Characterization of a fast gas analyzer based on Raman scattering for the analysis of synthesis gas.

A sensor system for fast analysis of synthesis gas (mixtures of CO and H(2)) is proposed and characterized. The system is based on spontaneous Raman scattering, which enables simultaneous concentration measurements of all relevant species. For typical synthesis gas applications, this system has to face large variations of temperature and pressure. In addition, strong fluctuations in mixture composition may occur, which lead to rather inconvenient signal intensities. In this paper, we describe a low resolution spectrometer designed to function as a synthesis gas sensor and characterize pressure and temperature effects on concentration measurements. In addition, the use of different spectral ranges and calibration strategies is investigated in view of measurement accuracy and precision.

Nasal carriage of Staphylococcus aureus in house dust mite allergic patients and healthy controls.

BACKGROUND: Staphylococcal colonization may influence the course of allergic diseases such as atopic dermatitis or allergic rhinitis. The frequency of Staphylococcus aureus (SA) nasal carriage and its possible influence on persistent allergic rhinitis was investigated. METHODS: In nasal lavages from 22 patients with house dust mite allergy and 18 healthy controls, the number of SA colony forming units per ml were assessed and related to nasal symptom scores, the concentrations of three inflammatory cell activation markers, nasal total IgE and 17 cytokines in nasal secretions. RESULTS: SA was found in 15/22 allergic patients and 4/18 controls (P < 0.01). Comparing allergic SA carriers with allergic noncarriers, nasal symptom scores tended to be higher (P < 0.1), and the cell activation markers ECP (10(2.23+/-0.33)vs 10(1.45+/-0.50) ng/ml; P < 0.05) and elastase (10(2.70+/-0.21)vs 10(2.12+/-0.34) ng/ml; P < 0.01), and nasal total IgE-levels (10(1.66+/-0.38)vs 10(1.2+/-0.28) kU/ml; P < 0.05) were significantly higher in allergic SA carriers. Nasal SA carriers had a higher nasal IL-13/IFN-gamma ratio (P < 0.01), and this was correlated with higher nasal total IgE in allergic patients (r = 0.6, P < 0.05). CONCLUSION: Nasal SA carriage is frequent in patients with persistent allergic rhinitis. The data of this study suggest that they are not only secondary bystanders, but actively modulate the disease by promoting local IgE production.

Local production of Aspergillus fumigatus specific immunoglobulin E in nasal polyps.

BACKGROUND: Aspergillus spp. play a significant role in the etiology of immunoglobulin (Ig)E mediated allergic fungal sinusitis (AFS). It is unclear whether Aspergillus spp. are also involved in nasal polyps without the characteristic clinical features of AFS. OBJECTIVES: The frequency of Aspergillus spp. and Aspergillus-specific IgE in nasal lavages and serum of patients with severe nasal polyps (n = 33) without clinical features of AFS should be investigated. STUDY DESIGN: Prospective study. METHODS: An aliquot of nasal lavage fluid was treated with dithiothreitol and examined for Aspergillus fumigatus by culture and an Aspergillus-specific polymerase chain reaction (PCR) assay. An additional aliquot of nasal fluid and serum of the same patient were tested for specific IgE (Unicap, Pharmacia, Freiburg, Germany) to recombinant Aspergillus fumigatus allergen (rAspf) 1 to 6. RESULTS: All patients had negative skin prick tests for Aspergillus fumigatus. Four of 33 (12%) lavage samples were positive for Aspergillus spp. by PCR. In one of these samples, rAspf-specific IgE was detected but none in the serum. Nasal lavage and serum samples of the remaining 29 patients were negative for rAspf-specific IgE. CONCLUSIONS: Aspergillus spp. detection is rare in patients with severe nasal polyps without characteristic clinical features of AFS. Specific IgE in nasal secretions may be elevated in patients with negative skin prick tests and serum IgE. In these cases, immunologic mechanisms similar to AFS may be involved. Fungal etiology has been proposed to underlie severe nasal polyps in general. However, Aspergillus spp. seem not to play a significant role.

Prognostic significance of free gastrointestinal tumor cells in peritoneal lavage detected by immunocytochemistry and polymerase chain reaction.

AIMS: The aim of our study was to identify tumor cells in peritoneal lavage comparatively with immunocytochemistry (ICC) and half-nested reverse transcriptase-polymerase chain reaction (RT-PCR) using carcinoembryonic antigen (CEA) as marker and to evaluate their prognostic significance. PATIENTS AND METHODS: In 75 patients who underwent surgery for a carcinoma of the colorectum (n=49), stomach (n=17) or pancreas (n=9) and 13 patients with an abdominal aortic aneurysm (control group) the abdomen was irrigated with saline solution immediately after laparotomy. Cells were separated by Ficoll-density centrifugation and divided into 2 equal volumes for ICC and RT-PCR. For ICC cells were spun onto slides by cytospin centrifugation and stained with a monoclonal antibody (mab) against CEA using the APAAP method. For RT-PCR total RNA was extracted from the cells, transcribed into cDNA and amplified with CEA-specific primers. Lavages of 13 patients with an abdominal aortic aneurysm and blood samples of 6 healthy donors served as controls. RESULTS: Immunostained tumor cells were found in peritoneal lavage in 23% (17/75) of all patients, whereas 63% (47/75) of patients gave a positive result by RT-PCR analysis. In the control group (n=13) no patient presented with tumor cells in ICC, however 5 of 13 (38%) showed amplified CEA-mRNA by RT-PCR, and so did one of six blood samples. Using ICC technique, we found significant correlations between detection rates and pT-, pN-, pM-categories as well as tumor stage. On the contrary, by RT-PCR significant correlations were observed only between pT- and pM-categories and detection rates. Detection of tumor cells in peritoneal lavage with both techniques was associated with poor prognosis. Moreover, these tumor cells are an independent prognostic factor and may have an influence on the development of peritoneal carcinomatosis. CONCLUSION: ICC is a useful method for detection of tumor cells in peritoneal lavage. In contrast, half-nested RT-PCR cannot be recommended, as the detection rates are unproportionally high, obviously as a result of CEA-mRNA expression in nontumor cells.