Feasibility of noise reduction by a modification in ICU environment.

Noise is a proven cause of wakefulness and qualitative sleep disturbance in critically ill patients. A sound pressure level reduction can improve sleep quality, but there are no studies showing the feasibility of such a noise reduction in the intensive care unit (ICU) setting. Considering all available evidence, we redesigned two ICU rooms with the aim of investigating the physiological and clinical impact of a healing environment, including a noise reduction and day-night variations of sound level. Within an experimental design, we recorded 96 h of sound-pressure levels in standard ICU rooms and the modified ICU rooms. In addition, we performed a sound source observation by human observers. Our results show that we reduced A-weighted equivalent sound pressure levels and maximum sound pressure levels with our architectural interventions. During night-time, the modification led to a significant decrease in 50 dB threshold overruns from 65.5% to 39.9% (door side) and from 50% to 10.5% (window side). Sound peaks of more than 60 decibels were significantly reduced from 62.0% to 26.7% (door side) and 59.3% to 30.3% (window side). Time-series analysis of linear trends revealed a significantly more distinct day-night pattern in the modified rooms with lower sound levels during night-times. Observed sound sources during night revealed four times as many talking events in the standard room compared to the modified room. In summary, we show that it is feasible to reduce sound pressure levels using architectural modifications.

Optical properties of strain-compensated CdSe/ZnSe/(Zn,Mg)Se quantum well microdisks.

Strain-compensated CdSe/ZnSe/(Zn,Mg)Se quantum well structures that were grown on (In,Ga)As allow for efficient room-temperature photoluminescence and spectral tuning over the whole visible range. We fabricated microdisk cavities from these samples by making use of a challenging chemical structuring technique for selective and homogeneous removal of the (In,Ga)As sacrificial layer below the quantum structure. The observed whispering gallery modes in our microdisks are mainly visible up to photon energies of ~ 2.3 eV due to strong self-absorption. As extinction coefficients and effective refractive indices are dominated by the quantum well material CdSe, thick quantum wells (> 3 monolayer) are necessary to observe resonances in the corresponding quantum well emission.

Preparation of a candidate primary reference material for the international standardisation of HbA1c determinations.

We prepared a candidate primary reference material for the forthcoming international standardisation of beta-N-terminal glycated hemoglobin A measurements. It consists of well-defined mixtures of purified beta-N-terminal glycated hemoglobin A and non-glycated hemoglobin A. First, beta-N-terminal glycated hemoglobin A and non-glycated hemoglobin A were isolated, purified to homogeneity, and characterised. The techniques used were cation exchange and affinity chromatography for the purification, and high performance liquid chromatography, capillary isoelectric focusing, electrospray ionisation mass spectrometry, and peptide mapping for the characterisation. Hemoglobins from blood of healthy, non-diabetic volunteers were obtained with a purity of > 99.5% for non-glycated hemoglobin A and of > 98.5% for beta-N-terminal glycated hemoglobin A. However, results from peptide mapping indicate that the beta-N-terminal glycated hemoglobin A preparations still contain some non-beta-N-terminal glycated hemoglobins, co-eluting with beta-N-terminal glycated hemoglobin A. The exact content of beta-N-terminal glycated hemoglobin A in these preparations could be determined by a procedure consisting of standard addition, enzymatic cleavage and quantification of the resulting beta-N-terminal peptides to be in the range from 95-97.5%. Since the beta-N-terminal glycated hemoglobin A and non-glycated hemoglobin A content could be exactly determined in the materials prepared, mixtures of both components could be successfully used to calibrate the candidate reference methods.

Candidate reference methods for hemoglobin A1c based on peptide mapping.

A reference method that specifically measures hemoglobin (Hb) A1c is an essential part of the reference system for the international standardization of Hb A1c/glycohemoglobin. We have developed a new method for quantification, based on the specific N-terminal residue of the hemoglobin beta-chains. Enzymatic cleavage of the intact hemoglobin molecule with endoproteinase Glu-C has been optimized to obtain the beta-N-terminal hexapeptides of Hb A1c and Hb A0. These peptides have been separated by reversed-phase HPLC and quantitated by electrospray ionization-mass spectrometry (method A) or by capillary electrophoresis (method B). With these peptides and hyphenated separation techniques, it has been possible to overcome the insufficient resolution of currently used protein separation systems for Hb A1c.

Cáncer gástrico precoz / Early gastric cancer

Presentamos un estudio retrospectivo de 19 casos de cáncer gástrico precoz intervenidos en nuestro servicio en un período de 11 años. El síntoma más frecuente fue el dolor epigástrico que se presentó en el 82,3 por ciento de los casos y sólo en 11,8 por ciento eran asintomáticos. El diagnóstico se hizo por endosopia-biopsia en el 100 por ciento de los casos. Se practicó gastrectomía subtotal en 9 casos y gastrectomía total en 10. Había tumor limitado sólo a la mucosa en el 26,3 por ciento. En el 73,7 por ciento la infiltración alcanzaba hasta la submucosa y 21,1 por ciento de los tumores tenía metástasis ganglionares, todos del tipo intestinal. Macroscópicamente había un promedio del tipo intestinal (84,2 por ciento). Lesiones premalignas asociadas se encontraron en el 76,5 por ciento de las piezas operatorias. El 31,6 por ciento de los tumores eran multicéntricos. La sobrevida a 5 años fue de 85 por ciento

Biosynthesis of the Escherichia coli K5 polysaccharide, a representative of group II capsular polysaccharides: polymerization in vitro and characterization of the product.

Biosynthesis of the capsular K5 polysaccharide of Escherichia coli, which has the structure 4)-beta GlcA-1,4-alpha GlcNAc-(1, was studied with membrane preparations from an E. coli K5 wild-type strain and from a recombinant K-12 strain expressing the K5 capsule. Polymerization occurs at the inner face of the cytoplasmic membrane without the participation of lipid-linked oligosaccharides. The serological K5 specificity of the in vitro product was determined with a K5-specific monoclonal antibody in an antigen-binding assay. The K5 polysaccharide, as obtained from the membranes after an in vitro incubation, has 2-keto-3-deoxyoctulosonic acid as the reducing sugar, which indicates that the polysaccharide grows by chain elongation at the nonreducing end.

CMP-KDO-synthetase activity in Escherichia coli expressing capsular polysaccharides.

The temperature-regulated expression of capsular group II polysaccharides of Escherichia coli (B. Jann and K. Jann, (1990) Curr. Top. Microbiol. Immunol. 150: 19-42) depends on an elevated concentration of CMP-KDO, as evidenced by an increased activity of CMP-KDO synthetase. The increase in activity of CMP-KDO synthetase is observed only in cytoplasmic fractions of bacteria which had been grown at 37 degrees C but not after growth at 18 degrees C. The activity of CMP-KDO synthetase thus parallels the activity of the (membrane-associated) system synthesizing capsules of group II in E. coli. No such dependence of capsule expression on CMP-KDO was observed with E. coli with capsules of group I. A number of E. coli strains with capsular polysaccharides, which on the basis of genetic determination and chemical characteristics are considered as group II capsules, show no temperature regulation of their capsules and do not depend on an elevated CMP-KDO concentration for capsule expression. The capsular polysaccharides of these E. coli strains, which possibly represent a new group of E. coli capsules are tentatively classified as group I/II.

Activity of CMP-2-keto-3-deoxyoctulosonic acid synthetase in Escherichia coli strains expressing the capsular K5 polysaccharide implication for K5 polysaccharide biosynthesis.

The activity of the cytoplasmic CMP-2-keto-3-deoxyoctulosonic acid synthetase (CMP-KDO synthetase), which is low in Escherichia coli rough strains such as E. coli K-12 and in uncapsulated strains such as E. coli O111, was significantly elevated in encapsulated E. coli O10:K5 and O18:K5. This enzyme activity was even higher in an E. coli clone expressing the K5 capsule. This and the following findings suggest a correlation between elevated CMP-KDO synthetase activity and the biosynthesis of the capsular K5 polysaccharide. (i) Expression of the K5 polysaccharide and elevated CMP-KDO synthetase activity were observed with bacteria grown at 37 degrees C but not with cells grown at 20 degrees C or below. (ii) The recovery kinetics of capsule expression of intact bacteria, in vitro K5 polysaccharide-synthesizing activity of bacteria, and CMP-KDO synthetase activity of bacteria after temperature upshift from 18 to 37 degrees C were the same. (iii) Chemicals which inhibit capsule (polysaccharide) expression also inhibited the elevation of CMP-KDO synthetase activity. The chromosomal location of the gene responsible for the elevation of this enzyme activity was narrowed down to the distal segment of the transport region of the K5 expression genes.

[Modification of the caffeine metabolism in mouse liver slices by previous treatment of the experimental animals with ethanol, aminophenazone and phenobarbital]. / Metabolisierung von Coffein durch Leberschnitte der Maus und deren Beeinflussung durch Athanol und Aminophenazon sowie Phenobarbitalvorbehandlung der Versuchstiere.

The influence of ethanol, aminophenazon, and phenobarbital on the caffeine metabolism of mice liver slices was tested using 1-methyl-14C-caffeine as the marker substance. In these experiments the following results were obtained: 1. Caffeine metabolism was increased by the extension of the incubation time. The caffeine metabolism increased almost linearly up to 60 min, and during this time 109.5 nmol caffeine were metabolized per gram liver wet weight. 2. Ethanol decreased the caffeine metabolism of mice liver slices. Ethanol concentrations of 23.36, 46.72 and 93.44 mM showed a clear and dose-dependent inhibition of caffeine metabolism, reaching a maximal value of 67.1%. 3. Aminophenazon also decreased the metabolism of caffeine. This effect was augmented by increasing the concentrations of aminophenazon (10.4, 20.8, 41.6, 104.0 M) and an inhibition of 63.8% was observed after giving the highest concentration. 4. Pretreatment of mice with phenobarbital, producing an enzyme induction of the liver, clearly increased the metabolism of caffeine of mice liver slices. Under these conditions, the caffeine metabolism was increased by more than 300%. 5. In contrast to liver slices no important caffeine metabolism could be detected in kidney or brain slices of mice. 6. Mice liver slices were able to metabolize caffeine more quickly than liver slices of the rat. Within 60 min the metabolized caffeine per gram liver wet weight was more than twice higher for mice as compared to rats.