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C Krause

Publications and source records attributed to C Krause.

At least 19 recordsLinked to original sources
PubMed2006

[Validation of antibody screening by indirect antigloblin test and ABO blood typing by filtration and microplate techniques: assessment of robustness].

According to requirements of the French Committee for Accreditation (Cofrac), it is essential to use validated and standardised methods in Immunohematology. This imposes first the knowledge of metrological tolerances for all the technics. Two multicenter studies were carried out to define the maximal acceptable deviations concerning incubation temperature and time, volumes of patient plasma and tests cells for antibody screening using indirect antiglobulin test on one hand and for reverse grouping on another hand. All equipment used (temperature test chamber, chronometer, pipettes) were calibrated according to Cofrac standards. The antibody screenings were performed manually using 3 different filtration systems: ID Diamed, Biovue Ortho and Scangel Biorad, the same tests cells, a standard 20 ng/mL anti RH1, a positive control anti KEL1 and a negative control; the reverse blood grouping was performed manually using the above mentionned filtration systems and microplate technic with the same A1 and B test cells. These two studies showed that all the tests from the multiples combinations of the above parameters gave the same results and allowed us to define a range of tolerance for 4 critical physical parameters involved in the antibody screening and blood typing.

ABO Blood-Group System↗
PubMed2006

Peptaibiomics: an advanced, rapid and selective analysis of peptaibiotics/peptaibols by SPE/LC-ES-MS.

"Proteomics" and "peptidomics" are used as technical terms to define the analysis and study of all proteins and peptides expressed in an organism or tissue. In analogy we propose the name peptaibiomics for the analysis of a group of fungal peptide antibiotics (peptaibiotics) containing the characteristic amino acid Aib (alpha-aminoisobutyric acid). In analogy to the peptidome the complete expression of peptaibiotics by fungal multienzyme complexes should be named the peptaibiome. Peptaibiotics are defined as peptides containing Aib and exerting a variety of bioactivities. They comprise the sub-groups of N-acetylated peptaibols, characterized also by a C-terminal amide-linked 2-amino alcohol, and lipopeptaibols having in place of an acetyl group a lipophilic fatty acid acyl group. Furthermore, lipoaminopeptides are also known with long-chain fatty acid on the N-termini, a lipoamino acid in position three and a strongly basic secondary or tertiary amine form a subgroup of mixed forms which could not be integrated in one of these three previously mentioned groups. Here we present a specific and rapid screening method on the peptaibiome applicable directly onto filamentous fungi cultured in a single Petri dish. The method comprises solid-phase extraction (SPE) of peptaibiotics followed by on-line reversed-phase HPLC coupled to an ion trap electrospray tandem mass spectrometer (ES-MS). The presence of these peptides is indicated by characteristic mass differences of Deltam = 85.1 Da representing Aib-residues which can be observed in the b-series of acylium fragment ions resulting from ES-MS. Partial sequences can be deduced from the data and compared with structures compiled in electronic peptaibol data bases. The judgement is possible whether or not structures are novel, already known or related to known structures. Suitability of the method is demonstrated with the analysis of strains of Trichoderma and its teleomorph Hypocrea. New sequences of peptaibiotics are presented and those being related to established 10- to 18-residue peptaibols trichovirin, trichogin and trichotoxin, which have been described in the literature.

Anti-Bacterial Agents↗
PubMed2002

[Extra-intestinal Manifestations of chronic inflammatory Bowel diseases].

Approximately one third of all patients with Crohn's disease and ulcerative colitis suffer from extra-intestinal manifestations of their inflammatory bowel disease. Most commonly those symptoms occur simultaneously with the CED symptoms; they can, however, either precede them or appear later on in the course of the disease. The most frequent extra-intestinal symptoms are arthralgias of peripheral joints and spine, which are usually bland and self-limiting, while ankylosing spondylitis and erosive arthritides are rare. Skin lesion and eye affections can also parallel the bowel condition, but occasionally they precede intestinal manifestations and can be a first diagnostic clue. In addition, different extra-intestinal symptoms tend to simultaneously co-occur more frequently in some patients with CED, while others are not affected at all. Immunogenetic parameters play a role for the manifestations of the pathologic immune response both in the gut and in the musculo-skeletal systems, as indicated by associations with MHC class I alleles. Enteropathic microorganisms are also thought to be involved in the pathogenetic mechanisms.

Arthritis↗
PubMed2001

A new type of phosphorescent nanospheres for use in advanced time-resolved multiplexed bioassays.

A new concept to design phosphorescent nanospheres is presented. The spheres are distinguishable by their individual decay time and spectral distribution of their emission spectra. They are composed of a phosphorescent ruthenium metal-ligand complex (MLC) dissolved, along with certain strongly fluorescent cyanine dyes, in modified polyacrylonitrile-based nanospheres. Since the emission spectrum of the MLC overlaps the absorption spectrum of the cyanine and both the MLC (the donor) and the cyanine (the acceptor) are in close spatial proximity, efficient resonance energy transfer (RET) does occur. Thus, the nanospheres emit dual luminescence, one from the acceptor dye and the other from the donor MLC. Variation of the concentrations of the acceptor dye results in a varying efficiency of RET, thus making the spheres distinguishable. Hence, a set of multiplexable sphere labels is obtained by using one MLC (acting as the phosphorescent donor and present in constant concentration) and one acceptor dye (which varies in terms of both spectral properties and concentration). The nanospheres can be identified by the emission maximum (reflecting the kind of acceptor dye) and by decay time (reflecting its concentration). Since the same donor MLC is used throughout, all nanospheres can be excited with the same light source.

Biological Assay↗
PubMed2001

Fluorescent imaging of pH with optical sensors using time domain dual lifetime referencing.

We present a referenced scheme for fluorescence intensity measurements that is useful for imaging applications. It is based on the conversion of the fluorescence intensity information into a time-dependent parameter. A phosphorescent dye is added in the form of approximately 10-microm particles to the sample containing the pH-sensitive fluorescent indicator. Both the reference dye and the pH probe are excited simultaneously by a blue LED, and an overall luminescence is measured. In the time-resolved imaging method presented here, two images taken at different time gates were recorded using a CCD camera. The first image is recorded during excitation and reflects the luminescence signal of both the fluorophore (pH) and the phosphor (reference). The second image, which is measured after a certain delay (after switching off the light source), is solely caused by the long-lived phosphorescent dye. Because the intensity of the fluorophore contains the information on pH, whereas phosphorescence is pH-independent, the ratio of the images displays a referenced intensity distribution that reflects the pH at each picture element (pixel). The scheme is useful for LED light sources and CCD cameras that can be gated with square pulses in the microsecond range. The fundamentals and potential of this new method, to which we refer as time domain dual lifetime referencing (t-DLR), are demonstrated.

Journal Article↗
PubMed2001

Dual lifetime referencing as applied to a chloride optical sensor.

A membrane with an optical response to chloride has been developed that contains two luminophores that display two largely different decay times. The first luminophore (the "reference") is a chloride-insensitive ruthenium metal-ligand complex possessing a decay time in the microsecond range. The second luminophore is the short-lived chloride-quenchable fluorescent probe lucigenin. Both are contained in a hydrogel matrix and are excited by a blue LED emitting sinusoidally modulated light. Under these conditions, the chloride-dependent fluorescence intensity of lucigenin can be converted in an analyte-dependent fluorescence phase shift that depends on the ratio of the two luminescence intensities and can be measured at modulation frequencies of typically 45 kHz. The dynamic range of this sensor can be adjusted by either varying the ratio of the two luminophores or selecting a particular optical filter combination.

Acridines↗
PubMed2001

Endoscopic ultrasound-guided fine-needle aspiration in focal pancreatic lesions: a prospective intraindividual comparison of two needle assemblies.

BACKGROUND AND STUDY AIMS: The results of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) in focal pancreatic lesions are less impressive than those in the mediastinum. The aim of this prospectively randomized study was to compare two commercially available needle assemblies with regard to handling and cytopathological yield. PATIENTS AND METHODS: A total of 30 patients (19 men, 11 women; mean age 61) with focal pancreatic lesions underwent EUS-FNA with each of the two needles (GIP, Wilson-Cook). The sequence was randomized for the examiner and blinded for the cytologist. Three patients had to be excluded because of the impossibility of sample assignment or patient follow-up. EUS-FNA was performed using the standard technique with linear echo endoscopes. RESULTS: None of the characteristics evaluated by the examiner differed significantly between either of the needles. Inadequate results were obtained in 11% using the GIP needle, but in none with the Wilson-Cook needle. GIP needle cytology revealed malignancy in 11 patients (sensitivity, specificity, and accuracy were 55%, 100%, and 65%, respectively, including inadequate results). The aspirates obtained with the Wilson-Cook needle identified malignancy in 16 patients (sensitivity, specificity, and accuracy were 85%, 100%, and 89%, respectively). CONCLUSIONS: No statistically significant differences were detected in the handling of either of the two needle assemblies. No complications were reported using the GIP needles. However, in four procedures breakages of the outer Teflon sheath of the Wilson-Cook needle occurred, and in another four cases re-insertion of the stylet was impossible. Nevertheless, cytopathologic results were significantly better with the Wilson-Cook needle.

Adult↗
PubMed2001

Detection of pancreatic metastases by EUS-guided fine-needle aspiration.

BACKGROUND: Metastases to the pancreas are usually found incidentally. Tissue diagnosis is imperative because imaging alone is incapable of differentiating them from primary pancreatic tumors. This study tested whether it is possible to differentiate metastases from other focal pancreatic lesions by using EUS-guided fine-needle aspiration (EUS-FNA) for cytodiagnosis. METHODS: One hundred fourteen consecutive patients (mean age 61 years) with focal pancreatic masses, detected on CT, underwent EUS-FNA by using a linear-array echoendoscope and 22-gauge needles. RESULTS: Adequate specimens were obtained from 112 lesions. Carcinomas were identified in 68 cases (60.7%), 56 (50%) of pancreatic origin and 12 (10.7%) from distant primary tumors. The metastases were all located in the head and body of the pancreas and measured 1.8 to 4.0 cm. The echo-texture was heterogeneous or hypoechoic in all cases and resembled that of primary tumors. Six of the 12 patients with metastatic disease had a prior diagnosis of cancer (breast, 3; renal cell, 2; salivary gland, 1), 4 of them with a recurrence and 2 with a second carcinoma metastasizing to the pancreas. Six patients without a prior diagnosis of cancer had metastases from renal cell, colonic, ovarian, and esophageal carcinomas; one metastasis was from an unknown primary and another was from a malignant lymphoma. These findings influenced the therapeutic strategy in 8 patients who underwent nonsurgical palliation. There were no complications. CONCLUSIONS: Pancreatic metastasis is an important cause of focal pancreatic lesions, but the EUS features are not diagnostic. Simultaneous EUS-FNA allows cytodiagnosis and can have a decisive influence on the selection of appropriate therapeutic strategies.

Adult↗
PubMed2000

Effects of 902 MHz electromagnetic field emitted by cellular telephones on response times in humans.

The present study examined possible influences of a 902 MHz electromagnetic field emitted by cellular telephones on cognitive functioning in 48 healthy humans. A battery of 12 reaction time tasks was performed twice by each participant in a counterbalanced order: once with and once without the exposure to the field. The results showed that the exposure to the electromagnetic field speeded up response times in simple reaction time and vigilance tasks and that the cognitive time needed in a mental arithmetics task was decreased. The results suggest that exposure to the electromagnetic field emitted by cellular telephones may have a facilitatory effect on brain functioning, especially in tasks requiring attention and manipulation of information in working memory.

Adolescent↗
PubMed2000

Hydrophilic sensor membrane based on cation-selective protic chromoionophore.

The first potassium optode based on a protic chromoionophore immobilized in a hydrogel matrix is presented. The highly selective protic chromoionophore consists of a cryptohemispherand moiety and a trinitroanilino chromophore part. The acidifying power of potassium ions over sodium ions is 0.6 pH units. This correlates with the findings in solution. In contrast to several crown and aza-crown based chromophores the highly pre-organized moiety allows ion detection even in aqueous environment. The detection limit for potassium ions at pH 7.7 is 5 microM.

Biosensing Techniques↗
PubMed2000

Partial interferon-gamma receptor signaling chain deficiency in a patient with bacille Calmette-Guérin and Mycobacterium abscessus infection.

Complete deficiency of either of the two human interferon (IFN)-gamma receptor components, the ligand-binding IFN-gammaR1 chain and the signaling IFN-gammaR2 chain, is invariably associated with early-onset infection caused by bacille Calmette-Guérin vaccines and/or environmental nontuberculous mycobacteria, poor granuloma formation, and a fatal outcome in childhood. Partial IFN-gammaR1 deficiency is associated with a milder histopathologic and clinical phenotype. Cells from a 20-year-old healthy person with a history of curable infections due to bacille Calmette-Guérin and Mycobacterium abscessus and mature granulomas in childhood were investigated. There was a homozygous nucleotide substitution in IFNGR2, causing an amino acid substitution in the extracellular region of the encoded receptor. Cell surface IFN-gammaR2 were detected by flow cytometry. Cellular responses to IFN-gamma were impaired but not abolished. Transfection with the wild-type IFNGR2 gene restored full responsiveness to IFN-gamma. This is the first demonstration of partial IFN-gammaR2 deficiency in humans.

Adult↗
PubMed2000

Mediastinal lymphadenopathy in patients with or without previous malignancy: EUS-FNA-based differential cytodiagnosis in 153 patients.

OBJECTIVE: Mediastinal lymphadenopathy (ML) is a cause for concern, especially in patients with previous malignancy. The investigation of choice is thoracic CT with a variable sensitivity and specificity requiring tissue diagnosis. We used endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) for cytodiagnosis of ML in patients with and without previous malignancy. The cause, distribution of lesions, and incidence of second cancers were investigated. METHODS: Linear echoendoscopes and 22-gauge needles for cytology were used for EUS-FNA. A cytological diagnosis of malignancy was accepted, and histology or consistent follow-up of at least 9 months confirmed benign results. RESULTS: One hundred fifty-three patients underwent EUS-FNA between November 1997 and November 1999 (mean age, 60 yr; range, 13-82 yr; 105 men). Cytology was adequate in 150 patients. Final diagnosis was malignancy in 84 and benign in 66 patients (sensitivity, specificity, and diagnostic accuracy: 92%, 100%, 95%, respectively). In 101 patients without previous cancer cytology identified 48 malignant (lung, 41; extrathoracic, 7) and 51 benign lesions (inflammation, 35; various, 9; sarcoidosis, 7) (sensitivity, specificity, accuracy: 88%, 100%, 94%). Fifty-two patients had prior malignancy, mostly in extrathoracic sites. Cytology revealed recurrences in 21 patients, second cancer in 9 and benign lesions in 21 patients (inflammatory, 11; sarcoidosis, 8; tuberculosis, 1; abscess, 1) (sensitivity, specificity, accuracy: 97%, 100%, 98%). CONCLUSIONS: In patients without previous cancer malignant ML originates from the lung >80%. In those with previous malignancy recurrence of extrathoracic sites is the major cause. Benign lesions and treatable second cancers occur in a significant frequency, emphasizing the need for tissue diagnosis. EUS-FNA is a safe and minimally invasive alternative for cytodiagnosis in the mediastinum.

Adolescent↗
PubMed2000

Endosonography-guided, fine-needle aspiration cytology extending the indication for organ-preserving pancreatic surgery.

OBJECTIVE: Organ preserving pancreatic resections are considered whenever malignant disease is ruled out. In tumors of low malignant potential such as cystadenomas and neuroendocrine tumors, the diagnosis is rarely established preoperatively. We studied the feasibility of cytodiagnosis using endosonography-guided fine-needle aspiration in determining the operative approach. METHODS: A total of 78 patients (16 female, 62 male; mean age 61.4 yr, range 31-82 yr) with focal pancreatic lesions underwent EUS-FNA. Final diagnosis was confirmed by histology, cytology, or clinical follow up (>9 months). Patients with tumors of low malignant potential were managed by customized pancreatic resections. RESULTS: Final diagnosis was malignant tumors in 36 patients, tumors of low malignant potential in nine (six, neuroendocrine, two, borderline mucinous cystadenomas, one, borderline adenocarcinoma), and benign in 31 (two inadequate smears). No complications occurred. With six false-negative and no false-positive results, the accuracy, sensitivity, specificity, and positive and negative predictive values were 92%, 84%, 100%, 100%, and 86%, respectively. Five patients with low malignant tumors underwent duodenum-preserving pancreatic head resection, three mid segment resection, and one pylorus-preserving pancreatoduodenectomy. CONCLUSIONS: EUS-FNA is useful in the preoperative cytodiagnosis of pancreatic tumors of low malignant potential. It extends the indication for organ-preserving pancreatic resections and avoids the unnecessary sacrifice of adjacent organs.

Adenocarcinoma↗
PubMed1999

Indoor risk factors for atopic eczema in school children from East Germany.

This study aimed to investigate the relation between environmental influences such as arsenic, cadmium, lead, and mercury, as well as environmental tobacco smoke, pet keeping, and heating systems on the prevalence of atopic eczema. Therefore, a multicenter cross-sectional study of school children aged 5-14 years, including a standardized questionnaire, blood and urine analyses, and a dermatological examination, was undertaken. A cases-control approach was chosen in order to identify relevant risk factors. A total of 2200 school children (response 79.1%) of two areas (Bitterfeld, Hettstedt) polluted by industrial activities and an agricultural control region (Zerbst) of the former German Democratic Republic were examined. Atopic eczema as identified by dermatological examination and history was the outcome variable of interest. Body burden of arsenic and heavy metals and questionnaire data on environmental tobacco smoke exposure, pet keeping, and heating system were investigated as potential risk factors. The overall prevalence of atopic eczema was 2.6%, with higher prevalences in the industrial areas (2.5 and 2.9%) compared to the control area (1.6%, not significant). Bivariate analyses did not reveal statistically significant associations between atopic eczema and tobacco smoke exposure or the body burden of arsenic and heavy metals. According to multiple logistic regression analysis, atopic eczema was significantly more frequent in predisposed families and those who reported keeping guinea pigs (OR=4.37, CI 2.15-8.91), but not other pets, like dogs, cats, and hamsters. In comparison to a distant heating system, a decreased risk was observed in households with central heating system (OR=0.30, CI 0.10-0.90), whereas the presence of a gas heater with an exhaust pipe connection to the wall was associated with a significantly elevated risk for eczema (OR=8.22, CI 2.44-27.66). The heating system and exposure to certain animal allergens are related to the manifestation of atopic eczema. Further studies are needed to clarify how far a causal relationship is reflected by these findings.

Adolescent↗
PubMed1999

Reference values and human biological monitoring values for environmental toxins. Report on the work and recommendations of the Commission on Human Biological Monitoring of the German Federal Environmental Agency.

This article describes the working principles and working procedures of the Commission on Human Biological Monitoring, which was established in 1993 as a joint commission of the Federal Health Office (Bundesgesundheitsamt) and the Federal Environmental Agency (Umweltbundesamt) in Germany. One of the main tasks of the commission is to develop scientifically based criteria for the application of human biological monitoring and for the evaluation of human monitoring data in environmental medicine. In principle, two different kinds of criteria are recommended: (a) reference values and (b) human biological monitoring values (HBM values). Reference values are intended to indicate the upper margin of the current background exposure of the general population to a given environmental toxin at a given time. Reference values can be used to identify subjects with an increased level of exposure (in relation to background exposure) to a given environmental toxin. However, reference values do not represent health-related criteria for the evaluation of human biological monitoring data. HBM values are derived from human toxicology and epidemiology studies and are intended to be used as a basis for a health-related evaluation of human biological monitoring data. Usually the commission recommends two different HBM values: HBM I, the concentration of an environmental toxin in a human biological material (usually blood, serum, plasma, or urine) below which there is--according to the knowledge and judgement of the commission--no risk for adverse health effects in individuals of the general population: and HBM II, the concentration of an environmental toxin in a human biological material (usually blood, serum, plasma, or urine) above which there is--according to the knowledge and judgement of the commission and with regard to the environmental toxin under consideration--an increased risk for adverse health effects in susceptible individuals of the general population. The HBM I value can be considered a kind of alert value (from the toxicological point of view), whereas the HBM II value represents a kind of action level, at which attempts should be undertaken to reduce the level of exposure immediately and to carry out further medical examinations. Values between HBM I and HBM II should be considered a warning signal of the need to control the analytical measurement and to reduce the level of exposure of the concerned individual as reasonably as is achievable. At present, reference and HBM values are available for lead in blood, for cadmium and mercury in blood and urine, and for pentachlorophenol in plasma/serum and urine. Reference values have been established for some polychlorinated biphenyls in blood and plasma as well as for hexachlorocyclohexane and hexacholorobenzene in blood as well as for some organochlorine in human milk.

Adolescent↗