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  • 1990-1994  (2,029)
  • 1975-1979  (709)
  • Analytical Chemistry and Spectroscopy  (1,705)
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  • Rat  (304)
  • Magnetic resonance imaging  (194)
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Year
  • 11
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 523-529 
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Non-planar conformational distortions have recently been implicated in the biological activity of porphyrins and related tetrapyrroles in proteins, and several studies have used highly substituted porphyrins to model these nonplanar conformational distortions. Several aspects of non-planarity in the highly substituted metalloporphyrins are discussed, focusing on resonance Raman spectroscopy as a technique for investigating these structural issues. First, different non-planar distortions cause characteristic changes in the Raman spectrum. Specifically, the decreases in frequency of several Raman lines when compared with planar porphyrin analogs are shown to be similar for several classes of non-planar highly substituted porphyrins. Second, the effect of the central metal ion [ M = Ni(II), Co(II), Cu(II), Zn(II), Co(III), Fe(III)] on the conformation of the sterically constrained non-planar porphyrin octaethyltetraphenylporphyrin is considered. Responding to the conformational adjustments resulting from different metal size, the frequency of the structure-sensitive Raman line v2 correlates with several structural parameters obtained from either mechanics calculations or crystallographic studies. The parameters include Cβ—Cβ bond length, core size and Cα—N—Cα angle. Finally, an effect of electron-withdrawing substituents on the Raman frequencies is evident for the different classes of highly substituted porphyrins.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-0851
    Keywords: Bispecific monoclonal antibody ; Lymphokine-activated killer cell ; Rat ; CD8
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In vivo targeting of lymphokine-activated killer (LAK) cells to tumour deposits by bispecific monoclonal antibodies (bimAb) may be a way to improve adoptive immunotherapy. We developed a bimAb against adherent LAK (ALAK) cells and colon tumour CC531 in Wag rats. The bimAb was produced by somatic hybridization of two mouse hybridomas, one producing monoclonal antibodies (mAb) against CD8 (IgG2b, OX8), and the other producing mAb against a CC531-associated antigen (IgG1, CC52). A bimAb-producing clone was selected by an enzyme-linked immunosorbent assay with CC531 tumour cells. BimAb were purified from ascitic fluid by protein A affinity chromatography. Each of five pooled peak fractions was analysed by flow cytometry for the presence of bimAb. Most bimAb were found in a fraction that was eluted at pH 4.5 from protein A. FPLC analysis of this fraction revealed that no parental antibodies were present. The OX8 × CC52 bimAb greatly increased conjugate formation in vitro between ALAK cells and CC531. Results of51Cr-release assays with CC531 as target cells and ALAK cells as effector cells were not significantly different in the presence or in the absence of the bimAb. The methods we used here, a cell enzyme-linked immunosorbent assay and flow cytometry, are simple methods for development and purification of a bimAb when a functional selection method is not a priori available. The OX8 × CC52 bimAb we developed this way may increase in vivo tumour targeting of ALAK cells and thus augment antitumour effect in vivo.
    Type of Medium: Electronic Resource
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  • 13
    ISSN: 1432-0851
    Keywords: Lymphokine-activated killer activity ; Interleukin-2 ; 2-Mercaptoethanol ; Macrophages/monocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the present study we investigated the inhibition of interleukin-2(IL-2)-induced lymphokine-activated killer (LAK) activity in rat splenocyte cultures in relation to the presence of 2-mercaptoethanol and macrophages/monocytes. The presence of 2-mercaptoethanol is necessary for induction of LAK activity in rat splenocyte cultures. Removal of macrophages/monocytes from rat splenocytes by plastic or nylon-wool adherence, or iron ingestion resulted in LAK induction by IL-2 in the absence of 2-mercaptoethanol. The effect of macrophages/monocytes on LAK activity was also studied in transwell co-cultures. In the absence of 2-mercaptoethanol, the induction of LAK activity was very low in macrophage/monocyte-depleted splenocytes with macrophages/monocytes in the upper compartment of a transwell culture. In contrast, in the presence of 2-mercaptoethanol a high level of LAK activity was induced in these transwell cultures, showing that 2-mercaptoethanol abolished the LAK-inhibiting capacity of macrophages/monocytes. In addition, established LAK activity was strongly inhibited when, after LAK induction, splenocytes were cultured with supernatant of unfractionated splenocytes, which were cultured with IL-2 but in the absence of 2-mercaptoethanol. Addition of 2-mercaptoethanol abrogated the inhibiting effect of the supernatant completely. These experiments demonstrate that rat macrophages/monocytes produce 2-mercaptoethanolsensitive soluble LAK-inhibiting factors. Ultrafiltration of conditioned culture medium of macrophages/monocytes revealed the presence of LAK-inhibiting factors larger than 10 kDa. We concluded that 2-mercaptoethanol-sensitive soluble factors produced by macrophages/monocytes determine the level of LAK induction in rat splenocyte cultures.
    Type of Medium: Electronic Resource
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  • 14
    ISSN: 1432-1106
    Keywords: Acetylcholine ; Fimbria/fornix ; Hippocampus ; Intracerebral grafts ; Muscarinic receptors ; Noradrenaline ; Phosphoinositides ; Serotonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Long Evans female rats sustained aspirative lesions of the septohippocampal pathways; subsequently, they received intrahippocampal suspension grafts of fetal septal-diagonal band or hippocampal tissue. The long term (8–10 months post-surgery) effects of these treatments were examined in the hippocampus for the following variables: concentration of hippocampal acetylcholine (ACh), muscarinic-stimulated (carbachol) formation of inositol monophosphate, accumulation of tritiated choline, noradrenaline (3H-NA) and serotonin (3H-5-HT), electrically evoked release of 3H-acetylcholine (3H-ACh), 3H-NA and 3H-5-HT, and choline acetyltransferase (ChAT) activity. The lesions decreased the levels of endogeneous ACh, the accumulation of 3H-choline and 3H-5-HT and the evoked release of both 3H-ACh and 3H-5-HT as well as the ChAT activity, but they failed to significantly affect the muscarinic-stimulated formation of inositol monophosphate and the accumulation and release of 3H-NA. Grafts of hippocampal cells were found to be ineffective on all lesion-induced effects. In contrast, grafts of septal-diagonal band origin attenuated the deficit of hippocampal concentrations of ACh and accumulation of 3H-choline without, however, improving release of 3H-ACh, accumulation and release of 3H-5-HT, and ChAT activity. These observations suggest that: (i) denervation-induced hippocampal muscarinic supersensitivity might not be long-lasting or the lesions, which in some cases spared the lateral edges of the fimbria, failed to induce any muscarinic supersensitivity, (ii) intrahippocampal grafts rich in cholinergic neurons do not foster recovery from the lesion-induced noncholinergic deficits we assessed, (iii) recovery of function may be expressed by some but not all biochemical or pharmacological cholinergic variables and (iv) graft-derived hippocampal reinnervation may be less efficient than the endogenous innervation of intact rats as indicated by the restoration of only some of the variables related to cholinergic function by intrahippocampal septal-diagonal band grafts.
    Type of Medium: Electronic Resource
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  • 15
    ISSN: 1432-1106
    Keywords: 5-Hydroxytryptophan ; Parachlorophenylalanine ; Benserazide ; Sleep ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the rat, the insomnia which follows the administration of parachlorophenylalanine (p-CPA), a serotonin synthesis inhibitor, is transiently reversed either by intra-cisternal injection of L-5-HTP or by an associated injection of 5-HTP and an L-aromatic-aciddecarboxylase inhibitor (benserazide). Histochemical, immunohistochemical and chemical investigations showed that 5-HTP administration does not lead to a detectable increase in cerebral 5-HT. These findings suggest that the restoration of sleep after p-CPA treatment could be mediated by the central action of 5-HTP.
    Type of Medium: Electronic Resource
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  • 16
    ISSN: 1432-1106
    Keywords: Fibroblast growth factor receptor ; Basic fibroblast growth factor ; Forebrain ischemia ; Astrocyte ; In situ hybridization ; Hippocampus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recently, we demonstrated that transient forebrain ischemia in rats leads to an early and strong induction of basic fibroblast growth factor (bFGF) synthesis in astrocytes in the injured brain regions. In this study, in order to clarify the targets of such raised endogenous bFGF levels, the messenger RNA (mRNA) expression of its receptors (flg and bek) at in the hippocampus following transient forebrain ischemia induced by four-vessel occlusion for 20 min was investigated using an in situ hybridization technique. Transient forebrain ischemia induced an increase in the number of flg mRNA-positive cells from an early stage (24 h after ischemia) in the hippocampal CA1 subfield where delayed neuronal death occurred later (48–72 h after ischemia). This increase became more marked with the progression of neuronal death and was still evident in the same area 30 days later. The time course of the appearance and distribution pattern of flg mRNA-positive cells in the CA1 subfield were quite similar to those of bFGF mRNA-positive cells. On the other hand, in situ hybridization for bek mRNA showed only slight and transient (observed 72 h and 5 days after ischemia) increases in the number of mRNA-positive cells in the CA1 subfield following ischemia. The use of in situ hybridization and glial fibrillary acidic protein immunohistochemistry in combination demonstrated that the cells in the CA1 subfield that exhibited ischemia-induced flg or bek mRNA expression were astrocytes. These data indicate that transient forebrain ischemia induces upregulation of fibroblast growth factor-receptor expression, accompanied by increased bFGF expression in astrocytes, and suggest that the increased astrocytic bFGF levels in injured brain regions act on the astrocytes via autocrine systems and are involved in the development and maintenance of astrocytosis.
    Type of Medium: Electronic Resource
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  • 17
    ISSN: 1432-1106
    Keywords: Subcommissural organ ; Reissner's fibre ; Immunological blockade ; Cerebrospinal fluid circulation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The subcommissural organ is an ependymal brain gland that secretes glycoproteins to the cerebrospinal fluid (CSF) of the thrid ventricle. They condense to form a fibre, Reissner's fibre (RF), that runs along the aqueduct and fourth ventricle and the central canal of the spinal cord. A single injection of an antibody against the secretory glycoproteins of RF into a lateral ventricle of adult rats results in animals permanently deprived of RF in the central canal and bearing a “short” RF extending only along the aqueduct and the fourth ventricle. These animals, together with untreated control animals were used to investigate the probable influence of RF in the circulation of CSF in the central canal of the spinal cord. For this purpose, two tracers (horseradish peroxidase and rabbit immunoglobulin) were injected into the ventricular CSF. The animals were killed 13, 20, 60, 120 and 240 min after the injection, and the amount of the tracers was estimated in tissue sections obtained at proximal, medial and distal levels of the spinal cord. In rats deprived of RF, a significant decrease in the amount of tracers present in the central canal was observed at all experimental intervals, being more evident at 20 min after the injection of the tracers. This suggests that lacking a RF in the central canal decreases the bulk flow of CSF along the central canal. Turbulences of the CSF at the entrance of the central canal of RF-deprived rats might explain the inability of the regenerating RF to progress along the central canal, as well as the reduced flow of CSF in the central canal of these animals.
    Type of Medium: Electronic Resource
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  • 18
    ISSN: 1432-1084
    Keywords: White matter lesions ; Cerebrovascular disease ; Magnetic resonance imaging ; Brain infarction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To establish data about prevalence, number and topography of “unspecific” white matter lesions as seen on MRI, the T2-weighted MRI scans of 83 patients with hyperintense focal white matter changes were reviewed. Patients with known inflammatory central nervous system disease were excluded. There was an approximately linear increase in prevalence and number of lesions with age. Prevalence ranged from 18% in the third decade to over 90% in those over 70 years. We found a close correlation with concomitant periventricular hyperintensity. However, rating of Virchow-Robin spaces did not correlate with the number of white matter lesions. Both hemispheres were involved nearly equally with a minimal non-significant right side preponderance. Lesions showed a strong predilection for the frontal and parietal paraventricular “watershed” areas.
    Type of Medium: Electronic Resource
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Neuroradiology 33 (1991), S. 357-359 
    ISSN: 1432-1920
    Keywords: Ganglioglioma ; Neurofibromatosis ; Computed tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the occurrence of a left frontal lobe ganglioglioma in a patient with neurofibromatosis type I (von Recklinghausen's disease) and conclude that the occurrence of a cerebral ganglioglioma in a patient with neurofibromatosis must probably be considered coincidental.
    Type of Medium: Electronic Resource
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  • 20
    ISSN: 1432-1920
    Keywords: Cerebrotendinous xanthomatosis ; Computed tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the findings on cranial computed tomography (CT) and magnetic resonance imaging (MRI) and their correlation with the clinical manifestations, disease severity and biochemical abnormalities in eight patients with cerebrotendinous xanthomatosis. CT revealed cerebral atrophy in seven cases, cerebellar atrophy in four and focal low density lesions in the cerebral white matter in two. T2-weighted MRI showed high signal lesions in the cerebral white matter, focal in four cases and diffuse in one, and in the globus pallidus in three patients, two of whom also had lesions in the cerebellar white matter. While severely affected patients showed variable CT and MRI abnormalities, our cases did not show the dramatic findings expected from the neurological manifestations. Diffuse lesions in the cerebral and cerebellar white matter have been emphasized in previous reports, but in our study the focal lesions in the cerebral white matter were also present; the globus pallidus was frequently involved.
    Type of Medium: Electronic Resource
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