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  • 1
    ISSN: 1437-2320
    Keywords: Brain tumour ; histological finding ; laser ; laser coagulation ; laser surgery ; Nd-YAG laser
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The extent of thermal penetration of Nd-YAG laser was studied histologically. The material was obtained from seven cases of various types of intracranial and extracranial tumours and normal temporal muscle obtained at operation. After irradiation of the tumour surface with the laser, the tumours were removed and depth and width of pathological changes caused by heat were studied. Histologically, materials consisted of a vaporized surface, carbonized, vesicular, necrotic, oedematous layers and surrounding intact brain tumour tissue. There was a direct relationship between the thermal effect and the irradiated thermal energy (watt × exposure time × pulse number). The results showed that the thermal effect was limited to a depth of 6 to 10 mm from the irradiated surface when irradiated 4 times at the power of 90 watts for 2 seconds.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Neurosurgical review 5 (1982), S. 169-172 
    ISSN: 1437-2320
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0021-9304
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine , Technology
    Notes: Aiming at alleviating the problems of using 2-cyanoacrylates as a material for therapeutic embolization, this experiment made some physical modifications by mixing contrast media. It was found that the physicochemical properties of 2-cyanoacrylates can be altered by changing the concentration and the composition of the contrast media added. A 50 wt% cyanoacrylate-50 wt% contrast medium mixture has enough radiopacity for the practical requirement for embolization. A mixture of 50 wt% (ethoxyethyl cyanoacrylate-5 wt% lactide/ ∊-caprolactone copolymer), 25 wt% lipiodol and 25 wt% tetrafluorodibro-moethane provides a viscosity of 13.8 cP, a bonding strength of 14.9 kg/cm2, a set time of 6 s, and a spreading in canine blood of 33 mm. It was concluded that the mixture is much more satisfactory than the conventional cyanoacrylates as an embolus material in vitro. The results obtained by in vivo experiments and clinical trials so far suggest that the mixture is very promising as a material for embolization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0533
    Keywords: Key wordsp16 ; CDK4 ; RB ; Glioblastoma ; Progression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Primary glioblastomas develop rapidly de novo through a genetic pathway characterized by amplification/overexpression of EGFR and of MDM2 genes. Secondary glioblastomas develop more slowly through progression from low grade or anaplastic astrocytoma and show a high incidence of a p53 mutation. In the present study, primary and secondary glioblastomas were analyzed for p16 deletions and CDK4 amplification by differential PCR and for loss of expression of the retinoblastoma (RB) gene by immunohistochemistry. Except for one case, alterations in the structure or expression of p16, CDK4 and RB were mutually exclusive. The overall incidence of aberrant expression of these genes coding for components of the cell-cycling-regulatory system was similar in primary (14/28; 50%) and secondary glioblastomas (9/23; 39%). However, p16 deletions were significantly more frequent in the former (10/28; 36%) than in the latter (1/23, 4%; P = 0.0075), suggesting that this alteration constitutes an additional genetic hallmark of the primary (de novo) glioblastoma.
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  • 5
    ISSN: 1433-0350
    Keywords: Moyamoya disease ; PET ; Cerebral blood flow ; Oxygen consumption ; Cerebral blood volume
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cerebral rCBF, rOEF, rCMRO2, and rCBV in moyamoya disease were studied by means of positron emmission tomography (PET), using 15O as a tracer. Steady-state methods with C15O2 and 15O2 were used to obtain the functional images of rCBF, rCMRO2, and rOEF. The 15O single-inhalation method was used to obtain the rCBV image. Five children (two boys and three girls) with mean age of 11 years and eight normal volunteers with mean age of 31 years were included in the study. The symptoms of moyamoya disease were due to cerebral ischemia, such as transient ischemic attack (TIA), reversible ischemic neurological deficit (RIND), and minor stroke. The interval between the latest ictus and PET scan ranged from 3 days to 3 years 6 months. Physiological parameters (rCBF, rCMRO2 etc.) in cerebral gray matter, cerebral white matter and basal ganglia were calculated from the single functional images. Any, low density areas appearing in X-ray-CT performed just prior to the PET study were carefully excluded from the analysis. The parameters of moyamoya disease were statistically compared with normal control parameters. Though the value of rCBF was slightly higher in moyamoya disease, this difference was not statistically significant. On the other hand, in moyamoya disease rCBV increased significantly in gray matter, white matter, and basal ganglia. The ratio of CBF to CBV is considered to be the index of perfusion pressure and reciprocal of cerebral mean transit time under the normal autoregulation of CBF. This ratio was calculated and compared with the normal value for each tissue. The ratio was significantly decreased in each tissue in moyamoya disease, indicating the presence of a low perfusion pressure in the moyamoya brain. In general, when the reduction of perfusion pressure becomes profound the decrease in the CBF-to-CBV ratio is followed by an increase in rOEF. In spite of the reduction in the CBF-to-CBV ratio there was no significant increase in rOEF in moyamoya disease. Thus, the cerebral circulation in childhood moyamoya disease of ischemic type was characterized by a mild decrease in perfusion pressure and a prolonged circulation time.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 91 (1996), S. 549-553 
    ISSN: 1432-0533
    Keywords: Key words Astrocytoma ; Neuromelanin ; Melanogenesis ; Pigmented glioma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of pigmented pilocytic astrocytoma (WHO grade I) incidentally found in a right temporopolar lobectomy specimen is reported. The patient, a 41-year-old woman, underwent surgery because of long-standing complex partial epilepsy of presumed post-traumatic origin. Using immunohistochemistry and electron microscopy, the tumor was shown to be composed of astrocytes without evidence of neurosecretory or melanocytic differentiation. The cytoplasmic pigment was identified as neuromelanin by its histochemical staining properties and ultrastructure. Although rare cases of ependymoma, subependymoma, choroid plexus papilloma and ganglioglioma with melanogenesis are on record, no melanotic astrocytoma has been described so far.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0533
    Keywords: Key words Astrocytoma ; Glioblastoma ; Glioma ; progression ; p53 mutation ; Gemistocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Low-grade diffuse astrocytomas have an intrinsic tendency for malignant progression but the factors determining the kinetics of this process are still poorly understood. We report here the case of a male patient who developed a fibrillary astrocytoma at the age of 33 years and who underwent six surgical interventions over a period of 17 years without radiotherapy or chemotherapy. The first three biopsies spanned a period of 11 years and led to the diagnosis of low-grade, diffuse astrocytoma (WHO grade II), with a growth fraction (MIB-1 labeling index) of 2.3–3.7%. The fourth to sixth biopsies showed histological features of anaplastic astrocytoma (WHO grade III), with growth fractions between 5.0 and 10.5%. The fraction of gemistocytic neoplastic astrocytes also increased, from 0.3% in the first biopsy to 17.5% in the last biopsy and preceded the increase in proliferative activity and transition to anaplastic astrocytoma. The fraction of tumor cells immunoreactive to BCL-2 increased from 0.3% to 8.2%. A p53 mutation in codon 273 (CGT→TGT, Arg→Cys) was identified in the first biopsy and persisted throughout the course of the disease. However, the fraction of cells with p53 protein accumulation increased significantly during progression, from 3.2% in the first biopsy to 13.7% in the last. The absence of additional genetic alterations (PTEN mutations, loss of chromosome 10 and 19q) may be responsible for the slow progression and lack of glioblastoma features even after a 17-year disease duration.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of plastic surgery 3 (1976), S. 263-270 
    ISSN: 1435-0130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Micro-venous anastomosis using the external jugular and posterior facial vein in rats were performed. The patency rate employing 19 methods using 6 kinds of drugs was examined. A combination of heparin i.v. and topical procaine was found to be the most effective. After reviewing the literature and our experimental results, we discuss the problems of micro-venous anastomosis, and conclude as follows, 1. venous spasm is a very important factor influencing postoperative patency, 2. an anastomosed vein is very apt to thrombose, 3. application of appropriate drugs is necessary, 4. it is effective to cut a vein obliquely at an anastomosis only when appropriate drugs are used, 5. recanalisation takes place very often at a micro-venous anastomosis within 2 weeks.
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  • 9
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Changes in content of brain mitochondrial phospholipids were examined in rats after 30 and 60 min of decapitation ischemia compared with controls, to explore the degradation of the mitochondrial membrane and its relation to dysfunction of mitochondria. Activities of respiratory functions and respiratory enzymes (cytochrome c oxidase; F0F1-ATPase) decreased significantly during ischemia. Considerable decreases in cardiolipin and phosphatidylinositol content were observed after 60 min, and other phospholipids showed similar but nonsignificant decreases in content. The amount of polyunsaturated fatty acid chains, such as arachidonic and docosahexaenoic acids, was reduced in each phospholipid, in some cases significantly, after 30 and 60 min of ischemia in time-dependent manners. Degradation of mitochondrial phospholipids during ischemia associated with the deterioration of mitochondrial respiratory functions suggested the significance of such changes in phospholipid content in disintegration of cellular energy metabolism during cerebral ischemia.
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  • 10
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The haematopoietic growth factor erythropoietin is the primary regulator of mammalian erythropoiesis and is produced by the kidney and the liver in an oxygen-dependent manner. We and others have recently demonstrated erythropoietin gene expression in the rodent brain. In this work, we show that cerebral erythropoietin gene expression is not restricted to rodents but occurs also in the primate brain. Erythropoietin mRNA was detected in biopsies from the human hippocampus, amygdala and temporal cortex and in various brain areas of the monkey Macaca mulatta. Exposure to a low level of oxygen led to elevated erythropoietin mRNA levels in the monkey brain, as did anaemia in the mouse brain. In addition, erythropoietin receptor mRNA was detected in all brain biopsies tested from man, monkey and mouse. Analysis of primary cerebral cells isolated from newborn mice revealed that astrocytes, but not microglia cells, expressed erythropoietin. When incubated at 1% oxygen, astrocytes showed 〉l OO-fold time-dependent erythropoietin mRNA accumulation, as measured with the quantitative reverse transcription-polymerase chain reaction. The specificity of hypoxic gene induction in these cells was confirmed by quantitative Northern blot analysis showing hypoxic up-regulation of mRNA encoding the vascular endothelial growth factor, but not of other genes. These findings demonstrate that erythropoietin and its receptor are expressed in the brain of primates as they are in rodents, and that, at least in mice, primary astrocytes are a source of cerebral erythropoietin expression which can be up-regulated by reduced oxygenation.
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