transition of bacterial spatial organization in a biofilm monitored by FISH and subsequent image analysis.

The dynamic transition of bacterial community structure in a biofilm was monitored by the fluorescence in situ hybridization (FISH) technique and subsequent image analysis. Heterotrophic bacteria that had occupied the outer layer were gradually decreased whereas ammonia-oxidizing bacteria (AOB) gradually increased their growth activity and extended their existence area to the outer layer of the biofilm through the gradual reduction of the C/N ratio. The spatial organization of AOB in the biofilm dynamically changed responding to the environmental conditions such as pH fluctuation and lack of dissolved oxygen (DO) and had great influence on the nitrification activity. The accumulation of nitrite was observed at lower DO concentration, which might be due to the property that nitrite-oxidizing bacteria (NOB) possess of higher Km values for oxygen than AOB.

Real-time monitoring of ammonia-oxidizing activity in a nitrifying biofilm by amoA mRNA analysis.

Ammonia monooxygenase encoding mRNA (amoA mRNA) transcription in the wastewater treatment process was investigated using reverse transcription PCR (RT-PCR) as the model indicating specific function and activity in nitrifying processes. The dynamic response of amoA mRNA transcription and ammonia-oxidizing activity to the change of environmental conditions such as pH and concentration of ammonia was examined to determine the inductive factor and the inhibitor for amoA mRNA expression. Furthermore, we semiquantitatively investigated the response of amoA mRNA transcription to the pH fluctuation in a continuous fed nitrifying reactor. As a result, amoA mRNA oriented analysis enabled real-time assay of ammonia-oxidizing activity within 2 h as a response time. In contrast, rRNA and amoA encoding DNA were constantly detected at almost the same amount throughout the experiment. mRNA transcription was regulated by the many environmental conditions: ammonia seems to be one of the strong inducers for transcription of amoA mRNA, whereas low pH seems to be a strong inhibitor. These factors simultaneously affected the mRNA transcription and enzymatic activity leading to the complex phenomena of ammonia-oxidizing activity and amoA mRNA transcription in the continuous feeding reactors.

Isolation of Pseudomonas aeruginosa from Ushubetsu River water in Hokkaido, Japan.

To provide information on the ecology of Pseudomonas aeruginosa in nature, bacteriological surveillance was performed in the defined area in Hokkaido, Japan. P. aeruginosa was isolated from water samples of Ushubetsu River in the down stream from the urban area of Asahikawa. P. aeruginosa was isolated from fecal samples of pigs but not from samples of soil of a tomato field, sand of sandboxes in vest-pocket parks, fresh vegetables, or feces of wild deer. The present results indicate that P. aeruginosa strains isolated from the river water is originated from the environment of human activity and not from wild life or domestic animals.

Roles of nitric oxide (NO) and NO synthases in healing of dextran sulfate sodium-induced rat colitis.

We examined the effects of various NO inhibitors on the healing of DSS-induced rat colitis. Experimental colitis was induced by feeding rats for 6 days with 2.5% DSS in drinking water. After DSS treatment, the animals were fed normally and killed various days up to 7 days later. L-NAME (a nonselective NOS inhibitor) or aminoguanidine (a selective iNOS inhibitor) was given p.o. twice daily for 6 days starting from the termination of DSS treatment. The area of lesions, colon length and MPO activity were measured on day 7 after DSS treatment. DSS treatment caused severe lesions in the colon, accompanied by an increase in MPO activity and a decrease in colon length. The lesions healed gradually after discontinuation of DSS treatment, with a histological restoration and subsidence of inflammation. The healing of DSS-induced colonic lesions was significantly impaired by daily administration of L-NAME or aminoguanidine, the effects being all but equivalent between these drugs, and the effect of L-NAME was significantly reverted by the co-administration of L-arginine. The expression of nNOS protein was observed in the colonic mucosa with or without DSS treatment, while those of iNOS and eNOS were markedly upregulated after DSS treatment. Likewise, the expression of VEGF was also up-regulated in the colon following DSS treatment, and this response was suppressed by both L-NAME and aminoguanidine. These results suggest that endogenous NO produced by mainly iNOS and partly eNOS contributes to the healing of DSS-induced colonic lesions, through the upregulation of VEGF expression and enhancement of angiogenesis.

Single-stage autotrophic nitrogen-removal process using a composite matrix immobilizing nitrifying and sulfur-denitrifying bacteria.

We developed a novel single-stage autotrophic nitrogen-removal process comprised of two composite immobilized biomass layers-one of nitrifying bacteria and one of sulfur-denitrifying bacteria and elemental sulfur-in a Fe-Ni fibrous slag matrix. Nitrification and consumption of dissolved oxygen occurred in the outer part and sulfur denitrification in the anoxic inner part of the composite matrix, thus realizing autotrophic nitrogen removal in a single reactor. The complete conversion of ammonia into N2 in a single reactor was demonstrated in both batch-mode incubation and continuous-feed operation. The spatial profiles of the ammonia-oxidizing bacteria and denitrifying bacteria were evaluated by real-time PCR, targeting their functional genes, and stratification of these two types was observed in the matrix after several months of incubation. This process does not require any specific reactor type or conditions and thus has the potential to be applied to many different wastewater treatment processes due to its simplicity in both operation and construction.

Sialic acid content and growth control of mouse cells transformed by a temperature-sensitive mutant of SV40.

The sialic acid content of mouse cells transformed by a temperature-sensitive mutants (ts-mutant) of Simian virus 40 (SV40) was measured, and proved to be derived from changes in the sialic acid content in the plasma membrane which resulted from changes in the microsomal sialytransferase activity. Plasma membrane glycoproteins of ts-mutant transformed cells showed significantly different patterns on electrofocusing, but when treated with neuraminidase, differences of elution patterns were extinguished. It was concluded that there was a positive correlation between sialic acid content and loss of contact inhibition in the cell line examined.

Biosynthesis of glycoprotein-glycosyl transferases during the cell cycle.

The levels of glycoprotein-glycosyl transferases increased at the late G1-early S phase during the cell cycle both in the plasma membrane and in the microsomal fraction. The levels of the enzyme showed a "peak pattern" during the cell cycle. Elevation of the enzyme activity at earlier stages was not influenced by cytosine arabinoside but that at late G1 was completely inhibited.

Newly synthesized glycoproteins in plasma membranes of cells transformed by SV40 and its gene A function.

SV40 temperature sensitive mutant transformed mouse cells synthesized different membrane glycoproteins at 5 to 10 hr after temperature shift and inhibition of DNA synthesis by cytosine arabinoside (Ara C) after temperature shift led to the alterations in the patterns of newly synthesized membrane glycoproteins analyzed by polyacrylamide gel electrophoresis.