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  • 1995-1999  (665)
  • 1999  (665)
  • Industrial Chemistry  (469)
  • Human  (119)
  • CT  (77)
  • Inorganic Chemistry
  • Nuclear reactions
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Years
  • 1995-1999  (665)
Year
Keywords
  • 1
    ISSN: 1432-2307
    Keywords: Key words Peroxisomes ; Hepatocellular tumors ; Immunocytochemistry ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A significant reduction of catalase activity, a peroxisomal marker enzyme, occurs in human hepatic neoplasias, but no information is available on other peroxisomal proteins. We have studied by means of immunohistochemistry four specific proteins of peroxisomes (catalase and three enzymes of lipid β-oxidation) in human hepatocellular tumors of various differentiation grades from adenoma to anaplastic carcinoma. In all tumors, except the adenomas, the tumor cells contained fewer peroxisomes than extrafocal hepatocytes and the reduction of antigenic sites in the tumor types generally correlated with the degree of tumor dedifferentiation as assessed by classical histopathological criteria. Two poorly differentiated tumors had no detectable peroxisomes at all. There were no major differences in the intensities of the immunocytochemical staining for all four studied peroxisomal antigens in different tumors, suggesting that the neoplastic transformation affects the biogenesis of the entire organelle and not merely the individual peroxisomal enzyme proteins. Some tumors exhibited a distinct peripheral distribution of peroxisomes. In cases with associated liver cirrhosis, the hepatocytes in the adjacent liver showed marked peroxisome proliferation, forming large perinuclear aggregates, occupying occasionally the entire cytoplasm. Taken together, our observations indicate that peroxisomes are significantly altered in both hepatocellular tumors and liver cirrhosis and, thus, could be responsible for some of the metabolic derangements observed in those disease processes.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2161
    Keywords: Key words Chronic expanding hematoma ; Ancient hematoma ; CT ; MRI ; Soft tissue mass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. To identify the characteristic MRI findings of chronic expanding hematoma correlated with the pathology. Design and patients. Three patients who had a chronic expanding hematoma involving the musculoskeletal system were reviewed retrospectively. Results and conclusion. Huge soft tissue masses suggestive of malignancy with destruction of the bony structure were revealed on radiography and computed tomography. MRI showed the masses to exhibit heterogeneous signal intensity on both T1- and T2-weighted images with a peripheral rim of low signal intensity, reflecting the central zones of fluid collection due to fresh and altered blood with a wall of collagenous fibrous tissue. These MRI findings were seen in all three patients and are considered to be characteristic; they assist in differentiation from neoplasm in consideration of the history of trauma or surgery.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 470-472 
    ISSN: 1432-2161
    Keywords: Key words Telangiectatic osteosarcoma ; CT ; Paget’s disease ; skull
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Sarcomatous transformation is the most dreaded complication of Paget’s disease. We report on a case of post-Paget telangiectatic osteosarcoma of the skull, a variant of osteogenic osteosarcoma, in a 79-year-old woman. We discuss the radiological pattern in relationship to the differential diagnosis.
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  • 4
    ISSN: 1432-2161
    Keywords: Key words Chondrosarcoma ; Osteochondroma ; Bursa ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Multiple hereditary osteochondromatosis is an uncommon autosomal dominant condition in which patients are predisposed to the development of chondrosarcoma. We report a case of a patient who developed a secondary low-grade chondrosarcoma in this setting. The tumor was associated with an unusual multinodular invasive growth pattern into a pre-existing bursa that was present overlying the osteochondroma.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 584-589 
    ISSN: 1432-2161
    Keywords: Key words Myxopapillary ependymoma ; Sacrum ; Osteolysis ; X ray ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The authors report an unusual case of sacral osteolytic myxopapillary ependymoma treated with curettage and radiotherapy. There is no evidence of recurrence 8 years after treatment. A review of the literature is presented on sacral ependymomas presenting with an osteolytic radiographic appearance (24 cases in 18 reports). The differential diagnosis with other sacral neoplasms is discussed.
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  • 6
    ISSN: 1432-2161
    Keywords: Key words Osteochondroma ; Chondroma ; Extraskeletal tumor ; Soft tissue tumor ; Foot ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A case of pathologically proven extraskeletal osteochondroma is presented with magnetic resonance imaging (MRI), computed tomography (CT), bone scan and radiographic findings. The diagnosis of extraskeletal osteochondroma should be considered when a discrete, ossified mass is localized in the soft tissues of the distal extremities. Nomenclature surrounding this entity is controversial and is discussed.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 703-709 
    ISSN: 1432-2161
    Keywords: Key words Proliferative myositis ; Childhood ; Lumbar muscles ; Ossification ; X-ray ; CT ; MRI ; PET
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A case of proliferative myositis in the lumbar paraspinal muscles in a 14-year-old boy is presented. Imaging investigations including plain radiograph, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), bone scan and positron emission tomography (PET) were suggestive of an inflammatory process such as myositis ossificans. The diagnosis was made by incisional biopsy. More pronounced edema, more muscle fiber necrosis and a higher cellularity were found compared to adult cases. The karyotype of the lesion was normal. Clinically, the mass disappeared spontaneously. After 24 months, asymptomatic bridging ossification between the third and fourth lumbar vertebrae was noted.
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  • 8
    ISSN: 1432-2161
    Keywords: Key words Osteosarcoma ; conventional ; Metastasis ; Soft tissues ; Retroperitoneum ; CT ; X-ray
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Osteosarcoma (osteogenic sarcoma) metastasizes primarily to the lung. With the introduction of neoadjuvant chemotherapy as part of the treatment, the overall and disease-free survival rates have dramatically improved. In this case report, a young man with multiple soft tissue and bone metastases, including a rare large bone-forming retroperitoneal metastasis, is described. Despite the extensive extrapulmonary metastases, the patient did not develop pulmonary metastases in the 4 years following initial presentation of the primary tumour.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 717-722 
    ISSN: 1432-2161
    Keywords: Key words Sarcoid ; vertebrae ; Sarcoid ; rib ; Sarcoid ; calvarium ; Osteolytic ; CT ; MRI ; Surgical fusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Skeletal sarcoidosis is rare. This report describes a 31-year-old African American man who presented with a destructive osteolytic lesion of C2 and another lesion in a rib. The lesion at C2 was treated with corpectomy and bone graft. Four months later the lesion recurred and a new lesion was discovered in the cervical vertebral column. The patient declined surgery for instability for another 3 months, choosing to remain in a halo. Seven months following the initial operation, a technetium bone scan showed spread of the disease to the calvarium and thoracic and lumbar vertebrae. The patient had no symptoms referable to these sites. The patient agreed to have his neck fused at this point. For the next 10 months, the patient was on steroids and a further new lesion appeared at L5 without localizing signs or symptoms. The patient declined further evaluation over the next 12 months and is now considered lost to follow-up.
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  • 10
    ISSN: 1432-2161
    Keywords: Key words Stress fractures ; CT ; MR imaging ; Radionuclide study ; Femur ; stress fractures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We present five cases of a distinctive type of longitudinal stress fracture of the upper femoral shaft in which the fracture line is parallel to the outer surface of the bone, in contrast to the perpendicular orientation to the cortical surface in previously reported cases of diaphyseal stress fractures. In two cases the fracture recurred after 15 and 18 months, respectively.
    Type of Medium: Electronic Resource
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  • 11
    ISSN: 1432-2161
    Keywords: Key words Bone tumor ; Chondrosarcoma ; CT ; Magnetic resonance imaging ; Tumor of the ankle ; Tumor of the foot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The foot is an uncommon location for chondrosarcoma. The presentation, diagnosis, pathological findings, surgical treatment and follow-up of three patients with chondrosarcoma in this rare location are presented. Though nonspecific, MR imaging findings were of aid in the diagnosis and treatment planning of these patients. If the diagnosis of this tumor is rapidly made, a tumor excision instead of limb amputation may be sufficient treatment at surgery.
    Type of Medium: Electronic Resource
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 159-162 
    ISSN: 1432-2161
    Keywords: Key words SAPHO syndrome ; CT ; Parosteal osteosarcoma ; Sternoclavicular joints
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Considerable attention has been paid in the past 10 years to the radiological spectrum of disease entities belonging to the SAPHO syndrome. We report an unusual case presenting with an extra-axial (femoral) lesion, prior to description of this syndrome, which was radiologically and histologically mistaken for a parosteal osteosarcoma. Nineteen years later, a further lesion developed in the scapula together with the typical sternoclavicular manifestations, at which stage the correct diagnosis of SAPHO syndrome was established.
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  • 13
    ISSN: 1432-2161
    Keywords: Key words Malignant peripheral nerve sheath tumor ; Schwannoma ; Neurofibroma ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. To distinguish between benign and malignant tumors in the peripheral nerves. Design and patients. The clinical, imaging and histologic findings of 99 benign and 16 malignant tumors in the peripheral nerves were reviewed retrospectively. Results. Preoperative motor weakness was observed in only six of 99 benign tumors and was mild, while slight to severe motor weakness was present in 15 of 16 malignant lesions. Pain at rest was present in five of 99 benign tumors and in 15 of 16 malignant tumors. All benign lesions showed a smooth tumoral margin, while half the malignant lesions showed an invasive margin on CT or MRI. Thirteen of 28 benign lesions on CT and nine of 23 on MRI showed round to geographic central enhancement, but this pattern was not seen in malignant lesions. Conclusion. Absence of severe motor weakness and a central enhancement pattern strongly suggest a benign nature, while severe rest pain and invasive tumor margin suggest malignant lesions in peripheral nerve tumors.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 33-40 
    ISSN: 1432-2161
    Keywords: Key words Osteoblastoma ; Spine ; Radiography ; CT ; MRI ; Pathology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objectives. To illustrate the CT and MRI features of spinal osteoblastomas and correlate the imaging with histological findings. Design. In a retrospective review the CT and MRI features of spinal osteoblastomas with respect to mineralisation, signal intensity (SI), adjacent reactive changes, enhancement following gadolinium-DTPA (5 cases) and adjacent soft tissue masses were compared and correlated with the histological findings including the degree of osteoid formation and matrix mineralisation, vascularity and surrounding reactive changes in bone and soft tissue. Patients. Eleven patients (7 males and 4 females; age range 8–43 years, mean age 19.5 years) with 12 osteoblastomas (1 patient suffered a recurrence) were studied. Results. All lesions showed classical features on CT with varying degrees of matrix mineralisation, whereas MRI identified mineralisation in only eight of 12 cases. MRI showed low signal intensity of the lesion on both T1- and T2-weighted sequences in several cases in the absence of heavy mineralisation. In these cases, histological examination revealed diffuse osteoid production by the tumour. All patients given gadolinium showed enhancement within the tumour on MRI. Reactive bone marrow changes were identified on MRI in 10 cases, and in five of these the changes were at multiple levels. An adjacent soft tissue mass was demonstrated in five cases, but extraosseous tumour was present histologically in only two of these. Conclusions. The MRI appearances of spinal osteoblastomas are varied and show no characteristic features. MRI may also overestimate the extent of the lesion due to extensive reactive changes and adjacent soft tissue masses. CT should continue to be the investigation of choice for the characterisation and local staging of suspected spinal osteoblastomas.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Skeletal radiology 28 (1999), S. 49-51 
    ISSN: 1432-2161
    Keywords: Key words Cryptococcoma ; sacrum ; Cryptococcoma ; immunocompromised ; MRI ; sacrum ; CT ; sacrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Cryptococcoma of the sacrum was the initial presentation of systemic cryptococcosis in a patient on chronic steroid therapy for autoimmune hepatitis. The bone lesion was the only overt manifestation of systemic cryptococcal disease, which preceded other clinical manifestations and led to the subsequent diagnosis of systemic infection.
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  • 16
    ISSN: 1432-2161
    Keywords: Key words Chondroblastoma ; malignant ; recurrent ; p53 mutation ; Aneuploidy ; Pelvis ; Femur ; Xray ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report a rare case of malignant chondroblastoma, which presented in a 47-year-old man as a recurrent tumor, 18 years following wide excision of a typical pelvic chondroblastoma. Radiologic studies of the recurrent tumor showed a large, lytic, destructive lesion of the right pelvic bones and femur, with a pathologic fracture of the latter, a large pelvic soft tissue mass, and multiple pulmonary metastases. Biopsy tissue showed typical features of chondroblastoma, but also increased nuclear atypia, hyperchromasia, and pleomorphism, compared to the original tumor, and, most significantly, abnormal mitotic figures. Immunohistochemical studies of the recurrent tumor revealed p53 mutation and extensive proliferative activity, and flow cytometric studies showed DNA aneuploidy, none of which was present in the original tumor. The patient received chemotherapy and radiation, but died of disease eight months after presentation. We also review chondroblastoma in general, to assign this unusual lesion to a tumor subtype.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 39 (1999), S. 958-964 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Spiral-CT ; Mehrzeilen-Spiral-CT ; Pankreaskarzinom ; Tumorstaging ; 2D-/3D-Bildgebung ; Key words Computed tomography ; Computed tomography ; helical ; Computed tomography ; technology ; Computed tomography ; thin-section ; Pancreatic neoplasms ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose. Investigation of the capabilities of MSCT and its value for the staging of pancreatic carcinomas. Methods. 50 Patients with suspected pancreatic carcinoma were examined with a biphasic multislice-spiral-CT protocol: slice collimation 4×1 mm, Pitch 3.5–4 mm. After administation of 120 ml contrast medium and 50 ml NaCl with a flow rate of 3.0 ml/s the examination was started with a delay of 40 s (pancreatic phase) and 80 s (portalvenous phase). Results. Multislice spiral CT allows the examination of the whole upper abdomen with nearly isotropic data sets. This is the premise for the optimal assessment of the tumor extent in all planes, excellent demarcation of the tumor against the adjacent vessels and organs and the demarcation of small peripancreatic lymph nodes. Conclusions. Multislice spiral CT and the use of interactive multiplanar reconstructions improve the staging of pancreatic cancer.
    Notes: Zusammenfassung Ziel unserer Untersuchungen war es, die Möglichkeiten der Mehrzeilen-Detektor-Spiral-CT und ihre Bedeutung für das Staging von Pankreastumoren zu evaluieren. Bei insgesamt 50 Patienten, bei denen der Verdacht auf ein Pankreaskarzinom bestand, wurde im Rahmen der Tumorstagings ein biphasisches hochaufgelöstes Mehrzeilen-Spiral-CT mit einer Schichtkollimation von 4×1 mm, einem Pitch von 3,5–4, 120 ml Kontrastmittel, 50 ml 0,9%NaCl-Bolus, 3,0 ml/s Fluß und einem Startdelay von durchschnittlich 40 s (Pankreasparenchymphase) und 80 s (portalvenöse Phase) durchgeführt. Die Mehrzeilen-Spiral-CT ist in der Lage die gesamte Pankreasloge und auch die angrenzenden Organe mit hoher Ortsauflösung in allen Raumebenen abzubilden. Die nahezu isotrope multiplanare Bildgebung erlaubt die vollständige Erfassung der Tumorausdehnung in allen Raumebenen und eine bessere Abgrenzung der Tumoren gegenüber dem angrenzenden Fettgewebe, den benachbarten Organen (Gefäße, Duodenum, Magen) und einen sichereren Nachweis von peripankreatischen Lymphknoten. Die Mehrzeilen-Spiral-CT und der Einsatz von interaktiven multiplanaren Rekonstruktionen verbessern nachhaltig die Bestimmung der Ausdehnung von Pankreaskarzinomen.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Der Radiologe 39 (1999), S. 610-618 
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Staging ; Gynäkologische Karzinome ; Schnittbildverfahren ; Computertomographie (CT) ; Magnetresonanztomographie (MRT) ; Sonographie (US) ; Key words Staging ; Gynecologic neoplasm ; Cross-sectional imaging modalities ; CT ; MRI ; Sonography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary The prognosis in patients with gynecologic cancers depends not only on the stage but also on a wide spectrum of other findings. Cross-sectional imaging modalities, including sonography, CT and MRI, have increasingly been used for optimal treatment planning in gynecologic cancers. Their staging criteria are based on the well-established FIGO staging system. CT and MRI compete with sonography, which plays a pivotal role in the evaluation of the female pelvis. This paper reviews the role of sonography, CT and MRI in the staging of gynecologic malignancies. It puts the emphasis on MRI, which has been established as imaging modality of choice in the preoperative evaluation of cervical and endometrial cancer, and which seems slightly superior to CT in the staging of ovarian cancer.
    Notes: Zusammenfassung Die Prognose gynäkologischer Karzinome hängt nicht nur vom Stadium, sondern von einem breiten Spektrum anerkannter Kriterien ab. Zur optimierten Therapieplanung werden heute zunehmend die Schnittbildverfahren Sonographie, CT und MRT für die morphologische Charakterisierung der Veränderungen eingesetzt. Die Stagingkriterien der bildgebenden Verfahren orientieren sich an der anerkannten FIGO-Klasssifikation. CT und MRT konkurrieren mit der Sonographie, die als anerkannte und weitverbreitete Modalität in der Gynäkologie etabliert ist. In dieser Übersichtsarbeit werden die Schnittbildverfahren Sonographie, CT und MRT im Staging gynäkologischer Karzinome einander gegenübergestellt. Der Schwerpunkt der Ausführungen liegt dabei auf der MRT, die als Methode der Wahl zum Staging des Zervix- und Endometriumkarzinoms gilt, beim Ovarialkarzinom der CT ebenbürtig und in manchen Fragestellung tendentiell überlegen ist.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 185 (1999), S. 297-304 
    ISSN: 1432-1351
    Keywords: Key words Odor coding ; Learning ; Enhanced sensitivity ; Rabbit ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The olfactory system is faced with a particular problem – the high dimensionality and inherent unpredictability of the chemical world. Most natural odorants encountered in everyday life are complex mixtures of many different volatiles. This means that from the outset the olfactory system has to contend with a great and often unpredictable diversity of molecules, making it difficult for stable primary features of the chemical world to be mapped onto the sensory surface. One solution to such unpredictability is provided by learning. Learning confers flexibility, enabling individuals of a given species to acquire and make use of the most appropriate information in a particular environment. Two examples of this are presented: learning of maternal odors in neonatal rabbits, including evidence that the sensory surface itself may be influenced by environmental conditions so as to enhance sensitivity to molecules of particular ecological relevance, and cross-cultural human studies suggesting that experience with everyday odors influences not only the way these are evaluated, but also their perceived intensity. It is concluded that an adequate understanding of odor coding and olfactory function will not be possible without taking such experience-dependent factors into account.
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  • 20
    ISSN: 1432-1912
    Keywords: Key words Blood pressure ; Endothelium ; Human ; Mesenteric artery ; Rat ; Smooth muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The majority of the findings concerning arterial physiology and pathophysiology originate from studies with experimental animals, while only limited information exists about the functional characteristics of human arteries. Therefore, the aim of the present work was to compare the control of vascular tone in vitro in mesenteric arterial rings of corresponding size (outer diameter 0.75–1 mm) from humans and Wistar-Kyoto rats. The relaxations to acetylcholine (ACh) were clearly less marked in the mesenteric arteries of humans when compared with rats. How-ever, when calcium ionophore A23187 was used as the vasodilator, the endothelium-mediated relaxations did not significantly differ between these species. The NO synthase inhibitor N G-nitro-l-arginine methyl ester (l-NAME) attenuated the relaxations to ACh and A23187 in both groups. The endothelium-independent relaxations to the β-adrenoceptor agonist isoprenaline and the nitric oxide (NO)-donor nitroprusside were somewhat lower in human arteries, while vasodilation induced by the K+ channel opener cromakalim was similar between humans and rats. Arterial contractile sensitivity to noradrenaline and serotonin was slightly lower in human vessels, whereas contractile sensitivity to KCl was similar between these species. The contractions induced by cumulative addition of Ca2+ with noradrenaline as the agonist were effectively inhibited in both groups by the calcium channel blocker nifedipine, the effect of which was clearly more pronounced in human arteries. In conclusion, the control of vascular tone of isolated arteries of corresponding size from humans and rats appeared to be rather similar. The most marked differences between these species were the impaired endothelium-mediated dilation to ACh and the more pronounced effect of nifedipine on the Ca2+-induced contractions in human arteries.
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  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 73 (1999), S. 7-14 
    ISSN: 1432-0738
    Keywords: Key words Organophosphates ; Acetylcholinesterase ; Oximes ; Human ; Reactivation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Human poisoning by organophosphates bearing two methoxy groups, e.g. by malathion, paraoxon-methyl, dimethoate and oxydemeton-methyl, is generally considered to be rather resistant to oxime therapy. Since the oxime effectiveness is influenced not only by its reactivating potential but also by inhibition, aging and spontaneous reactivation kinetics, experiments were performed with human acetyl- (AChE) and butyrylcholinesterase (BChE) to determine the respective kinetic constants. The efficacy of obidoxime in reactivating dimethylphosphoryl-AChE was 40, 9 and 3 times higher than of HI 6, pralidoxime and HLö 7, respectively. Aging (t 1/2 3.7 h) and spontaneous reactivation (t 1/2 0.7 h) occurred concomitantly, with the portion of the aged enzyme being dependent on the presence of excess inhibitor. Calculation of steady-state AChE activity in the presence of inhibitor and oxime revealed that obidoxime was superior to pralidoxime. In addition, organophosphate concentrations up to 10−6 M (paraoxon-methyl) and 10−4 M (oxydemeton-methyl) could be counteracted at clinically relevant oxime concentrations (10 μM). These data indicate that oximes may effectively reactivate human dimethylphosphoryl-AChE. Failure of oximes may be attributed to megadose intoxications and to prolonged time intervals between poison uptake and oxime administration. The potency of the oximes to reactivate dimethylphosphoryl-BChE was much lower and the spontaneous reactivation slower (t 1/2 9 h), while aging proceeded at a comparable rate. Thus, BChE activity determination for diagnosis and therapeutic monitoring may give no reliable information on AChE status.
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  • 22
    ISSN: 1432-069X
    Keywords: Key words Chronic diabetic wounds ; Human ; fibroblasts ; Wound healing ; Cell culture ; Proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Patients with diabetes mellitus experience impaired wound healing often resulting in chronic foot ulcers. Hospital discharge data indicate that 6–20% of all diabetic individuals hospitalized (mostly with type 2 diabetes) have a lower extremity ulcer. Maintaining glucose levels at acceptable levels (below 10 mmol/l) is considered to be an important part of the clinical treatment, but the exact mechanism by which diabetes delays wound repair is not yet known. We studied this phenomenon by determining the potential of fibroblasts isolated from the ulcer sites of four patients with non-insulin-dependent diabetes mellitus to proliferate in vitro. Controls were fibroblasts isolated from normal skin of the upper leg of five healthy age-matched volunteers and of six non-insulin-dependent diabetes patients. Proliferative capacity was analysed by evaluation of plates after trypsinization and [3H]thymidine incorporation. Fibroblast morphology was studied by light and transmission electron microscopy. Diabetic ulcer fibroblasts, measured by [3H]thymidine incorporation, proliferated significantly more slowly than the nonlesional control fibroblasts (P 〈 0.00047) and age-matched control fibroblasts (P 〈 0.00003). After culturing the fibroblasts for a prolonged period in high-glucose (27.5 mM) and low-glucose (5.5 mM, i.e. physiological) medium, this difference in proliferation rate between diabetic ulcer fibroblasts and nonlesional diabetic fibroblasts remained (P 〈 0.0001 for high-glucose and P 〈 0.0009 for low-glucose on day 7). Fibroblast proliferation in all three groups was slightly lower in high-glucose than in low-glucose medium, although not significantly at any time-point. Light microscopy showed diabetic ulcer fibroblasts to be large and widely spread. Transmission electron microscopy of cultured diabetic ulcer fibroblasts and nonlesional diabetic skin fibroblasts revealed a large dilated endoplasmic reticulum, a lack of microtubular structures and multiple lamellar and vesicular bodies. These results show a diminished proliferative capacity and abnormal morphology of fibroblasts derived from diabetic ulcers of non-insulin-dependent diabetes patients.
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  • 23
    Electronic Resource
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    Archives of dermatological research 291 (1999), S. 247-252 
    ISSN: 1432-069X
    Keywords: Key words T cell activation ; Nickel ; Human ; Interferon-gamma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Contact hypersensitivity to nickel is the most common form of allergic contact dermatitis. To gain insight into the induction of this frequent disease, T cell reactivity towards nickel was investigated in “nonallergic” individuals defined as those with no skin manifestations and a negative patch test towards NiSO4. Surprisingly, we found that nickel induced proliferation of peripheral blood mononuclear cells (PBMC) from 16 of 18 adult individuals tested. This activation was specific, and no stimulation of PBMC was observed using control stimulants at equimolar concentrations. Furthermore, the NiSO4-induced activation required the presence of professional antigen-presenting cells. To describe the functional capacity of the nickel-inducible T cells, cytokine release was investigated in both nickel-allergic and nonallergic individuals. The T cells from both groups released interferon-γ but no interleukin-4 upon stimulation with nickel, suggesting that the functional capacities of these cell populations were similar in nickel-allergic and nonallergic individuals. Thus, at this level, no qualitative differences could be demonstrated between T cells obtained from nickel-allergic and nonallergic individuals.
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  • 24
    ISSN: 1432-069X
    Keywords: Key words ORS cells ; Melanocytes ; Human ; Organotypic cultures ; Melanosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Because outer root sheath (ORS) cells are valuable substitutes for interfollicular epidermal keratinocytes, we wanted to determine whether epidermal equivalents generated from ORS cells and containing cultured melanocytes can serve as an in vitro model for skin pigmentation. In such epidermal equivalents prepared with ORS cells and melanocytes from donors of phototypes II, III and VI, a stratified epithelium resembling normal epidermis developed within 14 days, as documented by histological, ultrastructural (e.g. basement membrane-like structure, keratohyalin granules, keratinosomes) and immunohistochemical (e.g. keratins, integrins, gp80, involucrin, filaggrin) criteria. The melanocytes were localized in the basal layer and accounted for 10% of the total cell number. Heavily pigmented melanocytes from black donors contained regular melanosomes in all stages of maturation, whereas melanocytes derived from white donors contained predominantly melanosomes of stages I and II. Melanosome-laden dendrites were readily detected extending from the heavily pigmented melanocytes, while they were less conspicuous in melanocytes from white donors. The extent of melanosome transfer was independent of the racial origin of the ORS cells. Melanosomes could also be transferred “through racial barriers”. Melanosomes, mainly of stages III and IV, were detected in the ORS cells, being distributed either as single or compound melanosomes, again irrespective of the racial origin of the ORS cells. In conclusion, pigmented epidermal equivalents generated from ORS cells offer practical advantages over other in vitro pigmentation models: (1) the ORS cells are easily and repeatedly available from any donor regardless of age; (2) primary cultures of ORS cells are free of contaminating melanocytes, a bias if using interfollicular epidermal keratinocytes; (3) a high degree of epidermal differentiation is maintained for 3 weeks in fully defined medium, enabling labelling and stimulation experiments to be performed and compounds interfering with melanin pigmentation to be tested.
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  • 25
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    Anatomy and embryology 199 (1999), S. 45-56 
    ISSN: 1432-0568
    Keywords: Key words Skin ; Proteoglycan ; Development ; Human ; Fetal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The extracellular matrix of human fetal skin differs substantially from that of adult skin. Fetal skin contains sparse amounts of fibrillar collagen enmeshed in a highly hydrated amorphous matrix composed of hyaluronan and sulfated proteoglycans. Both fetal and adult skin contain two major interstitial proteoglycans that are extracted by chaotrophic agents and detergents. These are the large chondroitin sulfate proteoglycan versican and the small dermatan sulfate proteoglycan decorin. For this study, proteoglycans extracted from fetal and adult skin were compared on Western blots to determine the relative amounts of versican. Decorin present in the same samples provided an internal standard for these studies. Fetal skin differed from adult skin in that it contained a significantly higher proportion of versican than did adult skin. Immunohistochemical studies compared early-fetal with mid-fetal skin and found that versican was a significant component of the interstitial extracellular matrix at both of these stages of skin development. However, by the mid-fetal period, interstitial versican became restricted to the upper half of the dermis, although versican also continued to be highly expressed around hair follicles, glands, and vasculature in the lower half of the dermis. Fetal skin extracts differed from an adult skin extract by the presence of a 66-kDa protein immunologically related to versican and by the absence of a 17-kDa core protein of a proteoglycan related to decorin. Both of these molecular species may represent degradation products of their respective proteoglycans. Monoclonal antibodies which detect epitopes in native chondroitin sulfate glycosaminoglycan chains recognized versican extracted from fetal skin. However, the tissue distribution of these antigens did not entirely conform to that for versican core protein, suggesting that versican in different regions of the skin may be substituted with glycosaminoglycan chains with different microchemistries. The results of these studies indicate that human fetal skin is structurally different from adult skin in terms of both the distribution and the composition of the large, aggregating chondroitin sulfate proteoglycan versican.
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  • 26
    ISSN: 1432-0533
    Keywords: Key words Amantadine ; Human ; N-methyl-d-aspartate ; Phencyclidine ; Postmortem brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Low doses of N-methyl-d-aspartate (NMDA)-type glutamate receptor antagonists induce morphological alterations in neurons of the cingulate gyrus and retrosplenial cortex of the rat. Neuronal cell death may result at higher doses. These effects are a major concern with regard to the introduction of new NMDA receptor antagonists into clinical trials. Amantadine is an uncompetitive NMDA receptor antagonist, which has been in clinical use for many years. In the present study we have looked for possible morphological alterations like necrosis in postmortem human brain tissue of patients previously treated with amantadine. Formalin-fixed tissue samples were taken from the hippocampus, cingulate gyrus, and retrosplenial cortex of 8 patients on previous amantadine medication and of 11 controls. Histopathological examination of sections was performed blind. All brains except one revealed either nonspecific age-related or cerebrovascular changes or other neurodegenerative disorders including Alzheimer’s, Parkinson’s or Lewy body disease. In conclusion, histopathological examination of the hippocampus, retrosplenial cortex, and cingulate gyrus of human brain did not reveal changes suggested to be specific for previous amantadine treatment.
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  • 27
    ISSN: 1432-0533
    Keywords: Key words Purkinje cell ; Cerebellum ; Development ; Inositol 1 ; 4 ; 5-triphosphate type 1 receptor ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunohistochemical analyses were carried out on the Purkinje cells from 21 autopsied fetal and early postnatal normal cerebella using a monoclonal antibody against the inositol 1, 4, 5-triphosphate type 1 receptor (IP3R1) as a cytochemical marker of Purkinje cells. In normal adult cerebella used as positive controls, the cell bodies, axons, and dendrites, including spiny branchlets of the Purkinje cells, were specifically stained by the antibody. In the fetal cerebella examined, the IP3R1 immunoreactivity was first detected in the soma of multilayered cells just beneath the molecular layer at 16 weeks of gestation. The IP3R1 immunoreactivity gradually increased in area of positive staining from soma to dendrites and spiny branchlets, and the dendritic outgrowth rapidly progressed during 6 months after birth. The Purkinje cell maturation was more advanced in the vermis than in the hemisphere, more in the posterior lobe than in the anterior lobe, and more at the bottom of the folia than at the top. Partial absence of the Purkinje cells in the cerebellar cortex was observed in three cases. Heterotopias including Purkinje cells were often noted in the cerebellar white matter in five cases.
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  • 28
    ISSN: 1432-0851
    Keywords: Key words In vitro immunisation ; MUC1 ; Human ; antibodies ; Phage display ; Carcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have recently described an efficient method to study the human humoral immune response in vitro and to generate isotype-switched, antigen-specific human B cells, which has allowed us to produce high-affinity IgG antibodies against different peptides. In an attempt to study the in vitro immune response against self-antigens, such as tumour-associated antigens, this protocol was used to immunise resting human peripheral blood B cells with a peptide epitope from the human-adenocarcinoma-associated antigen, MUC1. After the two-step in vitro immunisation, the secondary immunised cultures were tested for MUC-1-specific antibodies by enzyme-linked immunosorbent assay (ELISA). Phage molecular libraries were subsequently constructed, using the variable parts of Ig genes derived from cells taken from ELISA-positive wells. The libraries were selected on the MUC1 core peptide. Antigen-specific Fab fragments, specific for the self antigen MUC1, were found in the library of secondary immunised IgG+ B cells and these antibodies were evaluated by BIAcore analysis. The specific Fab fragments exhibited an unusually rapid dissociation rate constant and the overall response frequency was lower, as compared to other antibodies generated by this protocol, which might be explained by the repetitive nature of the core peptide used for immunisation.
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  • 29
    ISSN: 1432-0932
    Keywords: Key words Synovial cyst ; CT ; MRI ; Surgical treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The authors describe the case of a 58-year-old man with a 6-month history of severe myelopathy. CT scan and MRI of the spine revealed a cystic formation, measuring about 1 cm in diameter, at C7-T1 at a right posterolateral site at the level of the articular facet. At operation the mass appeared to originate from the ligamentum flavum at the level of the articular facet and was in contact with the dura mater. Once the mass had been removed, there was a significant amelioration of the patient’s symptoms. As previously suspected, histological aspect was synovial cyst. Cervical synovial cysts are extremely rare and, as far as we know, only 22 cases have so far been described in the literature. Diagnostic radiological investigations used were CT scan and MRI. At CT scan the most important diagnostic findings are a posterolateral juxtafacet location of the mass, egg-shell calcifications on the wall of the cyst, and air inside the cyst. At MRI the contents of the cyst are iso/hypointense on T1- and hyperintense on T2-weighted images. There may also be a hypointense rim on T2-weighted images, which enhances after i.v. administration of gadolinium. Surgical treatment consists of removal of the mass. Fixation of the vertebral segments involved is not always necessary.
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  • 30
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    European spine journal 8 (1999), S. 261-265 
    ISSN: 1432-0932
    Keywords: Key words Vertebral rotation ; Idiopathic scoliosis ; CT ; Method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract CT measurement methods have good reliability for idiopathic scoliosis transverse plane deformity evaluation. However, because of application difficulties and variations in how these methods are applied, more sensitive methods are needed. This paper presents a new method for measurement of vertebral rotation from tomographic scans. First, the method was subject to clinical, intra-observer and inter-observer analysis. Twenty-three patients with adolescent idiopathic scoliosis were studied to test the clinical reliability of this method. There were no statistical differences between the results of the new method and Ho’s method (P = 0.3380) in the clinical study. Intra-observer and inter-observer analysis showed that this method was reliable. An experimental study was then conducted to show the confidence limits of our new method, which were found to be ± 1.6°, and there was no significant difference between the mean rotation value obtained from CT scans using our new method and that obtained using the mechanical method. These results suggest that our new method is a simple, practical and reliable method for measurement of vertebral rotation from CT scans.
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  • 31
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    European journal of clinical pharmacology 55 (1999), S. 349-352 
    ISSN: 1432-1041
    Keywords: Key words Ischaemic stroke ; Vinpocetine ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objectives: To determine whether vinpocetine decreases short- and long-term case fatality and proportion of dependent survivors if administered within 2 weeks of stroke onset. Methods: All published and unpublished trials were attempted to be identified using the standard search strategy of the Cochrane Collaboration Stroke Review Group, using MEDLINE searches performed with all known manufacturer code names and trade names of vinpocetine and by contacting manufacturers of vinpocetine to give information of all randomised controlled trials on vinpocetine in stroke. Researchers who participated in trials on vinpocetine in Hungary were asked for further information. Only truly randomised, unconfounded clinical trials that compared the effect of vinpocetine to either placebo or another reference treatment for acute stroke where treatment started no later than 14 days after stroke onset were eligible for inclusion. Data synthesis and analysis was performed using the Cochrane Review Manager software (RevMan version 3.0). Results: Among the identified studies on vinpocetine in stroke, only one fulfilled the selection criteria for inclusion in the review. No death occurred in the study groups and no statistically significant difference was found in dependency between the treatment and the placebo groups. No adverse effects were reported. Conclusions: Based on only one small randomised controlled unconfounded study, presently there is not enough evidence to decide whether the administration of vinpocetine does or does not decrease case fatality and dependency in acute stroke.
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  • 32
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    European radiology 9 (1999), S. 208-210 
    ISSN: 1432-1084
    Keywords: Key words: Muscles ; diseases ; Neoplasms ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Skeletal muscle is one of the most unusual sites of metastasis from any malignancy. We report a patient with rapidly progressive contractures due to metastatic infiltration of a carcinoma of unknown origin into the skeletal muscle. This 61-year-old man presented with a 1-month history of rapidly evolving, painful restriction of mobility of his right arm and his legs. Computed tomography showed diffuse metastatic nodules in all muscles, particularly in the hip abductors. Muscle biopsy revealed extensive infiltration of the muscle with carcinoma cells.
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  • 33
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    European radiology 9 (1999), S. 336-343 
    ISSN: 1432-1084
    Keywords: Key words: Cryptorchidism ; Scrotum ; US ; CT ; MRI ; Testis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Imaging evaluation of the patient with a non-palpable testis has evolved over recent decades. The rational explanation of imaging in these patients requires a clear understanding of the various causes of a non-palpable testis, and an appreciation of the utility and limitations of the available imaging modalities. This review describes the classification of non-palpable testis and discusses the role of modern imaging in evaluation. In particular, the relative accuracies of ultrasound, CT and MRI is reviewed.
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  • 34
    ISSN: 1432-1084
    Keywords: Key words: Lymphangioleiomyomatosis ; Lymphangiomyomatosis ; CT ; Lung ; CT ; comparative studies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Lymphangioleiomyomatosis (LAM) of the lung is a very rare disease. There are obvious discrepancies in the literature concerning the appearance of LAM on CT scans of the lung. This study adds the imaging findings of 11 patients and demonstrates how the imaging findings changed over time in four patients. Twenty-two CT examinations, and radiographs that had been obtained close to the CT examinations, of 11 patients with LAM confirmed by open lung biopsy were retrospectively evaluated with particular attention to the size of cystic lesions and wall thickness. Furthermore the CT scans were analysed for the type of pulmonary infiltration process and its distribution, presence or absence of pleural effusion, pneumothorax and lymph node enlargement. Clinical and CT follow-up studies were available in four patients. The CT scans revealed an increase in the interstitial pattern in all patients. Architectural distortion was seen in two patients and cystic lesions were present in all. The size of the cysts varied from small lesions to bullous emphysema. The cystic lesions revealed a wall thickness up to 2 mm but a wall was not perceptible in all. Pneumothorax was seen in only two patients; pleural effusion was seen in two patients. CT examination of patients with LAM reveals neither a uniform nor a pathognomonic appearance. In the early stages of LAM or in cases with interstitial changes the differential diagnosis of centrilobular emphysema or idiopathic pulmonary fibrosis seems to be more difficult than most authors believe.
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  • 35
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    European radiology 9 (1999), S. 68-72 
    ISSN: 1432-1084
    Keywords: Key words: Gastrointestinal tract ; Neoplasms ; Stomach ; Neoplasms ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this study was to evaluate the capabilities of subsecond spiral CT in detecting and staging of gastric cancer. Our study included 40 patients with endoscopically detected gastric carcinomas. Two-phase spiral CT was performed within one breathhold each. Distension of the stomach was achieved by intravenous application of scopolamine and drinking of 500 ml water. After bolus injection of contrast medium, scanning was performed in the arterial and venous phase. Gastric tumour extention and lymph node involvement was assessed. Gastric cancer was detected in 39 of 40 cases (sensitivity 97.5 %). Location of the tumour was correctly assessed in all cases. In 31 of the 39 cases (79.4 %) CT staging was accordant with pathological staging. One hundred two (70 %) of 145 nodes infiltrated by tumour tissue were detected and 144 (42.8 %) of 336 nodes free of metastatic involvement were found. The predictive values of positive and negative results for the detection of lymph node metastases were 67.1 and 75 %, respectively. Spiral CT is recommended for staging of gastric cancer.
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  • 36
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    European radiology 9 (1999), S. 205-207 
    ISSN: 1432-1084
    Keywords: Key words: Extramedullary hematopoiesis ; Paget's disease ; Thorax ; Neoplasm ; CT ; MR imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Extramedullary hematopoiesis usually occurs in hematological diseases but may also be found as an uncommon complication of Paget's disease, probably due to bone effraction mechanism. We present a case of intrathoracic extramedullary hematopoiesis related to Paget's disease. To our knowledge, this is the seventh case reported in the literature. We describe and correlate the conventional X-ray, CT, MR imaging, and cytological findings.
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  • 37
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    European radiology 9 (1999), S. 287-291 
    ISSN: 1432-1084
    Keywords: Key words: Lung ; CT ; Pneumonia ; Aspiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to assess high-resolution computed tomography (HRCT) findings of exogenous lipoid pneumonia. High-resolution computed tomography was obtained in 25 patients with proven exogenous lipoid pneumonia resulting from aspiration of squalene (derived from shark liver oil). Diagnosis was based on biopsy (n = 9), bronchoalveolar lavage (n = 8), or sputum cytology and clinical findings (n = 8). The clinical history of taking squalene was confirmed in all patients. The CT findings were classified into three patterns: diffuse ground-glass opacity, consolidation, and interstitial abnormalities. Distribution of the abnormalities, duration of taking squalene, predisposing factors for aspiration, and route of administration were analyzed. Ten patients showed diffuse ground-glass opacity pattern. Seven of 10 patients had predisposing conditions such as unconsciousness, pharyngeal dysmotility, or motor disturbances, and 6 patients had a recent history of taking large amount of squalene through nasal route. Seven patients who had consolidation pattern had a history of taking squalene for several months and did not have any predisposing factor. All of the 5 patients who had a pattern of interstitial abnormalities had a history of taking squalene longer than 1 year and showed segmental distribution of interstitial thickening with interposing ground-glass opacities. Three patients simultaneously had two different patterns at different lobes of the lung. The HRCT findings of lipoid pneumonia are ground-glass opacities, consolidation, and interstitial abnormalities. These HRCT findings with appropriate inquiries could be useful for diagnosis of exogeneous lipoid pneumonia.
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  • 38
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    European radiology 9 (1999), S. 643-647 
    ISSN: 1432-1084
    Keywords: Key words: MRI ; CT ; Lumbar vertebrae ; Osteoporosis ; Trabeculae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of the study was to assess the relative number of bone trabeculae in different orientations by using magnetic inhomogeneity measurements by MR imaging. Twelve defatted human vertebrae (L2–L4) were studied by MR imaging and CT. In the MR measurements the reversible transaxial decay rate, R2', was determined using the GESFIDE sequence. The relative contribution to R2' of bone trabeculae oriented along the x (R2'x), y (R2'y) and z (R2'y) axes was assessed, by rotation of the specimen in the magnetic field. The results were validated by CT measurements of trabecular structure at a resolution of 0.2 × 0.2 × 1 mm, using custom-made software. R2' ranged from 4.9 to 32 s–1. After separation, theoretical R2'x ranged from 2.3 to 10.7 s–1, R2'y ranged from 2.6 to 14.0 s–1 and R2'z ranged from 4.7 to 17.9 s–1. The number of bone trabeculae per millimeter identified in axial CT images ranged from 0.15 to 0.38 and from 0.039 to 0.22 per millimeter in sagittal images. The difference between axial and sagittal CT images was statistically significant and due to anisotropic voxels. The correlation between R2' and the number of bone trabeculae per millimeter was statistically significant (r = 0.83, p 〈 0.001 for x orientation; r = 0.63 for y orientation, and r = 0.59 for z orientation, p 〈 0.05 for both). The relative amount of bone trabeculae in different orientations can be assessed in vitro using R2' measurements.
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  • 39
    ISSN: 1432-1084
    Keywords: Key words: Appendicitis ; Diverticulitis ; US ; CT ; Pitfalls
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We describe four patients in whom ultrasound (US) and/or computed tomography (CT) demonstrated a thickened appendix, secondarily enlarged due to perforated sigmoid diverticulitis (n = 2) or carcinoma (n = 2). The underlying pathology was correctly recognized in all cases. Secondary thickening of the appendix due to perforated sigmoid disease provides a potential pitfall mainly on US and may lead to an incorrect diagnosis and thus to unnecessary surgery or a wrong surgical intervention. Although US alone is enough to diagnose periappendicitis and sigmoid disease, combined use of US and CT may improve assessment of its origin and extension.
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  • 40
    ISSN: 1432-1084
    Keywords: Key words: Kidney ; Ureteropelvic junction obstruction ; CT ; Trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to present CT findings of occult ureteropelvic junction obstruction in patients with renal trauma and to describe the clinical signs and singular CT features that are characteristically observed with trauma and are relevant to management of these patients. We retrospectively reviewed 82 helical CT studies in patients with renal trauma referred to our institution. We found 13 cases of occult preexisting renal pathology, six of which were occult ureteropelvic junction obstructions. The clinical presentation, radiologic findings of trauma according to the Federle classification, and CT findings of obstructed ureteropelvic junction are presented. We found three category-I lesions (one in a horseshoe kidney), two of them treated with nephrostomy because of increased ureteropelvic junction obstruction due to pelvic clots; two category-II lesions (parenchymal and renal pelvis lacerations) that had presented only with microhematuria; and one category-IV lesion (pelvic laceration alone). Pelvic extension was demonstrated in all the cases with perirenal collections. The CT studies in all the cases with suspected ureteropelvic junction obstruction showed decreased parenchymal thickness and enhancement, and dilatation of the renal pelvis and calyx, with a normal ureter. Computed tomography can provide information to confidently diagnose underlying ureteropelvic junction obstruction in renal trauma, categorize the traumatic injury (at times clinically silent) and facilitate proper management according to the singularities observed, such us rupture of the renal pelvis alone (Federle category IV) and increasing ureteropelvic obstruction due to clots which can be decompressed by nephrostomy.
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  • 41
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    European radiology 9 (1999), S. 841-852 
    ISSN: 1432-1084
    Keywords: Key words: Liver transplantation ; Hepatocellular carcinoma ; Cholangiocarcinoma ; MR Imaging ; CT ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Hepatic transplantation has emerged as a potentially curative treatment of certain malignant hepatic neoplasms such as hepatocellular carcinoma, bile duct carcinoma, fibrolamellar hepatocellular carcinoma, metastases from neuroendocrine tumors, and epithelioid hemangioendothelioma. In the early years of hepatic transplantation, there was great enthusiasm to cure patients with unresectable hepatobiliary malignancy. This early enthusiasm was tempered by the unfavorable outcome of transplantation in advanced cases of malignancy and the organ-donor shortage. Presently, patients have to be selected with predictable likelihood for long-term survival. Pre-transplantation imaging is indispensable for detection, characterization, staging, and surgical road-mapping before the procedure. The present article focuses on the role of imaging modalities in these different aspects of preoperative assessment.
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  • 42
    ISSN: 1432-1084
    Keywords: Key words: Abdomen ; Neoplasms ; CT ; Lymphatic system ; Anatomy ; Metastases ; Omentum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to enhance our understanding of the pathways of lymphatic spread of primary carcinomas in the upper abdomen by recognizing the development, configuration, and frequency of nodal enlargement in discrete anatomic regions. The study included 417 patients with histologically confirmed carcinomas (CC) of the stomach (n = 267), liver (n = 98), gallbladder (n = 25), and bile ducts (n = 27). All patients were studied by high-resolution CT and tumor extension to the lymph nodes of the subperitoneal space was clearly identified in 59 patients [33 with CC of the stomach, 8 with CC of the gallbladder, 3 with CC of the bile ducts, and 15 with hepatocellular carcinoma (HCC)]. In 47 of 59 patients this extension was confirmed by surgery or aspiration biopsy. Three discrete anatomic groups of lymph nodes were recognized producing a relatively distinct CT configuration when involved: (a) the hepatoduodenal seen in 49 patients; (b) the peripancreatic demonstrated in 33 patients; and (c) the aortocaval recognized in 16 patients. These groups of lymph nodes can be seen individually involved or in combination. Recognition of involvement of these nodes is important for correct diagnosis and staging of upper abdominal malignancies. The development of this involvement follows the natural flow of lymph via the lesser omentum to the retroperitoneal space.
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  • 43
    ISSN: 1432-1084
    Keywords: Key words: Osteomyelitis ; Radiography ; Bone scintigraphy ; CT ; Ultrasound ; MR imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Conventional radiographs remain the initial imaging modality involved in the diagnosis of osteomyelitis. Bone scintigraphy and its specific agents did not only eliminate the problems of inherent low sensitivity of conventional radiographs, but also increased the specificity to higher degrees. Spiral CT, on the other hand, has solved several diagnostic problems, such as osteomyelitis of the sterno-clavicular junction and hidden areas in the pelvic bones. Magnetic resonance imaging with its multiplanar capability, greater anatomic details and excellent soft tissue bone marrow contrast resolution has a significant role in surgical planning and limb preservation. Ultrasound and US-guided aspiration has recently been involved in the diagnosis and management of osteomyelitis with several advantages particularly in children. Our goal in this review is to outline the ability of various imaging techniques by comparing their strengths and weaknesses in the diagnosis of osteomyelitis. Finally, we suggest various imaging algorithms for specific clinical scenarios. Spondylitis and septic arthritis are not discussed in this review.
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  • 44
    ISSN: 1432-1084
    Keywords: Key words: Vena cava ; Stenosis ; Obstruction ; Interventional procedure ; Neoplasm ; Grafts and prosthesis ; Thrombolysis ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this study was to report our experience on the management of superior vena cava obstruction (SVCO) secondary to malignant disease, using endovascular procedures. Twenty-six patients with SVCO due to primary or secondary tumors of the lung or the mediastinum, or catheter inserted for treatment of an extra-thoracic neoplasm, had an endovascular therapy which consisted of stenting, angioplasty, thrombo-aspiration or local fibrinolysis. Immediately after the procedure, rapid relief of symptoms occurred in 24 (90 %) of the patients. The mean Kishi's score decreased from 5.5 to 0.96. Immediate complications included one death related to pericarditis bleeding following fibrinolysis. Three patients relapsed after 20 days, 4 months and 6 months, and needed a second stenting. At 6 months the primary patency rate was 83 % and the secondary patency rate was 89 %. Endovascular treatment of SVCOs is a simple and safe procedure to restore the patency of the superior vena cava in malignant SVCO. It should be indicated in most cases as first-line treatment and performed as early as possible.
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  • 45
    ISSN: 1432-1084
    Keywords: Key words: Diaphragm ; Hepatic hernia ; Blunt trauma ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We report a case of blunt traumatic right diaphragm rupture with hepatic hernia. The diagnosis was first suggested by an abnormal hepatic location depicted on axial CT. This finding can be considered as a potentially new indirect sign of right diaphragm rupture in patients with blunt trauma. The diagnosis was then confirmed by reformatted CT and MR images.
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  • 46
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    European radiology 9 (1999), S. 1104-1106 
    ISSN: 1432-1084
    Keywords: Key words: Tendinitis ; CT ; Tendons ; Calcification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Two cases of calcific tendinitis of gluteus maximus muscle are presented. The CT findings, including amorphous calcification without soft tissue mass and possible cortical erosion at the femoral enthesis of the gluteus maximus muscle, are highly suggestive of calcific tendinitis at this unusual but classical location. Ossifying entheses with well-defined cortical defect are frequent at the femoral insertion of the gluteus maximus muscle in asymptomatic subjects and must be differentiated from a real cortical erosion sometimes associated with these calcific tendinitis.
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  • 47
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    European radiology 9 (1999), S. 1117-1119 
    ISSN: 1432-1084
    Keywords: Key words: Tuberculosis ; Skeletal ; CT ; MR imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Chest wall involvement is an uncommon manifestation of musculoskeletal tuberculosis. We present computed tomography and magnetic resonance imaging findings in a case with multifocal musculoskeletal tuberculosis presenting as a breast mass. These radiological modalities are not diagnostic without histopathological confirmation, but they are valuable guides to surgery in defining the extent of disease involvement.
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  • 48
    ISSN: 1432-1084
    Keywords: Key words: Lipoid pneumonia ; Diagnosis ; Lung ; Disease ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The objective of this study was to describe high-resolution CT (HRCT) and MR findings of exogenous lipoid pneumonia and to correlate them with pathologic findings. A retrospective review of the medical records of our institution revealed seven patients with a diagnosis of lipoid pneumonia based on clinical data, chest films, bronchoalveolar lavage, and follow-up. Both HRCT and MR imaging were reviewed by two readers. Pathologic examination of the resected specimen or surgical biopsies were also reviewed in the four available cases. The HRCT findings were pulmonary consolidations (n = 6) with fatty (n = 3) or unspecific but low attenuation values (n = 3), areas of ground-glass opacities (n = 5), septal lines, and centrilobular interstitial thickening (n = 5). In five of the seven cases, a crazy-paving pattern of various spread was also present, either isolated (n = 1) or surrounding a pulmonary consolidation. In two cases traction bronchiectasis and cystic changes consistent with fibrosis were seen. At MR imaging (n = 2) a pulmonary consolidation of high signal intensity on T1-weighted image consistent with lipid content was present in one case. Pathologic examination (n = 4) showed the coexistence of lobules with lesions of various ages, sometimes in contiguous lobules, within the same patient. Recent lesions were those with alveolar fill-in by spumous macrophages and almost normal alveolar walls and septae. In more advanced lesions, lobules were filled in with larger vacuoles often surrounded by inflammatory infiltrates of alveolar walls, bronchiolar walls, and septa. The oldest lesions were characterized by fibrosis and parenchymal distortion around large lipid-containing vacuoles. The HRCT findings reflect pathologic findings in exogenous lipoid pneumonia. Although non-specific, consolidation areas of low attenuation values and crazy-paving pattern are frequently associated in exogenous lipoid pneumonia and are indicative of the diagnosis.
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  • 49
    ISSN: 1432-1084
    Keywords: Key words: Lung nodule ; CT ; Inflammatory pseudotumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Lung inflammatory myofibroblastic tumor is an uncommon cause of solitary lung nodule (0.7 % of lung tumors). The principal site of inflammatory pseudotumor is the lung, but it can also occur elsewhere in various organs. Although benign, they may be locally very aggressive. Recurrent and multifocal forms have been described. Since they are likely to mimic malignant neoplasms, accurate histopathologic diagnosis is necessary in order to guide appropriate surgical excision and avoid aggressive treatments. We report a case of lung involvement in a young adult with radiologic and pathologic correlations.
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  • 50
    ISSN: 1432-1084
    Keywords: Key words: Castleman disease ; CT ; MR imaging ; Paraneoplastic pemphigus ; Abdomen ; Neoplasms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We describe the CT and MRI features of a case of Castleman disease which was unusual by both its retroperitoneal location and its association with paraneoplastic pemphigus.
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  • 51
    ISSN: 1432-1084
    Keywords: Key words: Lung neoplasms ; Staging ; Pleura ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of this investigation was to evaluate whether thin-sectional CT with different reconstruction algorithms can improve the diagnostic accuracy with regard to chest wall invasion in patients with peripheral bronchogenic carcinoma. Forty-one patients with intrapulmonary lesions and tumor contact to the thoracic wall as seen on CT staging underwent additional 1-mm CT slices with reconstruction in a high-resolution (HR) and an edge blurring, soft detail (SD) algorithm. Five criteria were applied and validated by histological findings. Using the criteria of the intact fat layer, HRCT had a sensitivity of 81 % and a specificity of 79 %, SD CT had a sensitivity of 96 % and a specificity of 78 %, and standard CT technique had a sensitivity of 50 % and a specificity of 71 %, respectively. Regarding changes of intercostal soft tissue, HRCT achieved a sensitivity of 71 % and a specificity of 96 %, SD CT had a sensitivity of 94 % and a specificity of 96 % (standard CT technique: sensitivity 50 % and specificity 96 %) . For the other criteria, such as pleural contact area, angle, and osseous destruction, no significant differences were found. Diagnostic accuracy of chest wall infiltration can be improved by using thin sectional CT. Especially the application of an edge-blurring (SD) algorithm increases sensitivity and specificity without additional costs.
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  • 52
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    European radiology 9 (1999), S. 1321-1323 
    ISSN: 1432-1084
    Keywords: Key words: Hydatid disease ; Chest ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The greatest difficulty in the CT diagnosis of perforated pulmonary hydatid cyst (PPHC) is the increase in the attenuation numbers following infection. Because of the solid density of infected hydatid cysts, the differentiation from an abscess or neoplasm is usually impossible. The aim of this study was to evaluate the value of “air bubble” as a new CT sign in the diagnosis of PPHC. Sixty-five patients (28 men and 37 women) with PPHC were included in the study. As a control group, 55 patients who had malignant (n = 36) or non-malignant (n = 19) pulmonary diseases were also examined. Radiological diagnosis with classical CT findings was made in only 38 of 65 patients (58.5 %) with PPHC. Air bubble sign was positive in 54 of the patients with PPHC (sensitivity 83.1 %) but only 3 of 55 patients in control group (specificity 94.5 %). When we analyzed the CT scans with classical CT findings including air bubble, the diagnosis of PPHC was made in 61 of patients (93.8 %). It is concluded that “air bubble sign” is a valuable CT finding in the diagnosis of PPHC.
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  • 53
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    European radiology 9 (1999), S. 1335-1338 
    ISSN: 1432-1084
    Keywords: Key words: Sclerosing stromal tumor ; MR imaging ; CT ; Dynamic study ; Ovarian tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Sclerosing stromal tumor is a rare ovarian neoplasm. We describe the radiologic findings of sclerosing stromal tumor in two patients. In both patients, MR and CT images showed a large mass in the left adnexal region. On dynamic contrast-enhanced images, the tumors showed early peripheral enhancement with centripetal progression.
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  • 54
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    European radiology 9 (1999), S. 1366-1375 
    ISSN: 1432-1084
    Keywords: Key words: Myelofibrosis ; Plain film ; Ultrasound ; CT ; MR imaging ; Extramedullary hematopoiesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this review is to illustrate the wide range of radiological abnormalities in myelofibrosis. Myelofibrosis, also called myeloid metaplasia, is a myeloproliferative disorder of unknown etiology. The common imaging findings in patients with myelofibrosis are osteosclerosis, hepatosplenomegaly, and lymphadenopathies. In addition, extramedullary hematopoiesis may develop in multiple sites such as chest, abdomen, pelvis, and central nervous system, simulating malignant disease. Selected plain-film, CT, and MR images in patients with myelofibrosis are shown as pictorial essay to allow ready recognition of the most common imaging abnormalities of the disease.
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  • 55
    ISSN: 1432-1084
    Keywords: Key words: Blood diseases ; CT ; Extramedullary haematopoiesis ; Presacral mass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We present the case of a 60-year-old woman with no known blood disease who developed an extramedullary haematopoiesis of presacral localization that affected the right sciatic nerve. The diagnosis was made with imaging studies and CT-guided fine-needle aspiration.
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  • 56
    ISSN: 1432-1084
    Keywords: Key words: Esophageal varices ; CT ; Endoscopic variceal ligation ; MPR ; 3D image
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The purpose of this study was to demonstrate the utility of helical CT in assessing the therapeutic effects of endoscopic variceal ligation (EVL). Twenty-four patients with esophageal varices were examined. Helical scanning was initiated 60 s after intravenous injection (Iopamidol 300 mgI/ml, total 120 ml, 3 ml/s) was started. Esophageal varices were clearly depicted as high-density areas. Multiplanar reformation and 3D images demonstrated collateral circulation three-dimensionally. After EVL, mucosal high-density areas had diminished markedly, but collateral veins around the esophagus, and gastro- and/or spleno-renal shunts, were unchanged in all patients. Of 21 patients with collateral circulation, esophageal varices recurred endoscopically in 6 patients within 12 months. In 3 patients without collateral circulation, esophageal varices did not recur within 12 months. From these findings, we conclude that helical CT is a useful method for assessing the therapeutic effects of EVL.
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  • 57
    ISSN: 1432-1084
    Keywords: Key words: Coronary vessels ; anomalies ; Coronary vessels ; CT ; Coronary vessels ; MR studies ; Coronary angiography ; Electron-beam CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. An anomalous origin of the left coronary artery arising from the pulmonary artery is a congenital malformation rarely described in adults. We report the case of a 65-year-old patient with this anomaly. Clinical presentation, imaging identification (coronary angiogram, MRI and electron-beam CT), surgical treatment and angiographic long-term follow-up are described.
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  • 58
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    European radiology 9 (1999), S. 1590-1592 
    ISSN: 1432-1084
    Keywords: Key words: Kidney ; Kidney neoplasms ; CT ; Fat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The differential diagnosis of renal masses containing fatty foci is limited to a small number of well-defined tumors, angiomyolipoma being the most frequent. In recent years clear cell carcinomas with intratumoral fatty foci have been reported, due to either entrapment of local fat or to regressive adipose metaplasia. Demonstration of focal calcifications is a valuable sign, being relatively common in carcinomas while rare in more benign lesions. We report a case of a foreign-body granuloma of the kidney, containing both calcifications and foci of fat. The value of this case, in our opinion, is that it demonstrates that detection of the previously mentioned features in a renal mass does not necessarily imply a presumptive diagnosis of renal cell carcinoma.
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  • 59
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    European radiology 9 (1999), S. 1596-1598 
    ISSN: 1432-1084
    Keywords: Key words: Penile metastasis ; Corpus cavernosum ; Bladder cancer ; CT ; MRI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Metastases of the penis are uncommon, with only approximately 300 cases reported since 1870. In up to 70 % of patients, the primary tumour is located in the urogenital tract. Furthermore, isolated metastases of the penis are exceptionally rare. We report a case of solitary squamous cell metastasis of the penis presenting with painful swelling initially thought to be inflammatory in origin. The CT and MR imaging findings are presented with a short review of the literature.
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  • 60
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    European radiology 9 (1999), S. 1599-1601 
    ISSN: 1432-1084
    Keywords: Key words: Kidney ; US ; CT ; Lipomatosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Replacement lipomatosis of the kidney is the result of severe atrophy or destruction of the renal parenchyma often caused by calculous disease with secondary marked proliferation of renal sinus, renal hilus, and perirenal fatty tissue. The diagnosis is difficult to establish with conventional radiographic methods. Although ultrasonography may show highly suggestive findings, computed tomography seems to be the most accurate method for demonstrating the distinctive features of replacement lipomatosis. Ultrasonographic and computed tomographic features in three cases of replacement lipomatosis of the kidney are reported.
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  • 61
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    European radiology 9 (1999), S. 1638-1642 
    ISSN: 1432-1084
    Keywords: Key words: Bone ; Tuberculosis ; CT ; Rib ; Sternum ; Chest wall
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The objective of this study was to determine the utility of CT scan findings for the diagnosis of chest wall tuberculosis, excluding the spine. We reviewed 15 patients (13 Africans and 2 Indians) with chest wall tuberculosis, retrospectively. The radiologic examination consisted of a plain X-ray and a CT scan of the chest for each patient. The site of disease was the rib in 13 patients or the body of the sternum in 2 patients. One rib was involved in 11 patients, 2 contiguous ribs (one site) in 2 patients, and bilateral disease (two sites) was observed in the remaining patient. The 14 rib sites involved the posterior arc or costovertebral joint in 11 cases, the anterior arc in 2 cases, and the anterior and middle arc in 1 case. The CT scan findings were an abscess (n = 14) or a soft tissue mass (n = 2), osteolytic lesions (n = 13), periosteal reaction (n = 10), and sequestrum (n = 14). Bone sclerosis was observed only in 3 cases of rib involvement. The association of a soft tissue abscess, an osteolytic lesion, and sequestrum, especially in immigrants to France, suggests chest wall tuberculosis on CT scan.
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  • 62
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    European radiology 9 (1999), S. 1650-1652 
    ISSN: 1432-1084
    Keywords: Key words: Bone tumors ; Cranial fasciitis ; CT ; MR imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Cranial fasciitis is a rare bone lesion in childhood. We report the first case in an adult, with CT and MR imaging, and suggest some diagnostic keys.
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  • 63
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    European radiology 9 (1999), S. 1653-1655 
    ISSN: 1432-1084
    Keywords: Key words: Plexiform schwannoma ; Soft tissue tumor ; Plexiform neurofibroma ; CT ; MR imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The present report describes a plexiform schwannoma involving the subcutis of the foot in an 8-year-old boy. Gross findings revealed thin fibrous septa in a multilobulated tumor that was partly separated into free body-like nodules in the subcutis. Preoperative CT and MRI failed to delineate this multinodular architecture or free bodies. This is a case presentation including the CT and MR findings associated with plexiform schwannoma.
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  • 64
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    European radiology 9 (1999), S. 1672-1674 
    ISSN: 1432-1084
    Keywords: Key words: Congenital diaphragmatic hernia ; Delayed presentation ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. A case of an 11-month-old infant with a delayed presentation of congenital diaphragmatic hernia is reported. Incarceration of the herniated colon caused a misleading appearance on the chest X-ray which was interpreted as massive pleuropneumonia. Computed tomography, performed because of continuing deterioration in the clinical condition, showed fluid-filled bowel loops in the chest and dilated bowel loops with air–fluid levels in the abdomen, suggesting the correct diagnosis.
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  • 65
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    European radiology 9 (1999), S. 1804-1809 
    ISSN: 1432-1084
    Keywords: Key words: Thalassemia ; Extramedullary hematopoiesis ; MRI ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Thalassemia is a kind of chronic, inherited, microcytic anemia characterized by defective hemoglobin synthesis and ineffective erythropoiesis. In all thalassemias clinical features that result from anemia, transfusional, and absorptive iron overload are similar but vary in severity. The radiographic features of β-thalassemia are due in large part to marrow hyperplasia. Markedly expanded marrow space lead to various skeletal manifestations including spine, skull, facial bones, and ribs. Extramedullary hematopoiesis (ExmH), hemosiderosis, and cholelithiasis are among the non-skeletal manifestations of thalassemia. The skeletal X-ray findings show characteristics of chronic overactivity of the marrow. In this article both skeletal and non-skeletal manifestations of thalassemia are discussed with an overview of X-ray findings, including MRI and CT findings.
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  • 66
    ISSN: 1432-1084
    Keywords: Key words: Aberrant left brachiocephalic vein ; CT ; Embryonic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Computed tomography was utilized to evaluate aberrant left brachiocephalic vein (ALBCV), an infrequently discussed congenital vascular anomaly among Chinese people. Associated vascular variation and possible embryonic correlation are discussed. Since 1990, a total of 14 cases of ALBCV have been reported in patients receiving CT scan of chest, and was mainly an incidental diagnosis. One case was confirmed angiographically and two others were confirmed by magnetic resonance imaging. Emphasis was placed on the entry of the azygos vein into the superior vena cava (SVC), the length of the SVC, and the presence of other cardiovascular abnormalities. Of the 14 cases of ALBCV, the level of azygos vein entry was higher than the origin of the SVC in 7 cases: 4 were approximately the same level and 3 were lower. The average length of the SVC was approximately 5.6 cm shorter than that of the general population, which is approximately 7.0 cm. Three cases had associated vascular anomaly. Most cases of ALBCV had azygos vein drainage level higher than or equal to the origin of the SVC. Right-sided aorta is one of the causes giving rise to the ALBCV during embryonic development. The CT scan remains a definitive diagnostic modality for ALBCV.
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  • 67
    ISSN: 1432-1084
    Keywords: Key words: Pharynx ; Larynx ; Neoplasms ; Radiography ; CT ; Deglutition disorders
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. In light of recent endoscopic techniques the current value of double-contrast pharyngography (DCP) and of CT for detection and staging of hypo-, oropharyngeal, and supraglottic tumors is evaluated. The DCP of 151 patients and CT obtained from 99 of these patients were retrospectively analyzed in a double-blinded manner. We used a standard protocol which comprised all relevant anatomical subregions. Results were compared with direct microlaryngoscopy (DL), indirect laryngoscopy (IL), and post-operative histopathological findings. Sensitivity and specificity of DCP was 75.0 % and 86.7 %, respectively. The DCP and IL techniques together yielded a higher sensitivity (96.7 %) than each method separately. Sensitivity and specificity of CT was 87.5 and 100 %, respectively. In 74.7 % CT provided correct staging. Subregional analysis revealed that the results of DCP and CT depend highly on the localization of the tumor. Our results indicate that DCP represents an important screening method for diagnosing hypo-, oropharyngeal, and supraglottic tumors to complete IL and DL. We show that CT is a reliable method for preoperative staging, although small superficial tumors may occasionally be missed by this method.
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  • 68
    ISSN: 1432-1084
    Keywords: Key words: Temporal bone ; CT ; Ear ; middle ; Ear ; labyrinth ; Three-dimensional CT ; hybrid rendering ; Virtual endoscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Recent developments in 3D reconstructions can enhance the quality and diagnostic value of axial 2D image data sets with direct benefits for clinical practice. To show the possible advantages of a hybrid rendering method [color-coded 3D shaded-surface display (SSD)- and volume rendering method] with the possibility of virtual endoscopy we have specifically highlighted the use in relation to the middle and inner ear structures. We examined 12 patients with both normal findings and postoperative changes, using image data sets from high-resolution spiral computed tomography (HRSCT). The middle and inner ear was segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded SSD rendering method. The temporal bone was visualized using a transparent volume rendering method. The 3D- and virtual reconstructions were compared with the axial 2D source images. The evaluated middle and inner ear structures could be seen in their complete form and correct topographical relationship, and the 3D- and virtual reconstructions indicated an improved representation and spatial orientation of these structures. A hybrid and virtual endoscopic method could add information and improve the value of imaging in the diagnosis and management of patients with middle or inner ear diseases making the understanding and interpretation of axial 2D CT image data sets easier. The introduction of an improved rendering algorithm aids radiological diagnostics, medical education, surgical planning, surgical training, and postoperative assessment.
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  • 69
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    European radiology 9 (1999), S. 1873-1875 
    ISSN: 1432-1084
    Keywords: Key words: Fibroepithelial polyp ; Kidney cyst ; CT ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Fibroepithelial polyps are the most frequently observed mesenchymal tumors of the renal pelvis. We report on one case of fibroepithelial polyp of the renal pelvis with unusual CT findings of totally cystic structure with septations.
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  • 70
    ISSN: 1432-1084
    Keywords: Key words: Duodenal cyst ; CT ; Endoscopic ultrasonography ; Duodenal diverticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Intraluminal duodenal diverticulum is a rare congenital web of membrane which may be symptomatic when it becomes distended. This report describes a case revealed by presenting as an acute pancreatitis. The radiological findings are reported. The findings at CT, upper gastro-intestinal series, endoscopic ultrasound and endoscopic retrograde cholangiopancreatography are described and differential diagnostic features from choledochocele and duodenal duplication are discussed. By endoscopic ultrasonography, observation of a thin wall, without different layers such as choledochocele or duodenal duplication, may be useful for diagnosis.
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  • 71
    ISSN: 1432-1106
    Keywords: Key words Spasticity ; Gait ; Spinal cord ; Human ; Clonidine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We studied the effect of the intrathecal (i.t.) injection of clonidine (30, 60 and 90 µg) on the polysynaptic spinal reflexes (PSR) elicited by electrical stimulation of flexor reflex afferents (FRA), monosynaptic reflex and gait of 11 subjects with spinal cord injuries. The effect of clonidine administration on gait velocity, stride amplitude and duration was measured in eight subjects who were able to walk. Five subjects were able to walk after intrathecal injection of clonidine and three were not able to stand up. Three subjects improved their gait velocity after clonidine administration; one (S6) increased his stride amplitude; the two others decreased their cycle durations. The tibialis anterior seemed to be more regularly activated during gait. Spasticity was reduced dramatically (P〈0.0001) after i.t. clonidine injection, but there was no statistically significant difference in the soleus H reflex (no effect on Hmax/Mmax). Clonidine administration decreased the amplitude of the early PSR (90–120 ms, N=4) and the threshold and maximal integrated EMG corresponding to the late response (140–450 ms, N=7). This effect was dose dependent (30, 60 and 90 µg). Placebo injection (N=4) caused no change. The changes in spinal reflexes, with a large reduction in spasticity, no change in motoneurone excitability and a large decrease in PSR, suggest that clonidine acts at a premotoneuronal level, possibly by presynaptic inhibition of group II fibres. The increase in gait velocity in three subjects could have been due to reduced spasticity or activation of spinal circuitry.
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  • 72
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    Experimental brain research 126 (1999), S. 289-306 
    ISSN: 1432-1106
    Keywords: Key words Motor control ; Trajectory formation ; Coordination ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The degrees of freedom problem is often posed by asking which of the many possible degrees of freedom does the nervous system control? By implication, other degrees of freedom are not controlled. We give an operational meaning to ”controlled” and ”uncontrolled” and describe a method of analysis through which hypotheses about controlled and uncontrolled degrees of freedom can be tested. In this conception, control refers to stabilization, so that lack of control implies reduced stability. The method was used to analyze an experiment on the sit-to-stand transition. By testing different hypotheses about the controlled variables, we systematically approximated the structure of control in joint space. We found that, for the task of sit-to-stand, the position of the center of mass in the sagittal plane was controlled. The horizontal head position and the position of the hand were controlled less stably, while vertical head position appears to be no more controlled than joint motions.
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  • 73
    ISSN: 1432-1106
    Keywords: Key words Optokinetic nystagmus ; Positron emission tomography ; Visual motion ; Area V5 ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Positron emission tomography (PET) was used to address the issue of physiological changes in the cerebral cortex associated to optokinetic nystagmus (OKN) in humans. We studied regional cerebral blood flow in eight volunteers during reflexive induction of OKN by a pattern of dots moving unidirectionally (toward the left side). We used two control conditions, with subjects passively viewing either stationary or incoherently moving dots. This paradigm was designed in order to differentiate the OKN-related activations from blood flow changes related to visual motion. When compared with the stationary condition, OKN activated a set of occipital areas known to be sensitive to visual motion. Bilateral activation was found in the striate cortex (V1) and the parieto-occipital fissure, while area V5, the intraparietal sulcus, and the pulvinar were activated only in the left hemisphere. When compared with incoherent motion, OKN activated the V1 and the parieto-occipital fissure bilaterally and the right lingual gyrus, while a signal decrease was observed in the V5 region in both hemispheres. No significant signal changes were found in areas implicated in saccades or in processing vestibular information. These results indicate that processing of OKN-related information is associated with neural activity in a specific set of visual motion areas and suggest that this network can be asymmetrically activated by a strictly unidirectional stimulation. Results are also discussed in terms of the specific kinds of OKN-related information processing subserved by each area in this network.
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  • 74
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    Experimental brain research 126 (1999), S. 175-186 
    ISSN: 1432-1106
    Keywords: Key words Listing’s plane ; Vergence ; Binocular ; Eye movements ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Earlier studies have reported temporal rotation of Listing’s plane with convergence of the eyes causing torsion, which is dependent on eye elevation. The amount by which the planes rotate differs from study to study. To gain insight into the functional significance of the temporal tilt of Listing’s plane for vision, we examined whether the rotation of the plane depends on the visual conditions, namely on the stimuli driving vergence. In different conditions, accommodative vergence, disparity-vergence, combinations of disparity with accommodation or depth perception were used and the resulting rotation of Listing’s plane was measured. Our findings show, for the first time, that the relationship between convergence and Listing’s-plane temporal rotation depends on the stimuli driving vergence. When the stimulus contains only disparity cues, vergence and Listing’s plane rotate immediately and consistently among subjects. Accommodative vergence, the mutual couplings between vergence and accommodation, can influence the orientation of Listing’s plane, but they do so in a idiosyncratic way. The largest rotation was elicited by stereograms combining disparity-vergence with depth perception. These findings support the idea of a functional role of Listing’s plane rotation for binocular vision, perhaps for depth perception.
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  • 75
    ISSN: 1432-1106
    Keywords: Key words Corpus callosum ; Interhemispheric transfer ; Positron emission tomography ; Split brain ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We studied with PET the intra- and interhemispheric pathways subserving a simple, speeded-up visuomotor task. Six normal subjects and one patient with a complete section of the corpus callosum (M.E.) underwent regional cerebral blood flow (rCBF) measurements under conditions of lateralized tachistoscopic visual presentations in a simple manual reaction time paradigm. Confirming previous behavioural findings, we found that on average crossed hand and/or hemifield conditions, i.e. those requiring an interhemispheric transfer of information, yielded a longer RT than uncrossed conditions. This difference (0.7 ms) was dramatically larger (45.6 ms) in the callosum-sectioned patient M.E. In normal subjects the cortical areas selectively activated in uncrossed and crossed conditions were different. In the former condition, most activation foci were anterior to the ventral anterior commissure (VAC) plane, whereas in the latter there was a prevalent parietal and occipital activation. This shows that a simple model in which the cortical visuo-motor pathways are similar in the intra- and the interhemispheric condition, with an extra callosal route for the latter, is too simplistic. Furthermore, these results suggest that the bulk of visuomotor interhemispheric transfer takes place through the widespread callosal fibres interconnecting the parietal cortices of the two hemispheres. The pattern of activation in the two crossing conditions was markedly different in M.E., in whom interhemispheric transfer might take place via his intact anterior commissure or subcortical commissures.
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  • 76
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    Experimental brain research 127 (1999), S. 355-370 
    ISSN: 1432-1106
    Keywords: Key words Visual cortex ; Motion ; Functional imaging ; Human ; Flicker
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Functional magnetic resonance imaging was used to map motion responsive regions of the human brain by contrasting passive viewing of moving and stationary randomly textured patterns. Regions were retained as motion responsive if they reached significance either in the group analysis or in the majority of hemispheres in single-subject analysis. They include well-known regions, such as V1, hMT/V5+, and hV3A, but also several occipito-temporal, occipito-parietal, parietal, and frontal regions. The time course of the activation was similar in most of these regions. Motion responses were nearly identical for binocular and monocular presentations. Flicker-induced-activation introduced a dichotomy amongst these motion responsive regions. Early occipital and occipito-temporal regions responded well to flicker, while flicker responses gradually vanished as one moved to occipito-parietal and then parietal regions. Finally, over a more than four-fold range, stimulus diameter had little effect on the motion activations, except in V1.
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  • 77
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    Experimental brain research 129 (1999), S. 241-246 
    ISSN: 1432-1106
    Keywords: Key words Selective attention ; Visual attention ; Putamen ; Orienting ; Positron emission tomography ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used positron emission tomography (PET) in ten subjects to study the brain regions involved in voluntary shifts of attention. For six scans, subjects performed a visual target detection task in which the location of the target was indicated in advance on some proportion of trials by the appearance of an arrow cue at fixation. The informative cues were successful in speeding reaction time to the target. Blood flow in the left putamen was correlated with the proportion of informative cues provided within a scan. We discuss this finding in terms of three possible interpretations: attentional shifts, response inhibition, and motor preparation related to the use of the right hand to respond. Blood flow in cortical regions commonly associated with attention was not related to cue ratio, a finding that may reflect automatization of the processes involved in interpreting and using the cues.
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  • 78
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    Experimental brain research 125 (1999), S. 109-114 
    ISSN: 1432-1106
    Keywords: Key words Motor control ; Visual pathways ; Illusions ; Prehension ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Visual size illusions have been shown to affect perceived object size but not the aperture of the hand when reaching to those same objects. Thus, vision for perception is said to be dissociated from vision for action. The present study examines the effect of visual-position and visual-shape illusions on both the visually perceived center of an object and the position of a grasp on that object when a balanced lift is required. The results for both experiments show that although the illusions influence both the perceived and the grasped estimates of the center position, the grasp position is more veridical. This partial dissociation is discussed in terms of its implications for streams of visual processing.
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  • 79
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    Experimental brain research 125 (1999), S. 43-49 
    ISSN: 1432-1106
    Keywords: Key words Proprioception ; Visual localization ; Visual context ; Multisensory integration ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In a previous study we investigated how the CNS combines simultaneous visual and proprioceptive information about the position of the finger. We found that localization of the index finger of a seen hand was more precise (a smaller variance) than could reasonably be expected from the precision of localization on the basis of vision only and proprioception only. This suggests that, in localizing the tip of the index finger of a seen hand, the CNS may make use of more information than proprioceptive information and visual information about the fingertip. In the present study we investigate whether this additional information stems from additional sources of sensory information. In experiment 1 we tested whether seeing an entire arm instead of only the fingertip gives rise to a more precise proprioceptive and/or visual localization of that fingertip. In experiment 2 we checked whether the presence of a structured visual environment leads to a more precise proprioceptive localization of the index finger of an unseen hand. In experiment 3 we investigated whether looking in the direction of the index finger of an unseen hand improves proprioceptive localization of that finger. We found no significant effect in any of the experiments. The results refute the hypothesis that the investigated effects can explain the previously reported very precise localization of a seen hand. This suggests that localization of a seen finger is based exclusively on proprioception and on vision of the finger. The results suggest that these sensory signals may contain more information than is described by the magnitude of their variances.
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  • 80
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    Experimental brain research 125 (1999), S. 302-312 
    ISSN: 1432-1106
    Keywords: Key words Overarm throwing ; Finger opening ; Proprioceptive feedback ; Perturbations ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Accuracy in an overarm throw requires great precision in the timing of finger opening. We tested the hypothesis that finger opening in an overarm throw is triggered by proprioceptive feedback from elbow extension or wrist flexion. The hypothesis was tested in two ways: first, by unexpectedly perturbing elbow extension or slowing wrist flexion and determining whether changes occurred in finger opening, and second, by measuring the latency from the start of these joint rotations to the start of finger opening. Subjects threw balls fast and accurately from a sitting or standing position while joint rotations were recorded with the search-coil technique. Elbow extension was unexpectedly blocked near the start of forward motion of the hand by a rope attached to the wrist that passed through a catch mechanism located behind the subject. In spite of a slowing or complete block of elbow extension, and in some cases a replacement of elbow extension by elbow flexion, finger opening always occurred and at the same latency as for normal throws. Wrist flexion was slowed in seven of eight subjects when subjects changed from throwing with a light ball (14 g, 70 mm diam.) to a heavy ball (210 g, 65 mm diam.). For the first throw with the heavy ball, this slowing was neither fully anticipated by the subject nor compensated for by the changed proprioceptive feedback associated with the slowing. Consequently, the timing of finger opening was unchanged and (to the surprise of the thrower) the ball went high. Furthermore, in unperturbed throws with tennis balls, the latency from onset of wrist flexion or elbow extension to onset of finger opening was too short for either to have triggered finger opening (across subjects means were 4 ms for wrist flexion and 21 ms for elbow extension). In additional analysis, no relation was found between the time of onset of earlier occurring rotations at the shoulder and the time of onset of finger opening. We concluded that, although a role for all proprioceptive feedback in triggering finger opening cannot be disproved by these experiments, it can be ruled out for feedback arising from elbow extension and wrist flexion, and it seems unlikely for feedback arising from events occurring very early in the throw. The more likely possibility is that finger opening in an overarm throw is triggered by a central command based on an internal model of hand trajectory.
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  • 81
    ISSN: 1432-1106
    Keywords: Key words Corticospinal tract ; Handedness ; Spinal premotoneurones ; Voluntary movement ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The possibility was investigated that human handedness is associated with an asymmetrical cortical and/or peripheral control of the cervical premotoneurones (PreMNs) that have been shown to mediate part of the descending command to motoneurones of forearm muscles . Heteronymous facilitation evoked in the ongoing voluntary extensor carpi radialis (ECR) electromyographic activity (EMG) by weak (0.8 times motor threshold) stimulation of the musculo-cutaneous (MC) nerve was assessed during tonic co-contraction of biceps and ECR. Suppression evoked by stimulation of a cutaneous nerve (superficial radial, SR) at 4 times perception threshold in both the voluntary EMG and in the motor evoked potential (MEP) elicited in ECR by transcranial magnetic stimulation (TMS) was investigated during isolated ECR contraction. Measurements were performed within time windows or at interstimulus intervals where peripheral and cortical inputs may interact at the level of PreMNs. Results obtained on both sides were compared in consistent right- and left-handers. MC-induced facilitation of the voluntary ECR EMG was significantly larger on the preferred side, whereas there was no asymmetry in the SR-evoked depression of the ongoing ECR EMG. In addition, the suppression of the ECR MEP by the same SR stimulation was more pronounced on the dominant side during unilateral, but not during bilateral, ECR contraction. It is argued that (1) asymmetry in MC-induced facilitation of the voluntary EMG reflects a greater efficiency of the peripheral heteronymous volley in facilitating PreMNs on the dominant side; (2) asymmetry in SR-induced suppression of the MEP during unilateral ECR contraction, which is not paralleled by a similar asymmetry of voluntary EMG suppression, reflects a higher excitability of cortical neurones controlling inhibitory spinal pathways to cervical PreMNs on the preferred side.
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  • 82
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    Keywords: Key words Hyperventilation ; Magnetoencephalography ; Somatosensory cortex ; Auditory cortex ; Somatosensory evoked response ; Auditory evoked response ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  It is well established that voluntary hyperventilation (HV) slows down electroencephalographic (EEG) rhythms. Little information is available, however, on the effects of HV on cortical responses elicited by sensory stimulation. In the present study, we recorded auditory evoked potentials (AEPs) and magnetic fields (AEFs), and somatosensory evoked magnetic fields (SEFs) from healthy subjects before, during, and after a 3- to 5-min period of voluntary HV. The effectiveness of HV was verified by measuring the end-tidal CO2 levels. Long-latency (100–200 ms) AEPs and long-latency AEFs originating at the supratemporal auditory cortex, as well as long-latency SEFs from the primary somatosensory cortex (SI) and from the opercular somatosensory cortex (OC), were all reduced during HV. The short-latency SEFs from SI were clearly less modified, there being, however, a slight reduction of the earliest cortical excitatory response, the N20m deflection. A middle-latency SEF deflection from SI at about 60 ms (P60 m) was slightly increased. For AEFs and SEFs, the center-of-gravity locations of the activated neuronal populations were not changed during HV. All amplitude changes returned to baseline levels within 10 min after the end of HV. The AEPs were not altered when the subjects breathed 5% CO2 in air in a hyperventilation-like manner, which prevented the development of hypocapnia. We conclude that moderate HV suppresses long-latency evoked responses from the primary projection cortices, while the early responses are less reduced. The reduction of long-latency responses is probably mediated by hypocapnia rather than by other nonspecific effects of HV. It is suggested that increased neuronal excitability caused by HV-induced hypocapnia leads to spontaneous and/or asynchronous firing of cortical neurones, which in turn reduces stimulus-locked synaptic events.
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  • 83
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    Experimental brain research 125 (1999), S. 389-396 
    ISSN: 1432-1106
    Keywords: Key words Neck muscles ; Vibration ; Proprioception ; Sound localization ; Space perception ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The effect of transcutaneous vibration of the posterior neck muscles on the lateralization of dichotic sound was investigated in human subjects. Two-alternative forced-choice (left/right) judgements were made on acoustic stimuli presented with different interaural level differences via headphones during neck-muscle vibration. A shift of the subjective auditory median plane toward the side contralateral of vibration was found, indicating that the sound was perceived as shifted toward the side of vibration. The mean magnitude of the vibration-induced intracranial shift was 1.5 dB. The results demonstrate a neck-proprioceptive influence on sound lateralization and suggest that this proprioceptive input is used for a central-nervous transformation of auditory spatial coordinates onto a body-centered frame of reference.
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  • 84
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    Experimental brain research 125 (1999), S. 435-439 
    ISSN: 1432-1106
    Keywords: Key words Transcranial magnetic stimulation ; Plasticity ; Synchronization ; Motor system ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used focal transcranial magnetic stimulation to examine the effects of 120 synchronized thumb and foot movements on the motor output map of the right abductor pollicis brevis muscle (APB) (experiment 1). To evaluate the performance, the latencies between the onset of the electromyographic activity (EMG) of the two muscles were measured. As control, 120 asynchronous thumb and foot movements were performed (experiment 2). Exclusively in experiment 1, the center of gravity (CoG) of the output map moved medially in the direction of the foot representation area (mean 7 mm, P〈0.05) and returned into its original location within 1 h. In experiment 2, the CoG remained unchanged (mean displacement, 0.68 mm into a lateral direction; not significant). The effect in experiment 1 was independent of an improvement in performance. We conclude that a short-lasting training of synchronous movements induces modulations of motor output maps which probably occur due to interactions between hand and foot representation areas in the motor cortex.
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  • 85
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    Keywords: Key words Reach to grasp ; Human ; Perturbation ; Kinematics ; Motor control ; Parkinson’s disease ; Elderly
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This study assessed the adaptive response of the reach-to-grasp movement of 12 Parkinson’s disease (PD) and 12 control subjects to a simultaneous perturbation of target object location and size. The main aim was to test further the reported dysfunction of PD subjects in the simultaneous activation of movement components. Participants were required to reach 30 cm to grasp a central illuminated cylinder of either small (0.7 cm) or large (8 cm) diameter. For a small percentage of trials (20/100) a visual perturbation was introduced unexpectedly at the onset of the reaching action. This consisted of a shift of illumination from the central cylinder to a cylinder of differing diameter, which was positioned 20° to the left (n=10) or to the right (n=10). The subject was required to grasp the newly illuminated cylinder. For the Parkinson’s disease subject group, the earliest response to this ’double’ perturbation was in the parameter of peak reaching acceleration, which was on average 50 ms earlier for ’double’ perturbed than for non-perturbed trials. The grasp component response followed more than 500 ms after the earliest transport response. For the control subjects initial signs of a response to the ’double’ perturbation were seen almost simultaneously in the transport parameter of peak arm deceleration, and in the manipulation parameter of maximum grip aperture, but these changes were not evident until more than 400 ms after movement onset. These results indicate that the basal ganglia can be identified as part of a circuit which is involved in the integration of parallel neutral pathways, and which exercise flexibility in the degree to which these components are ’coupled’ functionally. With basal ganglia dysfunction the activation of integration centres that at first gate the flow of information to the parallel channels of reach and grasp seems inefficient.
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  • 86
    ISSN: 1432-1084
    Keywords: Key words: Langerhans' cell histiocytosis ; Liver ; Spleen ; CT ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. We present a case of Langerhans' cell histiocytosis (LCH) of the liver and spleen in an adult. The imaging features are different from those in the few previously reported cases of individual organ involvement by LCH.
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  • 87
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    European radiology 9 (1999), S. 259-261 
    ISSN: 1432-1084
    Keywords: Key words: Liver neoplasms ; CT ; Fat ; CT
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Follow-up of two hepatic angiolipomas in a patient without evidence of tuberous sclerosis is reported. Initially, the lesions presented as homogenously enhancing masses, which were nearly isodense to normal liver tissue on plain CT scans. Focal nodular hyperplasia was assumed. One year later, fat was detected in the growing tumors and percutaneous core biopsy revealed hepatic angiolipomas. Natural history of these rare lesions is unknown, and this is to the best of our knowledge the first observation of fatty metamorphosis in such a benign, mesenchymal hepatic neoplasm.
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  • 88
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    Experimental brain research 128 (1999), S. 353-368 
    ISSN: 1432-1106
    Keywords: Key words Multijoint arm ; Simulations ; Muscle torques ; Kinetics ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Adults are able to reach for an object for the first time with appropriate direction, speed, and accuracy. The rules by which the nervous system is able to set muscle activities to accomplish these outcomes are still debated and, indeed, the sensitivity of kinematics to variations in muscle torques is unknown for complex arm movements. As a result, this study used computer simulations to characterize the effects of change in muscle torque on initial hand path. The same change was applied to movements towards 12 directions in the horizontal plane, and changes were systematically manipulated such that: (1) torque amplitude was changed at one joint, (2) timing of torque was changed at one joint, and (3) amplitude and/or timing was changed at two joints. Results showed that simultaneous changes in torque amplitude at shoulder and elbow joints affected initial speed uniformly across direction. These results add to conclusions from previous experimental and modeling work that the simplest rule to produce a desired change in speed for any direction is to scale torque amplitude at both joints. In contrast, all simulations showed nonuniform effects on initial path direction. For some regions of the workspace, initial path direction was little affected by either a ±30% change in amplitude or a ±100-ms change in timing, whereas for other regions the same changes produced large effects on initial path direction. These findings suggest that the range of possible torque solutions to achieve a particular initial path direction varies within the workspace and, consequently, the requirements for an accurate initial path will vary within the workspace.
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  • 89
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    Experimental brain research 124 (1999), S. 287-294 
    ISSN: 1432-1106
    Keywords: Key words Magnetoencephalography ; V1 cortex ; V2 cortex ; V6 complex ; Horizontal meridian ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We recorded whole-scalp magnetoencephalographic (MEG) responses to black-and-white checkerboards to study whether the human cortical responses are quantitatively similar to stimulation of the lower and upper visual field at small, 0–6°, eccentricities. All stimuli evoked strongoccipital responses peaking at 50–100 ms (mean 75 ms). The activation was modeled with a single equivalent current dipole in the contralateral occipital cortex, close to the calcarine fissure, agreeing with an activation of the V1/V2 cortex. The dipole was, on average, twice as strong to lower than to upper field stimuli. Responses to hemifield stimuli that extended to both lower and upper fields resembled the responses to lower field stimuli in source current direction and strength. These results agree with psychophysical data, which indicate lower visual field advantage in complex visual processing. Parieto-occipital responses in the putative V6 complex were similar to lower and upper field stimuli.
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  • 90
    ISSN: 1432-1106
    Keywords: Key words Vibration-induced kinesthetic illusions ; Antagonist vibratory response ; Motor units ; Wrist extensor muscles ; Human ; Microelectromyography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  In humans, vibration applied to muscle tendons evokes illusory sensations of movement that are usually associated with an excitatory tonic response in muscles antagonistic to those vibrated (antagonist vibratory response or AVR). The aim of the present study was to investigate the neurophysiological mechanisms underlying such a motor response. For that purpose, we analyzed the relationships between the parameters of the tendon vibration (anatomical site and frequency) and those of the illusory movement perceived (direction and velocity), as well as the temporal, spatial, and quantitative characteristics of the corresponding AVRs (i.e., surface EMG, motor unit firing rates and activation latencies). Analogies were supposed between the characteristics of AVRs and voluntary contractions. The parameters of the AVR were thus compared with those of a voluntary contraction with similar temporal and mechanical characteristics, involving the same muscle groups as those activated by vibration. Wrist flexor muscles were vibrated either separately or simultaneously with wrist extensor muscles at frequencies between 30 and 80 Hz. The illusory movement sensations were quantified through contralateral hand-tracking movements. Electromyographic activity from the extensor carpi radialis muscles was recorded with surface and intramuscular microelectrodes. The results showed that vibration of the wrist flexor muscle group induced both a kinesthetic illusion of wrist extension and a motor response in the extensor carpi radialis muscles. Combined vibration of the two antagonistic muscle groups at the same frequency evoked neither kinesthetic illusion nor motor activity. In addition, vibrating the same two antagonistic muscle groups at different frequencies induced both a kinesthetic illusion and a motor response in the muscle vibrated at the lowest frequency. The surface EMG amplitude of the extensor carpi radialis as well as the motor unit activation latency and discharge frequency were clearly correlated to the parameters of the illusory movement evoked by the vibration. Indeed, the faster the illusory sensation of movement, the greater the surface EMG in these muscles during the AVRs and the sooner and the more intense the activation of the motor units of the wrist extensor muscles. Moreover, comparison of the AVR with voluntary contraction showed that all parameters were highly similar. Mainly slow motor units were recruited during the AVR and during its voluntary reproduction. That the AVR is observed only when a kinesthetic illusion is evoked, together with the similarities between voluntary contractions and AVRs, suggests that this vibration-induced motor response may result from a perceptual-to-motor transformation of proprioceptive information, rather than from spinal reflex mechanisms.
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  • 91
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    Experimental brain research 124 (1999), S. 351-362 
    ISSN: 1432-1106
    Keywords: Key words Saccadic adaptation ; Gaze ; Short term adaptation ; Transfer to hand movements ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We investigated whether and how adaptive changes in saccadic amplitudes (short-term saccadic adaptation) modify hand movements when subjects are involved in a pointing task to visual targets without vision of the hand. An experiment consisted of the pre-adaptation test of hand pointing (placing the finger tip on a LED position), a period of adaptation, and a post-adaptation test of hand pointing. In a basic task (transfer paradigm A), the pre- and post-adaptation trials were performed without accompanying eye and head movements: in the double-step gaze adaptation task, subjects had to fixate a single, suddenly displaced visual target by moving eyes and head in a natural way. Two experimental sessions were run with the visual target jumping during the saccades, either backwards (from 30 to 20°, gaze saccade shortening) or onwards (30 to 40°, gaze saccade lengthening). Following gaze-shortening adaptation (level of adaptation 79±10%, mean and s.d.), we found a statistically significant shift (t-test, error level P〈0.05) in the final hand-movement points, possibly due to adaptation transfer, representing 15.2% of the respective gaze adaptation. After gaze-lengthening adaptation (level of adaptation 92±17%), a non-significant shift occurred in the opposite direction to that expected from adaptation transfer. The applied computations were also performed on some data of an earlier transfer paradigm (B, three target displacements at a time) with gain shortening. They revealed a significant transfer relative to the amount of adaptation of 18.5±17.5% (P〈0.05). In the coupling paradigm (C), we studied the influence of gaze saccade adaptation of hand-pointing movements with concomitant orienting gaze shifts. The adaptation levels achieved were 59±20% (shortening) and 61±27% (lengthening). Shifts in the final fingertip positions were congruent with internal coupling between gaze and hand, representing 53% of the respective gaze-amplitude changes in the shortening session and 6% in the lengthening session. With an adaptation transfer of less than 20% (paradigm A and B), we concluded that saccadic adaptation does not ”automatically” produce a functionally meaningful change in the skeleto-motor system controlling hand-pointing movements. In tasks with concomitant gaze saccades (coupling paradigm C), the modification of hand pointing by the adapted gaze comes out more clearly, but only in the shortening session.
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  • 92
    ISSN: 1432-1106
    Keywords: Key words Locomotion ; Load ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Prior work from mammals suggests that load experienced by extensor muscles of the hindlimbs (i.e. Duysens and Pearson 1980; Pearson and Collins 1993; Fouad and Pearson 1997) or cutaneous afferents from the plantar surface of the foot (Duysens and Pearson 1976; Guertin et al. 1995) enhances activity in extensor muscles during the stance phase, and delays the onset of flexor activity associated with the swing phase. The presumed functional significance of this phenomenon is that extensor activity of the supporting limb during walking can: (a) reinforce the supporting function in proportion to the load experienced, and (b) prolong the stance phase until unloading of the limb has occurred. Whether a similar functional role exists for load-sensitive afferents during walking in the human is unknown. In this study, the effect of adding or removing a substantial load (30% of body weight) at the centre of mass was studied in healthy adult human subjects. Loads were applied near the centre of mass to avoid the need for postural adjustments which might confound the interpretation of the results. Subjects walked on a treadmill with either: (a) a sustained increase or decrease in load, or (b) a sudden unexpected increase or decrease in load. In general, subjects responded to the changes in load by changing the amplitude of the extensor electromyographic (EMG) bursts. For example, with sudden unexpected additions in load, the average increase in amplitude was 40% for the soleus across the stance phase, and 134% for the quadriceps during the early part of the stance phase. Extensor EMGs increased with both sustained and sudden increases in load. Extensor EMG durations also increased (average increase in duration of 4% for soleus with sudden loading, and 7% for sustained loading). Cycle duration hardly changed (average increase of 0.5% with both sudden and sustained loading). These results differ from those of infants subjected to a similar perturbation during supported walking. A large change in timing (i.e. an increase in the duration of the stance phase by 30% and the step cycle by 28%) was seen in the infants, with no change in the amplitude of the EMG burst (Yang et al. 1998). These results suggest that the central nervous system can control the timing and amplitude of extensor EMG activity in response to loading independently. Maturation of the two components most likely occurs independently. In the adult, independent control of the two components may provide greater flexibility of the response.
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  • 93
    ISSN: 1432-1106
    Keywords: Key words Motor development ; Reaching ; Anticipatory postural control ; EMG ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The present study focused on the developmental changes of postural adjustments accompanying reaching movements in healthy infants. We made a longitudinal study of ten infants between 6 and 18 months of age. During each session multiple surface electromyograms of arm, neck, trunk and leg muscles at the right side of the body were recorded during right-handed reaching movements in two positions (”upright sitting” in an infant chair and ”long-leg” sitting without support). Simultaneously the whole session was recorded on video. Comparable data were present from the same infants at 3–5 months. Additionally, 18 infants (8–15 months) were assessed once during similar reaching tasks, but in these infants electromyographic activity of the trunk and neck muscles at both sides of the body were recorded. Our data revealed two transitions in the development of postural adjustments. The first transition was present around 6 months of age. At this age the postural muscles were infrequently activated during reaching movements. At 8 months ample postural activity reappeared and the infants developed the ability to adapt the postural adjustments to task-specific constraints such as arm movement velocity or the sitting position at the onset of the reaching movement. The second transition occurred between 12 and 15 months. Before 15 months the infants did not show consistent anticipatory postural activity, but from 15 months onwards they did, particularly in the neck muscles.
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  • 94
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    Experimental brain research 126 (1999), S. 536-544 
    ISSN: 1432-1106
    Keywords: Key words Magnetic brain stimulation ; Afferent input ; Motor cortex ; Plasticity ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Previously, we had described a technique for investigating probable GABAergic cortical inhibitory circuits in conscious man using transcranial magnetic stimulation. This type of inhibition has been termed intracortical inhibition. During voluntary contraction, activity in the circuits responsible for this inhibition is reduced. The mechanism by which this reduction in activity is brought about is unknown. However, evidence exists to suggest that afferent input may be, at least in part, responsible for the reduction in inhibition. The experiments described here were designed to investigate this possibility further. The results of these experiments showed that afferent input, produced by electrical peri- pheral-nerve stimulation, reduced the level of intracortical inhibition. Also, motor imagery, which activates similar brain regions as overt movement, but does not result in afferent input, failed to produce significant changes in intracortical inhibition. We conclude from these results that afferent input is capable of altering activity in cortical inhibitory circuits. The relevance of these findings to the mechanisms involved in cortical reorganisation is discussed.
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  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 126 (1999), S. 556-562 
    ISSN: 1432-1106
    Keywords: Key words Acceleration ; Ocular microtremor ; Eye movements ; Partial coherence ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A novel technique for the study of human eye movements was used to investigate the frequency components of ocular drift and microtremor in both eyes simultaneously. The tangential components of horizontal eye accelerations were recorded in seven healthy subjects using light-weight accelerometers mounted on scleral contact lenses during smooth pursuit movements, vestibulo-ocular reflexes and eccentric gaze with and without fixation. Spectral peaks were observed at low (up to 25 Hz) and high (60–90 Hz) frequencies. A multivariate analysis based on partial coherence analysis was used to correct for head movement. After correction, the signals were found to be coherent between the eyes over both low- and high-frequency ranges, irrespective of task, convergence or fixation. It is concluded that the frequency content of ocular drift and microtremor reflects the patterning of low-level drives to the extra-ocular muscle motor units.
    Type of Medium: Electronic Resource
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  • 96
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 127 (1999), S. 83-94 
    ISSN: 1432-1106
    Keywords: Key words Target interception ; Reaching ; Grasping ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The goal of the present study was to understand which characteristics (movement time or velocity) of target motion are important in the control and coordination of the transport and grasp-preshape components of prehensile movements during an interception task. Subjects were required to reach toward, grasp and lift an object as it entered a target area. Targets approached along a track at four velocities (500, 750, 1000 and 1250 mm/s) which were presented in two conditions. In the distance-controlled condition, targets moving at all velocities traveled the same distance. In the viewing-time-controlled condition, combinations of velocity and starting distances were performed such that the moving target was visible for 1000 ms for all trials. Analyses of kinematic data revealed that when, target distance was controlled, velocity affected all transport-dependent measures; however, when viewing time was controlled, these dependent measures were no longer affected by target velocity. Thus, the use of velocity information was limited in the viewing-time-controlled condition, and subjects used other information, such as target movement time, when generating the transport component of the prehensile movement. For the grasp-preshape component, both peak aperture and peak-aperture velocity increased as target velocity increased, regardless of condition, indicating that target velocity was used to control the spatial aspects of aperture formation. However, the timing of peak aperture was affected by target velocity in the distance-controlled condition, but not in the viewing-time-controlled condition. These results provide evidence for the autonomous generation of the spatial and temporal aspects of grasp preshape. Thus, an independence between the transport and grasp-preshape phases was found, whereby the use of target velocity as a source of information for generating the transport component was limited; however, target velocity was an important source of information in the grasp-preshape phase.
    Type of Medium: Electronic Resource
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  • 97
    ISSN: 1432-1106
    Keywords: Key words Frontal eye field ; Saccade ; Efference copy ; Spatial short-term memory ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Physiological studies in monkeys have shown that the frontal eye field (FEF) is involved in the preparation and triggering of purposive saccades. However, several questions of FEF function remain unclear: the role of the FEF in visual short-term memory, its ability to update its spatial map and its role in reflexive saccade inhibition. We have addressed these issues in a patient with a small acute ischemic lesion whose location corresponded very accurately to the region of the left FEF according to the most recent cerebral blood flow studies. An initial study was conducted on days 7 and 8 after the stroke, i.e., before substantial recovery. A first group of paradigms (smooth pursuit, simple saccade tasks) was performed to assess FEF dysfunction. In a second group of paradigms, (1) visual short-term memory was tested by means of memory-guided saccade paradigms with short and long delays (1 and 7 s), (2) spatial updating abilities were tested by a double-step saccade task and two memory-guided saccade tasks in which the central fixation point was displaced during the memorization delay, and (3) reflexive saccade inhibition was tested by the antisaccade task. Results show that the FEF is involved in short-term memorization of the parameters of the forthcoming memory-guided saccade encoded in oculocentric coordinates. Normal results in the antisaccade task suggest that the FEF is not involved in reflexive saccade inhibition.
    Type of Medium: Electronic Resource
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  • 98
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    Electronic Resource
    Springer
    Experimental brain research 129 (1999), S. 378-390 
    ISSN: 1432-1106
    Keywords: Key words Manual tracking ; Microgravity ; Visuomotor transformation ; Adaptation ; Human ; Spaceflight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A series of step-tracking experiments was conducted before, during, and after a 3-week space mission to assess the effects of prolonged microgravity on a non-postural motor-control task. In- and post-flight accuracy was affected only marginally. However, kinematic analyses revealed a considerable change in the underlying movement dynamics: too-small force and, thus, too-low velocity in the first part of the movements was mainly compensated by lengthening the deceleration phase of the primary movement, so that accuracy was regained at its end. The observed in-flight decrements in peak velocity and peak acceleration point to an underestimation of mass, in agreement with the re-interpretation hypothesis of Bock et. al. Post-flight no reversals of the in-flight changes (negative aftereffects) were found. Instead, there was a general slowing down, which could be due to post-flight physical exhaustion.
    Type of Medium: Electronic Resource
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  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 125 (1999), S. 50-60 
    ISSN: 1432-1106
    Keywords: Key words Pointing errors ; Remembered target Navigation ; Active self-movements ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We studied pointing movements to remembered visual targets in a completely darkened room with and without self-made step movements in order to investigate in which coordinate system and to what extent target representations relative to the body are updated for self-induced egomotion. A small red-light-emitting diode on the fingertip provided visual feedback about fingertip position at all times. We asked subjects to make pointing movements that started 2 s after disappearance of a visual target. In this interval of 2 s the subject did or did not make a step. The pointing errors without a step showed that subjects undershot faraway targets in a systematic way, whereas they sometimes overshot nearby targets. We found that the step causes larger pointing errors both in amplitude and direction with a bias in the direction of the step. We explored three different versions of a descriptive model in which polar coordinates were used to describe the pointing movement, and in which either Cartesian or polar coordinates were used to update target position relative to the shoulder for the step. The results suggest that incorporation of the step displacement in the new target position relative to the subject is done in a Cartesian frame of reference. Moreover, the amplitude of the step displacement tends to be underestimated by subjects.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 125 (1999), S. 139-152 
    ISSN: 1432-1106
    Keywords: Key words Reaching movements ; Direction ; Amplitude ; Initial kinematics ; Spatial variability ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The accuracy of reaching movements to memorized visual target locations is presumed to be determined largely by central planning processes before movement onset. If so, then the initial kinematics of a pointing movement should predict its endpoint. Our study examined this hypothesis by testing the correlation between peak acceleration, peak velocity, and movement amplitude and the correspondence between the respective spatial positions of these kinematic landmarks. Subjects made planar horizontal reaching movements to targets located at five different distances and along five radially arrayed directions without visual feedback during the movements.The spatial dispersion of the positions of peak acceleration, peak velocity, and endpoint all tended to form ellipses oriented along the movement trajectory. However, whereas the peaks of acceleration and velocity scaled strongly with movement amplitude for all of the movements made at the five target distances in any one direction, the correlations with movement amplitude were more modest for trajectories aimed at each target separately. Furthermore, the spatial variability in direction and extent of the distribution of positions of peak acceleration and peak velocity did not scale differently with target distance, whereas they did for endpoint distributions. Therefore, certain features of the final kinematics are evident in the early kinematics of the movements as predicted by the hypothesis that they reflect planning processes. However, endpoint distributions were not completely predetermined by the Initial kinematics. In contrast, multivariate analysis suggests that adjustments to movement duration help compensate for the variability of the initial kinematics to achieve desired movement amplitude. These compensatory adjustments do not contradict the general conclusion that the systematic patterns in the spatial variability observed in this study reflect planning processes. On the contrary, and consistent with that conclusion, our results provide further evidence that direction and extent of reaching movements are planned and determined in parallel over time.
    Type of Medium: Electronic Resource
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