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Biomedical subjects

M Seidel

Publications and source records attributed to M Seidel.

At least 19 recordsLinked to original sources

Study on DNA diversity of Iranian populations of Erysiphe betae causal agent of sugar beet powdery mildew.

107 samples of E. betae were collected on infected leaves from all over Iranian beet cultivation areas. Their choosing were based on geographical and host origin(sugar beet, red beet, fodder beet and wild beet). 30 isolates were single colonized and grown on sugar beet susceptible genotype 7233. 107 specimens were analyzed by restriction fragment length polymorphism (RFLP) of the ribosomal internal transcribed spacers (ITS) and 5.8s DNA which previously amplified by the polymerase chain reaction (PCR) with 2 universal primers, ITS1 and ITS4. PCR product was affected by 9 different restriction enzymes. PCR product was a 645 bp band for all of the isolates. 3 restriction enzymes; CfoI, MspI and HaeIII could cut this fragment into smaller bands, but electrophoretic patterns were identical for all of the isolates. 30 single colonized isolates were used in RAPD experiments. In RAPD-PCR experiment genetic diversity was investigated with 30 isolates from different parts of the country. 59 random primers were used and then 21 primers that displayed good consistency and reproducibility were selected. Most of the primers revealed identical patterns between 3 to 14 bands. 5 primers that showed more polymorphism were selected to analyze 30 isolates. For these 5 primers 61 distinct bands were obtained which 62% of these bands were polymorphic. Results indicated that there is no relationship between cluster grouping and geographical origin and the isolates showed a high similarity.

Ascomycota↗

Efficacy and tolerability of levetiracetam in patients with therapy-resistant epilepsy and learning disabilities.

INTRODUCTION: The purpose was to evaluate the effects of levetiracetam (LEV) in routine therapy in learning disabled patients with therapy-resistant epilepsy. METHODS: In an open observational add-on study design, 46 patients (residents of the Bethel Epilepsy Centre) with severe therapy-resistant epilepsy and different degrees of learning disabilities, who were treated with LEV between its introduction in Autumn 2000 and February 2002, were evaluated retrospectively. Information on monthly seizure frequencies, seizure severity and psychiatric status was extracted from the current patient case records. A 3 months baseline and a 3 months LEV treatment period (after 3 months of titration) were compared. Responders were defined as having a 50% reduction in seizure frequency and being evaluated as good or very good in an ad hoc global clinical efficacy scale. When only one criterion was positive, a careful individual decision was made based on the impact on the patients' daily activities. RESULTS: The responder rate was 41.3% (34.8 for 50% seizure reduction). It was higher in focal and multifocal epilepsy as compared to symptomatic generalised epilepsy/Lennox Gastaut Syndrome (P<0.05). Antiepileptic response occurred in doses between 500 and 4000 mg/day. Changes in seizure severity were rare. Nine patients experienced positive psychotropic effects (mostly improved vigilance and mood); six of these patients had antiepileptic effects as well. Twelve patients had adverse effects, mostly mild; in three cases, however, more severe effects led to discontinuation. CONCLUSIONS: LEV is an effective and generally well-tolerated drug for this patient group, especially in focal and multifocal epilepsy.

Adolescent↗

[Atypical epilepsy symptomatology as cause of a dementia like state in a mentally and physically retarded patient].

We report on a 50-year-old man with mental retardation and right-sided hemi-paresis. He seemed to be cured from epilepsy. In a short time a mental and physical deterioration developed which looked like a dementia, which was suggested by vascular risk factors. The EEG showed marked epileptic activity characterized by spikes appearing every 10 seconds over the left temporal lobe. After introduction of carbamazepine, a fast and long-term improvement of symptoms was noticed resulting in self sufficiency. The fast and marked effect of an antiepileptic drug being given to the patient with an non-typical reactivation of epilepsy in which the dementia-syndrome was caused by a transitory cognitive impairment due to sub-clinic electric seizures or non-convulsive status epilepticus.

Anticonvulsants↗

Expression of 5-HT3A receptors in cells of the immune system.

There is evidence from both human and animal research that 5-hydroxytryptamine3 (5-HT3) receptor antagonists, particularly tropisetron, exert analgesic and antiinflammatory effects. However, the underlying mechanisms of these effects including the expression of 5-HT3 receptors in cells of the immune system have not yet been investigated in detail. Therefore, we investigated the expression of the 5-HT3A receptor in primary human monocytes, chondrocytes, T-cells, dendritic cells, and synovial tissue. We found that 5-HT3A receptors are expressed in monocytes, chondrocytes, T-cells, and synovial tissue but not in dendritic cells. Our data show that 5-HT3A receptors are widely expressed in cells of the immune system and that they might play an important role in inflammatory events and in the observed antiphlogistic effects of 5-HT3 receptor antagonists.

Dendritic Cells↗

Ruthenium-catalyzed two-component addition to form 1,3-dienes: optimization, scope, applications, and mechanism.

A two component coupling of an allene and an activated olefin to form 1,3-dienes has been developed. The requisite allenes are synthesized either from terminal alkynes by a one carbon homologation using copper(I) iodide, paraformaldehyde, and diisopropylamine, via an ortho ester-Claisen rearrangement from a propargylic alcohol, or via a Wittig type reaction on a ketene generated in situ from an acid chloride. Mono- through tetrasubstituted allenes could be synthesized by these methods. Either cyclopentadienylruthenium(II) cyclooctadiene chloride or cyclopentadienylruthenium(II) trisacetonitrile hexafluorophosphate catalyze the addition reaction. When the former catalyst is employed, an alkyne activator is added to help generate the active catalyst. Through systematic optimization studies, a range of conditions was examined. The optimal conditions consisted of the use of cerium(III) trichloride heptahydrate as a cocatalyst in dimethylformamide as a solvent at 60 degrees C. The reaction was found to be chemoselective, and a wide range of functionality was tolerated, including esters, alcohols, nitriles, and amides. When substituted allenes are used, good selectivity can be obtained with proper substitution. A mechanism involving a ruthenacycle is proposed to account for the selectivity or lack thereof in product formation. With disubstituted allenes, selectivity is obtained when beta-hydrogen elimination is favored from a specific site. In tri- and tetrasubstituted allenes, steric issues concerning the C-C bond forming event appear to be the dominant factor in determining product formation. This process represents a highly atom-economical synthesis of 1,3-dienes in a controlled fashion. The utility of the 1,3-diene products was demonstrated by their use in Diels-Alder reactions to form a variety of cyclic systems including polycyclic structures. This sequence represents a convergent atom economic method for ring formation by a series of simple additions.

Alkadienes↗

Overlapping recognition determinants within the ssrA degradation tag allow modulation of proteolysis.

The ssrA tag, an 11-aa peptide added to the C terminus of proteins stalled during translation, targets proteins for degradation by ClpXP and ClpAP. Mutational analysis of the ssrA tag reveals independent, but overlapping determinants for its interactions with ClpX, ClpA, and SspB, a specificity-enhancing factor for ClpX. ClpX interacts with residues 9-11 at the C terminus of the tag, whereas ClpA recognizes positions 8-10 in addition to residues 1-2 at the N terminus. SspB interacts with residues 1-4 and 7, N-terminal to the ClpX-binding determinants, but overlapping the ClpA determinants. As a result, SspB and ClpX work together to recognize ssrA-tagged substrates efficiently, whereas SspB inhibits recognition of these substrates by ClpA. Thus, dissection of the recognition signals within the ssrA tag provides insight into how multiple proteins function in concert to modulate proteolysis.

ATPases Associated with Diverse Cellular Activitie↗

High-gradient millimeter-wave accelerator on a planar dielectric substrate.

We report the first high-gradient studies of a millimeter-wave accelerator, employing for the first time a planar dielectric accelerator, powered by means of a 0.5-A, 300-MeV, 11.424-GHz drive electron beam, synchronous at the 8th harmonic, 91.392 GHz. Embedded in a ring-resonator circuit within the electron beam line vacuum, this structure was operated at 20 MeV/m, with a circulating power of 200 kW, for 2 x 10(5) pulses, with no sign of breakdown, dielectric charging, or other deleterious high-gradient phenomena. We also present the first measurement of the quadrupolar content of an accelerating mode.

Journal Article↗

Molecular diagnosis of a Mycobacterium chelonae infection.

A 23-year-old female presented with enlarged cervical lymph nodes, and a diagnosis of nonspecific lymphadenitis with formation of pyogranulomas was rendered. Despite an initial oral antibiosis and subsequent long-term intravenous and oral antibiosis under hospitalized conditions, the symptoms progressed. The lymph nodes became larger and then affected the cervical region bilaterally. Her general condition worsened, and an exanthema of the extremities accompanied by a reactive arthritis occurred. Serological assays of various viral and bacterial markers and blood cultures were negative. Application of a polymerase chain reaction (PCR) protocol allowing specific amplification of mycobacterial DNA revealed DNA of Mycobacterium chelonea in formalin-fixed, paraffin-embedded lymph node tissue. Sequencing of the PCR product showed a 97% homology with the known Mycobacterium chelonae sequence. Modification of the antibiotic therapy with clarithromycin, imipenem and amikacin resulted in a rapid regression of the symptoms. The clinical course, in combination with the difficulties in detecting the infectious agent, supports the usefulness of molecular pathological analyses specific for nontuberculous mycobacteria (NTM).

Adult↗

18F-Fluorodeoxyglucose PET in a patient with primary small bowel lymphoma: the only sensitive method of imaging.

This report describes the case of a patient with primary small bowel lymphoma. Well-established methods of imaging did not give a hint on diagnosis. Increased 18F-fluorodeoxyglucose uptake was visualized on performance of positron emission tomography, corresponding with the intraoperatively found tumorous process. The present case points to a potential superiority of positron emission tomography in visualizing primary small bowel lymphoma.

Aged↗

A specificity-enhancing factor for the ClpXP degradation machine.

Events that stall bacterial protein synthesis activate the ssrA-tagging machinery, resulting in resumption of translation and addition of an 11-residue peptide to the carboxyl terminus of the nascent chain. This ssrA-encoded peptide tag marks the incomplete protein for degradation by the energy-dependent ClpXP protease. Here, a ribosome-associated protein, SspB, was found to bind specifically to ssrA-tagged proteins and to enhance recognition of these proteins by ClpXP. Cells with an sspB mutation are defective in degrading ssrA-tagged proteins, demonstrating that SspB is a specificity-enhancing factor for ClpXP that controls substrate choice.

Adenosine Triphosphatases↗

[Penetrating duodenal ulcer as the primary manifestation of intraductal papillary-mucinous pancreatic tumor].

A 60-year-old patient with a history of chronic pancreatitis and insulin-dependent diabetes was admitted to our hospital with a deeply excavated duodenal ulcer showing no signs of regression under 4-week parenteral nutrition and proton pump inhibitor therapy. Radiologic and endoscopic diagnostics could demonstrate a primary tumor of the pancreatic head penetrating into the duodenal lumen. After surgical treatment by pylorus-preserving pancreatoduodenectomy an abscessing intraductal papillary-mucinous neoplasm of the pancreas was established morphologically.

Adenocarcinoma, Papillary↗

[Abrikossoff's tumor--a rare differential diagnosis in neoplastic lesions of the esophagus].

We report the case of a 49-year-old male patient who was referred to our department in February 1998. Due to his complaints of dysphagia and retrosternal pain an upper gastrointestinal endoscopy was performed showing a polypoid lesion of the lower esophagus. This lesion presenting with a wide base and indurated surface was removed by endoscopic snare and forceps biopsies. Histologic and immunohistochemical analyses revealed this lesion to be a benign granular-cell tumor (Abrikossoff's tumor) which is considered to be of neuroectodermal origin. Abrikossoff's tumor is a rare differential diagnosis of polypoid lesions of the esophagus.

Diagnosis, Differential↗

Prospective randomized trial of two different immunoadsorbers in severe systemic lupus erythematosus.

Experiences with extracorporeal therapy in systemic lupus erythematosus have been published over the last 20 years and more. In addition to plasmapheresis, specific adsorption columns have been developed to deplete pathogenic antibodies and immune complexes in the plasma of patients with SLE. We conducted a prospective randomized trial to compare the efficacy of a disposable adsorption column, which contained a specific ligand, phenylalanine (IMPH-350|Pt, Diamed, Köln, Germany) with a regenerable Ig-adsorbing column containing sheep anti-human antibodies (Ig-Therasorb|Pt, Therasorb, München, Germany). Twenty SLE patients inadequately controlled with corticosteroids, anti-malarials, azathioprine or cyclosporine A, had strong evidence of disease in general, or an organ related SLAM score. They were randomized to receive either a perfusion of IMPH-350, or Ig-Therasorb, immunoadsorbed with 2.5 ml of plasma, three times each. The treatment regime was repeated after 4 weeks when the response was limited or non-existent. Response was defined as a reduction in the SLAM score of at least 30%. SLAM scores in the IMPH group decreased from 14.3+/-5.6 to 9.2+/-6.2 after 1 month and to 9.4+/-3.9 after 6 months; corresponding scores in the Ig-Therasorb group were 18.3+/-5. 5 to 11.2+/-7.6, decreasing to 9.2+/-2.9. After 1 month, 8/10 patients in both groups showed a response; after 6 months, 5/10 patients in the IMPH-350 group and 8/10 in the Ig-Therasorb group fulfilled the response criteria. Reduction of dsDNA antibodies directly after treatment was 50.8+/-6.6% in the IMPH-350 group and 61.0+/-8.0% in the IgTherasorb group. Results indicate that immunoadsorption is an additional option in the treatment of severe SLE. Choice of type of immunoadsorber and immunosuppressive treatment has to take into account the severity and chronicity of common disease activity and organ involvement, as well as economic aspects.

Adult↗

Seed strength determination for eye plaque therapy.

Standardized radioactive plaques have been used in the irradiation of intraocular tumors. These plaques have defined slots to accommodate 125I seeds and hence produce predictable isodose distributions. The seed strength has to be adjusted to deliver 100 Gy to the prescription point, which varies with the tumor size. The purpose of this work is to develop lookup tables that relate the seed strength to different prescription distances. Dose rates were determined for a set of standardized eye plaques. Using these dose rates and the source strength decaying expression, the seed strengths were determined as a function of distance along a line through the plaque. Two seed-strength tables were created based on four-day and five-day treatment times delivering a 100 Gy to the prescription distance.

Brachytherapy↗

[The segmental organization and horny structure of the claw of the dog].

This study classifies the segments of the dog claw and presents a new conception to define crown and wall segments that deviates from the common statements in literature. The perioplic segment extends along the internal surface of the claw fold (vallum). The crown segment lies in the unguicular groove, and there in a semicircular zone. In the crown segment there is development of horn tubuli, but these lose their tubular structure before they have reached the top of the claw. The wall segment, adjacent distally, comprises a dorsal ridge, and lateral surfaces proximally and distally which are all marked by superficial lamellar-shaped surface configurations. The sole segment shows desquamative soft horn and is situated between the free margin of the wall segment palmar/plantar to the unguicular process. The new conception of homology of dog claw distinguishes between main and secondary criteria. The main criterion is the epidermal and dermal configuration. Secondary criteria are the typical horn products (for example perioplic horn) and dimension, shape and topography of segments. The sterile/fertile-bed theory, which was believed to be the determining factor for the classification of the dog claw, is neither the proper method to define the individual segments nor to judge the rate of cornification.

Animals↗