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Biomedical subjects

A Becker

Publications and source records attributed to A Becker.

At least 37 records · Page 2Linked to original sources
PubMed2005

[Persistent fever in a patient with Salmonella typhimurium gonarthritis].

A 65-year-old patient with systemic lupus erythematodes (SLE) developed fever and gonarthritis whilst taking prednisone and hydrochloroquine. Salmonella typhimurium, sensitive to amoxicillin, was grown in cultures of synovial fluid, blood and urine. After high dosages of intravenous amoxicillin, blood cultures and knee punctate became negative, but fever seemingly without a clinical focus persisted. By means of a fluoro-18-deoxyglucose positron emission tomography (FDG-PET) scan, an abscess was located in the left upper leg and successfully treated. In patients with impaired cell-mediated immunity, an extra-intestinal manifestation of Salmonella should be taken into consideration particularly if there appears to be no clinical focus. This may be detected by FDG-PET.

Aged↗
PubMed2005

Tic disorders and obsessive compulsive disorder: where is the link?

Over the last years evidence on the overlap between tic-disorders (TD) and obsessive compulsive behavior/disorder (OCB/OCD) has increased. The main focus of research have been the phenomenological and epidemiological similarities and differences in samples of different age, primary diagnosis (TD vs. OCD) including the co-occurrence of both. Unfortunately, only a minority of studies included all three groups (TD, TD + OCD, OCD). Nevertheless, new insight concerning possible subtypes for both TD and OCD has been gained. While some authors concentrated on OCD with/without tics we will summarize the field of TD and OCB/OCD from the viewpoint of tics, since OCB plays an important role in patients with TD. Thereby we will not only sharpen the clinicans' awareness of known differences in phenomenology, epidemiology, genetics and neurobiology, aimed to improve their diagnoses and treatment but also highlight the gaps of knowledge and discuss possibilities for further research in this field.

Child↗
PubMed2005

[Syncope and epileptic seizures].

Syncope is one of the most common symptoms leading to hospital admission. Thereby syncope can be induced by several diseases. It is crucial to detect underlying structural heart disease or high grade arrhythmias, as these are associated with an increased mortality. The careful history and physical examination can often give sufficient evidence to evaluate the origin of syncope. Additional examinations should only be applied selectively. In patients with structural heart disease the specific treatment should be initiated, in patients with cardiac arrhythmias the implantation of a pacemaker or ICD might be indicated. The most common neurally-mediated and orthostatic syncopes can often be treated successfully by physical training. Beside syncope epilepsy might be responsible for a transient loss of consciousness. Again careful history taking helps to differentiate between these two entities.

Acute Disease↗
PubMed2005

Bed, bath and beyond: pitfalls in prompt eradication of methicillin-resistant Staphylococcus aureus carrier status in healthcare workers.

Healthcare workers (HCWs) in close contact with patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) were screened for MRSA acquisition. From 1995 to 2001, MRSA was identified from the nasopharyngeal swabs of 87 HCWs, collected one to two weeks after contact with 592 known MRSA-positive patients. These HCWs were withdrawn from work and treated with topical antibiotics/antiseptics. They were advised to disinfect their bathrooms and personal hygiene articles, and to wash bed linen and pillows. They were screened for successful eradication for up to three months. Seventy-three (84%) HCWs lost their carrier status. The eradication regimen failed in 14 cases. In 11 of these MRSA was detected only in later nasopharyngeal swabs (suspected recolonization). Screening identified nasal colonization of close household contacts in eight of these 11 cases. Environmental sampling detected contamination in seven out of eight screened home environments. When eradication treatment was applied to household contacts and when household surfaces were cleaned and disinfected, the carriage cleared in most cases within a few weeks. However, when home environments are heavily contaminated, despite adequate medical treatment, eradication took upto two years. Due to withdrawal from work, the 14 carriers without prompt and lasting eradication after the first course of treatment accounted for about 70% of all lost working days. These experiences support the hypothesis that control measures should not be restricted to antibiotic or antiseptic treatment of long-term carriers (HCWs as well as patients), but must also include cleaning and disinfection of the household.

Carrier State↗
PubMed2005

Magnetic particles as markers and carriers of biomolecules.

The detection and manipulation of biomolecules on a common platform is of considerable interest not only for application in devices such as diagnostic tools but also for basic research in biological and medical systems. A promising approach is the utilisation of magnetic particles as markers and carriers for biomolecules. The principle functionality of this approach is demonstrated by the authors. Magnetic particles used as markers can be detected by highly sensitive magnetoresistive sensors resulting in a purely electronic signal. A direct comparison with the standard fluorescence method reveals the advantages of using the magnetic particles. In addition, magnetic particles used as carriers can be manipulated on-chip via currents running through especially designed line patterns. Some current drawbacks and future aspects are discussed. The combination of sensing and manipulating magnetic particles is a promising choice for future integrated lab-on-a-chip systems.

Biomarkers↗
PubMed2005

[Identification of Sinorhizobium meliloti genes influencing synthesis of surface polysaccharides and competitiveness].

A new approach to isolating mutants with altered composition of capsular polysaccharides (CPS) and lipopolysaccharides (LPS) in nodule bacteria of alfalfa Sinorhizobium meliloti based on analysis of their respiratory activity was proposed. Random Tn5-mob mutants of symbiotically effective strain SKhM1-105 were tested for slime-production ability and coloration on diagnostic media containing the indicator of reducing equivalents, triphenyltetrasolium chloride (TTC), the inhibitor of respiratory activity, 2-methyl-4-chlorphenoxybutyric acid and Congo Red, the stain for LPS and exopolysaccharides (EPS). Electrophoretic analysis (SDS-PAGE) of polysaccharides in seven mutants, markedly differing from the parental strain with respect to their growth on diagnostic media demonstrated that (1) the production of CPS was either decreased (in mutants T64 and T835) or blocked (in T71, T94, T124, T134, and T170); (2) the R form of LPS had changed mobility (in T134); (3) the S form of LPS contained only one component instead of two (T71). In symbiosis with alfalfa Medicago sativa, all mutants exhibited a decreased competitive ability for adsorption on roots of host alfalfa plant, compared to the parental strain. At early stages of symbiosis, mutants had a tendency toward a decrease in the number of nodules, in comparison with the parental strain (a statistically significant decrease was observed in mutants T71 and T64). In mutants T64, T71, and T134, nodulation competitiveness was lower than in the parental strain. Analysis of Tn5-mob tagged sequences of the mutants revealed homologies with the genes encoding methionine synthase, luciferase-like monooxygenase, UDP-glucuronic acid epimerase, sensor hystidine kinase, acetoacetyl-CoA-reductase, oligopeptide uptake ABC transporter, and a transcription activator.

Bacterial Capsules↗
PubMed2004

[Technique and possibilities of cardiac computed tomography].

Electron beam computed tomography no longer has a role to play in Germany. In contrast, multidetector spiral CT has great potential for replacing some coronary catheter studies, in particular for the exclusion of coronary artery disease, and this in particular since the forthcoming introduction of a 64-slice MDCT scanner promises a further improvement in temporal and special resolution. Currently, however it is no alternative to invasive angiography, since quantification of coronary stenoses is not possible; nor can a diagnostic evaluation be made in the presence of coronary calcifications or intracoronary stents. In particular, however, before applying CT angiography to the heart, the patient groups that can benefit from this method must be defined, especially in light of the fact that radiation exposure is three times as high as with diagnostic coronary catheterization.

Coronary Angiography↗
PubMed2004

[Coronary calcifications and the diagnosis of coronary artery disease].

Coronary calcium is a sensitive marker of coronary atherosclerosis, even at an early stage. With the aid of multislice computed tomography, noninvasive visualization of the microcalcification is possible. This enables the identification of asymptomatic patients at risk of developing future cardiovascular disease, and the initiation of effective preventive measures. In addition, in symptomatic patients, CT angiography with calcium scoring is of high negative predictive value in the exclusion of coronary artery disease.

Calcinosis↗
PubMed2004

[Detection and characterization of atherosclerotic coronary plaques with multislice spiral computed tomography].

Provided that adequate image quality is achieved, contrast-enhanced multislice spiral computed tomography enables the identification and characterisation of calcified and non-calcified coronary plaques. This is a major advance in the non-invasive assessment of coronary atherosclerosis that promises to open up new opportunities for a better understanding and risk stratification of this condition, with visualization of non-calcified hypodense lesions in particular appearing to be of prognostic importance. Current limitations of the technique relating mainly to temporal and spatial resolution may be eliminated by the introduction of a new generation of scanners enabling 64 slices and more.

Angina Pectoris↗
PubMed2004

Platinum levels in nasal lavage fluid as a biomarker for traffic-related exposure and inflammation in children.

Platinum (Pt) is a well-known constituent of particles emitted by catalytic converters during car operation. To evaluate Pt as a potential marker for traffic related particle exposure, we investigated Pt content along with metals vanadium (V) and chromium (Cr) in coarse and fine particulate matter (PM), sampled in four areas with different traffic density, as well as in the nasal lavage (NAL) of 67 children (average age: 6 years) living in these areas. The different sites were characterised by significant differences in air pollutants including PM, NO, NO(2), CO and Cr, but differences in V or Pt were absent. No significant differences in neutrophil and epithelial cell counts or concentrations of the neutrophil chemoattractant interleukin-8 (IL-8) were found in the NAL of children living in the different areas. In addition, the concentrations of V, Cr and Pt, which were detectable in 64%, 73% and 93% of the individuals, respectively, did not differ between the different locations. However, in the NAL of the children, a significant correlation between Pt and the number of neutrophils/ml (r=0.40, p<0.001) as well as of epithelial cells/ml (r=0.41, p<0.001) was found. No relation was present between nasal inflammation and nasal Cr levels, whereas a relatively weak association was observed between V and epithelial cells counts (r=0.30, p=0.018). In conclusion, our data suggests a role for nasal lavage Pt as a candidate biomarker for traffic-related PM, which is able to induce inflammation in the upper respiratory tract.

Air Pollutants↗
PubMed2004

Wide-range transcriptional modulating effect of ntrR under microaerobiosis in Sinorhizobium meliloti.

A mutation in the second gene in the ntrPR operon results in increased expression of nodulation (nod) and nitrogen fixation (nif) genes in Sinorhizobium meliloti. Since this pleiotropic effect is particularly pronounced in the presence of external combined nitrogen, a nitrogen regulatory function has been suggested for NtrR. To identify the complete set of protein-coding genes influenced by loss of ntrR function, microarray hybridizations were carried out to compare transcript levels in the wild type and mutant strains grown under aerobic and microaerobic conditions. Of the 6207 genes examined, representing the entire genome of S. meliloti, 7% exhibited altered expression: 4.5% of the genes are affected under oxic, 2.5% under microoxic conditions. 0.4% of all the genes are affected under both oxygen concentrations. A microoxic environment is required for the induction of genes related to symbiotic functions but results in the down-regulation of other (e.g. metabolic) functions. When the alterations in transcription levels at low oxygen concentration in the mutant strain were compared to those of the wild type, a modulating effect of the ntrR mutation was observed. For example, symbiotic nif/fix genes were induced in both strains, but the level of induction was higher in the ntrR mutant. In contrast, genes related to transcription/translation functions were down-regulated in both strains, and the effect was greater in the wild-type strain than in the ntrR mutant. A relatively wide range of functions was affected by this modulating influence, suggesting that ntrR is not a nitrogen regulatory gene. Since genes encoding various unrelated functions were affected, we propose that NtrR may either interfere with general regulatory mechanisms, such as phosphorylation/dephosphorylation, or may influence RNA stability.

Aerobiosis↗
PubMed2004

Detection and manipulation of biomolecules by magnetic carriers.

The detection and manipulation of single molecules on a common platform would be of great interest for basic research of biological or chemical systems. A promising approach is the application of magnetic carriers. The principles are demonstrated in this contribution. It is shown that paramagnetic beads can be detected by highly sensitive magnetoresistive sensors yielding a purely electronic signal. Different configurations are discussed. The capability of the sensors to detect even single markers is demonstrated by a model experiment. In addition, the paramagnetic beads can be used as carriers for biomolecules. They can be manipulated on-chip via currents running through specially designed line patterns. Thus, magnetic markers in combination with magnetoresistive sensors are a promising choice for future integrated lab-on-a-chip systems.

Biopolymers↗
PubMed2004

Global transcriptional analysis of the phosphate starvation response in Sinorhizobium meliloti strains 1021 and 2011.

The global response to phosphate starvation was analysed at the transcriptional level in two closely related strains of Sinorhizobium meliloti, Rm1021 and Rm2011. The Pho regulon is known to be induced by PhoB under conditions of phosphate limitation. Ninety-eight genes were found to be significantly induced (more than three-fold) in a phoB -dependent manner in phosphate-stressed cells, and phoB -independent repression of 86 genes was observed. Possible roles of these genes in the phosphate stress response are discussed. Twenty new putative PHO box sequences were identified in regions upstream of 17 of the transcriptional units that showed phoB -dependent, or partially phoB -dependent, regulation, indicating direct regulation of these genes by PhoB. Despite the overall similarity between the phosphate stress responses in Rm1021 and Rm2011, lower induction rates were found for a set of phoB -dependent genes in Rm1021. Moreover, Rm1021 exhibited moderate constitutive activation of 12 phosphate starvation-inducible, phoB -dependent genes when cells were grown in a complex medium. A 1-bp deletion was observed in the pstC ORF in Rm1021, which results in truncation of the protein product. This mutation is probably responsible for the expression of phosphate starvation-inducible genes in Rm1021 in the absence of phosphate stress.

ATP-Binding Cassette Transporters↗
PubMed2004

Comparison of a prototype magnetoresistive biosensor to standard fluorescent DNA detection.

We present a comparative analysis of a magnetoresistive biosensor to standard fluorescent DNA detection. The biosensor consists of giant magnetoresistive (GMR) type Cu/Ni(80)Fe(20) multilayers in the second antiferromagnetic coupling maximum. Each of the 206 elements of the magnetoresistive biosensor is patterned into a spiral-shaped line that can cover the area of a typical DNA spot (70 microm diameter). The probe DNA is assembled on top of the sensor elements in different concentrations ranging from 16 pg/microl to 10 ng/microl. Complementary biotin-labeled analyte DNA is hybridized to the probe DNA at a concentration of 10 ng/microl. A number of different commercially available magnetic microspheres are investigated to determine the most appropriate markers. The experimental comparison shows that the relative sensitivity of the magnetoresistive biosensor is superior to the fluorescent detection at low probe DNA concentrations.

Biosensing Techniques↗
PubMed2004

Accelerated kindling development in mu-opioid receptor deficient mice.

The relevance of mu-opioid systems for central excitability and kindling related disturbed learning performance was underlined by investigations using mu-opioid receptor knockout mice. Mice lacking mu-opioid receptors showed an accelerated kindling development induced by the convulsant drug pentylenetetrazol. Blockade of delta-opioid receptors by naltrindole suppressing kindling development in wild-type animals led to a further acceleration of kindled seizure development in the knockout mice. Mice lacking mu-opioid receptors showed such a low learning performance in the shuttle box, that the kindling induced learning deficit as seen in wild-type mice was not detected. The results were discussed on the basis of receptor binding studies with regard to subtypes of glutamatergic receptors, delta-opioid and somatostatin receptors. An increase in glutamate and somatostatin binding could contribute to the enhanced excitability in the-mu-opioid receptor knockout mice.

Animals↗
PubMed2004

[Disease-oriented Internet use in outpatients with inflammatory rheumatic diseases].

OBJECTIVE: On behalf of the "systemic inflammatory rheumatic diseases network" comprehensive, nationwide horizontal and vertical cross-linking of research and care is to be developed for the first time. The quality of scientific work and patient care is to be increased in the medium term through this improved communication and co-operation. Our objective was to determine what hardware and software are available to the patients involved, with a view to the Internet being used as a basis for communication. The ultimate aim was to provide patients with an adequate source of information on care. METHODS: A survey was carried out among 400 patients attending our outpatient clinics. Data on the hardware and software used and on Internet access and patterns and degree of utilization were collected using a unilateral questionnaire. RESULTS: 326 patients filled in the questionnaire. 163 of those responding had Internet access, with younger and better educated patients using the Internet significantly more frequently. No dependency was noted on gender or marital status. Mean time duration for Internet use was longer in men. 55.8% of the internet users searched for medical questions. Major search topics included up to date therapeutic options (46.6%) and information on specific diseases (28.8%). CONCLUSION: Internet is an important information medium for patients. Technical requirements and high motivation make communication practicable for about 50% of patients. To ensure acceptance, the Internet platform of the systemic inflammatory rheumatic diseases network needs to be aligned to patients' requirements, bearing in mind the need for extensive high-value, reliable scientific information to be offered on the website.

Adult↗
PubMed2004

[Occlusion of central venous port catheters after simultaneous 24 h infusions of 5-FU and calcium-folinic acid in patients with gastrointestinal cancer].

Folinic acid-modulated 5-FU regimens are standard elements in several chemotherapy combinations like FOLFIRI, FOLFOX or AIO-regimen in the palliative treatment of patients with gastrointestinal cancer. When the simultaneous mixed infusion of 5-FU and calcium-folinic acid (Leucovorin) was authorized by the BfArM in 2002, we introduced this application regimen in the treatment of our cancer patients. 19 patients (AIO-regimen [5], FOLFIRI [12] and FOLFOX [2]) received a simultaneously mixed infusion of calcium-folinic acid and 5-FU over 24 hours with a total of 110 applications. 5-FU doses varied between 2000 and 2600 mg/m2, calcium-folinic acid was given with 500 mg/m2, infusion rate was 10 ml/hour using a 24 h pump. Central venous catheters employed included single Barth-Port in 18 cases, 1 patient had a Viggon-Port. In 3 out of the 19 patients catheter occlusion was noticed after 8-10 weekly applications of the mixed infusion. Heparine and subsequently urokinase were not successful in reversing the obstruction. All three catheters had to be explanted. Catheter tips in all cases showed a yellow cristalline precipitation. The crystallographic analysis exhibited calcium carbonate (CaCO3) in its polymorphic form (calcite). Thus, we confirmed calcite formation causing catheter occlusion as a frequent complication during a continuous 24 h-infusion of mixed high dose 5-FU and calcium-folinic acid. This reaction could not be avoided by increasing infusion volume and the application flow rate. As a result of our findings, recommending using calcium-folinic acid mixed with 5-FU has been withdrawn in the meantime.

Aged↗