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Biomedical subjects

A Wagner

Publications and source records attributed to A Wagner.

At least 127 records · Page 7Linked to original sources
PubMed2001

Measurement of the recoil polarization in the p(e-->, e'p-->)pi(0) reaction at the Delta(1232) resonance.

The recoil proton polarization has been measured in the p(e-->,e'p-->)pi(0) reaction in parallel kinematics around W = 1232 MeV, Q2 = 0.121 (GeV/c)2, and epsilon = 0.718 using the polarized cw electron beam of the Mainz Microtron. All three proton polarization components, Px/P(e) = (-11.4+/-1.3+/-1.4)%, P(y) = (-43.1+/-1.3+/-2.2)%, and P(z)/P(e) = (56.2+/-1.5+/-2.6)%, could be measured simultaneously. The Coulomb quadrupole to magnetic dipole ratio, CMR = (-6.4+/-0.7(stat)+/-0.8(syst))%, was determined from Px in the framework of the Mainz Unitary Isobar Model. The consistency among the reduced polarizations and the extraction of the ratio of longitudinal-to-transverse response is discussed.

Journal Article↗
PubMed2001

Evidence for a Soft Nuclear Equation-of-State from Kaon Production in Heavy-Ion Collisions.

The production of pions and kaons has been measured in 197Au+197Au collisions at beam energies from 0.6 to 1.5A GeV with the kaon spectrometer at SIS/GSI. The K+ meson multiplicity per nucleon is enhanced in Au+Au collisions by factors up to 6 relative to C+C reactions, whereas the corresponding pion ratio is reduced. The ratio of the K+ meson excitation functions for Au+Au and C+C collisions increases with decreasing beam energy. This behavior is expected for a soft nuclear equation-of-state.

Journal Article↗
PubMed2001

Psychological impact of receiving a BRCA1/BRCA2 test result.

Mutation analysis for autosomal dominant hereditary breast/ovarian cancer genes (BRCA1/BRCA2) became an important technique for women at risk of carrying these mutations. Healthy female mutation carriers have a high lifetime risk for breast and/or ovarian cancer and may opt for frequent breast and ovary surveillance or prophylactic surgery (mastectomy and/or oophorectomy). Psychological distress was assessed in 78 healthy women at risk of having inherited a BRCA1/BRCA2 mutation opting for genetic testing and 56 partners several weeks prior to ("pre-test") and after ("post-test") learning about their DNA test result. Twenty-five women were found to be mutation carriers, and 53 were non-mutation carriers. One goal of the study was to identify individuals at risk for high distress in the weeks following disclosure of the test result. Interview transcripts were used to give a fuller picture of pre- and post-test distress. High post-test anxiety was reported by 20% of the mutation carrier women and by 35% of their partners. Eleven percent of women without the mutation and 13% of their partners reported high post-test anxiety levels. High post-test anxiety in women was significantly related to 1) a high level of pre-test anxiety and 2) being a mutation carrier. Women without a mutation who had a sister identified as a mutation carrier recently had higher post-test levels of depression than the other non-mutation carriers. It is suggested to consider seriously the need for psychological support in mutation carriers who had been anxious at pre-test already. For most non-mutation carriers, psychological follow-up might be of lesser importance, but those having a sister receiving an unfavorable test result should be informed about the possibility that they might not feel relief.

Adult↗
PubMed2001

[Contralateral and ipsilateral repetitive transcranial magnetic stimulation in Parkinson patients].

In seven women and two men with Parkinson's disease, Hoehn and Yahr stage 1 or 2, the effect of repetitive transcranial magnetic stimulation (rTMS) was evaluated. Primary endpoint outcome measure was the changing of the motor items of the Unified Parkinson's Disease Rating Scale (subscale III of UP-DRS) 24 h after stimulation. Kinesiologic tests and writing samples were secondary outcome measures. After discontinuing all medication, stimulation was performed with 5 Hz at 90% of the motor threshold over the primary motor cortex of the more affected. There were 2250 stimuli applied, divided into 15 trains at intervals of 10 s. The identical treatment of the opposite side served as control treatment. Only treatment of the more affected side resulted in a significant improvement of the clinical symptoms of 46% as assessed by the UPDRS (p < 0.02). This effectiveness differed significantly from the control treatment (21%, p < 0.02). The kinesiological testing did not show any significant speeding of movements (p > 0.05). Some patients showed a normalisation of the previously disturbed handwriting specimen. These data confirm the previous observation that rTMS of primary motor regions leads to at least temporary clinical improvement of symptoms in patients with Parkinson's disease.

Dominance, Cerebral↗
PubMed2001

[Acetabulum revision. Classifications and treatment possibilities].

Several different defect classifications have been published. The most commonly used are described. For clinical practice, differentiation between "contained" and "noncontained" or segmental defects has proven useful. If the acetabular rim provides support, press-fit cups can be used without screws. With an appropriate reaming technique, it is possible to create a sufficiently supportive bed for the implant in many cases. This allows the use of a press-fit acetabular component over a wide range of defects as long as a tilting of the cup can be avoided. Between 1988 and 1995, 439 acetabular cups were revised at the Orthopedic University Clinic in Basel, 171 of them using the Morscher press-fit cup. After a mean follow-up of 7.1 years, not a single cup had to be revised for aseptic loosening. The 9.5% dislocations were due to abductor insufficiencies because of trochanteric pathologies or muscular alterations from former approaches.

Acetabulum↗
PubMed2001

Differential alteration of the nigrostriatal dopaminergic system in Wilson's disease investigated with [123I]ss-CIT and high-resolution SPET.

Wilson's disease (WD) is a copper deposition disorder which can result in a number of extrapyramidal motoric symptoms such as parkinsonism. Therefore, this study was carried out to investigate, for the first time, nigrostriatal dopaminergic function in WD in relation to different courses and severity of the disease. Using high-resolution single-photon emission tomography (SPET) after administration of 2ss-carbomethoxy-3ss-(4[123I]iodophenyl)tropane ([123I]ss-CIT), striatal dopamine transporters (DAT) were imaged in 43 WD patients and a control group of ten subjects. From the SPET images, specific [123I]ss-CIT binding ratios were obtained for the caudate heads, putamina and entire corpus striatum. In addition, to evaluate a putative dissociation between the caudate and putaminal [123I]ss-CIT binding ratios, the ratio between these binding ratios was calculated (CA/PU ratio). The SPET data were compared with clinical data on the course of the disease (CD), the severity of neurological symptoms and the degree of hepatic alteration. Whereas the specific regional [123I]ss-CIT binding ratios in patients with asymptomatic/hepatic CD did not differ from those in the control group (e.g. striatal ratios: 13.4+/-3.0 vs 11.7+/-2.8), in patients with neurological CD the ratios were significantly reduced for all striatal substructures (P=0.003 after one-factor ANOVA). For the different subgroups a tendency was detected towards a stepwise decrease in the specific [123I]ss-CIT binding ratios from pseudo-sclerosis CD (9.4+/-2.3), through pseudo-parkinsonian CD (9.1+/-2.1) to arrhythmic-hyperkinetic CD (8.5+/-1.6). However, these group differences reached significance only for the comparison with asymptomatic/hepatic CD (P=0.02). The CA/PU ratio was significantly higher in WD than in the control group (1.30+/-0.19 vs 1.11+/-0.08; P=0.003). Severity of neurological symptoms was significantly correlated with all specific regional [123I]ss-CIT binding ratios (r=-0.49 to -0.57). For degree of liver alteration, significant correlations were obtained with the putaminal binding ratio (r=-0.37) and the CA/PU ratio (r=0.44). From these results is concluded that in WD the nigrostriatal dopaminergic function is compromised to varying extents. The degree of this presynaptic alteration of dopaminergic neurotransmission depends on the clinical course and severity of this copper deposition brain disorder and also varies in the different striatal substructures.

Adult↗
PubMed2001

Birth and death of duplicated genes in completely sequenced eukaryotes.

Gene and genome duplications are commonly regarded as being of major evolutionary significance. But how often does gene duplication occur? And, once duplicated, what are the fates of duplicated genes? How do they contribute to evolution? In a recent article, Lynch and Conery analyze divergence between duplicate genes from six eukaryotic genomes. They estimate the rate of gene duplication, the rate of gene loss after duplication and the strength of selection experienced by duplicate genes. They conclude that although the rate of gene duplications is high, so is the rate of gene loss, and they argue that gene duplications could be a major factor in speciation.

Animals↗
PubMed2001

Topically applied liposome encapsulated superoxide dismutase reduces postburn wound size and edema formation.

The overproduction of biochemical mediators, and activation of leukocytes and endothelial cells, generated in thermally injured tissue, gives rise to both local and distant effects. The formation of short-lived, highly reactive metabolites, such as oxygen free radicals, increases with increasing tissue ischemia, and causes further cell damage. Human recombinant Cu/Zn-superoxide dismutase (rh-Cu/Zn-SOD), an enzyme which captures these radicals, may have a beneficial effect on the postburn inflammation processes. In this study, the influence of rh-Cu/Zn-SOD application to thermally injured tissue of rabbit backskin was examined. Three different delivery strategies were compared, pure or liposomally encapsulated enzyme, or intralesionally injected rh-Cu/Zn-SOD. For control, one animal group was treated with plain gel and another group was kept untreated. At 24 h following trauma a statistically significant difference in lesion sizes between the enzyme treated and control groups was observed. After 72 h tissue swelling had diminished significantly more in the rh-Cu/Zn-SOD treated groups as compared to the control animals. The best results were achieved by spreading liposomes encapsulating the enzyme onto the wounds. Our results suggest that local treatment of burn wounds with enzymatic radical scavengers such as rh-Cu/Zn-SOD has a beneficial effect on the extent of the postburn damage.

Animals↗
PubMed2001

Large regional differences in the frequency of distinct BRCA1/BRCA2 mutations in 517 Dutch breast and/or ovarian cancer families.

In 517 Dutch families at a family cancer clinic, we screened for BRCA1/2 alterations using the Protein Truncation Test (PTT) covering approximately 60% of the coding sequences of both genes and direct testing for a number of previously identified Dutch recurrent mutations. In 119 (23%) of the 517 families, we detected a mutation in BRCA1 (n=98; 19%) or BRCA2 (n=21; 4%). BRCA1/2 mutations were found in 72 (52%) of 138 families with breast and ovarian cancer (HBOC), in 43 (13%) of the 339 families with breast cancer only (HBC), in 4 (36%) of 11 families with ovarian cancer only (HOC), and in nine of 29 families with one single young case (<40 years) of breast cancer. Between the different subgroups of families (subdivided by the number of patients, cancer phenotype and age of onset) the proportion of BRCA1/2 mutations detected, varied between 6 and 82%. Eight different mutations, each encountered in at least six distinct families, represented as much as 61% (73/119 families) of all mutations found. The original birthplaces of the ancestors of carriers of these eight recurrent mutations were traced. To estimate the relative contribution of two important regional recurrent mutations (BRCA1 founder mutation IVS12-1643del3835 and BRCA2 founder mutation 5579insA) to the overall occurrence of breast cancer, we performed a population-based study in two specific small regions. The two region-specific BRCA1 and BRCA2 founder mutations were detected in 2.8% (3/106) and 3.2% (3/93) of the unselected breast tumours, respectively. Of tumours diagnosed before the age of 50 years, 6.9% (3/43) and 6.6% (2/30) carried the region-specific founder mutation. Thus, large regional differences exist in the prevalence of certain specific BRCA1/BRCA2 founder mutations, even in very small areas concerning populations of approximately 200000 inhabitants.

Adult↗
PubMed2001

Second malignancies after ewing tumor treatment in 690 patients from a cooperative German/Austrian/Dutch study.

BACKGROUND: Ewing tumor treatment involves high cumulative doses of alkylating agents and topoisomerase inhibitors, drugs capable of inducing second cancers. We analyzed the second cancer risk in a large cohort of consistently treated patients. PATIENTS AND METHODS: Six hundred ninety Ewing tumor patients were treated between 1992 and 1999 with local therapy and vincristine. doxorubicin, ifosfamide and/or cyclophosphamide, and antinomycin D, with or without etoposide as a randomized question. Second cancer incidences were estimated by competing risk analyses; standardized incidence ratios (SIR) in comparison to registry data were compiled. RESULTS: After a median observation time of 56 months (32 months for survivors), 6 of 690 patients had developed second cancers: MDS/AML, two, ALL/NHL, two, squamous cell carcinoma, one, liposarcoma, one. SIR were increased 20-30 fold in comparison to the general population. The cumulative second cancer risk five years after diagnosis of the Ewing tumor was 0.0093 for the total group, zero for patients without etoposide, and 0.0118 with etoposide. Additional phase II high-dose therapy increased the risk to 0.0398 after five years. CONCLUSIONS: The second cancder risk observed was in the range to be expected in cancer survivors. High-dose therapy, and less markedly, etoposide, may contribute to the overall second cancer risk.

Adolescent↗
PubMed2001

Correlations of brain MRI parameters to disability in multiple sclerosis.

OBJECTIVES: The objective was to correlate magnetic resonance imaging (MRI) T2-weighted lesion load and measures of white matter atrophy in the brain to disability in a population-based sample of patients with multiple sclerosis (MS). MATERIAL AND METHODS: A well defined cohort of patients was drawn at random from the general MS population by using the Danish Multiple Sclerosis Registry. A semi-automated local thresholding technique was used to quantify T2-weighted lesions on MRI; whereas manual tracing was applied to measure the corpus callosum brain ratio (CCR) and the ventricle brain ratio (VBR). RESULTS: A sample of 86 patients with a mean age of 43.3 years (SD 4.3), mean disease duration of 13.6 years (SD 4.4) and a median Expanded Disability Status Score (EDSS) of 6.0 was identified. The correlation between total lesion area of the brain (TLA) and disability (EDSS) for the whole sample was moderate (Spearman rank correlation coefficient r=0.48, P<0.001). Also correlations of CCR and VBR to disability (r=0.32-0.46) were significant. CONCLUSIONS: Correlations of TLA and disability in this study were rather strong. Hence, T2-weighted MRI lesion load in the brain still plays an important role as a surrogate marker of disease and as a secondary outcome measure in phase III treatment trials.

Adult↗
PubMed2001

Men at risk of being a mutation carrier for hereditary breast/ovarian cancer: an exploration of attitudes and psychological functioning during genetic testing.

Males with a BRCA1/BRCA2 mutation are not at greatly increased risk for cancer, whereas their (grand)daughters, and other female relatives who carry the mutation, are. Males from BRCA1/BRCA2 families may opt for genetic testing to confirm whether or not they may have transmitted the mutation to their children and, if so, to inform them at an appropriate age about the genetic risk and its implications. The psychological implications of genetic testing for men at risk of being a BRCA1/BRCA2 mutation carrier have received little attention. We report on 28 men requesting BRCA1 or BRCA2 testing, and their partners. Men were at 25% (n =4) or 50% risk (n =24) of being a mutation carrier, the majority with daughters and half of them with daughters aged over 20 years. Levels of psychological distress were assessed several weeks before and after disclosure of the test result. In addition, we investigated the level of intrusive thoughts and feelings about breast and ovarian cancer and the tendency to avoid these. By means of interviews and questionnaires, participants could report on (expected) emotional implications of genetic testing for themselves and their children, on experiences with cancer in the family and on personality trait optimism. Distress levels prior to the result in tested men and their partners were low. Many men and partners expected the test result to affect their children's, but not their own level of problems. Men without daughters and those with an optimistic personality had especially low distress prior to disclosure. Most men reported that they did not actively avoid the issue. Only four of the 28 men were identified as mutation carriers. High distress after disclosure of the result was reported by one mutation carrier and by three non-mutation carriers. Verbatim transcripts from interviews showed a large variation of psychological reactions in male mutation carriers (eg regarding guilt feelings). Low pre-test distress in males does not necessarily indicate avoidance of the issue. Future studies may indicate which psychological reactions occur in male mutation carriers when the problem becomes more acute, eg when a daughter is found to carry the mutation and/or is diagnosed with breast or ovarian cancer.

Adult↗
PubMed2001

Leisure-time physical activity and regular walking or cycling to work are associated with adiposity and 5 y weight gain in middle-aged men: the PRIME Study.

OBJECTIVE: To examine the influence of physical activity on body mass index (BMI), waist circumference (W) and body mass changes (DeltaBMI) in middle-aged men, with special regard to moderate-intensity activities. DESIGN: Longitudinal study of adults who participated in the PRIME Study. SUBJECTS: A cohort of 8865 men aged 50-59 y, free of coronary heart disease. MEASUREMENTS: BMI and W at baseline, body mass changes over a 5 y period. Detailed baseline assessment of net energy expenditure due to physical activity (PAE) in the preceding year, according to category of activity, by means of the MOSPA Questionnaire. PAE was expressed in weekly metabolic equivalent scores (MET h/week). RESULTS: After adjustment for confounders, the multiple regression analyses indicated that BMI, W and DeltaBMI were inversely associated with PAE spent in getting to work (P<10(-5), <10(-5) and 0.04, respectively) and practice of high-intensity (>or=6 MET) recreational activities (<0.01, <10(-5) and <0.01). Men who regularly spent more than 10 MET h/week in walking or cycling to work had a mean BMI, W and DeltaBMI respectively 0.3 kg/m(2), 1 cm and 0.06 kg/m(2) lower than those who did not expend energy in getting to work. In the subgroup of subjects who did not perform high-intensity activities, the level of recreational PAE was inversely associated with BMI and W but not with subsequent weight-gain. CONCLUSION: These findings indicate that, in middle-aged men, physical activities of moderate-intensity, which are probably easier to promote than more vigorous activities and, in particular, a more current daily activity, walking or cycling to work, may have a favourable effect on body fat markers and body mass gain.

Activities of Daily Living↗
PubMed2001

Methodological issues in the development of a national database for primary care groups and trusts.

At the National Primary Care Research and Development Centre (NPCRDC) we have constructed a national database for all primary care groups (PCGs) in England. At its core, the database links information about population socio-economic and demographic characteristics to generic health status and to the organisation, resourcing and activities of general practice. In this paper we describe and discuss the problems with linking these data, and with defining the boundaries and the local populations of PCGs, given that they have been established on the basis of administrative expediency rather than geographical coherence. We then consider the implications of these difficulties for needs assessment in primary care groups.

Database Management Systems↗
PubMed2001

Unusual triplet expansion associated with neurogenic changes in a family with oculopharyngeal muscular dystrophy.

The occasional observation of neurogenic features in oculopharyngeal muscular dystrophy (OPMD) is unclear both in nosological and in etiological respects. Studies are reported here of a family with autosomal-dominant OPMD involving seven members over three generations. In three of them muscle biopsies were performed. Two of the patients (a 45-year-old sister and a 57-year-old brother of the third generation) were studied in more detail and, in addition to the typical changes of OPMD, showed a neurogenic component both by electrophysiology and morphology. Molecular genetic investigations revealed a repeat unit of (GCG/GCA)13 in the first exon of the poly(A)binding-protein2 gene in both siblings. A possible association of this unusually long triplet repeat extension with the atypical phenotype is considered and has to be verified in other cases.

Biopsy↗
PubMed2001

Principles of computer-assisted arthroscopy of the temporomandibular joint with optoelectronic tracking technology.

PURPOSE: This preliminary clinical study evaluated the applicability, accuracy, and benefits of computer-assisted arthroscopy of the temporomandibular joint (TMJ) with optoelectronic tracking technology. MATERIALS AND METHODS: A hybrid of reality and virtual reality is built as a composite-reality environment by extracting 3-dimensional anatomical structures through use of computed tomography, magnetic resonance imaging, radiography, and other types of imaging procedures commonly used in clinical praxis. These various independent sources of imaging data of a particular patient can be combined with and complemented by complex graphic simulations. Intraoperatively they are merged with online position data of surgical instruments inside the patient's TMJ. This hybrid model of detailed anatomical structures, guidelines, and real-time instrument positions allows the surgeon to accurately plan the arthroscopic intervention as well as to navigate effectively intraoperatively. RESULTS: In the first 10 cases of computer-assisted TMJ arthroscopy, composite reality environment technology permitted the online visualization of TMJ structures, puncture sites, instrument positions, and virtual pathways in relation to anatomical landmarks with high spatial accuracy (minimum, 0.0 mm; maximum, 2.5 mm; mean, 1.4 mm; SD, 0.6 mm) and high temporal resolution (100 ms). Past, present, and possible future instrument positions can be displayed. The application of computer-assisted arthroscopy caused little immobility for either surgeon or patient. CONCLUSION: Even experienced surgeons profit from improved precision in the handling of the arthroscope; thus this technology was found to be particularly useful in degenerative temporomandibular disorders and for triangulation procedures.

Arthroscopes↗
PubMed2001

How to reconstruct a large genetic network from n gene perturbations in fewer than n(2) easy steps.

MOTIVATION: The reconstruction of genetic networks is the holy grail of functional genomics. Its core task is to identify the causal structure of a gene network, that is, to distinguish direct from indirect regulatory interactions among gene products. In other words, to reconstruct a genetic network is to identify, for each network gene, which other genes and their activity the gene influences directly. Crucial to this task are perturbations of gene activity. Genomic technology permits large-scale experiments perturbing the activity of many genes and assessing the effect of each perturbation on all other genes in a genome. However, such experiments cannot distinguish between direct and indirect effects of a genetic perturbation. RESULTS: I present an algorithm to reconstruct direct regulatory interactions in gene networks from the results of gene perturbation experiments. The algorithm is based on a graph representation of genetic networks and applies to networks of arbitrary size and complexity. Algorithmic complexity in both storage and time is low, less than O(n(2)). In practice, the algorithm can reconstruct networks of several thousand genes in mere CPU seconds on a desktop workstation. AVAILABILITY: A perl implementation of the algorithm is given in the Appendix. CONTACT: wagnera@unm.edu

Algorithms↗