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At least 991 records · Page 55Linked to original sources
PubMed2000

[The importance of Arnold Pick for modern concepts of degenerative dementia. Retrospect and appreciation].

It will be shown that the contribution of Arnold Pick (1851-1924) goes far beyond the first description of the disorder associated with his name. His view that the process of dementia should not be conceptualised as a diffuse degradation of mental abilities but as a mosaic of circumscribed neuropsychological deficits is as modern now as it was then and is a prerequisite for the differential diagnosis of degenerative dementias during life.

Eponyms↗
PubMed2001

[Somatoform disorders. Historical development and modern diagnostic conceptualization].

Patients with "medically unexplained" bodily symptoms form a major group in the medical care system. Diagnostic and therapeutic problems very often arise, and the concept of "somatization" promotes a better understanding of this patient group. Important historical stages in the development toward a modern diagnostic classification of somatoform disorders are outlined. A critical comment on the diagnostic approaches according to DSM-IV and ICD-10 follows.

Conversion Disorder↗
PubMed2003

[Modern magnetic resonance techniques in stroke].

In industrialized nations, stroke is the most common cause of permanent disability and need of care. Causal treatment is possible only during the first few hours following the stroke, in the form of systemic fibrinolysis. An exact diagnosis of the causative pathology must be made before starting the therapy, and this must happen in the shortest possible period of time. Using imaging techniques, the whole spectrum of differential diagnoses of cerebral ischemia must be covered, including above all intracerebral and subarachnoid hemorrhage. Although computed tomography (CT) is excellently suited for determining hemorrhage, infarct can be recognized with much better contrast using diffusion-weighted magnetic resonance (MR) imaging (DWI). Stroke MR imaging additionally allows the representation of vital "tissue at risk"of infarction using perfusion images as well as the recognition of vessel occlusion using MR angiography. This paper is intended to define the usefulness of DWI in comparison to CT techniques and to elucidate the use of diffusion coefficients for differentiating the various stages of infarction. Besides presenting an explanation of the basic principles of modern stroke MR imaging, typical results of MR perfusion measurements and the appearance of hemorrhages on MR will be explained.

Brain Ischemia↗
PubMed2004

[Modern diagnosis of lung nodules].

Despite numerous technical improvements, modern diagnosis of lung nodules can still be divided into three partially overlapping stages: (1) detection, (2) characterization, and (3) follow-up and management. With respect to these steps, this article reviews the diagnostic significance of different modalities. New and not definitively evaluated techniques are considered. Furthermore, methods that are not routinely applied but have been published and are thought to have some value in the characterization of pulmonary lung nodules are discussed. Statistical data are included to assist the classification of the results of imaging. Remarks on biopsy of lung nodules to obtain histopathologic correlation complete this overview. The authors are convinced that the established methods (radiography for detection, spiral CT for characterization), after thorough evaluation, will soon be replaced by magnetic resonance imaging (MRI). Recent experience with MRI points to its potential for detection and characterization of pulmonary nodules while avoiding ionizing radiation. The development of indications for MRI of the lung (e.g. paediatric radiology) will be fascinating to observe.

Humans↗
PubMed1996

[Cost benefit considerations in modern diagnostic sectional imaging exemplified by upper abdominal organs].

Demands for increased productivity despite cuts in financial resources have renewed the discussion of cost effectiveness in medical care. Unfortunately, there is a lack of reliable data for evaluating the cost effectiveness of diagnostic procedures. The present article discusses various aspects of this topic and presents examples from the diagnostic evaluation of the upper abdomen. It is argued that modern imaging procedures have in the past helped to reduce costs and that they can become cost effective when they replace established combinations of diagnostic procedures. The present discussion is severely hampered by the fact that there are no generally accepted standards for evaluating diagnostic strategies and that there are no well-founded studies of the cost effectiveness of the strategies used in abdominal diagnosis. Cost effectiveness will in the future become an additional criterion for assessing the quality of medical care.

Cost-Benefit Analysis↗
PubMed1997

[Acute cerebral infarct: physiopathology and modern therapeutic concepts].

This review focuses on the pathophysiological changes in acute cerebral ischemia, with special emphasis on disturbances of the cerebral blood flow (CBF) and the associated penumbra concept. Alternatively, the model of peri-infarct depolarization is demonstrated. Metabolic and molecular changes caused by cerebral ischemia and reperfusion are discussed, namely energy failure, release of glutamate with an excitatoric burst, calcium influx in neurons, generation of free radicals, activation of different proteases, disturbances of protein synthesis, induction of gene expression and apoptosis, loss of membrane integrity, edema formation and microvascular disturbances. In summary, the pathophysiological changes after focal cerebral ischemia and reperfusion are most adequately described by a network of interacting different mechanisms of tissue alterations. The simple concept of a cascade of ischemic effects which would be easy to block seems to be less applicable. A time window of approximately 6 h for the acute stroke therapy is postulated on the base of the above mentioned pathophysiological changes. The recently introduced treatment regimen with optimized basic treatment, recanalization using thrombolysis and neuroprotection by different agents is presented. Different modes of a possible intervention are discussed. Modern concepts of stroke therapy including stroke-unit care and thrombolysis with add-on neuroprotection seem to have potential for improving the outcome of acute stroke patients.

Acute Disease↗
PubMed1999

[Modern network technologies for data communication in the hospital].

Modern network technologies provide the basic infrastructure for information and communication systems in the hospital today. The goal to build up a universal network infrastructure which meets the broadly varied requirements. Analysis of data communication in the hospital and the evaluation of established network technologies, as well as new developments, leads to the switching concept as the suitable solution. Two technologies play the major role in building enterprise networks: the Ethernet family, based on frame switching, and ATM, based on cell switching. Orientation on established standards is the key to free system choice and grants interoperability between systems from different manufacturers. However, the network design must meet the application and system architecture of the information technology in order to achieve successful mapping of the involved communication profiles. This means scaling of the bandwidth as needed, suitable segmenting of the network and resilient links. In a further step, policy-based networking takes advantages of prioritizing critical applications and therefore reduces interdependencies across the network.

Computer Systems↗
PubMed2003

[Modern diagnostics for urological infections].

This paper provides a short overview of modern, molecular-based diagnostic procedures of urogenital tract infections. Although gaining importance, molecular methods have not yet become a reliable substitution for the classic procedures in terms of costs and quality standards. As an example of a new molecular approach in microbiology, a method for the detection of the most relevant uropathogens in a single PCR is presented. Furthermore, the development of a real time PCR is described.

Bacteria↗
PubMed2006

[Georg Kelling (1866-1945): the man who introduced modern laparoscopy into medicine].

On 23 September 1901, Georg Kelling (1866-1945) from Dresden performed a celioscopy with a Nitze cystoscope on a dog in Hamburg. This was the beginning of the era of laparoscopy.His doctoral thesis already reflected his early interest in the anatomy and physiology of the gastrointestinal tract. This experience, together with his knowledge on air insufflation of the abdomen, enabled him to be the first to develop the procedure he named "celioscopy." During this pioneer time of laparoscopy, he developed various basic principles that are still valid today and demonstrated astonishingly visionary skills. Although his pioneering achievements have hardly been acknowledged to this day, modern laparoscopy has confirmed Kelling's visions and scientific work in almost all aspects. His name and achievements have most definitely earned a place in the history of endoscopy.

Germany↗
PubMed2002

Spelt-specific alleles in HMW glutenin genes from modern and historical European spelt ( Triticum spelta L.).

A partial promoter region of the high-molecular weight (HMW) glutenin genes was studied in two wheat specimens, a 300 year-old spelt ( Triticum spelta L.) and an approximately 250 year-old bread wheat ( Triticum aestivum L.) from Switzerland. Sequences were compared to a recent Swiss landrace T. spelta'Oberkulmer.' The alleles from the historical bread wheat were most similar to those of modern T. aestivumcultivars, whereas in the historical and the recent spelt specific alleles were detected. Pairwise genetic distances up to 0.03 within 200 bp from the HMW Glu-A1-2, Glu-B1-1 and Glu-B1-2 alleles in spelt to the most-similar alleles from bread wheat suggest a polyphyletic origin. The spelt Glu-B1-1 allele, which was unlike the corresponding alleles in bread wheat, was closer related to an allele found in tetraploid wheat cultivars. The results are discussed in context of the origin of European spelt.

Journal Article↗
PubMed2002

AFLP and pedigree-based genetic diversity estimates in modern cultivars of durum wheat [ Triticum turgidum L. subsp. durum (Desf.) Husn.].

A substantial amount of between and within cultivar genetic variation was detected in all the 13 registered modern Canadian durum wheat ( Triticum turgidum L. ssp. durum (Desf.) Husn.) cultivars based upon amplified restriction fragment polymorphism (AFLP). Of the approximately 950 detected AFLP markers, only 89 were polymorphic, with 41 between cultivars whereas the remaining 48 showed polymorphism within at least one cultivar. The ancestry of Canadian durum wheat cultivars was traced back to 125 cultivars, selections, and breeding lines including 17 landraces. Mean pair-wise genetic distance based on the kinship coefficient was 0.76. On the other hand, AFLP-based mean pair-wise genetic distance was 0.40. Even though there was a large difference between the means of the two diversity measures, a moderate positive correlation ( r=0.457, p<0.002) was detected between the two distance matrices. Cluster analysis with the entire AFLP data divided all cultivars into three major groups reflecting their breeding origins. One group contained 'Pelissier' alone, which was a selection from a landrace introduced into the US from Algeria. On the other hand such groupings among cultivars were not evident when KIN was used for genetic diversity measures instead. The level of genetic variation among individuals within a cultivar at the breeders' seed level was estimated based on an inter-haplotypic distance matrix derived from the AFLP data. We found that the level of genetic variation within the most-developed cultivars is fairly substantial despite rigorous selection pressure aimed at cultivar purity in breeding programs. Comparison of AFLP and pedigree-based genetic diversity estimates in crop species such as durum wheat can provide important information for plant improvement.

Journal Article↗
PubMed2006

Volume-targeted modes of modern neonatal ventilators: how stable is the delivered tidal volume?

OBJECTIVE: Volume-targeted modes are designed to deliver a constant tidal volume (V(t)) at lowest possible pressure independently of changes in compliance, resistance, and leak of the respiratory system. We examined whether these volume-targeted modes respond rapidly enough to sudden changes in respiratory mechanics (e.g., selective intubation, surfactant administration, endotracheal tube kinking, de-kinking, obstruction), resulting in insufficient or excessive V(t) delivery. DESIGN AND SETTING: Bench study of six neonatal ventilators in the volume-targeted mode simulating preterm and full-term infant settings on a test lung. MEASUREMENTS AND RESULTS: Breath-to-breath expiratory V(t) were measured after rapid compliance, resistance, and leak changes. Under our test settings all ventilators showed important volume overshooting following rapid increase in compliance or decrease in resistance. Between one and 16 inflations were required to return to the set V(t). Some ventilators delivered inaccurate V(t) under steady state condition while others showed considerable breath-to-breath V(t) variability. CONCLUSIONS: We observed inaccurate V(t) delivery under specific conditions as well as immediate and sometimes prolonged volume overshooting after a rapid respiratory system compliance increase or resistance decrease in volume-targeted modes of modern neonatal ventilators. Similar discrepancies between the set V(t) and the delivered inflations can be harmful in clinical situations, especially in newborns. Their clinical relevance needs to be clarified with safety studies in the neonatal population and we encourage manufacturers to further improve the ventilators algorithms.

Equipment Design↗
PubMed2003

Differential effects of modern immunosuppressive agents on the development of intimal hyperplasia.

Modern immunosuppressive agents such as tacrolimus and rapamycin are claimed to be associated with a reduction in vascular narrowing, a central feature of chronic rejection. This study assesses the effect of cyclosporine, tacrolimus and rapamycin on the development of intimal thickening, fibrosis-associated genes and deposition of extracellular matrix (ECM) proteins in a model of intimal hyperplasia. Male Sprague-Dawley rats received either no treatment or 5 mg/kg cyclosporine, 0.1 mg/kg tacrolimus or 0.05 mg/kg rapamycin. Animals underwent left common carotid balloon angioplasty, and intima medial ratios, pro-fibrotic gene expression and ECM accumulation were calculated at 14 and 28 days. Cyclosporine was associated with increased intimal thickening compared to controls ( P < 0.004). Tacrolimus had no effect on intimal thickening, whilst rapamycin significantly inhibited intimal thickening at both 14 and 28 days ( P < 0.004 and P < 0.026, respectively). All groups significantly inhibited matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinases (TIMP)-1, transforming growth factor (TGF)-beta and collagen III expression at 14 days ( P < 0.001), but increased ECM deposition. However, rapamycin marginally reduced ECM deposition compared to cyclosporine ( P < 0.06). Treatment with cyclosporine was associated with worsening of vascular narrowing, whilst rapamycin showed a beneficial reduction in intimal thickening. Treatment with all immunosuppressive agents resulted in increased ECM deposition. Rapamycin may halt the progression of vascular narrowing compared to both cyclosporine and tacrolimus.

Angioplasty, Balloon↗
PubMed2001

Analysis of corrosion layers on protective coatings and high temperature materials in simulated service environments of modern power plants using SNMS, SIMS, SEM, TEM, RBS and X-ray diffraction studies.

In three different examples, the effects of the oxidation behaviour as well as the microstructural stability of high temperature materials and protective coatings was determined by combining the results of kinetic studies with extensive analytical investigations using, among other techniques, SNMS, SIMS, SEM, TEM, Rutherford back scattering (RBS) as well as X-ray diffraction. 1). The effect of water vapour on the oxidation behaviour of 9% Cr steels in simulated combustion gases has been determined. The effects of O2 and H2O content on the oxidation behaviour of 9% Cr steel in the temperature range 600-800 degrees C showed that in dry oxygen a protective scale was formed with an oxidation rate controlled by diffusion in the protective scale. In the presence of water vapour, after an incubation period, the scales became non-protective as a result of a change in the oxidation limiting process. The destruction of the protective scale by water vapour does not only depend on H2O content but also on the H2O/O2-ratio. 2). The increase of component surface temperature in modern gas turbines leads to an enhanced oxidation attack of the blade coating. Improvements in corrosion resistance and longer lifetime thermal barrier coatings in gas turbines have been achieved by improvement of the high temperature properties of MCrAlY coatings by additions of minor alloying elements such as yttrium, silicon and titanium. 3). The use of oxide dispersion strengthened (ODS) alloys provides excellent creep resistance up to much higher temperatures than can be achieved with conventional wrought or cast alloys in combination with suitable high temperature oxidation/corrosion resistance. Investigation of the growth mechanisms of protective chromia and alumina scales were examined by a two-stage oxidation method with 18O tracer. The distribution of the oxygen isotopes in the oxide scale was determined by SIMS and SNMS. The results show the positive influence of a Y2O3 dispersion on the oxidation resistance of the ODS alloys and its effect on growth mechanisms.

Journal Article↗
PubMed2002

Curiously modern DNA for a "250 million-year-old" bacterium.

Studies of ancient DNA have attracted considerable attention in scientific journals and the popular press. Several of the more extreme claims for ancient DNA have been questioned on biochemical grounds (i.e., DNA surviving longer than expected) and evolutionary grounds (i.e., nucleotide substitution patterns not matching theoretical expectations for ancient DNA). A recent letter to Nature from Vreeland et al. (2000), however, tops all others with respect to age and condition of the specimen. These researchers extracted and cultured a bacterium from an inclusion body from what they claim is a 250 million-year (Myr)-old salt crystal. If substantiated, this observation could fundamentally alter views about bacterial physiology, ecology and evolution. Here we report on molecular evolutionary analyses of the 16S rDNA from this specimen. We find that 2-9-3 differs from a modern halophile, Salibacillus marismortui, by just 3 unambiguous bp in 16S rDNA, versus the approximately 59 bp that would be expected if these bacteria evolved at the same rate as other bacteria. We show, using a Poisson distribution, that unless it can be shown that S. marismortui evolves 5 to 10 times more slowly than other bacteria for which 16S rDNA substitution rates have been established, Vreeland et al.'s claim would be rejected at the 0.05 level. Also, a molecular clock test and a relative rates test fail to substantiate Vreeland et al.'s claim that strain 2-9-3 is a 250-Myr-old bacterium. The report of Vreeland et al. thus falls into a long series of suspect ancient DNA studies.

Bacteria↗
PubMed2001

The evolution of modern lineages of mouse L1 elements.

There are three known families of L1 elements in the Mus genome, V, F, and A. An individual L1 element is classified as a member of one of these families based on which of three different types of transcription promoters is at its 5' end. Initial evidence suggested that the only actively transposing L1 elements in the modern mouse genome were a young subfamily of A-type elements. That belief was overturned when a transposing F subfamily, T(F), was discovered. We used molecular phylogenetic methods to investigate the emergence of the two currently transposing L1 lineages, young A's and T(F)'s. Both of these subfamilies appear to be direct descendants from a specific clade of F-type L1's. Our results imply that recombination between L1 sequences occurred in the lineage from which the T(F) subfamily evolved. We also found that phylogenetic analysis of a L1 3' untranslated region (UTR) is diagnostic for the promoter type at the 5' end of the sequence and, therefore, for the family to which it belongs. As part of this investigation, we developed a set of full-length L1 sequences, which may serve as a general reference set for phylogenetic analyses in Mus. Our analyses included 21 full-length L1 elements from the GenBank nonredundant database that had not been phylogenetically analyzed previously.

Animals↗
PubMed2001

The geographic distribution of monoamine oxidase haplotypes supports a bottleneck during the dispersion of modern humans from Africa.

Every genetic locus mingles the information about the evolutionary history of the human species with the history of its own evolution. Therefore, to address the question of the origin of humans from a genetic point of view, evolutionary histories from many genetic loci have to be gathered and compared. We have studied two genes residing on the X chromosome encoding monoamine oxidases A and B (MAOA and MAOB). Both genes have been suggested to play a role in psychiatric and/or behavioral traits. To search for DNA variants of the MAO genes, the sequences of exonic and flanking intronic regions of these two genes were determined in a group of Swedish males. The sequence analysis revealed several novel polymorphisms in the MAO genes. Haplotypes containing high-frequency MAOA polymorphisms were constructed, and their frequencies were determined in additional samples from Caucasian, Asian, and African populations. We found two common haplotypes with similar frequencies in Caucasian and Asian populations. However, only one of them was also the most frequent haplotype in Africans, while the other haplotype was present in only one Kenyan male. This profound change in haplotype frequencies from Africans to non-Africans supports a possible bottleneck during the dispersion of modern humans from Africa.

Animals↗
PubMed2004

Modern imaging of tuberculosis in children: thoracic, central nervous system and abdominal tuberculosis.

Tuberculosis (TB) can affect any organ in the body. Children are a high-risk group for contracting the disease and pose a constant challenge to clinicians with regard to making a definitive diagnosis. Radiologists are playing a more active role in diagnosing TB, and armed with more accurate diagnostic investigations such as CT and MRI, they must face the cost implications as well as technical limitations. This review aims to guide the reader through the modern imaging techniques useful for diagnosing TB of the thorax, central nervous system and abdomen in children. The more specific features of each modality in the particular anatomical regions are highlighted.

Abdomen↗