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Biomedical subjects

I Moser

Publications and source records attributed to I Moser.

At least 19 recordsLinked to original sources
PubMed2006

Comparative macrorestriction and RFLP analysis of Mycobacterium avium subsp. avium and Mycobacterium avium subsp. hominissuis isolates from man, pig, and cattle.

In Germany, tuberculous lesions in slaughtered pigs due to infection with members of the Mycobacterium avium complex are increasingly reported. Contaminated food originating from pig or other livestock is discussed as potential source of human infection. M. avium isolates from man (n=45), pig (n=29), and cattle (n=13) were characterised by restriction fragment length polymorphism (RFLP) with respect to insertion sequences IS1245 and IS901 as well as by XbaI-based pulsed-field gel electrophoresis (PFGE) and the results were compared by computer cluster correlation analysis, to determine potential sources of infection in man. By PCR, 55% of animal isolates was identified as M. avium subsp. avium, and 45% as M. a. hominissuis. All human isolates belonged to M. a. hominissuis. IS1245-RFLP and PFGE resulted in two distinct main groupings reflecting the two subspecies, and dividing the isolates into several subgroups. Animal isolates of M. a. hominissuis were widely distributed within the subgroups of human isolates. M. a. avium isolates, further discriminated by IS901-RFLP, formed host-associated subgroups for animals. Comparison of RFLP patterns with those of PFGE resulted in different subgroups as well as different pairs of isolates with high similarities. Only two isolates exhibited identical patterns by both methods. In general, results of both methods support the possibility that M. a. hominissuis isolates from livestock represent a source of infection for man, probably by common environmental reservoirs. There was no evidence of human infections caused by M. a. avium in Germany.

Animals↗
PubMed2006

[Intermittent compression devices for swelling reduction and thrombosis prophylaxis--a pilot study after total hip replacement. Is the 2 hour daily minimum application sufficient?].

BACKGROUND: The use of intermittent compression devices for thrombosis prophylaxis and the reduction of postoperative swelling are widely accepted. The recommended minimum application of 2 h daily has never been statistically verified. Without evidence based data, the benefit of this costly equipment cannot be maximized. PATIENTS AND METHODS: A randomized clinical trial on 41 patients after total hip replacement was performed. The A-V Impulse System was applied for 2 h a day during the first 5 postoperative days to observe whether this time was sufficiently effective. RESULTS: In the control group, two deep vein thromboses occurred postoperatively, but there were none in the treatment group. Even though two patients from the treatment group had to be excluded from the study because of severe pain, all other parameters including visual analogue pain scale results and limb circumferences were comparable in both groups. CONCLUSION: These preliminary results suggest that pump systems can prevent deep venous thrombosis after hip surgery even when applied for only short intervals over a short period of time. However, large scale confirmatory studies are needed.

Adult↗
PubMed2006

Sensitivity enhancement for colorimetric glucose assays on whole blood by on-chip beam-guidance.

In this paper, we present a novel concept for optical beam-guidance to significantly enhance the sensitivity of colorimetric assays by extending the optical path length through the detection cell which linearly impacts the resulting attenuation of a probe beam according to the law of Beer-Lambert. In our setup, the incident probe beam is deflected by 90( composite function) into the chip plane at monolithically integrated V-grooves to pass a flat detection cell at its full width (i.e., with a path length of 10 mm) instead of its usually much smaller height. Afterwards, the attenuated beam is redirected by another V-groove towards an external detector. The general beam-guidance concept is demonstrated by a glucose assay on human whole blood on a centrifugal microfluidic "lab-on-a-disk" platform made of COC. We achieve an excellent linearity with a correlation coefficient (R (2)) of 0.997 paired with a lower limit of detection (200 microM) and a good reproducibility with a coefficient of variation (CV) of 4.0% over nearly three orders of magnitude. With an accelerated sedimentation of cellular constituents by centrifugal forces, the sample of whole blood can be analyzed in a fully integrated fashion within 210 s. This time-to-result can even be improved by the numerical extrapolation of the saturation value. Additionally, the direct assay on whole blood also shows a negligible correlation with the hematocrit of the blood sample.

Blood Chemical Analysis↗
PubMed2004

[Zoonoses in working- and wild animals and their significance in Germany. An overview].

The control of infectious diseases transmitted from animals to humans (zoonoses) was recently put on a new basis in the European Union when a new Zoonoses Directive entered into force. Brucellosis, campylobacteriosis, echinococcosis, listeriosis, salmonellosis, trichinosis, and the respective causative agents, tuberculosis due to Mycobacterium bovis, and verotoxigenic Escherichia coli must be included in monitoring. Additional zoonoses and zoonotic agents are to be monitored according to the epidemiological situation. Against this background, the current knowledge on important zoonoses transmitted from livestock and some wildlife animals to humans as well as the epidemiological situation in Germany with regard to these diseases is summarized.

Animals↗
PubMed2004

High-resolution genotyping of Campylobacter upsaliensis strains originating from three continents.

Ninety-six Campylobacter upsaliensis strains that originated from Australia, Canada, and Europe (Germany) and that were isolated from humans, dogs, and cats were serotyped for their heat-stable surface antigens. All of them were genotyped by enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR) profiling, and 83 strains were genotyped by macrorestriction analysis with the endonuclease XhoI. Eighty-four percent of the strains belonged to five different serotypes (serotypes OI, OII, OIII, OIV, and OVI), with the proportions of strains in each serotype being comparable among the groups of strains from all three continents. Two serotypes, OIII and OIV, were prevalent at rates of 35 to 40%. Serotypes OI, OII, and OVI were detected at rates of 1.5 to 15%. Between 10 and 17.7% of the strains did not react with the available antisera. Analysis of the ERIC-PCR profiles revealed two distinct genotypic clusters, which represented the German and the non-European strains, respectively. XhoI macrorestriction yielded two genotypic clusters; one of them contained 80.2% of the German strains and 34.6% of the non-European strains, and the second cluster consisted of 65.4% of the non-European strains and 19.8% of the German strains. Fourteen strains from all three continents were analyzed for their 16S rRNA gene sequences. Only two minor variations were detected in four of the strains. In conclusion, C. upsaliensis has undergone diverging processes of genome arrangement on different continents during evolution without segregating into different subspecies.

Animals↗
PubMed2003

Microdevice with integrated dialysis probe and biosensor array for continuous multi-analyte monitoring.

The simultaneous on-line determination of glucose and lactate using a microdevice that consisted of a dialysis sampling system incorporated to the flow-through cell of a microfabricated biosensor array is presented. The fluidic connections between the different device's components were realized by subsequent processing of stacked dry resist layers on a plastic support that provided also the means for electric connections. The performance of the device was evaluated in vitro. The cross-talk effect on the downstream sensor was investigated and found to be negligible. Recoveries of over 95% for both analytes were achieved when flow rates of the perfusion fluid </=0.5 microl/min were used. At this flow rate, the response time of the device was 2.4 min, which is acceptable for on-line analysis. The linear response concentration range extended up to 30 mM for glucose and 15 mM for lactate. Interference from electroactive species such as ascorbic acid, 2-acetamidophenol and uric acid, was minimal (less than 5% increase in biosensors signal for all substances tested). In addition, the device presented long-term run stability both in buffer and serum samples.

Artifacts↗
PubMed2003

Epidemiological study on clinical bovine dermatophilosis in northern Ethiopia.

A total of 5586 indigenous and cross breed cattle were examined for clinical dermatophilosis, and 292 (5.22%) were positive. In indigenous cattle, statistically discernible (p < 0.05) difference was recorded between the prevalence in wet (5.5%) and dry (4.0%) seasons. During both seasons, infestation with A. Variegatum significantly (p < 0.05, chi 2 = 59.9) influenced clinical dermatophilosis. A. variegatum-infested cattle were at 7x higher risk (OR, Odds Ratio = 6.8) of acquiring the disease than non-infested ones. Logistic regression analysis of the overall prevalence showed a significant difference (p < 0.05) between prevalence in indigenous and cross breeds; the crossbreeds being at about 3x higher risk (OR = 2.68). Improved management reduced the prevalence in cross breeds from 15.1% in dry to 8.6% in wet season suggesting the significance of management in the epidemiology of dermatophilosis. The disease occurrence was also significantly (p < 0.05, chi 2 = 133.05) affected by agro-climatic (altitude) variation suggesting the impact of rainfall, humidity, vegetation and vector population that varied with altitude. Age and gender had no influence (p > 0.05) on the disease. Our result showed that season of the year, breed, management, infestation with A. variegatum and agro climatic difference are important risk factors influencing the disease pattern in the region. A tick control strategy and a better and adequate management particularly when keeping cross breeds are recommended.

Actinomycetales Infections↗
PubMed2002

BioMEMS device with integrated microdialysis probe and biosensor array.

The fabrication of a microdevice for continuous sampling and on-line monitoring of glucose is described. The device comprised a microdialysis sampling system integrated on the flow through channel of a microfabricated enzyme sensor. The sensor was produced by thin film technology and was assembled to a printed circuit board (PCB) that provided the means for both electrical and fluidic connections. A polyacrilonitrile fibre, with a cut-off of 50 kDa, was used in the fabrication of the sampling probe. The performance of the device was evaluated in-vitro. High sampling efficiency of the microdialysis probe was achieved by appropriate selection of the perfusion fluid flow rate. Response times varying from 1.5 to 3.0 min were determined for flow rates ranging between 1 and 0.2 micro l/min. The linear response range was up to 30 mM glucose and interference from other electroactive substances was almost negligible. The device showed excellent stability under continuous operation for at least 5 days and sensitivity variation less than 3% over a period of 15 days.

Biosensing Techniques↗
PubMed2002

High resolution genotyping of Campylobacter jejuni strains by macrorestriction analysis with XhoI and polymerase chain reaction targeting enterobacterial repetitive intergenic consensus sequences: can we predict the zoonotic potential of strains?

Campylobacter jejuni isolates of human, canine, feline, bovine and poultry origin were investigated for their genomic diversity using O-antigen typing (n = 271), SmaI (n = 158) and XhoI (n = 158) macrorestriction analysis and ERIC-PCR (n = 107). The O-antigens O:1/44, O:2, O:4 complex, O:37. O:40 were identified and 53.7% of the human and 56.1% of the animal strains were typable with the available antisera. Two ERIC-PCR pattern groups were generated representing human and animal strains as well as those exclusively of animal origin. XhoI macrorestriction analysis also distinguished 'human' and 'non-human' strain clusters, but by SmaI restriction mainly serotype-associated clusters were found. In conclusion, genomic differences may occur between 'human' and 'non-human' strains and this may reflect their potential to overcome the barrier from animals to humans.

Animals↗
PubMed2001

Lipopeptide adjuvants: generation of lactate dehydrogenase isoenzyme-specific antibodies for immunochemical diagnosis.

Lactate dehydrogenase catalyzes the final step in glycolysis, the interconversion of pyruvate and lactate. The tetrameric enzyme is composed of one or two subunits (H and/or M) resulting in five isoenzyme forms: LDH-H4, -H3M1, -H2M2, -H1M3, and -M4. The relative distribution of the LDH isoenzymes is tissue dependent and a significant marker for the diagnosis of hepatoma of the liver, myocardial infarction, muscular dystrophy, and a wide variety of other acute and chronic diseases to be detected by alterations of the LDH isoenzyme pattern in serum. Immunochemical approaches to the routine determination of LDH depend on isoenzyme specific antibodies. Since the H- and M-subunits for human LDH are highly homologous, LDH isoenzyme specific antibodies for immunochemical monitoring are hard to generate. Here we present data on the generation and characterization of LDH isoenzyme-specific mono- and polyclonal antibodies in different species in the presence of lipopeptide adjuvants. Western-Blot and ELISA analysis showed that antisera and monoclonal antibodies recognize their homologous antigens with high specificity and are therefore suitable for immunochemical monitoring of the LDH isoenzymes H4 and M4. In addition, they can be used for the determination of LDH isoenzyme specific activity which is an essential prerequisite for online amperometric immunosensor monitoring.

Adjuvants, Immunologic↗
PubMed2001

Genomic heterogeneity and O-antigenic diversity of Campylobacter upsaliensis and Campylobacter helveticus strains isolated from dogs and cats in Germany.

A serotyping scheme based on heat-stable surface antigens was established for 101 Campylobacter upsaliensis and 10 Campylobacter helveticus strains isolated from 261 dogs and 46 cats of different ages originating from two geographically distinct regions in Germany. The prevalence of C. upsaliensis varied between 27.8% in juvenile dogs (<12 months of age) and 55.4% in adult dogs (P < 0.05). Of the cats, 19.6% harbored C. upsaliensis, whereas 21.7% carried C. helveticus. Of the C. upsaliensis isolates from both host species, 93.1% belonged to five different serogroups, two of them being prevalent at rates of 47.5 and 27.7%, with different frequencies in both regions. Six (54.6%) of the C. helveticus isolates also belonged to serotypes found among C. upsaliensis strains, whereas five (45.4%) possessed an O antigen unique for C. helveticus. In contrast, a considerable degree of genomic diversity of the isolates was assessed by macrorestriction analyses with the endonucleases SmaI and XhoI, using pulsed-field gel electrophoresis as well as enterobacterial repetitive intergenic consensus sequence PCR (ERIC PCR). Restriction with SmaI pointed towards the existence of clonal groups associated to some extent with serotypes, while restriction with XhoI disintegrated these groups to smaller noncoherent subgroups. Analysis of ERIC PCR profiles did not exhibit any associations with serotypes. In conclusion these data demonstrate the genomic heterogeneity among C. upsaliensis strains and indicate that the combination of SmaI restriction with serotyping is a useful tool to investigate the expansion of clonal groups of C. upsaliensis.

Animals↗
PubMed1998

Novel system for real-time ex vivo lactate monitoring in human whole blood.

The objective of the study was to evaluate the performance of an amperometric enzyme based lactate sensor and to investigate the possibility of replacing a double lumen catheter based blood withdrawal system with a heparin coated single lumen system. The inner lumen of a double lumen catheter which was placed in a peripheral vein was perfused with heparin solution. The outer lumen was used to collect heparinized blood samples at a defined flow rate. The single lumen system was attached to a heparinized catheter which was also placed in a peripheral vein. The undiluted blood samples were collected at a specified flow rate. A sensor flow chamber incorporating an amperometric thin-film lactate microbiosensor was placed in the sampling line for real-time lactate monitoring. Plasma lactate concentrations were measured during frequently performed hyperlactatemia bicycle ergometer experiments in six healthy volunteers (age 25.8 +/- 2.8 years, BMI 22.7 +/- 1 kg/m2). Additionally, plasma lactate was measured in real-time using the lactate sensors. The first three experiments were performed with a double lumen based catheter system whereas the following three experiments were performed with a heparin coated catheter system. The correlation coefficients of sensor readings and laboratory analyzer results in all six experiments were between 0.93 and 0.99, respectively (P < 0.001). The miniaturized lactate sensors showed a linear range up to 25 mmol/l lactate concentration and 95% response times < 30 s in undiluted serum. During the experiments maximum lactate concentrations of 14 mmol/l were achieved. Improvements of system performance using heparin coated catheter systems could be shown. The overall SD of the sensor readings compared to laboratory results using three double lumen catheter based systems was 0.91 mmol/l whereas the SD using three heparin coated systems was 0.65 mmol/l. In summary, real-time monitoring of lactate in human whole blood is feasible with such a device and can be improved by using heparin coated catheter systems.

Adult↗
PubMed1998

Continuous measurement of subcutaneous lactate concentration during exercise by combining open-flow microperfusion and thin-film lactate sensors.

The present study was carried out to investigate in vivo in healthy humans the method of open-flow microperfusion for monitoring of the subcutaneous (s.c.) lactate concentration during rest and cycle ergometer exercise. Using open-flow microperfusion, a perforated double lumen catheter with an inflow and an outflow connection is inserted into the s.c. adipose tissue and perfused with a sterile, isotonic, ionfree fluid. Due to the low flow rate, the fluid partially equilibrates with the surrounding tissue. The equilibrated perfusate passes a sensor flow chamber where the substance of interest and the rate of recovery (i.e. the ratio of sampled concentration to interstitial concentration) are continuously monitored. Within this study, the method was evaluated in four healthy volunteers during cycle ergometer exercise. The relative increase of the lactate concentration was approximately a third in the s.c. tissue compared to the capillary blood and the peak time was delayed on average by 10 min. The correlation coefficient between blood and s.c. tissue lactate concentration ranged from r = 0.41 to r = 0.90 (n = 29) in the individual experiments. The combination of open-flow microperfusion and lactate and conductivity sensors enables on-line monitoring of the s.c. lactate concentration without in vivo calibration during steady-state and cycle ergometer exercise.

Adipose Tissue↗
PubMed1997

Campylobacter jejuni major outer membrane protein and a 59-kDa protein are involved in binding to fibronectin and INT 407 cell membranes.

Campylobacter jejuni is one of the major causes of human diarrhea throughout the world. Attachment to host cells and extracellular matrix proteins is considered to be an essential primary event in the pathogenesis of enteritis. Outer membrane proteins of three C. jejuni strains, one of which was aflagellate, were investigated for their contribution to the process of adhesion to INT 407 cell membranes and the extracellular matrix protein fibronectin. Using a ligand-binding immunoblotting assay the flagellin, the major outer membrane protein and a 59-kDa protein were detected to be involved in adhesion to both substrates. The MOMP was able to inhibit the attachment of the bacteria to INT 407 cell membranes partly, when the protein was isolated under native conditions. However, it was totally lost when the protein was isolated in the presence of SDS. The 59-kDa protein of one strain was identified by N-terminal sequencing, and regarding the first 14 amino acids it was found to be identical to the 37-kDa CadF protein just recently described as fibronectin-binding protein of C. jejuni. Especially for the aflagellate strain this protein may be of special importance for adhesion of the bacteria to different substrates.

Amino Acid Sequence↗
PubMed1997

Primary structure analysis and adhesion studies on the major outer membrane protein of Campylobacter jejuni.

The major outer membrane protein of Campylobacter jejuni (MOMP, 43 kDa), supposed to be one of the structures responsible for adhesion to INT 407 cells, was isolated from the crude outer membrane preparation by treatment with n-octyl-beta-D-glucopyranoside followed by preparative SDS-polyacrylamide gel electrophoresis. By cleavage of the isolated protein with cyanogen bromide and proteolytic enzymes, peptides were generated, separated by reverse phase high pressure liquid chromatography, and sequenced by automatic Edman degradation. The protein was aligned by identification of overlapping peptides. Treatment of bacteria with proteinase K prior to preparation of the outer membrane yielded a truncated MOMP with an apparent molecular mass of 25 kDa consisting of the C-terminal part of the protein. The isolated MOMP was functionally characterized by significant binding activity towards INT 407 cell membranes when isolated by preparative native gel electrophoresis, however, no binding activity was detected when the protein was isolated in the presence of SDS.

Adhesins, Bacterial↗
PubMed1997

Hydrophobic characterization of thermophilic Campylobacter species and adhesion to INT 407 cell membranes and fibronectin.

Cell surface hydrophobicity of Campylobacter jejuni, C. coli, C. lari and C. upsaliensis was tested by hydrophobic interaction chromatography on octylsepharose CL-4B. The hydrophobicity was influenced by cultivation mode, presence or absence of intact lipopolysaccharide (LPS) and outer membrane protein structures. Species-specific differences of hydrophobic characteristics were not detected. Bacteria grown in fluid medium exhibited a high degree of hydrophobicity. Agar-grown bacteria showed hydrophobic interaction to a significant lower extent. By oxidation of LPS with sodium meta-periodate the hydrophobicity of agar-grown bacteria was slightly increased. Bacteria pretreated with proteinase K exhibited a marked decrease of hydrophobic interaction, whereas pretreatment with trypsin did not influence the hydrophobic interaction. Live bacteria were allowed to adhere to INT 407 cell membranes. With exception of one aflagellate strain, bacteria grown in fluid medium adhered better to the cellular substrate than agar-grown bacteria. This difference was not found when adhesion to fibronectin was tested. LPS-oxidized bacteria adhered significantly better to both cell membranes and fibronectin, whereas proteinase K treated bacteria exhibited a significant loss of adhesion capacity for both substrates.

Bacterial Adhesion↗