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  • 1
    ISSN: 1530-0358
    Keywords: Colostomy ; Colitis ; Permeability ; Colon ; Ussing chambers ; Rat ; Villus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: Barrier properties of an isolated colon loop and the remnant colon in continuity with the gastrointestinal tract after colostomy were studied in the rat. METHODS: The in vivo absorption after colonic loop administration of the marker fluorescein sodium was measured as the urinary recovery. The in vitro permeability was measured in Ussing diffusion chambers as the transmucosal passage of [14C]mannitol and of human serum albumin in the isolated and the nonexcluded colonic segments and was compared with the corresponding colonic regions from sham-operated rats at 1 to 14 days after operation. RESULTS: Body weight gain of the rats decreased and diarrhea appeared from day 2 after colostomy. Histologic examination showed mucosal atrophy with decreased villus height in the isolated colonic loop and an increased villus height in the nonexcluded colon segment. Absorption of fluorescein sodium in the isolated loop was increased at 8 and 14 days. Moreover, permeability in the isolated loop was increased for both mannitol and human serum albumin from four days after colostomy compared with the corresponding colonic segments after the sham operation, whereas a decrease in the passage of mannitol was noted in the nonexcluded colon. CONCLUSIONS: Experimentally performed colostomy diversion in the rat induced alterations of the barrier function in both the isolated colonic loop and the nonexcluded colon in continuity with the fecal stream.
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  • 2
    ISSN: 1530-0358
    Keywords: Anal sphincter ; Endoanal coil ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: To obtain high resolution images of the anal sphincter and adjacent anorectum using an endoanal coil in patients with sepsis, trauma, and low rectal tumors and to compare imaging appearances with findings at time of surgery. PATIENTS AND METHODS: A cylindrical saddle geometry coil (diameter, 9 mm; length, 75 mm) was used to examine 30 patients (mean age, 53.6 years). Pathologies included perianal sepsis (10 patients), obstetric trauma (7 patients), and low rectal tumors (13 patients). Imaging was performed on an 0.5-T Picker Asset or 1.0-T Picker HPQ Vista (Picker International, Highland Heights, OH). T 1 and T 2 weighted and short inversion time inversion recovery transverse images and T 1 weighted coronal images were obtained. Intravenous gadopentetate dimeglumine (0.1 mmol/kg) was given to all patients with suspected infection and neoplasms. RESULTS: Abscesses and fistulas identified using magnetic resonance imaging (MRI) in patients with perianal sepsis were confirmed at surgery in all cases; site of fistulous internal opening into the anal canal was correctly identified in 80 percent of cases. Extent of sphincter tear was correctly assessed on endoanal MRI in all patients with obstetric trauma when compared with surgical findings. Tumor invasion of anal sphincter was seen in 38.5 percent of low rectal carcinomas. CONCLUSIONS: MRI with an endoanal coil provides detailed images of the site and extent of anal fistulas, sphincter tears, and local tumors and is of considerable value in preoperative assessment.
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  • 3
    ISSN: 1530-0358
    Keywords: Delayed-type hypersensitivity ; Laparoscopy ; Phytohemagglutinin ; Keyhole limpet hemocyanin ; Laparoscopic-assisted colon resection ; Rat ; Murine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: We evaluated cell-mediated immune function after laparoscopic-assisted and open bowel resection in rats by measuring delayed-type hypersensitivity responses to keyhole limpet hemocyanin (KLH) and phytohemagglutinin (PHA). METHODS: Male Sprague-Dawley rats (n=120) were sensitized to 1 mg of KLH ten days before investigations. Rats were challenged preoperatively, immediately postoperatively, and on postoperative day (POD) 2 with an intradermal injection of 0.3 mg of KLH and 0.2 mg of PHA (at different sites). Averages of two measures of perpendicular diameters (taken 24 and 48 hours postchallenge) were used to calculate the area of induration using the formula for the area of an ellipse, A=(D1/2×D2/2)×π. Anesthesia control animals underwent no procedure (n=40). Open resection group underwent ligation and resection of the cecum (length=2 cm) through a 7 cm midline incision (n=40). In the laparoscopic-assisted resection group, under CO2 pneumoperitoneum (4–6 mmHg), the cecum was identified, dissected free, and exteriorized through a 4 mm port. The cecum was then ligated and resected extracorporeally (n=40). RESULTS: Preoperative responses to both KLH and PHA were the same in all three groups. Furthermore, within each group, postoperative responses were similar. When groups were compared, the anesthesia group responses were significantly greater than the open resection group responses at all time points (P 〈0.05 for all comparisons). Laparoscopic-assisted resection group responses differed from control at only two of eight postoperative measures. Laparoscopic resection group responses were significantly greater than open resection group responses to challenge with both KLH and PHA on POD1 (P 〈0.02, for both comparisons) and POD 4 (P 〈0.05, for both comparisons). CONCLUSIONS: Postoperative cell-mediated immune function is better preserved after laparoscopic-assisted bowel resection than after open resection as assessed by skin antigen testing.
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  • 4
    ISSN: 1534-4681
    Keywords: Regional drug delivery ; Rat ; Immunology ; Testis ; Cancer chemotherapy ; Infertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background: Testicular circulatory isolation (TCI), a regional drug exclusion approach designed to prevent chemotherapy-induced male infertility, can reduce testicular drug exposure and preserve fertility. The immunological sequelae of this surgical procedure were investigated. Methods: Forty Sprague-Dawley rats received unilateral TCI for 45 min and were killed at intervals of up to 43 days later. Testicular histology was evaluated qualitatively using hematoxylin and eosin stain, a direct immunofluorescent technique for detection of antigen-antibody complexes, and an indirect immunofluorescent technique to detect circulating antitestis antibodies. Results: No immune-mediated injury was evident up to 43 days after TCI. Conclusion: The current work, taken together with previously published data, indicate that TCI produces no immunological damage in the rat testis. Because TCI is well tolerated in humans, this work also supports the institution of human clinical trials of this technique in men about to receive fertility-threatening chemotherapy.
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  • 5
    ISSN: 1438-8359
    Keywords: Cervical sympathectomy ; Stellate ganglion block ; Adrenocorticotropic hormone ; Thyroid-stimulating hormone ; Growth hormone ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To examine the effects of bilateral cervical sympathectomy on the secretion of adrenocorticotropic hormone (ACTH), thyroid-stimulating hormone (TSH), growth hormone (GH), and prolactin (PRL), 18 male rats were divided into three groups: control (Cont), sham operation (Sham), and bilateral cervical sympathectomy (Symp). All rats were kept under a normal circadian rhythm for 2 weeks. Subsequently, blood was collected and plasma ACTH as well as serum TSH, GH, and PRL levels were measured. The difference in ACTH levels between the Cont and Sham groups was not significant, but ACTH levels in the Symp group were significantly higher than those in the other groups. The difference in TSH levels between the Cont and Sham groups was also not significant, but TSH levels in the Symp group were significantly lower than those in the Cont group. There were no statistically significant differences in GH and PRL levels among these groups. The present results suggest that cervical sympathectomy in the rat increases ACTH secretion and decreases TSH secretion in the pituitary. These effects seem to be due to a mildly increased secretion of melatonin in the pineal body that probably in turn increases corticotropin-releasing factor (CRF) secretion and decreases thyrotropin-releasing hormone (TRH) secretion in the hypothalamus. Extrapolation of these findings to humans suggests that longterm and repeated stellate ganglion block would affect the pituitary secretions of ACTH and TSH.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Amino acids 10 (1996), S. 49-57 
    ISSN: 1438-2199
    Keywords: Amino acids ; Taurine ; γ-Aminobutyric acid ; Synaptosome ; Olfactory bulb ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Superfusion of synaptosomes prepared from rat olfactory bulb revealed constant basal release of endogenous taurine (Tau), aspartate (Asp), glutamate (Glu) andγ-aminobutyrate (GABA): their release rates were 110.4 ± 13.0, 30.3 ± 6.7, 93.7 ± 13.1, and 53.3 ± 8.8 pmol/min/mg protein, respectively. The depolarizing-stimulation with 30mM KCl evoked 1.17-, 2.18-, 2.55- and 1.53-fold increases, respectively. Tau release was calcium-independent. However, the perfusion of synaptosomes with Tau (10µM) inhibited the evoked increase in GABA release by 63% without changing basal release, although it did not affect release of Asp and Glu. Phaclofen (10µM, a GABAB receptor antagonist), but not bicuculline (10µM, a GABAA receptor antagonist), counteracted the Tau-induced reduction in GABA release. These data suggest that Tau may be abundantly released from nerve endings of rat olfactory bulb and that it may regulate GABA release through the activation of presynaptic GABAB autoreceptors.
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  • 7
    ISSN: 1432-1912
    Keywords: α1-adrenoceptors ; Idazoxan ; Indanidine ; Noradrenaline ; Aorta ; Small mesenteric artery ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have studied the effects of idazoxan in rat aorta and small mesenteric artery. In the aorta, idazoxan behaved as a partial agonist (pKA=6.30). Prazosin produced rightward shift (pA2=9.88) and steepening of the idazoxan curve. In contrast, idazoxan had no effect of basal tension in the mesenteric artery, but shifted the noradrenaline curve to the right in a parallel manner (pA2=6.12). The selective al-adrenoceptor agonist, indanidine, also behaved as a partial agonist in the aorta and produced no significant contractions of the small mesenteric artery. Since idazoxan and indanidine have been reported to raise blood pressure in the pithed rat via an action at vascular α1-adrenoceptors, these results call into question the reliability of the small mesenteric artery assay as a predictor for α1-adrenoceptor-mediated pressor activity in vivo.
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  • 8
    ISSN: 1432-1912
    Keywords: Chronic haloperidol ; Dopamine D2 receptors ; NMDA receptors ; AMPA receptors ; Caudate-putamen ; Quantitative autoradiography ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the present study was to investigate the influence of chronic treatment with haloperidol on the striatal N-methyl-D-aspartate (NMDA), α-amino-3-hydro-xy-5-methyl-4-isoxasole-propionic acid (AMPA) and dopamine D2 receptors using a quantitative autoradiography in rats. Haloperidol was given to animals in a dose of ca. 1 mg/kg/day in drinking water for 6 weeks or 3 months and was afterwards withdrawn for 5 days. Haloperidol increased by 20–50% the binding of [3H]spiperone in different regions of the caudate-putamen. Haloperidol decreased by ca. 30% the binding of [3H]AMPA in the ventrolateral region of intermediate part of the caudate-putamen, but did not influence the binding of [3H]MK-801. The present results suggest that, apart from supersensitivity to dopamine, chronic treatment with haloperidol also induces subsensitivity of striatal AMPA receptors.
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  • 9
    ISSN: 1432-1912
    Keywords: Key words Diabetic neuropathy ; Somatosensorial evoked potentials ; Aminoguanidine ; L-carnitine ; Rat ; Alloxan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The effects of aminoguanidine (AG) and L-carnitine (LC) on somatosensorial evoked potential (SEP) latency and neural levels of thiobarbituric acid reactive substances (TBARS), products of lipid peroxidation, were compared in alloxan-diabetic rats. AG and LC were given to diabetic rats starting from the 3rd week after the induction of diabetes and lasting for 4 weeks. SEP latency was measured by stimulating via caudal nerve and recording via cortex, once weekly during the treatments. Diabetes caused deficits in SEP (P〈0.05 vs non-diabetic control rats, respectively). AG and LC restored SEP latencies slightly but not significantly, with the exception of the prominent effect of AG at the first week and both treatments at the 4th week of the treatments (P〈0.05 vs untreated diabetic rats, respectively). Diabetes caused elevation in neural TBARS levels (P〈0.05 vs non-diabetic group), which was prevented by both AG and LC (P〈0.05 vs untreated diabetic rats, respectively). Weight and the glucose levels were not influenced by the treatments. Our results suggest that AG improves SEP latencies better than LC. Our results also suggest that the beneficial effects of both AG and LC on diabetic neuropathy are not associated with the regulation of glycemia, but these effects may be related in part with prevention of lipid peroxidation.
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  • 10
    ISSN: 1432-1912
    Keywords: N-methyl-D-aspartate ; Glutamate ; Kainate ; Dissociated cerebellar cells ; Rat ; Mitochondrial membrane potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of three different glutamate receptor ligands on mitochondrial membrane potential has been studied in rat pup dissociated cerebellar cells by measuring rhodamine 123 fluorescence. L-glutamate, NMDA (N-methyl-D-aspartate) and kainate (from 10−8 to 10−3 M) decreased in a concentration-dependent manner the mitochondrial membrane potential with EC50 values of 6.7±1.7, 3.8±0.5, and 37.4±14 μM, respectively. Dizocilpine ((+)MK 801) was able to inhibit the NMDA- and L-glutamate-induced decrease in rhodamine 123 fluorescence, while kainate-induced fluorescence-decreases were unaffected. However, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) totally prevented the effect of kainate on mitochondrial membrane potential, but failed to block the L-glutamate effect. It is concluded that, in our cell preparation, L-glutamate exerts its action mainly through NMDA-subtype receptors, and that Ca2+ and Na+ entry through ionotropic glutamate receptors could be responsible for an impairment of mitochondrial membrane potential.
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  • 11
    ISSN: 1432-1912
    Keywords: Diabetic neuropathy ; Somatosensorial evoked potentials ; Aminoguanidine ; L-carnitine ; Rat ; Alloxan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of aminoguanidine (AG) and L-carnitine (LC) on somatosensorial evoked potential (SEP) latency and neural levels of thiobarbituric acid reactive substances (TBARS), products of lipid peroxidation, were compared in alloxan-diabetic rats. AG and LC were given to diabetic rats starting from the 3rd week after the induction of diabetes and lasting for 4 weeks. SEP latency was measured by stimulating via caudal nerve and recording via cortex, once weekly during the treatments. Diabetes caused deficits in SEP (P 〈 0.05 vs non-diabetic control rats, respectively). AG and LC restored SEP latencies slightly but not significantly, with the exception of the prominent effect of AG at the first week and both treatments at the 4th week of the treatments (P 〈 0.05 vs untreated diabetic rats, respectively). Diabetes caused elevation in neural TBARS levels (P 〈 0.05 vs non-diabetic group), which was prevented by both AG and LC (P 〈 0.05 vs untreated diabetic rats, respectively). Weight and the glucose levels were not influenced by the treatments. Our results suggest that AG improves SEP latencies better than LC. Our results also suggest that the beneficial effects of both AG and LC on diabetic neuropathy are not associated with the regulation of glycemia, but these effects may be related in part with prevention of lipid peroxidation.
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  • 12
    ISSN: 1432-1912
    Keywords: Key words N-methyl-D-aspartate ; Glutamate ; Kainate ; Dissociated cerebellar cells ; Rat ; Mitochondrial ; membrane potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of three different glutamate receptor ligands on mitochondrial membrane potential has been studied in rat pup dissociated cerebellar cells by measuring rhodamine 123 fluorescence. L-glutamate, NMDA (N-methyl-D-aspartate) and kainate (from 10–8 to 10–3 M) decreased in a concentration-dependent manner the mitochondrial membrane potential with EC50 values of 6.7±1.7, 3.8±0.5, and 37.4±14 μM, respectively. Dizocilpine ((+)MK 801) was able to inhibit the NMDA- and L-glutamate-induced decrease in rhodamine 123 fluorescence, while kainate-induced fluorescence-decreases were unaffected. However, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) totally prevented the effect of kainate on mitochondrial membrane potential, but failed to block the L-glutamate effect. It is concluded that, in our cell preparation, L-glutamate exerts its action mainly through NMDA-subtype receptors, and that Ca2+ and Na+ entry through ionotropic glutamate receptors could be responsible for an impairment of mitochondrial membrane potential.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 354 (1996), S. 670-676 
    ISSN: 1432-1912
    Keywords: Bradykinin ; Kininases ; Carrageenan ; Angiotensin converting enzyme ; Aminopeptidase P ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of some peptidase inhibitors on oedema and plasma extravasation induced by bradykinin and carrageenan in rat paw was evaluated. Bradykinin-induced oedema in normal rats was increased by o-phenanthroline (3.10−2 M), by captopril (10−6 M to 10−4 M), by lisinopril (10−6 M to 10−4 M), or by lisinopril (10−5 M) in combination with apstatin (8.10−5 M or 1.4 10−4 M). It was not modified by phosphoramidon (10−6 M to 10−5 M) and by diprotin A (10−3 M). It was increased by mergepta at high concentrations (2.10−4 M). Mergepta did not increase the potentiating effect of captopril. Carrageenan-oedema in normal rats was increased by captopril (10−5 M), lisinopril (10−5 M) and apstatin (1.4 10 M). It was not modified by mergepta (10−4 M), phosphoramidon (10−5 M) and diprotin A (10−3 M). Des-Argl-bradykinin and Des-Arg9-bradykinin have low oedema-promoting effects. Captopril (10−5 M) increased the effects of bradykinin but not those of carrageenan in kininogen-deficient Brown Norway rats. Angiotensin-converting enzyme and amino-peptidase P appear to be main kinin-inactivating enzymes in rat paws. Carboxypeptidase N, neutral endopeptidase 24.11 and dipeptidyl(amino)peptidase IV do not play a significant role in this inactivation.
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  • 14
    ISSN: 1432-1912
    Keywords: Key words Clozapine ; Haloperidol ; Chronic treatment ; Nucleus accumbens ; Caudate putamen ; Dopamine ; In vivo fast cyclic voltammetry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fast cyclic voltammetry at carbon-fibre microelectrodes was used to investigate the effects of chronic clozapine or haloperidol administration on electrically evoked dopamine efflux in the nucleus accumbens and caudate putamen of the anaesthetized rat. Stimulation trains were delivered to the median forebrain bundle (60 pulses, 350 μs duration) every 5 min, and the evoked dopamine efflux measured as a function of a) the applied stimulus intensity (range 0.2 mA–1.0 mA), and b) the applied stimulus frequency (range 10 Hz–250 Hz). Chronic administration of either clozapine (20 mg/kg × 21 days, p.o.) or haloperidol (1 mg/kg × 21 days, p.o.) significantly reduced electrically evoked dopamine efflux in the nucleus accumbens over the range of stimulus intensities and frequencies tested. The reduction in evoked dopamine efflux observed in the nucleus accumbens of clozapine- and haloperidol-treated rats showed no statistically significant difference. In contrast, only chronic haloperidol treatment significantly reduced evoked dopamine efflux in the caudate putamen. These findings demonstrate that chronic treatment with either the atypical neuroleptic, clozapine, or the typical neuroleptic, haloperidol, produce long-term changes in mesolimbic dopamine function; actions which may underlie their antipsychotic efficacy. They also provide further evidence that the sparing action of clozapine on nigrostriatal dopamine activity may underlie the lower incidence of extrapyramidal side effects associated with its long-term administration.
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  • 15
    ISSN: 1432-1912
    Keywords: Key words Basal ganglia ; Neuropeptides ; Monoamines ; Amino acids ; Microdialysis ; Chromogranin C ; Secretogranin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In vivo microdialysis was used to study the effect of secretogranin II-derived peptides on dynorphin B (Dyn B), dopamine, γ-aminobutyric acid (GABA), glutamate and aspartate release in the substantia nigra and neostriatum of halothane-anaesthesized rats. In the substantia nigra, local infusion of secretoneurin (secretogranin II 154–186) (1–50 μM) increased, in a concentration-dependent manner, extracellular aspartate, glutamate, Dyn B, dopamine and GABA levels. The effect was particularly prominent on aspartate and glutamate levels which, following 50 μM of secretoneurin, were increased by 〉20 and 〉10 fold, respectively. However, the effect of secretoneurin on Dyn B release appeared to be more specific, since a significant increase (〉2 fold) was already observed following 1 μM of secretoneurin. In the neostriatum, Dyn B, glutamate, aspartate and GABA levels were also increased by local secretoneurin infusion, but the effect was less prominent than in the substantia nigra. In the substantia nigra, only Dyn B levels were significantly increased following infusion of 10 μM of the secretoneurin-C terminal (secretoneurin-15C), whereas Dyn B and GABA levels were increased by the same concentration of the secretogranin II C terminus (YM). Only glutamate and aspartate levels were increased by local infusion of 10 μM of secretogranin II 133–151 (LF), a peptide adjacent to secretoneurin in the primary amino acid sequence. In the neostriatum, Dyn B and GABA levels were increased by 10 μM of secretoneurin-15C. Dyn B levels were also increased by 10 μM of YM, and glutamate and aspartate levels were increased by 10 μM of both YM and LF. Thus, secretogranin II-derived peptides affect extracellular levels of several putative neurotransmitter systems monitored in the basal ganglia of the rat with in vivo microdialysis. The effect of Dyn B appears to be specific and related to a physiological role of secretoneurin, since (i) it occurs in an area where secretoneurin-immunocytochemistry has been observed, (ii) is exerted at comparatively low concentrations, and (iii) is mimicked by secretoneurin-15C. The increases in excitatory amino acid levels produced by high concentrations of secretoneurin and other secretogranin II-derived peptides reflect, perhaps, a potential neurotoxicity produced by abnormal accumulation of these peptides.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 354 (1996), S. 736-745 
    ISSN: 1432-1912
    Keywords: Key words NMDA ; Ethanol ; Glycine ; Ca2+ fluxes ; Neurotoxicity ; Cerebellar granule cells ; Cortical cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of ethanol and/or glycine on NMDA-induced enhancement of cytoplasmic free Ca2+ concentrations ([Ca2+]i), 45Ca2+ influx, 4-b-[3H]phorbol-12,13-dibutyrate ([3H]PDBu) binding, and neuronal necrosis in cultured rat cortical and cerebellar granule neurons were examined. Using microfluorimetric techniques in combination with rapid perfusion of single brain neurons, we found that glycine (10 μM) was a necessary co-agonist for NMDA-induced depolarization in cerebellar granule cells. In contrast, depolarization with NMDA in cortical cells was observed even without the addition of exogenous glycine as well as in the absence or presence of 1 mM MgCl2. Ethanol (50 mM) inhibited the effects of NMDA in some, but not all, neurons indicative of the existence of ethanol-sensitive and ethanol-insensitive cortical and cerebellar granule neurons. In studies performed in monolayers of cortical and cerebellar granule cells, we observed that the presence of glycine (10 μM) was a necessary prerequisite to unmask inhibitory actions of ethanol on 45Ca2+ influx induced by NMDA. In another set of experiments, we noted that NMDA-induced stimulation of [3H]PDBu binding to monolayers of intact cerebellar granule cells was inhibited by ethanol (50 mM). Finally, we report that ethanol caused a concentration-dependent inhibition of NMDA-induced necrotic cell death, assessed by measuring the ability of cerebellar granule cells to transform 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) into formazan. In none of the four assays used to demonstrate the inhibitory effects of ethanol on NMDA receptor activity, the ethanol-induced inhibition was reversed by glycine (up to 100 μM). Thus, in contrast to earlier reports, our data suggest that ethanol and glycine produce their effects by acting at different regulatory sites within the NMDA receptor system in brain neurons.
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  • 17
    ISSN: 1432-1912
    Keywords: Basal ganglia ; Neuropeptides ; Monoamines ; Amino acids ; Microdialysis ; Chromogranin C ; Secretogranin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In vivo microdialysis was used to study the effect of secretogranin II-derived peptides on dynorphin B (Dyn B), dopamine, γ-aminobutyric acid (GABA), glutamate and aspartate release in the substantia nigra and neostriatum of halothane-anaesthesized rats. In the substantia nigra, local infusion of secretoneurin (secretogranin II 154–186) (1–50 μM) increased, in a concentration-dependent manner, extracellular aspartate, glutamate, Dyn B, dopamine and GABA levels. The effect was particularly prominent on aspartate and glutamate levels which, following 50 μM of secretoneurin, were increased by 〉20 and 〉10 fold, respectively. However, the effect of secretoneurin on Dyn B release appeared to be more specific, since a significant increase (〉2 fold) was already observed following 1 μM of secretoneurin. In the neostriatum, Dyn B, glutamate, aspartate and GABA levels were also increased by local secretoneurin infusion, but the effect was less prominent than in the substantia nigra. In the substantia nigra, only Dyn B levels were significantly increased following infusion of 10 μM of the secretoneurin-C terminal (secretoneurin-15C), whereas Dyn B and GABA levels were increased by the same concentration of the secretogranin II C terminus (YM). Only glutamate and aspartate levels were increased by local infusion of 10 μM of secretogranin II 133-151 (LF), a peptide adjacent to secretoneurin in the primary amino acid sequence. In the neostriatum, Dyn B and GABA levels were increased by 10 μM of secretoneurin-15C. Dyn B levels were also increased by 10 μM of YM, and glutamate and aspartate levels were increased by 10 μM of both YM and LF. Thus, secretogranin 11-derived peptides affect extracellular levels of several putative neurotransmitter systems monitored in the basal ganglia of the rat with in vivo microdialysis. The effect of Dyn B appears to be specific and related to a physiological role of secretoneurin, since (i) it occurs in an area where secretoneurin-immunocytochemistry has been observed, (ii) is exerted at comparatively low concentrations, and (iii) is mimicked by secretoneurin-15C. The increases in excitatory amino acid levels produced by high concentrations of secretoneurin and other secretogranin II-derived peptides reflect, perhaps, a potential neurotoxicity produced by abnormal accumulation of these peptides.
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  • 18
    ISSN: 1432-1912
    Keywords: Clozapine ; Haloperidol ; Chronic treatment ; Nucleus accumbens ; Caudate putamen ; Dopamine ; In vivo fast cyclic voltammetry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fast cyclic voltammetry at carbon-fibre microelectrodes was used to investigate the effects of chronic clozapine or haloperidol administration on electrically evoked dopamine efflux in the nucleus accumbens and caudate putamen of the anaesthetized rat. Stimulation trains were delivered to the median forebrain bundle (60 pulses, 350 μs duration) every 5 min, and the evoked dopamine efflux measured as a function of a) the applied stimulus intensity (range 0.2 mA-1.0 mA), and b) the applied stimulus frequency (range 10 Hz-250 Hz). Chronic administration of either clozapine (20 mg/kg × 21 days, p.o.) or haloperidol (1 mg/kg × 21 days, p.o.) significantly reduced electrically evoked dopamine efflux in the nucleus accumbens over the range of stimulus intensities and frequencies tested. The reduction in evoked dopamine efflux observed in the nucleus accumbens of clozapine- and haloperidol-treated rats showed no statistically significant difference. In contrast, only chronic haloperidol treatment significantly reduced evoked dopamine efflux in the caudate putamen. These findings demonstrate that chronic treatment with either the atypical neuroleptic, clozapine, or the typical neuroleptic, haloperidol, produce long-term changes in mesolimbic dopamine function; actions which may underlie their antipsychotic efficacy. They also provide further evidence that the sparing action of clozapine on nigrostriatal dopamine activity may underlie the lower incidence of extrapyramidal side effects associated with its long-term administration.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 354 (1996), S. 736-745 
    ISSN: 1432-1912
    Keywords: NMDA ; Ethanol ; Glycine ; Ca2+ fluxes ; Neurotoxicity ; Cerebellar granue cells ; Cortical cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of ethanol and/or glycine on NMDA-induced enhancement of cytoplasmic free Ca2+ concentrations ([Ca2+]i), 45Ca2+ influx, 4-b-[3H]phorbol-12,13-dibutyrate ([3H]PDBu) binding, and neuronal necrosis in cultured rat cortical and cerebellar granule neurons were examined. Using microfluorimetric techniques in combination with rapid perfusion of single brain neurons, we found that glycine (10 μM) was a necessary co-agonist for NMDA-induced depolarization in cerebellar granule cells. In contrast, depolarization with NMDA in cortical cells was observed even without the addition of exogenous glycine as well as in the absence or presence of 1 mM MgCl2. Ethanol (50 mM) inhibited the effects of NMDA in some, but not all, neurons indicative of the existence of ethanol-sensitive and ethanol-insensitive cortical and cerebellar granule neurons. In studies performed in monolayers of cortical and cerebellar granule cells, we observed that the presence of glycine (10 μM) was a necessary prerequisite to unmask inhibitory actions of ethanol on 45Ca2+ influx induced by NMDA. In another set of experiments, we noted that NMDA-induced stimulation of [3H]PDBu binding to monolayers of intact cerebellar granule cells was inhibited by ethanol (50 mM). Finally, we report that ethanol caused a concentration-dependent inhibition of NMDA-induced necrotic cell death, assessed by measuring the ability of cerebellar granule cells to transform 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MIT) into formazan. In none of the four assays used to demonstrate the inhibitory effects of ethanol on NMDA receptor activity, the ethanol-induced inhibition was reversed by glycine (up to 100 μM). Thus, in contrast to earlier reports, our data suggest that ethanol and glycine produce their effects by acting at different regulatory sites within the NMDA receptor system in brain neurons.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 353 (1996), S. 161-167 
    ISSN: 1432-1912
    Keywords: Key words Ageing ; Dihydroxyphenylacetic acid ; Homovanillic acid ; Hypothalamic paraventricular nucleus ; In vivo microdialysis ; Noradrenaline ; Phenylephrine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The effect of age on basal and stimulated noradrenaline release in the hypothalamic paraventricular nucleus (PVN) of the rat was examined by in vivo microdialysis. Microdialysis probes were inserted into the PVN of 3 and 18 month old anaesthetised Sprague Dawley rats and perfused with a modified Ringer solution. Following four basal 30-min collections, transmitter release was stimulated by perfusion with 100 mM potassium for one collection. After re-equilibration, blood pressure was raised 60 mmHg for 30 min by phenylephrine infusion (1–1.3 mg/kg) then a 2-h recovery period followed. Dialysate collections were injected directly onto a reverse phase HPLC-ECD (HPLC with electrochemical detection). Basal extracellular noradrenaline concentrations were found to be similar in adult and old animals. Basal dihydroxyphenylacetic acid (DOPAC) concentrations were significantly greater in old compared to adult rats (P〈0.05). Potassium depolarisation induced a significant increase in noradrenaline concentrations in both age groups (P〈0.001), however the noradrenaline response to potassium stimulation was significantly reduced in the aged rats (P〈0.05). Potassium-induced decreases in DOPAC and homovanillic acid (HVA) concentrations were seen in both age groups. Following phenylephrine infusion, a modest delayed reduction in noradrenaline levels, which failed to reach statistical significance, was seen. Phenylephrine-induced hypertension was associated with decreased DOPAC and HVA concentrations in adult (P〈0.05) and old (P〈0.05) rats, respectively. These results indicate that ageing is associated with changes in dopaminergic and noradrenergic activity in the PVN of the rat. A reduction in noradrenaline response to maximal stimulation induced by potassium depolarisation was observed with ageing. The alteration in the activity of the catecholaminergic pathways to the PVN induced by phenylephrine infusion appears to be age dependent.
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  • 21
    Electronic Resource
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    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 353 (1996), S. 168-174 
    ISSN: 1432-1912
    Keywords: Nucleus basalis magnocellularis ; Nicotine ; Physostigmine ; Cortical EEG ; FFT power spectra ; Unrestrained behaviour ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The basal magnocellular nucleus is assumed to play a crucial role in cholinergic activation of the cortical EEG. The aim of this study was to establish whether intraperitoneally applied nicotine may counteract the power asymmetry of the slow waves in the cortical EEG of both hemispheres after an unilateral lesion in the basal nucleus. In 17 rats the basal nucleus (substantia innominata/ventral pallidum) was unilaterally lesioned by ibotenic acid. The lesion produced unilateral power increases of all frequencies up to 20 Hz in the frontal EEG that increased with higher arousal level. Additionally, synchronized spike and wave discharges appeared in the frontal EEG. The results indicate that the basal nucleus suppresses especially the delta EEG waves in the frontal motor cortex during motor active behaviour. Nicotine (0.1 and 1 mg/kg) partially counteracts the power asymmetry of frontal slow waves (2–6 Hz) only during exploratory sniffing but not during grooming and waking immobility. Physostigmine (1 mg/kg) was also effective during exploratory sniffing. The results may indicate a role of nicotinic mechanisms in the information input component of exploratory behaviour.
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  • 22
    ISSN: 1432-1912
    Keywords: Key words Bradykinin ; Kininases ; Carrageenan ; Angiotensin converting enzyme ; Aminopeptidase P ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of some peptidase inhibitors on oedema and plasma extravasation induced by bradykinin and carrageenan in rat paw was evaluated. Bradykinin-induced oedema in normal rats was increased by o-phenanthroline (3.10–2 M), by captopril (10–6 M to 10–4 M), by lisinopril (10–6 M to 10–4 M), or by lisinopril (10–5 M) in combination with apstatin (8.10–5 M or 1.4 10–4 M). It was not modified by phosphoramidon (10–6 M to 10–5 M) and by diprotin A (10–3 M). It was increased by mergepta at high concentrations (2.10–4 M). Mergepta did not increase the potentiating effect of captopril. Carrageenan-oedema in normal rats was increased by captopril (10–5 M), lisinopril (10–5 M) and apstatin (1.4 10–4 M). It was not modified by mergepta (10–4 M), phosphoramidon (10–5 M) and diprotin A (10–3 M). Des-Arg1-bradykinin and Des-Arg9-bradykinin have low oedema-promoting effects. Captopril (10–5 M) increased the effects of bradykinin but not those of carrageenan in kininogen-deficient Brown Norway rats. Angiotensin-converting enzyme and aminopeptidase P appear to be main kinin-inactivating enzymes in rat paws. Carboxypeptidase N, neutral endopeptidase 24.11 and dipeptidyl(amino)peptidase IV do not play a significant role in this inactivation.
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  • 23
    ISSN: 1432-1912
    Keywords: ALEPH-2 Serotonin receptor binding ; Anxiolytics ; Serotonin syndrome ; Phenylisopropylamines ; Rat ; Hypothermia ; Psychedelics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Serotonergic behavioral responses, effects on motor activity and core temperature, and binding properties of the novel putative anxiolytic amphetamine derivative (±)1-(2,5-dimethoxy-4-ethylthiophenyl)-2-aminopropane (ALEPH-2), were examined in rodents in order to elucidate the mechanism underlying its anxiolytic-like effect. After peripheral administration in rats, ALEPH-2 induced some symptoms of the serotonergic syndrome, e.g. forepaw treading and flat body posture. Additionally, a decrease in motor activity was observed. No significant effects on the number of head shakes were observed after injection, although high inter-subject variability was noted. Higher doses of ALEPH-2, in the range exhibiting anxiolytic properties (4mg/kg), elicited significant hypothermia in mice. The affinity of the drug for 5-HT2A/2C receptors ([3H]ketanserin sites) was in the nanomolar range (Ki = 173 nM), whereas for 5-HT1A, benzodiazepine sites, and GABAA receptors, the affinity was micromolar or lower. Based on these results the mechanism of action and the anxiolytic-like properties of ALEPH-2 are discussed.
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  • 24
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 353 (1996), S. 161-167 
    ISSN: 1432-1912
    Keywords: Ageing ; Dihydroxyphenylaceticacid ; Homovanillic acid ; Hypothalamic paraventricular nucleus ; in vivo microdialysis ; Noradrenaline ; Phenylephrine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of age on basal and stimulated noradrenaline release in the hypothalamic paraventricular nucleus (PVN) of the rat was examined by in vivo microdialysis. Microdialysis probes were inserted into the PVN of 3 and 18 month old anaesthetised Sprague Dawley rats and perfused with a modified Ringer solution. Following four basal 30-min collections, transmitter release was stimulated by perfusion with 100 mM potassium for one collection. After re-equilibration, blood pressure was raised 60 mmHg for 30 min by phenylephrine infusion (1–1.3 mg/kg) then a 2-h recovery period followed. Dialysate collections were injected directly onto a reverse phase HPLC-ECD (HPLC with electrochemical detection). Basal extracellular noradrenaline concentrations were found to be similar in adult and old animals. Basal dihydroxyphenylacetic acid (DOPAC) concentrations were significantly greater in old compared to adult rats (P 〈 0.05). Potassium depolarisation induced a significant increase in noradrenaline concentrations in both age groups (P 〈 0.001), however the noradrenaline response to potassium stimulation was significantly reduced in the aged rats (P 〈 0.05). Potassium-induced decreases in DOPAC and homovanillic acid (HVA) concentrations were seen in both age groups. Following phenylephrine infusion, a modest delayed reduction in noradrenaline levels, which failed to reach statistical significance, was seen. Phenylephrine-induced hypertension was associated with decreased DOPAC and HVA concentrations in adult (P 〈 0.05) and old (P 〈 0.05) rats, respectively. These results indicate that ageing is associated with changes in dopaminergic and noradrenergic activity in the PVN of the rat. A reduction in noradrenaline response to maximal stimulation induced by potassium depolarisation was observed with ageing. The alteration in the activity of the catecholaminergic pathways to the PVN induced by phenylephrine infusion appears to be age dependent.
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  • 25
    ISSN: 1432-0584
    Keywords: Key words Bone marrow transplantation ; Magnetic resonance imaging ; Magnetic resonance spectroscopy ; Therapy monitoring
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Lumbar bone marrow was assessed by means of magnetic resonance (MR) in 23 examinations of eight patients who underwent autologous bone marrow transplantation (ABMT) or peripheral blood stem cell transplantation (PBSCT). Various imaging and spectroscopic techniques were applied for measurements carried out prior to conditioning for ABMT/PBSCT and in the course of reconstitution and correlated with clinical and blood chemistry data in these patients. The signal intensity from lumbar bone marrow was determined in T1-weighted and water- and fat-selective MR images. The distribution of the magnetic field was demonstrated by a field-mapping method. Localized proton spectroscopy was performed from volume elements of 2 ml located in the central region of vertebral bodies in order to evaluate the fraction of the water signals, the transverse relaxation times T2 of the signals from water and lipids, and the line widths of the spectral signals. Regions of bone marrow after inflammatory conditions or intensive irradiation are shown to be not involved in marrow reconstitution. Additional information about marrow composition was obtained by the magnetic field mapping and by the line widths in the spectra. Considerable alterations of the amount of paramagnetic hemosiderin were revealed following transplantation. Patients with low water signal and strong local inhomogeneities of the magnetic field in the marrow prior to transplantation had a delayed hematopoietic reconstitution compared with the patients lacking these MR features.
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  • 26
    ISSN: 1432-0843
    Keywords: Key words S-1 ; Biochemical modulation ; Rat ; Metabolism ; Intestinal toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  S-1, a new oral antitumor agent, is composed of 1-(2-tetrahydrofuryl)-5-fluorouracil (Tegafur, FT), 5-chloro-2,4-dihydroxypyridine (CDHP) and potassium oxonate (Oxo) in a molar ratio of 1 : 0.4 : 1. FT which is a masked compound of 5-fluorouracil (5-FU) acts as an effector, while both CDHP and Oxo which do not have antitumor activity themselves act as modulators. In this study, the antitumor activity and intestinal toxicity of S-1 were investigated using experimental tumor models in rats, and compared with those of other oral fluoropyrimidines, namely 5-FU, FT, FCD (1 M FT/0.4 M CDHP) and UFT (combination of FT and uracil). In rats bearing subcutaneous Yoshida sarcoma, S-1 inhibited tumor growth at the lowest dose (ED50 value: S-1 5, UFT 22, FT 82, FCD 5, and 5-FU 19 mg/kg per day), and induced the least host body weight suppression, leading to the highest therapeutic index (TI) (S-1 4.5, UFT 1.4, FT 1.8, FCD 2.0, and 5-FU 1.4). S-1 also showed a higher therapeutic effect than UFT against AH-130 and Sato lung carcinoma. After administration of S-1 and UFT at equitoxic doses, S-1 showed a higher and more prolonged concentration of 5-FU than UFT both in plasma (AUC0-∞: S-1 28 nmol h/ml, UFT 15 nmol⋅h/ml) and in tumor tissue (AUC0-∞: S-1 95 nmol h/g tissue, UFT 52 nmol h/g tissue), leading to a higher 5-FU level incorporated into the RNA fraction (F-RNA level) in tumor tissue (AUC0-24: S-1 7.0 nmol h/mg RNA, UFT 4.3 nmol h/mg RNA) and 5–8% higher thymidylate synthase (TS) inhibition in tumor tissue at every time-point through 24 h. Compared with other oral fluoropyrimidines after administration of the maximal tolerable dose (MTD), S-1 caused the lowest rates of intestinal toxicities, such as diarrhea and occult blood in feces. S-1 also showed a higher antitumor effect on Yoshida sarcoma implanted intracolonically than UFT at an equitoxic dose (tumor weight: S-1 64±30 mg, UFT 133±52 mg; P〈0.05). These results suggest that CDHP, which is a potent inhibitor of 5-FU degradation, increases the antitumor activity of FT, and that Oxo, which is an inhibitor of 5-FU phosphorylation, locally protects the gastrointestinal tract from 5-FU-induced toxicity without decreasing the antitumor activity.
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  • 27
    ISSN: 1432-0843
    Keywords: Key words 7-Hydroxymethotrexate ; Toxicity ; Lethal dose ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To elucidate mechanisms for methotrexate (MTX)-induced renal and hepatic toxicity, we investigated the acute effects of bolus plus continuous infusion of up to 0.4 g/kg 7-hydroxymethotrexate (7-OH-MTX) in the rat. We demonstrate for the first time in any species the occurrence of acute lethal toxicity within a few hours after 7-OH-MTX administration. Serum concentrations of 7-OH-MTX measured at the time of death were 1.4 mM (mean), about one-half of those achieved in some patients after infusion of high-dose MTX (HD-MTX) in the clinic. The data suggest an approximate LD50 (the dose lethal to 50% of the study population) of 0.3 g/kg and a steep dose/lethality curve for 7-OH-MTX. Moreover, acute renal and hepatic toxicity occurred as evidenced by severe morphological findings and increased serum levels of creatinine and liver transaminases. In all rats subjected to continuous infusion of 7-OH-MTX, yellow microscopic precipitations were apparent in the kidney tubules. Crystallization was also seen in bile ducts of the liver in some of the rats. These results further support that the formation of 7-OH-MTX is disadvantageous and that reported attempts to prevent its formation during MTX treatment are warranted.
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  • 28
    ISSN: 1432-0843
    Keywords: Key words Microdialysis ; Methotrexate ; Tissue ; Recovery ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We used a microdialysis technique to determine tissue methotrexate (MTX) levels during steady state in a rodent model. Two different approaches were employed to measure the actual extracellular MTX concentrations in muscle, liver, and kidney tissues of anesthetized Wistar rats. With the reduced-perfusion-rate technique, the flow in the microdialysis perfusate was gradually decreased toward zero to permit calculation of zero-flow intercepts. Using the net change technique, microdialysis probes were perfused with different MTX concentrations to allow an assessment of equilibrium drug levels. For these two methods to be used, drug concentrations in the matrix to be analyzed must remain unchanged during the experimental procedure. In the animal model, steady state was attained after 1.5 h and maintained throughout the rest of the experiments by the administration of MTX as continuous infusions through a venous catheter. In vitro and in vivo, both the reduced-perfusion-rate and net change techniques gave reproducible data that permitted the estimation of extracellular drug concentrations in the dialyzed tissue compartments. The data suggest that the level of unbound MTX in the circulation is fairly similar to the extracellular concentrations in the muscle and liver. In the kidney, MTX levels were measured to be 3–8 times higher than those of unbound, circulating MTX, and a considerable discrepancy between the two methods used for estimations was apparent. These results demonstrate that both the net change and reduced-flow microdialysis techniques can produce reproducible and precise data. The results may constitute a basis for determining recoveries and, thus, true extracellular drug levels during in vivo microdialysis of MTX. This may be of importance in delineation of the relationship between tissue MTX levels and outcome in a variety of normally inaccessible compartments during cancer pharmacotherapy.
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  • 29
    ISSN: 1432-0843
    Keywords: Key words 6-Mercaptopurine ; Pharmacokinetics ; Methotrexate ; Lymphoblastic leukemia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Clinical and experimental pharmacokinetic interaction between 6-mercaptopurine (6-MP) and methotrexate (MTX) was investigated in patients as well as in rats and in HL-60 human leukemic cells. Ten children affected by acute lymphoblastic leukemia (ALL) in remission received daily doses of 6-MP given at 25 mg/m2 and i.v. infusion of high-dose MTX at 2 or 5 g/m2 once every other week. When 6-MP was given alone, the mean peak plasma concentration (Cmax) and area under the curve (AUC) of 6-MP were 72.5 ng/ml and 225.3 h ng ml-1. Concurrent treatment with MTX at 2 or 5 g/m2 resulted in a mean increase of 108% and 121% in the Cmax and of 69% and 93% in the AUC, respectively. In rats treated with an oral dose of 6-MP at 75 mg/m2, MTX given i.p. at 5 g/m2 produced mean increases of 110% and 230% in the Cmax and AUC of 6-MP, respectively. In HL-60 human leukemic cells incubated with 6-MP at 250 ng/ml, the cumulative intracellular concentration of 6-thioguanine and 6-MP nucleotides was not significantly modified by treatment with 20 μg/ml of MTX. The present findings indicate that high-dose MTX enhances the bioavailability of 6-MP as evidenced by the observed increases in the plasma Cmax and AUC of 6-MP in humans and animals.
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  • 30
    ISSN: 1433-2965
    Keywords: Bisphosphonates ; Bone resorption ; Calcium balance ; Calcium metabolism ; Ibandronate ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The new bisphosphonate ibandronate was given at various doses and regimens to normal growing rats, and its effect on calcium metabolism investigated by means of45Ca kinetics. The bisphosphonate began to inhibit bone resorption at a dose of 0.1 µg P/kg, given daily. At higher doses intestinal calcium absorption, calciuria and calcium balance were also increased, calcemia being decreased. There was no difference in effect when the same amount of compound was given either daily for 10 days or all at once. Furthermore, the effect of a high dose of 100 µg P/kg was present 1 month after a single administration, whereas a dose 10 times lower was no longer effective. These results suggest that ibandronate may be effective in humans for decreasing bone resorption and increasing calcium balance in osteoporosis, when given either daily or discontinuously.
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  • 31
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    International urogynecology journal 7 (1996), S. 321-324 
    ISSN: 1433-3023
    Keywords: Magnetic resonance imaging ; Pelvic floor ; Puerperium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Magnetic resonance imaging (MRI) was used to assess anatomical changes in the pelvic floor after childbirth. Six women underwent serial MRI examination within 30 hours and at 1 week, 2 weeks, 6 weeks and 6 months after delivery; 8 additional women were studied only within 30 hours of delivery. T-1 and T-2-weighted images of the pelvis in the transverse and sagittal planes with a 1.5-T MR imager were obtained. In the sagittal section we assessed the urethrovesical angle, urethral length, distance from the symphysis to the proximal and distal vagina, vaginal length, width and length of the sphincters, and the presence of sphincter defects. Axial sections were assessed for sphincter defects for the distance between the symphysis and midurethra, vagina and rectum. Only one parameter (distance between symphysis and distal vagina) changed significantly over time, without a clear trend in direction. Interobserver variation was reasonable (〈15%) except for anal canal length, urethral length and distance between symphysis and anus. There were no significant correlations between birthweight and MRI parameters. There was a non-significant association (P=0.09) between the sole combined sphincter defect and rectal injury, but not with episiotomy or parity. We concluded that it is feasible to determine multiple measurements on MR images to evaluate structures of the pelvic floor.
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  • 32
    ISSN: 1433-2981
    Keywords: Rat ; Blood-brain barrier ; Development ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A mouse monoclonal antibody which specifically reacts with putative blood-brain barrier (BBB) competent endothelial cells of rat cerebral capillaries was used to identify barrier competent cells in the central nervous system (CNS). The development of the cerebral capillaries and the BBB was examined and quantified, from day 6 to day 40 postpartum, using immunocytochemical and unbiased stereological techniques. There was a progressive increase in capillary formation postnatally, with collateral branching observed with progressive age. BBB development was confined to individual endothelial cells located at the periphery of the cortex until day 10 postpartum. Antibody binding progressively increased postnatally, contributing 30% of the total capillary surface area by day 20. There was a rapid elevation of reactivity from day 20 to day 40, with a mean of 83% by day 40. The BBB constitutes minimal amounts of brain vascular capillaries before day 10 of life in the rat. There is a slower increase in BBB than in total capillaries between days 10 and 20. There is a reversal of this trend between days 20 and 40.
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  • 33
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    Der Unfallchirurg 99 (1996), S. 665-670 
    ISSN: 1433-044X
    Keywords: Schlüsselwörter: Hämarthros ; Kniegelenkerguß ; MRT-Arthroskopie ; Therapieplanung ; Key words: Hemarthrosis ; Magnetic resonance imaging ; Arthroscopy ; Treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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  • 34
    ISSN: 1433-2981
    Keywords: Control survey ; Haematology ; Inter laboratory variation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A survey was conducted to determine the accuracy and quality control of automated haematology analysers used in non-clinical toxicity studies. Pooled blood samples from male Sprague-Dawley rats were distributed to 98 laboratory facilities throughout Japan, the samples being delivered under refrigeration to each facility within 18 h of sample preparation. At each facility, the samples were analysed within 4 h of receipt. Commercially available normal human blood samples from a single lot were also analysed at the same time. Most haematological results were within the mean ±3SD (standard deviation), but some facilities gave either high or low values consistently for both human and rat samples. No facility gave high or low values to certain parameters sporadically, which suggests no problem with the accuracy of the equipment. However, it was suspected that there would be some problem in comparing analytical values determined in a unique way by specific equipment design. The use of certain equipment resulted, in rat haematocrit values in particular, being either too high or too low. In these cases, it was deemed necessary to make some adjustments or calibration changes. There were also platelet values with a ‘plus drift’ which was apparently due to contamination with, or failure to identify small red blood cells (RBC). There was no deviation in values which could be attributed solely to the mechanical operation of any of the analytical equipment. Non-standard, initial setting up of the equipment (originally intended for human use, but now used for a variety of animal species) has been recognised as the main cause for a wider range of the analytical values seen. The results of this survey suggest that it may be necessary to review equipment calibration at each facility, and to re-establish the historical background data.
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  • 35
    ISSN: 1433-2981
    Keywords: Clinical chemistry ; Haematology ; Rat ; Sampling technique(s)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Blood samples from male and female rats were collected from four different sampling sites by the same technicians and analysed by the same procedures. The sampling sites were the abdominal aorta, orbital venous plexus, dorsal anastomotic orbital vein and sublingual vein. Values obtained in blood samples collected from peripheral sites were compared to those from the abdominal aorta, a sampling site which is normally unaffected by the sampling technique. There were significant differences in haematological parameters, particularly in leucocyte counts which were higher in samples collected from the peripheral sites than in those withdrawn from the central one. No significant changes were observed in coagulation parameters. A significant increase in clinical chemistry parameters related to soft tissue damage, namely creatinine kinase, lactate dehydrogenase, hydroxybutyrate dehydrogenase and aspartate aminotransferase, was seen in samples collected from both orbital sites. From this study it can be concluded that haematological and biochemical values obtained from rats in toxicological studies using different sampling sites are reliable both in males and females, provided that they are compared to values obtained from the same site in untreated controls. Sampling from the orbital plexus proved to be the least invasive method.
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  • 36
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    Pediatric surgery international 11 (1996), S. 45-46 
    ISSN: 1437-9813
    Keywords: Purulent cystic lymphangioma ; Mesenteric cyst ; Intra-abdominal cystic lymphangioma ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Infected intra-abdominal cystic lymphangiomas are very rare. We report a case of a purulent mesenteric cyst, histologically a cystic lymphangioma, w which developed in a 1-year-old girl who presented with marked abdominal distension and high fever. Magnetic resonance imaging revealed that the huge cystic lesion occupied the entire peritoneal cavity. It originated from the mesocolon. It was removed completely, and contained sticky pus at the base where the right fallopian tube penetrated it, which indicated the focus of infection. This may be the first report of a purulent mesenteric cyst in which the route of infection was suspected.
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  • 37
    ISSN: 1432-2161
    Keywords: Key words Bone bruise ; Ankle sprain ; Lateral collateral ligament ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. The objective of this study was to elucidate the relationship between lateral collateral ligamentous injuries of the ankle (ankle sprain) and bone bruise (trabecular trauma) of the talus and/or malleoli in the patients with twisting injuries of the ankle. Design. Magnetic resonance studies of the ankle were retrospectively reviewed, focusing on the presence or absence of lateral collateral ligamentous injuries and the location of bone bruise in the talus and/or malleoli. Patients. Thirty-five patients with acute twisting injuries of the ankle were studied. Results and conclusion. Four patterns of bone bruise were found in 14 patients: (1) bone bruise in the talar dome equivalent to osteochondral fracture in two patients, (2) bone bruise in the posteromedial aspect of the talus and the medial malleolus singly or in combination in four, (3) bone bruise in the anteromedial aspect of the talus in six, and (4) bone bruise with a combination of the second and third patterns in two. The second pttern was associated with tear of the anterior talofibular (ATAF) ligament in all patients and injury of the calcaneofibular (CF) ligament in one out of four. The third and fourth patterns were associated with tears of both ATAF and CF ligaments in all patients. The identification of bone bruise was of value in indicating lateral collateral ligamentous injuries.
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  • 38
    ISSN: 1432-2161
    Keywords: Key words Rheumatoid arthritis ; Cervical spine ; Cervical myelopathy ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. Comparison of clinically observed neurologic long tract signs in a heterogeneous group of patients with rheumatoid arthritis (RA), with morphologic abnormalities of the cervical spine as depicted on radiographs and magnetic resonance (MR) images. Design. The patients were prospectively assigned to one of three classes on the basis of their neurologic status. Lateral cervical spine radiographs and sagittal T1-weighted and gradient echo images were performed. The qualitative MR features evaluated were erosion of the dens and atlas, brain stem compression, subarachnoid space encroachment, pannus around the dens, appearance of the fat body caudal to the clivus, and the signal intensity of the pannus. The quantitative imaging parameters were the cervicomedullary angle and the distance of the dens to the line of McRae. Patients. Sixty-three consecutive patients with RA and subjective symptoms, especially neck or occipital pain, and/or clinical objective signs consistent with a compromised cervical cord were included in this study. Results and conclusions. Damage documented with radiographs and MR imaging in patients with RA is often severe, even in those without neurologic signs (class 1). None of the abnormalities confined to the atlantoaxial level correlated significantly with neurologic classification. Subarachnoid space encroachment anywhere in the entire cervical spine did correlate significantly with neurologic classification.
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  • 39
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    Skeletal radiology 25 (1996), S. 127-132 
    ISSN: 1432-2161
    Keywords: Key words Computed tomography ; Diabetes mellitus ; Infarction ; Magnetic resonance imaging ; Ultrasound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. Diabetic muscle infarction (DMI) is frequently misdiagnosed clinically as abscess, neoplasm, or myositis, and is often biopsied. Clinical and radiologic findings are presented here to enable the radiologist to suggest the correct diagnosis. Design and patients. Four patients with severe diabetes mellitus presenting with acute thigh pain, tenderness, and swelling were evaluated by imaging techniques and biopsy. Results and conclusions. Edema in the affected muscles was seen in two patients with MRI studies. Femoral artery calcification and mild muscle swelling was present in one patient who underwent CT. Decreased echogenicity was seen in the involved muscle in a patient studied with ultrasound. Serum enzymes were normal or mildly elevated in three patients (not reported in one). Biopsy demonstrated necrosis and regenerative change in all cases. MRI, although nonspecific, is the best imaging technique to suggest the diagnosis of DMI in the appropriate clinical setting, thereby obviating biopsy.
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  • 40
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    Skeletal radiology 25 (1996), S. 165-170 
    ISSN: 1432-2161
    Keywords: Key words Massive bone allograft ; Magnetic resonance imaging ; Histology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. The objective of this study was to better understand the MRI appearance of massive bone allografts. Design. The MRI findings of three massive bone allografts imaged in vivo were correlated with the histologic findings following removal of the allografts. A fourth allograft, never implanted, was imaged and evaluated histologically. Patients. Allografts were placed for the treatment of primary or recurrent osteosarcoma. Results and conclusions. The in-vivo allografts have a heterogeneous appearance on MRI which we attribute to the revascularization process. Fibrovascular connective tissue grows into the graft in a patchy, focal fashion, down the medullary canal from the graft-host junction and adjacent to the periosteum. The marrow spaces are initially devoid of normal cellular elements and occupied by fat and gelatinous material. This normal postoperative appearance of massive bone allografts must not be interpreted as recurrent neoplasm or infection in the allograft. Recognition of these complications rests on features outside the marrow.
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  • 41
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    Skeletal radiology 25 (1996), S. 255-261 
    ISSN: 1432-2161
    Keywords: Key words Cystic angiomatosis ; Multifocal hemangiomas of bone ; Hemangioendothelioma of bone ; Angiosarcoma of bone ; Plain radiography ; Magnetic resonance imaging ; Radionuclide bone scintigraphy ; Radionuclide tagged red blood cell scan
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. Multifocal vascular processes which arise in bone are a very inhomogeneous class of diseases. Four of these processes are derived from endothelial precursors, however, and share a similar radiographic spectrum. These four entities are reviewed in order to clarify their imaging patterns and the diagnostic utility of imaging modalities. Methods. Eight cases of cystic angiomatosis, multifocal hemangioma, hemangioendothelioma and angiosarcoma presenting to a tertiary referral center over a 7-year period were reviewed. The medical literature was also reviewed for information concerning the imaging of these processes. Results. All four diseases produced radiolucent defects on plain radiographs with variable margination reflecting the aggressiveness of the lesions. Computed tomography was used to examine five patients and provided supportive, though generally non-diagnostic, information in the five cases in which it was performed. Radionuclide bone scintigraphy, as reported in the literature, underestimated the extent of skeletal involvement in all eight cases, though some lesions were identified. Radionuclide imaging with labeled red blood cells, performed in three cases, did not add any information, which is contrary to some reports in the literature. Magnetic resonance imaging proved the most sensitive for identifying lesions, although the imaging characteristics were not diagnostic. Conclusions. Plain radiographs are the mainstay for imaging multifocal endothelial processes. Radiographs provide information on aggressiveness, multifocality and distribution of lesions. Computed tomography provides similar information. Magnetic resonance imaging often detects additional lesions. The insensitivity of radionuclide bone scintigraphy is surprising. Reports of unique deposition of radionuclide in tagged red blood cell scanning has been reported to support the diagnosis of vascular lesions, but it did not do so in these cases.
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  • 42
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    Skeletal radiology 25 (1996), S. 283-286 
    ISSN: 1432-2161
    Keywords: Key words Lipoblastoma ; Neoplasm ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Lipoblastoma is an uncommon benign lipomatous soft tissue mass of childhood, occurring most commonly in children less than 3 years of age. We present a case of lipoblastoma occurring in the foot of a 14-year-old boy and review the literature. The appearance of the mass on magnetic resonance imaging (MRI) is illustrated and is correlated with the findings at gross and microscopic pathological examination. A lobulated architecture, the presence of adipose tissue, thin nonenhancing septa, peripheral lobules of more immature and therefore less specific tissue, and a peripheral pseudocapsule were evident on MRI and at pathological examination.
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  • 43
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    Skeletal radiology 25 (1996), S. 309-317 
    ISSN: 1432-2161
    Keywords: Key words Popliteal ; Mass ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A wide variety of masses may be visualized in the posterior knee. Some are encountered incidentally on MRI obtained for seemingly unrelated symptoms; others are palpable and present for MRI characterization. We describe the appearance, significance and pathophysiology of some of the most common lesions found in the popliteal fossa as well as several of the less common entities we have encountered. Thorough understanding of the appearance and location of the more specific masses should augment precise diagnosis in a majority of cases. In turn, this will eliminate unnecessary additional investigations and enable prompt and appropriate treatment.
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  • 44
    ISSN: 1432-2161
    Keywords: Key words Fungal infections ; Skeletal coccidioidomycosis ; Computed tomography ; Magnetic resonance imaging ; Skeletal scintigraphy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. The objective of this study was to describe the distribution and radiologic appearance of skeletal coccidioidomycosis in 19 documented cases. Design and patients. Medical records of 19 patients (17 men, 2 women; age range 17–62 years, mean age 34 years) with clinically confirmed skeletal coccidioidomycosis were retrospectively reviewed. The patients were studied with plain radiography (n=19), skeletal scintigraphy (n=6), computed tomography (CT) (n=5), and magnetic resonance imaging (MRI) (n=1). Results. Multiple lesions were seen in 11 of 19 patients (58%). Of a total of 46 lesions, 27 (59%) were described as punched-out lytic, 10 (22%) as permeative/destructive, and 9 (17%) as involving a joint and/or disk space. Lesions were identified in almost every bone (with the exception of the facial bones, ulna, carpus, and fibula) and were most commonly found in the axial skeleton (20 of 46; 43%). Conclusion. Skeletal coccidioidomycosis is frequently multicentric and may involve almost any bone. The axial skeleton is the most common site of involvement. Lesions are usually well demarcated but may present with an ill-defined border and permeative type of bone destruction, especially in the spine. Joint involvement is not uncommon. Plain radiographs are effective in the initial evaluation of bones and joints, scintigraphic studies can identify disseminated disease, and CT and MRI are effective in determining soft tissue involvement and spinal abnormalities.
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  • 45
    ISSN: 1432-2161
    Keywords: Key words Intra-arterial chemotherapy ; Soft tissues ; Magnetic resonance imaging ; Neoplasms ; Bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. Intra-arterial chemotherapy (IAC) is frequently used as an adjuvant treatment for musculoskeletal tumors. Past studies have noted that IAC not only induces favorable effects in tumor, but may also cause muscle edema and necrosis in previously normal tissue, reflected as increased signal on T2-weighted scans. In order to evaluate the prevalence of these effects, we reviewed all patients receiving IAC and MRI at our institution. Methods. Our study population consisted of 24 patients who underwent IAC. All subjects were studied with MRI both pre-and post-IAC. None of the subjects in this study underwent surgery or radiation therapy until after the post-IAC MRI examination. Any muscle group involved by the tumor or peritumoral edema on the initial scan was excluded from the study. Catheter position during IAC was recorded as central or peripheral. Scans were scored positive if muscle groups in regions remote from the tumor site demonstrated increased T2 signal following IAC. Results. Six out of these 24 patients (25%) were found to have positive results. A significant association was found between peripheral catheter position and a positive scan post-IAC (Fisher’s exact test, P=0.024). Conclusion. Because of our exclusion criteria, we are convinced that the finding of increased T2 signal in 25% of our patients was caused by IAC and represents muscle edema or necrosis. Knowledge of this post-chemotherapy MR finding should help prevent confusion during the interpretation of follow-up MR examinations.
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  • 46
    ISSN: 1432-2161
    Keywords: Key words Acetabular labrum ; Magnetic resonance imaging ; hip ; Gadolinium ; Traction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. The objective of this study was to evaluate the effects of continuous leg traction on contrast-enhanced MR imaging of the hip joint and to determine whether MR imaging under these conditions is useful for demonstrating acetabular labral tears. Design and patients. Nineteen hips underwent MR imaging with a T1-weighted spin-echo sequence, followed by MR imaging under continuous leg traction after intravenous injection of gadolinium-DTPA. Joint fluid enhancement and labral contour detection were evaluated. Eleven hips had labral tears shown by conventional arthrography, arthroscopy and macroscopic surgical findings. Assessment of labral tears by MR imaging was correlated with the diagnosis based on these standard techniques. Results and conclusions. Joint fluid enhancement was obtained in all hips at 30 min after injection. Superior and inferior labral surfaces were completely delineated in 1 hip on the unenhanced MR images, and in 7 and 13 hips, respectively, on the enhanced images under traction. The enhanced images under traction depicted 9 of the 11 labral tears. Comparison between the unenhanced image and the enhanced image under traction avoided mistaking undercutting of the labrum for a tear in 4 hips. Contrast-enhanced MR imaging under traction was valuable for detecting labral tears non-invasively and without radiation. Follow-up examinations using this method in patients with acetabular dysplasia can help to clarify the natural course of labral disorders and enable better treatment planning.
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  • 47
    ISSN: 1432-2161
    Keywords: Key words Tumoral calcinosis ; Cervical spine ; Soft tissue calcification ; Bone ; Computed tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report a case of a 12-year-old girl with idiopathic tumoral calcinosis of the neck. There are calcium deposits in the paraspinal soft tissue with bony involvement in the cervical spine. CT and MR images are presented along with clinical and pathological features. Bony involvement in this disease has not been recognized before.
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  • 48
    ISSN: 1432-2161
    Keywords: Key words Burst fracture ; Plain radiography ; Computed tomography ; Magnetic resonance imaging ; Diagnosis ; Management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The burst fracture of the spine was first described by Holdsworth in 1963 and redefined by Denis in 1983 as being a fracture of the anterior and middle columns of the spine with or without an associated posterior column fracture. This injury has received much attention in the literature as regards its radiological diagnosis and also its clinical managment. The purpose of this article is to review the way that imaging has been used both to diagnose the injury and to guide management. Current concepts of the stability of this fracture are presented and our experience in the use of magnetic resonance imaging in deciding treatment options is discussed.
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  • 49
    ISSN: 1432-2161
    Keywords: Key words Elbow ; Ulnar collateral ligament ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. The purpose of this study was to evaluate ulnar collateral ligament (UCL) injury of the elbow in throwing athletes by MRI and MR arthrography. Design. Ten elbows of throwing athletes were examined on both plain MRI and MR saline arthrography and the injuries subsequently surgically proven. Spin-echo (SE) T1-weighted and fast SE T2-weighted coronal images were obtained. Results. The UCL was unclear in all ten cases on T1-weighted MRI. In five cases an avulsion fracture was also found on T1-weighted MRI. On T2-weighted MRI, abnormal high-intensity areas were identified in or around the UCL. On T2-weighted MR arthrography images, extracapsular high-intensity areas, which represent extracapsular leakage, were found in four of five cases with avulsion fracture. At surgery, all these four cases showed avulsion fractures with instability; the other case had a fracture but it was stable and adherent to the humerus. On T2-weighted MR arthrography images, an extracapsular high-intensity area was found in one of the five cases without avulsion fracture. At surgery this patient had a complete tear of the UCL itself. Conclusion. MR arthrography provided additional information for evaluating the degree of UCL injury.
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  • 50
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    Skeletal radiology 25 (1996), S. 625-628 
    ISSN: 1432-2161
    Keywords: Key words Pectoralis muscle ; Rupture ; Magnetic resonance imaging ; Computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rupture of the pectoralis major muscle is a rare clinical entity. Only few reports have discussed its MRI or CT features. We have reviewed the imaging features of four cases of complete rupture of the pectoralis major muscle. One case of acute injury underwent surgical repair. MRI is useful in delineating the site and extent of the rupture in relation to the musculotendinous junction, which will help the surgeons with possible treatment options and surgical planning. Because of the complex anatomy of the pectoralis major muscle near its insertion on the humerus and the signal characteristics of hematoma and edema in the muscle, axial T2-weighted images were most valuable for the evaluation of acute and subacute injuries. Axial T1-weighted images were helpful in delineating chronic injuries. CT is inferior to MRI for direct visualization of muscle rupture.
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  • 51
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    Skeletal radiology 25 (1996), S. 775-778 
    ISSN: 1432-2161
    Keywords: Key words Lymphoma ; Calcaneus ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Primary non-Hodgkin’s lymphoma (NHL) of bone is a rare condition. Presented herein is a case of primary NHL of the calcaneus illustrating many of the classic features of the disease. Emphasized in this report are the nonspecific clinical and conventional radiographic features of primary NHL of bone, which may mimic inflammatory, neuropathic, infectious, or other neoplastic conditions of the extremities. The importance of early cross-sectional radiologic studies, such as magnetic resonance imaging, lies in the early characterization of the mass-like features and local extent of such lesions, helping to raise the suspicion of neoplastic disease.
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  • 52
    ISSN: 1432-2307
    Keywords: Soft tissue ; Aneurysmal bone cyst ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report a case of primary aneurysmal cyst of soft tissues in a 57-year-old woman presenting with a painful mass in her left arm. Conventional radiography showed a radiolucent soft tissue mass surrounded by a ring of bone. MRI displayed an unusual, ill-defined soft tissue lesion that was not connected to the nearby humerus and appeared to be an aggressive tumour. Microscopically, the mass consisted of multiple anastomosing cavernous channels surrounded by a peripheral band of mature trabecular bone. These bloody channels were separated by fibrous septa containing fibroblasts, histiocytes and multinucleated giant cells, as well as fibromyxochondroid material. Some of these giant cells lined the septa and partially occupied the lumen of the channels. Ultrastructurally, the features observed in this tumour were similar to those described in aneurysmal bone cyst; the giant cells lining the septa were an additional observation. Whereas most bone tumours have a well-known extraosseous counterpart, this unique lesion is not well recognized by surgical pathologists and the few published cases have been reported under different names. Gross, microscopic, radiological and ultrastructural findings are presented to familiarize pathologists with this underdiagnosed condition.
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  • 53
    ISSN: 1434-0879
    Keywords: Enolase ; Isozymes ; Rat ; Renal neoplasms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Concentrations of enolase isozymes in normal kidney and renal cell tumors in rats were determined using a highly sensitive enzyme immunoassay, and the isozymes were immunohistochemically localized in tissue sections. Levels of α-enolase in renal cell turnors were significantly lower than in normal kidney, whereas those of γ-enolase were significantly elevated (mean ±SD:211±129 ng/mg protein, n=15, as compared to 27.1±2.9 ng/mg protein, n=7). The proportion of γ-enolase in the total enolases in the tumor tissues (1.6±0.5%) was significantly higher than in normal kidney (0.15±0.005). Immunohistochemistry revealed epithelial cells of all nephron segments to be positive for the α-isozyme, whereas γ-enolase staining was strongly positive only in the loops of Henle, being faint in the distal tubules and absent in the proximal tubules. Both α- and γ-enolases demonstrated positive immunostaining in all of the seven renal cell tumors studied. These findings indicate that an isozyme switch from α- to γ-enolase occurs during rat kidney carcinogenesis, taking into account the derivation from proximal tubules, consistent with the findings for renal cell carcinomas in man.
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  • 54
    ISSN: 1573-0603
    Keywords: Brain ; Histology ; Organotypic culture ; Patch clamp recording ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The goal of the current research was to define an in vitro system that can replace in vivo experimentation but reflects as far as possible aspects of the intact situation of the developing nervous system of mammals. Tissue slices of postnatal rat hippocampi were continuously moved between the medium and gas phase. Under these conditions the complex cytoarchitecture was preserved for many weeks. Lactate dehydrogenase assay, cell size analysis and neuron- and glial cell specific immunocytochemical markers were employed to illuminate explant development in vitro. By scanning electron microscopy the explant surface was analysed in order to determine the conditions suitable for patch clamp recording. Electrophysiological analysis revealed a pronounced spontaneous activity showing the neurons to be functionally active. These data indicate that organotypic roller cultures reflect to a large extent the in vivo situation of the mammalian nervous system. The culture system provides a promising model system for developmental physiology, neurotoxicology and pharmacology.
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  • 55
    ISSN: 1432-0533
    Keywords: Key words Growth-associated protein 43 ; Immunohistochemistry ; Rat ; Spinal cord ; Trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Growth-associated protein 43 (GAP43) is one compound used to indicate growth of axonal endings during development and regeneration, particularly of peripheral neurons. Using immunohistochemistry, we have studied the expression of GAP43 in the spinal cord of rats subjected to mild, moderate or severe compression injury and used neurofilament immunostaining to demonstrate axonal injuries. Samples removed from the compressed T8–9, the cranial T7 and the caudal T10 segments were studied at 4 h, 24 h, 4 days and 9 days after injury. Control rats showed a moderate immunostaining of neurons in dorsal root ganglia, weak staining of ventral motor neurons and, with the exception of the corticospinal tracts, a weak staining in some axons of the longitudinal tracts of the cord. Injury in the compressed region led to increased GAP43 immunoreactivity in axons of normal and expanded size. This occurred particularly 1–4 days after injury and normalized 9 days thereafter. More marked immunostaining was present in the cranial and caudal segments. The corticospinal tracts never showed such staining. The increase of GAP43 immunostaining is presumably caused by disturbed axonal transport from neurons with the capacity to synthesize and transport the GAP43 antigen. Transported material may thus be available for regeneration of axons, but this source of material may vary between different classes of axons within the cord.
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  • 56
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    Acta neuropathologica 91 (1996), S. 616-623 
    ISSN: 1432-0533
    Keywords: Key words Insulinoma ; Peripheral neuropathy ; Morphometry ; Pathology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Peripheral nerve structure was systematically examined in rats with insulinoma induced by streptozotocin (STZ). Normal Wistar rats, aged 3 months (n = 10), were treated with intravenous injections of STZ (20 mg/ kg) and housed in plastic cages with free access to water and chow until 24 months of age. Three rats with insulinoma survived and were examined pathologically. Age-matched normal Wistar rats (n = 6) were used for comparison. The insulinoma-bearing rats showed a marked increase in body weight and decrease in blood glucose. In a teased nerve fiber study of the sciatic nerve, the percentage of abnormal fibers undergoing axonal degeneration and de- and remyelination in age-matched normal control rats was 3.9 ± 2.5% (means ± SD), whereas in the three insulinoma-bearing rats 49%, 50%, and 24%, respectively, of the fibers showed such changes. Regenerating fibers were also numerous in each insulinoma-bearing rat (36%, 42% and 27%, respectively). Morphometric analysis revealed smaller mean myelinated fiber and axonal areas in all the nerves examined (sciatic, tibial and sural) in insulinoma-bearing rats as compared to those in age-matched normal rats. Fiber area frequency histograms showed a decrease in large myelinated fibers and an increase in small regenerated fibers in insulinoma-bearing rats. Ultrastructurally, endoneurial microvessels exhibited a narrowed vascular lumen with swollen endothelial cells and vacuolar degeneration of pericytes, suggesting an involvement of vascular changes in the neuropathic development. The present study demonstrated marked structural changes in both motor and sensory peripheral nerves of rats bearing experimentally induced insulinoma. We consider that axonal degeneration, regeneration and demyelination constitute the main pathology in the peripheral nerves of insulinoma-bearing rats, although no particular difference in severity of the lesions between sensory and motor and between proximal and distal nerves was apparent.
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  • 57
    ISSN: 1432-055X
    Keywords: Schlüsselwörter Sedierung ; Kinder ; Magnetresonanztomographie ; Methohexital ; Propofol ; Key words Children ; Sedation ; Methohexital ; Propofol ; Spontaneous breathing ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract The purpose of the present study was to compare two sedation regimens with either propofol (P) or methohexital (M) for elective magnetic resonance imaging (MRI) in children with respect to safety, side effects, recovery, and discharge time. Methods. After Institutional Review Board approval, 120 unpremedicated children with a mean age of 26.5 ±21.4 months (M) and 28.1±19.9 months (P) were randomly assigned to receive a hypnotic induction dose of either M or P. Supplemental bolus injections of M or P were administered to maintain adequate sedation. The following parameters were measured: heart rate, oxygen saturation by pulse oximetry (SpO2), respiratory rate, end-tidal CO2 (PetCO2), side effects, and recovery and discharge times. Results. Spontaneous respiration was maintained in all patients, and ventilatory support was only necessary for 2 min in 1 M patient immediately after the induction dose. The mean loading and total doses for M were 2.3±0.7 and 6.1±3.3 mg/kg respectively, and for P 2.3±0.9 and 5.8±2.7 mg/kg. Following induction SpO2 〈90% occurred in 0.49% with M and in 0.64% with P (n.s.). Apnoe 〉20 s was observed in 2 children each after M and P (n.s.). The frequency of hypoventilation (PetCO2〉48 mmHg) was 0.36% in the M group and 0.71% in the P group (n.s.). MRI sequences had to be repeated in 5% of the children in each group because of spontaneous movements. The heart rate fell significantly during MRI in both groups, while P children had lower frequencies than M children (P〈0.01). Recovery and discharge times were significantly shorter in the P group, at 0.8 min (0.08–4.8) and 2.2 min (0.2–15.0), compared to 1.5 min (0.3–28.5) and 3.5 min (0.6–40.0) in patients receiving P (P〈0.01). No patient required admission to the postanaesthesia care unit and all were free from nausea and vomiting. Discussion. Intravenous sedation with M or P using the reported technique is a safe regimen for children undergoing elective MRI. The fast recovery and discharge times seem to offer advantages over general anaesthesia with endotracheal intubation. The faster recovery and discharge of only a few minutes after P compared with M is without clinical relevance.
    Notes: Zusammenfassung Es war das Ziel der vorliegenden Untersuchung, zwei intravenöse Sedierungstechniken mit Propofol (P) oder Methohexital (M) zur elektiven Magnetresonanztomographie (MRT) bei 120 Kindern unter 6 Jahren bezüglich Sicherheit, Nebenwirkungen, Aufwachverhalten und Verlegungszeiten zu vergleichen. Jeweils 60 unprämedizierte Kinder erhielten prospektiv, randomisiert eine Einschlafdosis von M oder P und zusätzliche Injektionen bei Anzeichen unzureichender Sedierungstiefe. Herzfrequenz (HF), pulsoxymetrische Sättigung (SpO 2 ), Atemfrequenz (AF) sowie endtidaler CO 2 -Partialdruck (PetCO 2 ) wurden kontinuierlich gemessen. Bei einer Untersuchungdauer von 28,4 min (M) bzw. 28,9 min (P) betrug die durchschnittliche Einschlaf- und Gesamtdosis für Methohexital 2,3±0,7 mg/kg und 6,1 ±3,3 mg/kg und für Propofol 2,3 ±0,9 mg/kg und 5,8±2,7 mg/kg. Erniedrigungen der SpO 2 〈90% traten nur nach der Erstinjektion mit einer Häufigkeit von 0,49% (M) bzw. 0,64% (P) aller Messungen auf. Apnoephasen 〉20 s wurden bei 2 Kindern jeder Gruppe, eine Erhöhung des PetCO 2 〉48 mm Hg in 0,36% (M) bzw. 0,71% (P) aller Meßbeobachtungen registriert. Spontane Bewegungen machten bei 5% der Kinder jeder Gruppe eine Wiederholung der vorangehenden MRT-Sequenz notwendig. Aufwach- und Verlegungszeiten waren mit 0,8 min und 2,2 min unter P signifikant kürzer als unter M (1,5 min und 3,5 min; p〈0,01). 10 min nach MRT-Ende waren alle Kinder gleich vigilant. Übelkeit und Erbrechen wurden weder unter M noch unter P beobachtet. Die vorgestellte intravenöse Monosedierung mit M oder P ist ein sicheres Verfahren zur Ruhigstellung von Säuglingen und Kindern zur elektiven MRT. Beide Medikamente sind gleich gut geeignet.
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  • 58
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    Acta neuropathologica 91 (1996), S. 155-160 
    ISSN: 1432-0533
    Keywords: Key words Ubiquitin ; Immunohistochemistry ; Rat ; Spinal cord ; Trauma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ubiquitin-mediated proteolytic pathway is an important mode of protein degradation in various tissues. Since breakdown of proteins may occur in axons after injury we evaluated the presence of ubiquitin-like immunoreactive material in rat spinal cord following compression injury of mild, moderate and severe degrees at T8–9 level, resulting in no neurological deficit, reversible paraparesis and paraplegia of the hind limbs, respectively. Rats with mild to severe compression injury surviving 1–4 days showed numerous, intensely immunoreactive expanded axons at the site of compression. The labelled axons were randomly distributed in the longitudinal tracts but they were never found in the corticospinal tracts. No labelling was detected by 9 days after injury. In addition, the presence of labelled axons was investigated in the T7 and the T10 segments from rats with moderate compression. No labelling was seen in T7, but in T10 segments many immunoreactive axons were present. Control rats did not show immunoreactive axons in the spinal cord. Neurons of dorsal root ganglia, trigeminal ganglia and of the grey matter of the spinal cord were immunoreactive. Cerebral cortical neurons did not show ubiquitin expression. Thus, compression of the rat spinal cord causes a transient accumulation of ubiquitin-like immunoreactive material in axonal swellings. Even though the dynamics of ubiquitin conjugates are not fully understood, the observed axonal accumulation presumably reflects arrested anterograde axonal transport of protein chiefly derived from neurons of dorsal root ganglia and the local neurons of the spinal cord. The presence of ubiquitin in damaged axons is one prerequisite for degradation of abnormal proteins by the ubiquitin-mediated proteolytic pathway, which may be activated in reactive axonal swellings.
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  • 59
    ISSN: 1432-0568
    Keywords: Aromatase ; Estrogen receptor ; Immunohistochemistry ; Brain ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We elucidated the anatomical relationship between estrogen receptors and aromatase, the enzyme converting androgens to estrogens, in the fetal and neonatal rat brain by means of double immunohistochemical labeling, using antibodies against rat estrogen receptors and human placental aromatase cytochrome P450. Numerous aromatase-immunoreactive neurons were found in the medial preoptic area, the bed nucleus of the stria terminalis, the medial amygdaloid nucleus and the ventromedial nucleus. Estrogen receptors were also abundant in these areas. Most of the aromatase-immunoreactive neurons showed immunoreactivity for estrogen receptors in the medial subdivision of the bed nucleus of the stria terminalis and in the posterodorsal division of the medial amygdaloid nucleus. There were also many double-labeled cells in the ventromedial nucleus. However, in the medial preoptic area the localization of aromatase-immunoreactive neurons was distinct from that of neurons containing estrogen receptors. These results suggested that estrogens, which are converted from androgens in aromatase-containing neurons, are involved in the sexual differentiation of the brain through estrogen receptors within aromatase-immunoreactive neurons in the bed nucleus of the stria terminalis, the medial amygdaloid nucleus and the ventromedial nucleus, but through estrogen receptors in aromatase-immunonegative neurons in the medial preoptic area.
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  • 60
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    Anatomy and embryology 194 (1996), S. 595-605 
    ISSN: 1432-0568
    Keywords: Neuropeptides ; Hybridization histochemistry ; Chemical anatomy ; Ontogeny ; Rat ; Brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Vasoactive intestinal peptide (VIP) expression was studied during rat brain development using in situ hybridization histochemistry with a 48mer, S35-ATP-labeled probe. First expression of VIP was found in the lateral thalamus at E17, in a region later recognized as the reticular nucleus. At E19, VIP mRNA was also found in the hypothalamus, especially the suprachiasmatic nucleus. The only other prenatal localizations were the cortex and the brainstem. VIP expression continously matured during the first three postnatal weeks, and adultlike patterns were found at P22, when cerebral cortex, ventrolateral and reticular thalamic nuclei, suprachiasmatic nucleus were the regions with most prominent VIP expression. These results demonstrate the relatively late appearance of VIP gene expression in the rat forebrain as compared with peptides like SRIF and CCK, suggesting it does not have a major role in early brain maturation.
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  • 61
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    Anatomy and embryology 195 (1996), S. 65-70 
    ISSN: 1432-0568
    Keywords: Key words α-Amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid receptor ; Glutamate receptor development ; Immunohistochemistry ; Synaptogenesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We studied the immunohistochemial localization of the glutamate receptors (GluR-1, -2, and -3,) in the developing rat cerebral cortex and hippocampus using antibodies to GluR1 and to an epitope common to GluR2 and GluR3 (GluR2/3) subunits. In the cerebral cortex, GluR1 immunoreactivity appeared in the neurons from postnatal day (PND) 0, increased with maturation, was highest at PND 10, decreased until PND 30, and thereafter remained at the same level as on PND 0. GluR2/3 immunoreactivity appeared earlier in scattered neurons on embryonal day (ED) 18, increased with maturation and reached a peak between PND 10 and PND 15, after which the immunoreactivity gradually decreased and reached a plateau at PND 30. For both GluR1 and GluR2/3, some of the pyramidal neurons showed intense staining. In the pyramidal layers of the hippocampus, GluR1 and GluR2/3 immunoreactivity was found in all the pyramidal neurons of the CA1–4 area from ED 20. In the dentate gyrus of the hippocampus, GluR1 and GluR2/3 immunoreactivity was found in the neurons of the granule cells after PND 0. Immunoreactivity in the neurons of the subiculum was found after PND 5 and that of the polymorphic cell layers was found after PND 15–20. Our results indicate that the development of glutamate receptor subunits in the rat cerebral cortex and hippocampus is expressed in different spatial patterns and distinct temporal patterns throughout development and is scheduled during the early postnatal period, when synaptic plasticity or synaptic connection occurs in these regions.
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  • 62
    ISSN: 1432-0568
    Keywords: Neuropeptides ; Limbic cortex ; Allocortex ; Mesocortex ; Parcellation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The expression of somatostatin mRNA within the allocortex of the rat was examined by in situ hybridization with an alkaline phosphatase labeled probe. We sought to determine whether parcellation of the allocortex could be based upon the number and laminar location of the hybridized cells and to contrast the allocortical features with those of the isocortical areas. The cingulate region was characterized by intense, moderate, and faint cells, small to medium in size throughout the laminae. The retrosplenial region demonstrated a somewhat stratified appearance with an abundance of cells expressing somatostatin mRNA in the upper portion of the composite layer II–IV and also in the upper portion of layer VI. The insular region displayed more heterogeneity. The distribution of the cells hybridized for somatostatin mRNA formed distinctive configurations within the insular region (dorsal and ventral agranular insular areas) with no obvious generality. The perirhinal area resembled the ventral agranular insular area, and the cell distribution of the entorhinal and prepiriform areas displayed a common characteristic in that the primary axis of the perikarya of somatostatin mRNA expressing cells within the lower layers were oriented at almost every possible angle. The conclusion of the investigation is that in situ hybridization for somatostatin mRNA provides a means by which the areal boundaries within the allocortex may be drawn.
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  • 63
    ISSN: 1432-0568
    Keywords: Apoptosis ; Programmed cell death ; Olfactory system ; Embryogenesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It has been previously shown that the embryonic olfactory nerve contains, in addition to glial ensheathing cells, a large population of differentiated neurons that migrate from the developing olfactory epithelium, in close association with the olfactory axon fascicles. The purpose of our study was to verify the hypothesis according to which a process of physiological cell death might be involved in the progressive disappearance of these migrating neurons that has been reported during late embryonic stages in several immunocytochemical studies. To do so, we have investigated the development of the olfactory nerve layer in rat embryos by using light and electron microscopy, with special reference to the presence of cell death processes within this structure. We have also applied the histochemical TUNEL method allowing in situ visualization of cells degenerating by apoptosis. In order to determine if neurons were present among dying cells, a procedure of double-labeling was performed by combining the DNA-specific bisbenzimide with two neuronal markers, the protein B-50/GAP-43 and the lectin Ulex europaeus I. Results brought out the precise temporal and spatial patterns of programmed cell death accompanying the morphogenesis of the olfactory nerve layer. A cell death process was observed within the olfactory nerve layer from its onset at embryonic day 13 (E13). While only few pycnotic cells were observed in E13 and E14 embryos, their number increased from E15 to reach a maximum at E16 and then diminished. Few dying cells were also observed along the olfactory axon fascicles when they penetrated the olfactory nerve layer. Degenerating cells appeared strongly TUNEL-labeled and exhibited morphological features of cell death by apoptosis. Double-labeling experiments revealed that some of the apoptotic cells were neurons. These observations indicate that apoptosis may account for the progressive decrease in the number of migrating neurons present within the embryonic olfactory nerve layer. Otherwise, a zone of massive cell death by apoptosis was observed at E14 within the nasal mesenchyme located ventrally and caudally to the olfactory nerve layer. Double-labeling experiments showed that apoptotic cells present within this zone were not neurons. Our findings strongly suggest that apoptotic cell death of migrating neurons may allow the elimination of non-functional cells whereas that of mesenchymal cells may facilitate outgrowth of the newly formed olfactory axon fascicles by pathway formation.
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  • 64
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    Surgical and radiologic anatomy 18 (1996), S. 133-135 
    ISSN: 1279-8517
    Keywords: Spinal cord ; Magnetic resonance imaging ; Cadaver ; Embalming ; Anatomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Il y aurait un grand intérêt à utiliser des vertèbres cervicales et des moelles épinières issues de cadavres pour évaluer quels degrés de subluxation traumatique et quelles lésions nerveuses sont liés. Cependant, avant d'entreprendre une telle étude, il serait important d'appréhender le degré de rétrécissement ou d'élargissement de la moelle épinière qui survient au cours de l'embaumement. C'est ce que nous avons réalisé dans ce travail en comparant les diamètres de la moelle épinière de cadavres à ceux de coupes sagittales obtenues par résonance magnétique nucléaire sur des sujets vivants. Les mesures géométriques sur des radiographies de sujets vivants ont déjà été évaluées, mais aucun modèle directement applicable aux traumatismes de la moelle épinière n'a été décrit [1]. Si les diamètres des moelles épinières embaumées représentaient fidèlement les diamètres des moelles épinières des sujets vivants, les colonnes cervicales de cadavres pourraient être utilisées comme modèles. On pourrait évaluer l'importance de la compression de la moelle épinière correspondant à des degrés variés de fractures et de luxations. Notre étude montre que les dimensions de moelles épinières augmentent après l'embaumement selon la technique de Cambridge [4].
    Notes: Summary It would be valuable to use cadaveric models of cervical vertebrae and spinal cord to assess how varying degrees of traumatic subluxation would relate to neurological damage. However, before such a study may be undertaken, it would be important to assess the degree of shrinkage or expansion of the spinal cord that occurs during the embalming process. This is achieved in this study by comparing diameters of cadaveric spinal cord to that of sagittal magnetic resonance scans of living subjects. The geometric measurements of radiographs in living subjects has been assessed but no direct model for spinal cord injury has been described [1]. If embalmed spinal cord diameters were a good estimator of living spinal cord diameters then cadaveric cervical spines could be used as a model. By reproducing various degrees of fracture and dislocation the extent of corresponding cord compression could be assessed. Our study shows that spinal cord dimensions increase after embalming using the Cambridge procedure [4].
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  • 65
    ISSN: 1432-0851
    Keywords: Key words Medullary thyroid carcinoma ; Rat ; Immunotherapy ; Interleukin-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The existence of inherited aggressive forms of medullary thyroid carcinoma (MTC), and their resistance to all classical therapies, make it a prime candidate for adoptive immunotherapy. As a prelude to a vaccine for the protection of family members at risk of developing the disease, we investigated the immunological antitumour response provoked by the 6/23 rMTC cell line, compared to that of the same cells engineered to secrete interleukin-2 (rMTC-IL2), in an animal model of familial human MTC, the inbred strain of Wag/Rij rats. The rMTC cells developed a tumour that invaded the whole neck 15 days after orthotopic injection (into the thyroid), while the rMTC-IL2 cells were progressively rejected. Co-injection of rMTC-IL2 with the parental cells induced the rejection of the rMTC transplants. When injected, both tumoral cell types showed a similar positive immunoreaction with anti-MHC class I (major histocompatibility complex class I) antibodies. They both recruited natural killer cells and eosinophils at the site of injection. In addition, CD8+ T lymphocytes infiltrated the rMTC-IL2 cells, and eosinophil recruitment was amplified. Neutrophils, macrophages and CD4+ T lymphocytes were scarce. Our results suggest that the CD8+ T lymphocytes are implicated in the antitumour reaction elicited by the Il-2-transfected cells. As these effectors are known to induce a specific immunological response, including memory, such a protocol should be tested as a vaccine on the young population genetically at risk of developing a MTC.
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  • 66
    ISSN: 1432-0851
    Keywords: Key words NK cell ; NKR-P1 ; Rat ; Colon tumor ; Tumor regression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  NKR-P1 has been identified as a triggering structure selectively expressed on rat natural killer (NK) cells and adherent lymphokine-activated killer (A-LAK) cells. In vivo treatment with anti-NKR-P1 monoclonal antibody (mAb 3.2.3) was shown to induce complete inhibition of NK cytotoxicity and elimination of LAK cell precursors in Lewis and Fisher rat strains. We investigated the effects of mAb 3.2.3 in a colon tumor model in BDIX rats. Inoculation of animals with mAb 3.2.3 even at very high doses induced a strong but incomplete inhibition of NK cytotoxicity in nylon-wool-non-adherent spleen and peripheral blood cells. Generation of adherent A-LAK cells from their spleen precursors was also strongly but not fully inhibited. We also investigated the effect of treatment with mAb 3.2.3 on the tumorigenicity of the NK-sensitive REGb cell line. When subcutaneously inoculated in syngeneic animals, REGb cells induce tumors that first grow for 2 weeks, then spontaneously regress and disappear. In contrast with previous results using anti-asialoGM1, no significant difference in tumor growth was observed between rats treated with mAb 3.2.3 and control animals, even with a long-term treatment. In vitro, mAb 3.2.3 exhibited the same incomplete efficiency. Nylon-wool-non-adherent spleen cells treated with mAb 3.2.3 plus complement were completely free of 3.2.3bright cells, but retained a substantial NK activity and generated LAK cells after culture with IL-2. After an overnight incubation in standard medium of 3.2.3-depleted spleen cells, 3.2.3bright cells were partially recovered and the NK cytotoxic activity, as well as the generation of LAK cells, was significantly enhanced. These results suggest that a strong expression of NKR-P1 is not required for BDIX mononuclear cells to exhibit NK function and generate LAK cells under IL-2 activation.
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  • 67
    ISSN: 1432-1238
    Keywords: Key words Acute pancreatitis ; Therapy ; Dextran ; Hypertonic ; Colloid ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective: Ultrahigh-molecular dextran (500000 Da) has been shown to prevent pancreatic necrosis when given 30 min after induction of pancreatitis. This study should clarify the following: (a) are dextrans still effective after prolongation of the therapy-free interval? (b) what is the impact of the molecular weight of the dextrans? and (c) is their effect influenced by the dextran concentration or by the addition of hypertonic saline? Animals and interventions: Acute pancreatitis was induced in 70 male dextran-tolerant Wistar rats using intraductal bile-salt infusion and intravenous hyperstimulation. After 3 h, animals were assigned to one of seven groups (n=10 per group) receiving either Ringer solution or different dextrans (10%) including 70000 Da (DEX-70), 160000 Da (DEX-160), 300000 Da (DEX-300) or 500000 Da (DEX-500). Additional groups included DEX-70 (6%) and DEX-70 (10%) in combination with hypertonic NaCl (7.5%) (HHS-70). Ringer solution was given at 24 ml/kg and all dextrans at 8 ml/kg. Measurements and results: Trypsinogen activation peptides (TAP) were quantified in ascites and acinar necrosis after death or sacrifice at 9 h. As an index of less pathological trypsinogen activation, the mean TAP levels in ascites were significantly lower in DEX-70 and DEX-160 compared to Ringer controls (p〈0.05, t-test). Furthermore, the amount of acinar necrosis was significantly lower in all dextran groups except the HHS-70 in comparison with Ringer controls (p〈0.01, t-test). Finally, mortality was significantly reduced from 60% in Ringer controls to 10 and 0%, respectively, in the groups treated with DEX-70 and DEX-160 (p〈0.03, Fisher‘s Exact test). There was a similar trend in all other groups except the HHS-70. Conclusions: Despite a therapy-free interval of 3 h, dextrans reduce trypsinogen activation, prevent acinar necrosis, and improve survival in necrotizing rodent pancreatitis. The molecular weight and concentration of dextran are of secondary importance for these beneficial effects.
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  • 68
    ISSN: 1432-1238
    Keywords: Acute pancreatitis ; Therapy ; Dextran ; Hypertonic ; Colloid ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Objective Ultrahigh-molecular dextran (500 000 DA) has been shown to prevent pancreatic necrosis when given 30 min after induction of pancreatitis. This study should clarify the following: (a) are dextrans still effective after prolongation of the therapy-free interval? (b) what is the impact of the molecular weight of the dextrans? and (c) is their effect influenced by the dextran concentration or by the addition of hypertonic saline? Animals and interventions Acute pancreatitis was induced in 70 male dextran-tolerant Wistar rats using intraductal bile-salt infusion and intravenous hyperstimulation. After 3 h, animals were assigned to one of seven groups (n=10 per group) receiving either Ringer solution or different dextrans (10%) including 70 000 Da (DEX-70), 160 000 Da (DEX-160), 300 000 Da (DEX-300) or 500 000 Da (DEX-500). Additional groups included DEX-70 (6%) and DEX-70 (10%) in combination with hypertonic NaCl (7.5%) (HHS-70). Ringer solution was given at 24 ml/kg and all dextrans at 8 ml/kg. Measurements and results Trypsinogen activation peptides (TAP) were quantified in ascites and acinar necrosis after death or sacrifice at 9 h. As an index of less pathological trypsinogen activation, the mean TAP levels in ascites were significatly lower in DEX-70 and DEX-160 compared to Ringer controls (p〈0.05,t-test). Furthermore, the amount of acinar necrosis was significantly lower in all dextran groups except the HHS-70 in comparison with Ringer controls (p〈0.01,t-test). Finally, mortality was significantly reduced from 60% in Ringer controls to 10 and 0%, respectively, in the groups treated with DEX-70 and DEX-160 (p〈0.03, Fisher's Exact test). There was a similar trend in all other groups except the HHS-70. Conclusions Despite a therapy-free interval of 3 h, dextrans reduce trypsinogen activation, prevent acinar necrosis, and improve survival in necrotizing rodent pancreatitis. The molecular weight and concentration of dextran are of secondary importance for these beneficial effects.
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  • 69
    ISSN: 1432-1084
    Keywords: Myelin ; Brain stem ; Pons ; Magnetic resonance imaging ; Electrolyte disorder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Central pontine myelinolysis (CPM) is a neurologic disorder once thought to be uniformly fatal. With the introduction of CT and MRI there was an increasing number of reports on nonfatal cases of CPM. Nearly all reports on nonfatal cases describe severe clinical syndromes with tetraparesis, bulbar palsy, and coma. We reviewed nine patients with CPM and compared the size of the pontine lesion on MRI and CT with the severity of clinical presentation. Clinical presentation of CPM was highly variable: The symptoms ranged from severe neurologic disorders to mild neurologic disturbances only. Two of nine patients died from CPM. The size of the pontine lesion did not correlate with the severity of the neurologic illness or the final outcome. Mild forms of CPM might be difficult to diagnose clinically. This applies even more for patients with underlying diseases such as Wernicke's encephalopathy, which in itself might cause a clinical picture similar to that of CPM. Central Pontine Myelinolysis is a major differential diagnosis in acute neurologic deterioration indicating pontine damage. Magnetic resonance imaging is the decisive diagnostic tool for CPM.
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  • 70
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    European radiology 6 (1996), S. 704-706 
    ISSN: 1432-1084
    Keywords: Ovary, torsion ; Magnetic resonance imaging ; Adnexal torsion ; children
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Torsion of the adnexa can be the cause of abdominal pain. An immediate diagnosis is very important because early surgical intervention is the only way to save the ovary from necrosis. Torsion of a normal adnexa is rare, but occurs more frequently than is generally appreciated. If US findings are equivocal, MRI can provide additional information. In our case the MRI findings leading to the diagnosis of ovarian torsion were: (a) A medial ovarian mass existed with dislocation of the uterus to the affected side with hyperintense, cystic lesions on T2-weighted images at the periphery of the ovary. (b) Beaked protrusion of the mass continuing in a band-like structure connecting it with the uterus obviously represented the Fallopian tube. (c) Low and inhomogeneous signal intensity of the stroma on T1- and T2-weighted images and lack of gadolinium uptake were indicative of infarction.
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  • 71
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    Experimental brain research 108 (1996), S. 119-128 
    ISSN: 1432-1106
    Keywords: Intracortical microstimulation ; Electromyographic activity ; Potentiation ; Ketamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The objectives of this study were to determine whether changes in electromyographic (EMG) responses observed during prolonged intracortical microstimulation (ICMS) were due to local plasticity of the motor system or to global changes in the preparation. Local effects would be expressed as changes only along the activated motor pathway, whereas global effects would be expressed as changes also appearing at distant cortical efferent microzones. The results of ICMS in the ketamine-anesthetized rat showed that the size of consecutive EMG responses increased gradually to a relatively stable magnitude over a period of four to six trains of stimuli. This early enhancement of EMG responses was maintained while continuously providing trains of stimuli at 1 Hz. However, it disappeared after a 5-min period of muscle inactivity. This response enhancement in the presence of ketamine (an NMDA, N-methyl-d-aspartate, receptor blocker) suggests that a neuronal mechanism involving non-NMDA-mediated homosynaptic short-term potentiation (STP) was responsible for the early enhancement of EMG responses. To compare ICMS effects at several time intervals it was necessary to average several evoked EMG responses because there was normal biological variability between single EMG responses. To determine the optimal number of EMG responses that would provide a reliable average EMG response, averages of 5, 10, 15, 20, and 25 EMG responses evoked from a single cortical site were collected at 5-min intervals. The results revealed that averages of 10 responses would provide reliable average EMG responses for all subsequent analyses. There were wide fluctuations in the average EMG responses when periodic injections of ketamine were used to maintain a low reflexive state in the animal. Switching to continuous infusion of ketamine abolished these fluctuations but there remained a small drift in the magnitudes of consecutive EMG responses. To test whether this drift reflected local plastic changes in the motor system induced by stimulation or some global changes, EMG responses evoked from another ICMS site were used as control. The rationale was that global effects would affect all motor output sites equally. The sizes of control EMG responses followed a similar time course to those evoked from the test site. Furthermore, standardizing the test EMG responses with respect to the control responses eliminated the drift in response magnitudes. Thus the drift was due to slow global changes in neuronal excitability possibly produced by the anesthesia. In conclusion, late changes occurring after hours of ICMS were not due to plasticity of the motor system but rather to global changes in the preparation, possibly resulting from the inability to set an ideal anesthetic infusion rate that could maintain a constant level of neuronal excitability over long periods of time. However, there was early enhancement of the EMG responses evoked by ICMS due to neuronal plasticity possibly mediated by a non-NMDA mechanism of homosynaptic STP such as post-tetanic potentiation (PTP). This early enhancement would favor recruitment of the previously activated motor pathway and lead to greater consistency in movement execution.
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  • 72
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    Experimental brain research 108 (1996), S. 382-388 
    ISSN: 1432-1106
    Keywords: Nitric oxide ; Iontophoresis ; 3 morpholino sydnonimin hydrochloride ; S-nitroso glutathione ; Periaqueductal grey matter ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Experiments were carried out in urethane-anaesthetized rats to examine the effect of nitric oxide (NO) on neuronal activity within the dorsolateral sector of the midbrain periaqueductal grey matter (PAG), an area which is rich in NO synthesizing neurones. NADPH dependent diaphorase histochemistry revealed small NO synthase containing perikarya, 15.4±3.1 μm (mean±SEM) in diameter, in a longitudinal column in the dorsolateral sector of the PAG. The labelled cell bodies were surrounded by a dense meshwork of stained fibres and processes in which unlabelled neurones were embedded. In order to establish whether NO was generated when NO donors were ejected iontophoretically from micropipettes, a chemiluminescence method was used to estimate the output of NO in vitro after iontophoresis of two chemically different classes of NO donor: the sydnonimine 3 morpholino sydnonimin hydrochloride (SIN 1) and the nitrosothiol S nitroso glutathione (SNOG). Iontophoresis of both NO donors into 200 μl aliquots of 165 mM NaCl using ejection currents between 6000 and 18000 nA·min produced a current related increase in the concentration of NO. Iontophoresis of SIN 1 in vivo produced a reproducible, current related inhibition of firing in 40 of 59 neurones in the dorsolateral PAG. In 8 of 10 neurones the effect of SIN 1 was significantly reduced after iontophoresis of methylene blue (10–30 nA for 2.7–5 min). The inhibition took up to 7 min to develop and lasted for up to 13 min. Inhibitory responses to GABA were not affected by methylene blue. Iontophoresis of SNOG also inhibited ongoing activity of 18 of 24 neurones tested in the PAG. The experiments demonstrate firstly that NO donors can be used in vivo to deliver NO in the vicinity of neurones by iontophoresis from micropipettes. Secondly, NO appears to inhibit neuronal activity within the PAG.
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  • 73
    ISSN: 1432-1106
    Keywords: Basal forebrain ; Sleep ; Glutamate antagonist ; Cholinergic system ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of this paper was to study the effects of microinjections of carbachol, a mixed cholinergic agonist, into the nucleus basalis of Meynert (NBM) of rats on the wake-sleep cycle. Carbachol (2.74 nmol) was able to increase wakefulness (W) and decrease desynchronized sleep (DS). To verify the hypothesis that the effects of carbachol are at least partially mediated by the glutamatergic system, the NMDA antagonist 2-amino-5-phosphonopentanoic acid and the non-NMDA antagonist d-γ-glutamylaminomethanesulfonic acid were injected into the NBM before carbachol. Pretreatment with these glutamate receptor antagonists counteracted the effect of carbachol on DS. The effect of carbachol on W was not modified by the pretreatment with the glutamate receptor antagonists. This is the first study showing that carbachol injected into the NBM increases W and decreases spontaneous DS in the rat. Moreover, our results tend to indicate that the decrease in DS following the injection of carbachol into the NBM is related to the release of endogenous glutamate.
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  • 74
    ISSN: 1432-1106
    Keywords: Respiration ; Cross-correlation ; Upper cervical inspiratory neurons ; Phrenic and intercostal motoneurons ; Decerebration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the synaptic connections from upper cervical inspiratory neurons to phrenic and intercostal motoneurons in decerebrate rats using cross-correlation. Upper cervical inspiratory neurons (n=79) were recorded from the C1 and C2 segments of the spinal cord in 38 vagotomized, paralyzed, ventilated, and decerebrate rats. The neurons were identified by their inspiratory firing pattern and antidromic activation from the ipsilateral spinal cord at C7. Whole-nerve recordings were made using bipolar electrodes from the central cut ends of the C5 phrenic nerve and the external and internal intercostal nerves at various thoracic levels. Cross-correlation histograms were computed between these recordings to detect short time-scale synchronizations indicative of synaptic connections. The 55 cross-correlation histograms computed between the upper cervical inspiratory neurons and the ipsilateral phrenic nerve showed seven (13%) narrow peaks (mean half-amplitude width±SD, 1.09±0.15 ms) at short latencies (mean latency±SD, 1.29±0.26 ms) suggestive of monosynaptic excitation, and four (7%) broader peaks (mean half-amplitude width±SD, 1.50±0.17 ms) at short latencies (mean latency±SD, 1.40±0.24 ms) suggestive of oligosynaptic excitation. Another 14 (25%) cross-correlation histograms displayed a central broad peak (mean half-amplitude width±SD, 1.59±0.23 ms) suggestive of common activation. The eight cross-correlation histograms computed between the upper cervical inspiratory neurons and the contralateral phrenic nerve were featureless. The 77 cross-correlation histograms computed between the upper cervical inspiratory neurons and the internal and external intercostal nerves at various thoracic levels (T2–8) showed no peaks suggestive of synaptic connections. We conclude that some upper cervical inspiratory neurons make monosynaptic and paucisynaptic connections to phrenic motoneurons but not to intercostal motoneurons.
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  • 75
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    Experimental brain research 112 (1996), S. 392-402 
    ISSN: 1432-1106
    Keywords: Intracellular free calcium ; Traumatic injury ; Spinal cord ; Intercellular communication ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Intracellular calcium ions are, in addition to free radicals, an important mediator of tissue destruction following traumatic injury to the spinal cord. In vivo measurements of calcium in the interstitial space and in the tissue suggest the occurrence of a posttraumatic shift of calcium from the extracellular to the intracellular compartment at the injury site. No information is, however, available on the posttraumatic changes of calcium in the intracellular compartment, where the ion exerts its crucial messenger function. We developed an in vitro model of local traumatic spinal injury, using a spinal cord slice preparation, allowing us to investigate injury-related changes of intracellular free calcium. The injury consisted of the impact of a small needle, and intracellular free calcium was measured with fura-2. Application of the injury at different places within the gray matter caused a transient and reproducible increase in the fura-2 fluorescence ratio. This injury-induced ratio increase was largely, but not completely, suppressed under zero extracellular calcium conditions. It was also largely depressed in the presence of high extracellular potassium and in the absence of extracellular sodium. It was modestly depressed by the calcium channel blocker nifedipin, by the calcium release channel blocker dantrolene, and by the gap junction blockers halothane and octanol. The calcium channel blocker flunarizine, the N-methyl d-aspartate (NMDA)-receptor-channel blocker MK-801 and the endoplasmic reticulum calcium-ATPase blocker thapsigargin had no effect. The experiments suggest that injury is associated with an increase in intracellular free calcium that is mediated by calcium influx, in part via L-type calcium channels. They furthermore give evidence that sodium influx and gap junctions are involved in these injury-associated changes of intracellular free calcium.
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  • 76
    ISSN: 1432-1106
    Keywords: Immediate plasticity ; Denervation ; Neuronal responses ; Somatosensory cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recordings were made from neurons in primary somatosensory (SmI) forepaw cortex of rats to study the time course of changes in responses beginning immediately following denervation (ligation) of a single digit. Before denervation, neuronal receptive fields (RFs) defined by tactile stimulation varied in size from small regions of one digit to larger areas covering several digits and palmar pads. With electrical stimulation, most neurons responded best to one (on-focus) digit and less to other (off-focus) digits; on-focus stimulation yielded more spikes per stimulus and shorter spike latencies (L min) than did off-focus stimulation. After ligation of the on-focus digit, most neurons showed increased responsiveness to stimulating one or several off-focus digits and palmar regions of the forepaw: (1) tactile stimulation showed that the RFs of all but one neuron expanded to include previously “ineffective” skin regions, such as digits or palmar pads adjoining the original RF; (2) electrical stimulation usually evoked stronger responses from neighboring off-focus digits and sometimes elicited novel responses from previously ineffective digits — seven of ten neurons showed increases in spikes per stimulus, which tended to approach stable values within 60–90 min after denervation; three of ten neurons showed decreases in L min with time, but most revealed no significant changes. These results suggest that dynamic response properties, as well as RFs, of SmI cortical neurons can be modified rapidly by blocking afferent input from dominant on-focus skin regions. RFs expand and novel responses appear, with concomitant increases in response magnitude and, in some cases, decreases in response latency over time. These findings seem to reflect a rapid increase in synaptic efficacy of weak or previously ineffective inputs from cutaneous afferent nerve fibers.
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  • 77
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    Experimental brain research 111 (1996), S. 215-232 
    ISSN: 1432-1106
    Keywords: Cerebral cortex ; Orbital ; Anatomy ; Connections ; Corticocortical ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The cortical and thalamic afferent connections of rat orbital cortex were investigated using fluorescent retrograde axonal tracers. Each of the four orbital areas has a distinct pattern of connections. Corticocortical connections involving the ventral and ventrolateral orbital areas are more extensive than those of the medial and lateral orbital areas. The medial orbital area has cortical connections with the cingulate, medial agranular (Fr2) and posterior parietal (PPC) cortices. The ventral orbital area has connections with the cingulate area, area Fr2, secondary somatic sensory area Par2, PPC, and visual areas Oc2M and Oc2L. The ventrolateral orbital area (VLO) receives cortical input from insular cortex, area Fr2, somatic sensory areas Par1 and Par2, PPC and Oc2L. The lateral orbital area has cortical connections limited to the agranular and granular insular areas, and Par2. Thalamic afferents to the four orbital fields are also topographically organized, and are focused in the submedial and mediodorsal nuclei. The ventrolateral orbital area receives input from the entirety of the submedial nucleus, whereas the other orbital areas receive input from its periphery only. Each orbital area is connected with a particular segment of the mediodorsal nucleus. The medial orbital area receives its principal thalamic afferents from the parataenial nucleus, the dorsocentral portion of the mediodorsal nucleus, and the ventromedial portion of the submedial nucleus. The ventral orbital area receives input from the lateral segment of the mediodorsal nucleus, the rostromedial portion of the submedial nucleus and the central lateral nucleus. Thalamic afferents to the ventrolateral orbital area arise from the entirety of the submedial nucleus and from the lateral segment of the mediodorsal nucleus. The lateral orbital area receives thalamic afferents from the central segment of the mediodorsal nucleus, the ventral portion of the submedial nucleus and the ventromedial nucleus. The paraventricular, ventromedial, rhomboid and reuniens nuclei also provide additional input to the four orbital areas. The connections of the ventrolateral orbital area are interpreted in the context of its role in directed attention and allocentric spatial localization. The present findings provide anatomical support for the view that areas Fr2, PPC and VLO comprise a cortical network mediating such functions.
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  • 78
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    Experimental brain research 111 (1996), S. 385-392 
    ISSN: 1432-1106
    Keywords: Estradiol ; Progesterone ; Network ; Gating ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study demonstrates that gating of responses of the rostral dorsal accessory olive (rDAO) to somatosensory stimulation varies across the estrous hormone cycle of the rat. The rDAO has been suggested as an “error” or event signal generator for the cerebellar cortex. Selective sensory gating of input to this structure may underlie this error signalling function. In the present study, as many as 23 single neurons were recorded simultaneously from either the forepaw or the snout areas of the rDAO. Responses of these neurons to electrical stimulation of peripheral afferents were determined during active movement or non-movement conditions. These results were then compared across the estrous cycle or after administration of the estrous hormones 17 β-estradiol (E2) and/or progesterone (P) to rats on diestrus or following E2 priming. Elevations in circulating estrous hormones produced greater excitatory responses of rDAO neurons to stimulation during non-movement, and, conversely, enhanced inhibition of rDAO activity during active movement of the stimulated peripheral area compared with control diestrous conditions, suggesting that selective gating processes to the rDAO are enhanced by estrous hormones. The results of this study suggest that the night of behavioral estrus is associated with enhanced selective sensory gating processes associated with improved detection and processing of error signals.
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  • 79
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    Experimental brain research 111 (1996), S. 424-428 
    ISSN: 1432-1106
    Keywords: Neuropeptides ; RP 67580 ; Neurogenic inflammation ; Migraine pain ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The role of the neuropeptide substance P (SP) in the control of dural arterial blood flow was examined in barbiturate-anaesthetised rats. The parietal skull was trephinised and the blood flow in branches of the medial meningeal artery was monitored with a laser Doppler flowmeter. Electrical stimulation of the dura mater encephali at a parasagittal site with pulses of 0.5 ms (10–20 V, 5–10 Hz, 30 s) caused a transient increase in dural blood flow which was reproducible in size with repetitive stimulation. Neither the basal flow nor the stimulus-evoked flow was significantly changed by topical administration of SP, the SP analog septide, or the NK1 antagonist RP 67580. It is concluded that SP released from dural nerve fibres upon local stimulation does not play an important role in the regulation of dural arterial flow.
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  • 80
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    Experimental brain research 112 (1996), S. 24-34 
    ISSN: 1432-1106
    Keywords: Odor sensitivity and selectivity ; Discrimination unit ; Olfactory bulb ; Unit activity ; Olfactometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Extracellular single-unit responses to odorants with various properties were recorded from mitral/tufted cells over large areas of the olfactory bulb of anesthetized rats. Each cell was exposed to one stimulus set consisting of five different odorants each at five concentrations. The resulting concentration-response profiles were compared. All mitral/tufted cells examined responded to two or more odorants, and the largest proportion of the cells were sensitive to all five odorants. Cells unresponsive to all five odorants regardless of concentration were not observed. Mitral/tufted cells sensitive to all three of the odorants that are known to evoke maximal electro-olfactograms in different regions of the olfactory epithelium were distributed widely throughout the olfactory bulb. There were no significant differences in latencies of odor responses either across recording sites or across odorants. A comparison of the concentration-response profiles suggested that all of the mitral/tufted cells were equally capable of responding to any odorant with their own distinctive pattern, but that the cells tended to show an identical pattern rather than variable pattern of response to different odorants. Five mitral/tufted cells isolated within 800 μm of one electrode track showed different concentration-response profiles. Of 18 simultaneously recorded spike pairs with different amplitudes and discharge patterns recorded incidentally through one electrode at different sites, 10 had different and 8 had identical response patterns to odorants. These results suggest that: (1) mitral/tufted cells are sensitive to a broad spectrum of odorants, but respond with their own patterns to odorants; (2) odor discrimination is not uniform in neighboring cells, and a discrimination unit is comprised of a single cell.
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  • 81
    ISSN: 1432-1106
    Keywords: Neurodegeneration ; Retrograde neuronal cell death ; Perivascular cells ; Fluorogold ; Phagocytosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Thalamic neuronal degeneration after neocortical lesions involve both anterograde and retrograde components. This study deals with the thalamic microglial response after neocortical aspiration lesions, using fluorogold fluorescent prelabeling, to identify retrogradely degenerating thalamocortical neurons, combined with histochemical or immunohistochemical staining of microglial cells. Adult male Wistar rats were injected with the retrograde fluorescent tracer fluorogold, in the right sensorimotor cortex (forepaw area) in order to retrogradely label thalamic neurons projecting to this area. After 1 week, the fluorogold injection site was removed by aspiration, axotomizing at the same time the thalamic projection neurons now retrogradely labeled with fluorogold. After 3, 7, 14, and 28 days the animals were killed and processed for nucleoside diphosphatase histochemistry or complement type 3 receptor immunohistochemistry and class I and II major histocompatibility complex immunohistochemistry using OX42, OX18, and OX6 antibodies. The histological analysis showed a prominent and progressive nucleoside diphosphatase-,OX42-, and OX6-positive microglial cell response in the ventrolateral, posterior, and ventrobasal thalamic nuclei with ongoing retrograde and anterograde neuronal degeneration. Initially the reactive microglia had a bushy morphology and were succeeded by ameboid microglia and microglial cluster cells as the reaction progressed. However, in the reticular thalamic nucleus, which suffered exclusively anterograde neuronal degeneration, a different picture was seen with only bushy microglia. The neurons undergoing retrograde degeneration in the ventrolateral, posterior, and ventrobasal thalamic nuclei were retrogradely labeled by the fluorogold tracer. Individual nucleoside diphosphatase-, OX42-, or OX6-positive microglial cells extended long cytoplasmic processes surrounding fluorogold-labeled neurons and had in some cases apparently phagocytized these. Several microglial cells were thus double-labeled with nucleoside diphosphatase or OX42 and fluorogold. In addition, small nucleoside diphosphatase-positive, fluorogold-labeled perivascular cells were observed in the neocortex near the fluorogold-injected and ablated neocortical areas and in the ipsilateral thalamus. This study demonstrates: (1) that the microglial response to thalamic degeneration after neocortical lesion is graded with a limited reaction to the well-known massive anterograde axonal degeneration and a more extended reaction to the axotomy-induced retrograde cell death; and (2) that also perivascular cells and possibly macrophages may contribute to this reaction, as seen by uptake of fluorogold from axotomized neurons in the degenerating thalamic nuclei.
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  • 82
    ISSN: 1432-1084
    Keywords: Trauma ; Epidermal cyst ; Computed tomography ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An unusual case of rapid-growing posttraumatic gluteal epidermal cyst with ischiorectal and presacral extension is reported. Pertinent clinical history and magnetic resonance imaging allowed accurate preoperative diagnosis. Cautious complate excision was important to prevent recurrence. To our knowledge, posttraumatic gluteal epidermal cyst with this unusual clinical presentation has not been described previously.
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    European radiology 6 (1996), S. 72-75 
    ISSN: 1432-1084
    Keywords: Magnetic resonance imaging ; Soft tissue neoplasms ; Pilomatrixoma ; Gadolinium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two patients (a 16-month-old boy and a 53-year-old man) were referred for MR imaging of a small, subcutaneous nodule at the forearm. Plain films were available in one patient and showed a non-specific well-circumscribed lesion. Upon ultrasonography (1 patient), a nodular, well-circumscribed, hyperechoic lesion was seen. In both cases spin-echo (SE) T1-weighted images (T1W1) showed homogeneous, intermediate signal intensity (SI). On gadolinium-enhanced T1W1 (1 patient), no enhancement was observed. Both lesions showed predominant low-to-intermediate SI on T2WI. At histological examination characteristic findings of pilomatricoma were observed.
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  • 84
    ISSN: 1432-1084
    Keywords: Magnetic resonance imaging ; Osteoid osteoma ; Osteoblastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We assessed the value of contrast-enhanced fat-suppressed MRI on nine patients with osteoid osteomas and osteoblastomas. The results were compared with plain films, bone scintigraphy, computed tomography (CT) and pathological specimens. On contrast-enhanced fat-suppressed T1-weighted images the non-calcified nidi showed homogeneous enhancement, whereas the calcified lesions showed a ring enhancement sign that was proportional in intensity to the extent of the remaining part of the vascularized nidus. The degree of bone marrow and soft tissue enhancement was relative to the size and reactive inflammatory changes of the lesions. Although CT was diagnostic in most of the cases and more specific to show the calcified lesions, MRI was confirmatory in one case. We concluded that, although CT is the primary diagnostic investigation in osteoid osteomas, MRI can be reserved for equivocal cases.
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  • 85
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    European radiology 6 (1996), S. 297-311 
    ISSN: 1432-1084
    Keywords: Magnetic resonance imaging ; Ultrafast magnetic resonance ; Echo-planar imaging ; Heart imaging ; Perfusion study ; Magnetic resonance angiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Conventional magnetic resonance imaging (MRI) has been shown to provide excellent morphological images of the body organs, particularly structures undergoing little physiologic motion. Nevertheless, the clinical usefulness of MRI has been hampered by long acquisition times, high cost of scanning because of limited patient throughput, and image artifacts due to patient motion. With recent technical developments, several ultrafast scanning techniques capable of acquiring images in a breath-hold now find their introduction into clinical use. The system improvements are potentially useful for a vast range of applications hitherto not accessible to MR imaging. Among these are functional brain imaging, realtime imaging of cardiac motion and perfusion, fast abdominal imaging, improved MR angiography, and potentially real-time monitoring of interventional procedures. Whereas some ultrafast techniques can be performed on conventional scanners, echo-planar imaging, the fastest currently available data acquisition strategy, requires specially designed hardware. This article provides on overview of the technical advances in the ultrafast MRI and discusses potential applications and the possible future impact on body scanning.
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  • 86
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    European radiology 6 (1996), S. 380-386 
    ISSN: 1432-1084
    Keywords: Magnetic resonance imaging ; Tuberculosis ; Meningitis ; Central nervous system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In this study 15 patients with clinical findings and positive cerebrospinal fluid analyses for tuberculous meningitis were evaluated with magnetic resonance imaging (MRI). Tuberculous meningitis was diagnosed in 11 cases when thick meningeal enhancement was present after intravenous injection of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) in T1-weighted images. Intra-axial tuberculomas were present in 8 patients, 2 of whom had intra-axial tuberculomas without MRI evidence of meningitis. Tuberculomas showed ring or nodular enhancement in postcontrast T1-weighted images, but the most significant MR feature of intraparenchymal tuberculomas was the hypointense appearance of the lesions on T2-weighted images.
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  • 87
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    European radiology 6 (1996), S. 451-453 
    ISSN: 1432-1084
    Keywords: Varices ; Portal hypertension ; Computed tomography ; Mediastinal mass ; Color Doppler sonogram ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We report a case of variceal changes of the azygos vein, hemiazygos vein, and paraesophageal collaterals presenting as bilateral posterior mediastinal masses in a patient with long-standing portal hypertension due to hepatosplenic schistosomiasis. The case is unusual because the varices were considerably larger than those usually encountered in portal hypertension. Dynamic CT allowed the diagnosis in demonstrating the vascular nature of these masses, which enhanced to the same degree as the other vessels. Noninvasive techniques, such as color Doppler sonography and MRI, may also be useful due to their multiplanar capabilities.
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  • 88
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    European radiology 6 (1996), S. 518-522 
    ISSN: 1432-1084
    Keywords: Magnetic resonance imaging ; Echo-planar imaging ; Brain ; Neoplasms ; Perfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A total of 17 patients with histologically proven diagnoses of low-grade astrocytoma (n = 4), high-grade astrocytoma (n = 8), lymphoma (n = 3), and meningioma (n = 2) were examined by using EPISTAR MR imaging. Meningiomas had the highest EPISTAR tumor/white matter contrast and low-grade astrocytomas and lymphomas the lowest. High-grade astrocytomas demonstrated elevated EPISTAR signal with marked regional heterogeneity. There was agreement between tumor vascularity by SPECT and EPISTAR in the five cases where both were done. Our results show that tumor vascularity can be assessed qualitatively by using EPISTAR without the need for contrast medium injection.
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  • 89
    ISSN: 1432-1106
    Keywords: Preoptic-anterior hypothalamic area ; cAMP ; Hypoxia ; Low ambient temperature ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The accumulation of adenosine 3′:5′-cyclic monophosphate (cAMP) was measured in the preopticanterior hypothalamic area, the cerebral cortex, and the hippocampus of rats exposed to different ambient temperatures: (1) 23±0.5°C, for 53 h±20 min (control);(2)-10°1 °C, for 53 h±20 min (exposure to low ambient temperature);(3) -10°C for 48 h and 23°C for the following 5 h±20 min (recovery). The capacity to accumulate cAMP was tested by subjecting animals to acute hypoxia, a stimulus which is known to induce a large increase in brain cAMP concentration. In the control condition, hypoxic stimulation increases cAMP concentration in all the brain regions studied. In contrast, during the exposure to low ambient temperature, whilst both the cerebral cortex and the hippocampus show the same levels of accumulation found in the control condition, cAMP accumulation is reduced in the preoptic-anterior hypothalamic area. However, during the first few hours of the recovery period, the preoptic-anterior hypothalamic area is able to reattain the capacity for cAMP accumulation observed in the control condition.
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  • 90
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    Experimental brain research 109 (1996), S. 185-196 
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Nociception ; Pain ; Tecto-reticular ; Predorsal bundle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Accumulating evidence suggests that the rodent superior colliculus (SC) plays as important a role in avoidance and defensive behaviours as it does in orientation and approach. These two complementary behaviours are associated with two anatomically segregated tectofugal output pathways, such that orientation and approach are mediated by the crossed descending projection, whereas avoidance and defence are subserved via the uncrossed projection. Because nociceptive neurones in the SC have been presumed to participate in withdrawal or defensive behaviours, it has been proposed that they have direct access only to the uncrossed efferent pathway. However, in certain behavioural situations, the most adaptive response to injury, or to a painful object in prolonged contact with the skin, is to orient towards the source of discomfort so that the skin can be licked and/or the offending object removed. Presumably then, nociceptive as well as low-threshold neurones would have access to the crossed descending pathway in order to initiate such behaviours. Determining whether or not this is the case was the objective of the present study. Both nociceptive-specific (82%) and wide-dynamic-range (18%) SC neurones were identified using long-duration (up to 6 s), frankly noxious mechanical and thermal stimuli in urethane-anaesthetised Long-Evans hooded rats. The majority (85.7%) of the nociceptive neurones encountered were located within the intermediate layers, which corresponds with the location of the cells-of-origin of the crossed descending projection. Nearly half (44.9%) were activated antidromically from electrical stimulation of the crossed descending pathway at a site in the brainstem below its decussation. The mean conduction velocity of these nociceptive output neurones was 9.02 m/s, which corresponds well to previous estimates of conduction velocity in the crossed tecto-reticulo-spinal tract. These data demonstrate that a significant proportion of nociceptive neurones in the rat SC have axons that project to the contralateral brainstem via the crossed descending projection. Nociceptive neurones could, therefore, effect orientation responses to noxious stimuli via similar output pathways that low-threshold neurones utilize to initiate orientation to innocuous stimuli.
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  • 91
    ISSN: 1432-1106
    Keywords: Field potential ; Timing ; Lidocaine ; Somatosensory cerebral cortex ; Crus IIa ; Mossy fiber ; Cerebellum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The spatial coincidence of somatosensory cerebral cortex (SI) and trigeminal projections to the cerebellar hemisphere has been previously demonstrated. In this paper we describe the temporal relationship between tactilely-evoked responses in SI and in the granule cell layer of the cerebellar hemisphere, in anesthetized rats. We simultaneously recorded field potentials in areas of common receptive fields of SI and of the cerebellar folium crus IIa after peripheral tactile stimulation of the corresponding facial area. Response of the cerebellar granule cell layer to a brief tactile stimulation consisted of two components at different latencies. We found a strong correlation between the latency of the SI response and that of the second (long-latency) cerebellar component following facial stimulation. No such relationship was found between the latency of the SI response and that of the first (short-latency) cerebellar component, originating from a direct trigeminocerebellar pathway. In addition, lidocaine pressure injection in SI, cortical ablation, and decerebration all significantly affected the second cerebellar peak but not the first. Further, when tactile stimuli were presented 75 ms apart, the response in SI failed, as did the second cerebellar peak, while the shortlatency cerebellar response still occurred. We found a wide spatial distribution of the upper lip response beyond the upper lip area in crus IIa for the long-latency component of the cerebellar response. Our results demonstrate that SI is the primary contributor to the cerebellar long-latency response to peripheral tactile stimulation. These results are discussed in the context of Purkinje cell responses to tactile input.
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  • 92
    ISSN: 1432-1106
    Keywords: Glutamate ; Glutamine synthetase ; Hippocampus ; Kainate ; Receptor ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Immunocytochemistry was used to study the distribution of the kainate receptors GluR1, GluR2/3 and GluR4 and of the N-methyl-d-aspartate (NMDA) receptor NMDAR1 as well as the astrocyte markers glutamine synthetase (GS) and glial fibrillary acidic protein (GFAP) in the hippocampus of normal and kainate-lesioned rats. Hippocampal pyramidal neurons and dentate granule neurons were labelled heavily for GluR1 and GluR2/3, but only lightly for GluR4. Dense GluR4 immunopositivity was, however, observed in oligodendrocyte-like glial cells. Hippocampal pyramidal neurons and dentate granule neurons were moderately labelled for NMDAR1. Intravenous kainate injections resulted in a decrease in GluR1 and GluR2/3 immunoreactivity on the apical dendrites of pyramidal neurons as early as 7 h postinjection. At 18 h, there was a marked reduction in GluR1 and GluR2/3 receptors in the terminal tuft of dendrites of most hippocampal pyramidal neurons in the affected area, although some cells showed labelling in other portions of the apical dendrites and in basal dendrites. Immunostaining for GluR4 and NMDAR1 was also reduced at this time. At postinjection day 3, only the cell bodies and the basal dendrites of a few scattered pyramidal cells were labelled. Taken together, these results indicate a progressive loss of glutamate receptors, which affects the apical dendritic tree before the basal dendritic tree. The decrease in receptor immunoreactivity could be due to a downregulation of the receptors, since it occurred as early as 7 h postlesion, before cell death was evident in Nissl-stained sections. At long intervals after kainate injection, all pyramidal cells at the centre of the lesion showed a lack of glutamate receptor staining, and no partially labelled pyramidal cells were observed. The periphery of the lesion, however, contained many partially labelled pyramidal neurons among the unlabelled cells and had features of early lesions. The present study also showed an early decrease in GS immunoreactivity in the affected CA fields of the hippocampus (18 h to 3 days postinjection), followed by a medium-term increase (5–68 days) and a late decrease in GS immunoreactivity (81 days). The decrease in GS immunoreactivity at 81 days is not due to an absence of astrocytes, since GFAP staining showed many densely labelled astrocytes in the affected CA field.
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  • 93
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    Experimental brain research 111 (1996), S. 178-186 
    ISSN: 1432-1106
    Keywords: Cross-correlation ; Ventral-group ; bulbospinal inspiratory neurons ; Upper-cervical ; inspiratory neurons ; Intercostal motoneurons ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the synaptic connections from ventral-group bulbospinal inspiratory neurons to upper cervical inspiratory neurons and phrenic and intercostal motoneurons in decerebrate rats using cross-correlation. Inspiratory neurons were recorded in the medulla (n=28) at the level of the obex and from the upper-cervical segments (C1 and C2) of the spinal cord (n=29) in 18 vagotomized, paralyzed, ventilated, and decerebrated rats. The neurons were identified by their inspiratory firing pattern and antidromic activation from the spinal cord at C7. Whole-nerve recordings were made using bipolar electrodes from the central cut ends of the C5 phrenic nerve and the external and internal intercostal nerves at various thoracic levels. Cross-correlation histograms were computed between these recordings to detect short time scale synchronizations indicative of synaptic connections. Cross-correlation histograms (n=20), computed between the activities of ventral-group bulbospinal inspiratory neurons and the phrenic nerve, all showed peaks (mean half-amplitude width±SD, 1.1±0.3 ms) at short latencies (mean latency±SD, 2.0±0.6 ms) suggestive of monosynaptic excitation. Cross-correlation histograms (n=33), computed between the activities of ventral-group bulbospinal inspiratory neurons and upper-cervical inspiratory neurons, displayed four (12%) peaks (mean halfamplitude width±SD, 0.9±0.1 ms) at short latencies(mean latency±SD, 1.8±0.6 ms) suggestive of monosynaptic excitation, and six (18%) peaks (mean half-amplitude width±SD, 1.4±0.4 ms) at latencies near zero suggestive of excitation fro m a common source. Cross-correlation histograms (n=34), computed between the activities of ventral-group bulbospinal inspiratory neurons and the internal and external intercostal nerves at various thoracic levels (T2-8), showed six (18%) peaks (mean half-amplitude width±SD, 2.5±0.5 ms) at short latency (mean latency±SD, 4.5±1.1 ms) suggestive of oligosynaptic connections. Cross-correlation histograms (n=42) computed between activities of intercostal nerves at various levels of the thoracic spinal cord showed central peaks suggestive of excitation from a common source. Although the size of the peaks decreased with segmental separation, the displacement of the peaks from time zero did not increase with segmental separation (mean displacement±SD, 0.6±0.6 ms) as would be expected if the common excitation resulted from a descending monosynaptic excitation by a source such as the ventral-groupbulbospinal inspiratory neurons. We conclude that all ventral-group bulbospinal inspiratory neurons make monosynaptic connections to phrenic motoneurons, a few make monosynaptic connections to upper-cervical inspiratory neurons, but connections to intercostal motoneurons are made via interneurons.
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  • 94
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    Experimental brain research 112 (1996), S. 58-62 
    ISSN: 1432-1106
    Keywords: H-reflex ; Operant conditioning ; Plasticity ; Spinal cord ; Soleus muscle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In response to an operant conditioning task, rats can gradually increase or decrease soleus H-reflex amplitude without change in background electromyographic activity or M response amplitude. Both increase (under the HRup mode) and decrease (under the HRdown mode) develop over weeks. The present study investigated reversal of conditioned H-reflex change. Following collection of control data, rats were exposed to one mode (HRup or HRdown) for 50 days, and then exposed to the opposite mode for up to 72 days. Rats responded to each mode exposure with gradual, mode-appropriate change in H-reflex amplitude. This finding is consistent with other evidence that H-reflex conditioning depends on spinal cord plasticity. The effects of exposure to the HRup (or HRdown) mode were not affected by whether exposure followed previous exposure to the HRdown (or HRup) mode. In accord with recent studies suggesting that HRup and HRdown conditioning have different spinal mechanisms, these results suggest that reversal of H-reflex change is due primarily to the superimposition of additional plasticity rather than to decay of the plasticity responsible for the initial change.
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  • 95
    ISSN: 1432-1106
    Keywords: Trigeminal nuclear complex ; Plasticity ; Mechanoreceptor afferents ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Previous light and electron microscopic studies in rat and cat have shown that transection of peripheral sensory nerve branches leads to alterations in the central branches of primary sensory neurons, so-called transganglionic changes. In this study the changes in choleragenoid (B)-horseradish peroxidase B-HRP-labeled primary sensory terminals and axons in the trigeminal nuclear complex 3–90 days following transection of vibrissae nerves in the rat have been studied. Since regeneration of the transected vibrissa nerve was not prevented, these experiments allowed the examination of degenerative changes in the earlier stage after nerve injury as well as those present during nerve regeneration and target reinnervation. Two different experimental approaches were used, depending on the postlesion survival time. For short-term experiments the deep vibrissa nerve was injected with a solution of B-HRP. Forty-eight hours later the nerve was transected at its entry in the follicle, and after survival times ranging from 3 to 15 days sections from the subnucleus caudalis and spinal trigeminal nucleus, were prepared for electron microscopic examination. For long-term experiments involving a 16- to 90-day posttransection survival time, the deep vibrissa nerve was cut first. Then B-HRP was injected into the reinnervated follicle 2 days before killing the rats. Atypical HRP-labeled terminals were seen from 4 to 90 days survival time. The changes observed included atypical swollen vesicles or lack of vesicles in parts of the terminals apposed to the synaptic cleft. Other terminals displayed dense clusters of vesicles, flocculent cytoplasm, and/or neurofilamentous hyperplasia. No evidence of complete disintegration or phagocytosis by glial cells was observed. From 4 to 12 days survival time the changes were most commonly seen in the larger terminals, from 19–90 days in smaller terminals. From 10 days survival time and onward, changes in axons were observed. The most commonly seen alterations were axons with expanded myelin sheaths. Normal-labeled terminals were seen at all survival times examined. Compared with earlier studies of transganglionic changes in the vibrissa system occurring after infraorbital nerve or vibrissa row nerve injury, the changes seen in this study are less pronounced. These observations indicate (1) that the initial changes in the central processes of peripherally injured vibrissae nerves are less extensive than those occurring after infraorbital nerve transection, possibly because of the distally located lesion, and (2) that transganglionic changes occur also after the injured nerve has regenerated.
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  • 96
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    Experimental brain research 112 (1996), S. 420-430 
    ISSN: 1432-1106
    Keywords: Plasticity ; Auditory cortex ; Neuronal assemblies ; Microstimulation ; Cortical maps ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Many manipulations are able to change or perturb various aspects of single neuron properties and interneuronal relationships. Changes of cerebral cortex organization have been observed in different cortical areas and at different time scales in relation to peripheral stimulation, peripheral damage, associative learning, and electrical stimulation. Here we describe studies on separable multineuron recordings in the rat's auditory cortex under two different anesthetics. Acoustic stimuli were used as a normal, physiological input, and weak electrical intracortical microstimulation (ICMS) as a perturbation that forces a rapid cortical reorganization. ICMS induced fast changes in the cortical map and in the receptive field properties of cells at the electrically stimulated and adjacent electrodes. In effect there was an enlargement of the cortical domain tuned to the acoustic frequency that had been represented at the stimulating electrode. ICMS also incremented afterdischarge responses; these consisted of an initial response to the auditory stimulus followed by less intense repetitive activity that was stimulus-time locked and had a period of 8–12 Hz, similar to that of the spontaneous synchronous activity. Cortical activity under ketamine differed from that under pentobarbital sodium, although in both situations we observed that cortical neurons were highly synchronous.
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  • 97
    ISSN: 1432-1106
    Keywords: Neurotrophins ; BDNF ; In situ hybridization ; Immunohistochemistry ; Status epilepticus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The messenger RNAs (mRNAs) for the neurotrophins, brain-derived neurotrophic factor (BDNF), and nerve growth factor (NGF), are upregulated during epileptic seizure activity, as visualized by in situ hybridization techniques. Neurotrophins might be protective against excitotoxic cell stress, and the upregulation during seizures might provide such cell protection. In this study, a high dose of pilocarpine (300 mg/kg) was used to induce long-lasting, limbic motor status epilepticus and a selective pattern of brain damage. The regulation of BDNF, trkB, and NGF mRNA was studied by in situ hybridization at 1, 3, 6, and 24 h after induction of limbic motor status epilepticus. BDNF immunoreactivity was examined with an anti-peptide antibody and the neuropathological process studied in parallel. BDNF mRNA increased in hippocampus, neocortex, piriform cortex, striatum, and thalamus with a maximum at 3–6 h. Hybridization levels increased earlier in the resistant granule and CA1 cells as compared to the vulnerable CA3 neurons. BDNF immunoreactivity was elevated in dentate gyrus at 3–6 h. trKB mRNA increased in the entire hippocampus. NGF mRNA in hippocampus appeared in dentate gyrus at 3–6 h and declined in hilar neurons at 6–24 h. Cell damage was found in the CA3 area, entire basal cortex, and layers II/III of neocortex. Endogenous neurotrophins are upregulated during status epilepticus caused by pilocarpine, which is related to the coupling between neuronal excitation and trophic factor expression. This upregulation of neurotrophic factors may serve endogenous protective effects; however, the excessive levels of neuronal hyperexcitation resulting from pilocarpine seizures lead to cell damage which cannot be prevented by endogenous neurotrophins.
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  • 98
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    Experimental brain research 110 (1996), S. 55-61 
    ISSN: 1432-1106
    Keywords: Nucleus of the solitary tract ; Antidromic mapping ; Prefrontal cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The medial prefrontal cortex (MPFC) has been described as a “visceromotor” cortical area, since autonomic effects such as depressor responses may be elicited from this area. The central circuitry which mediates these depressor responses may include a projection from the MPFC to the nucleus of the solitary tract (NTS). Neurones were recorded extracellularly in the MPFC and were tested for antidromic (AD) activation from the NTS. These were all tested for (1) constant spike latency, (2) ability to follow high-frequency stimulation to more than 200 Hz, and (3) where possible, collision of stimulation-evoked spike with spontaneous spike or spikes evoked by iontophoretic application of glutamate. Of the 34 cells studied, all had constant AD latency (30±1 ms, range 16–46 ms); they followed high-frequency stimulation up to 354±19 Hz, and only seven cells were spontaneously active (range 1–19 spikes/s). The threshold stimulation intensity for AD activation was 102±9 μA (n=34, range 8–200 μA). Depth-threshold curves (n=7) showed minimum-threshold AD activation currents that corresponded to the dorsal and ventral sub-divisions of the NTS. Small shifts in AD latency were found in the depth-threshold curves, suggesting axonal branching. Analysis of recording sites showed that NTS-projecting MPFC neurones were predominantly found in the infralimbic and ventral prelimbic regions of the MPFC. These findings indicate that there is a population of neurones in the MPFC that projects to, and probably terminates within, the NTS. It is possible that this projection may, in part, mediate the cardiovascular response to MPFC stimulation.
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  • 99
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    Neuroradiology 38 (1996), S. 34-37 
    ISSN: 1432-1920
    Keywords: Magnetic resonance imaging ; Gadolinium ; Malignant lymphoma, brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Primary central nervous system lymphoma (PCNSL) is rare, although its frequency has increased in recent years. Radiographically, almost all PCNSL enhance on CT and/or MRI, and nonenhancing PCNSL has been thought to be extremely rare. We present PCNSL showing multiple nonenhancing lesions on MRI in an immunocompetent patient.
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  • 100
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    Neuroradiology 38 (1996), S. 38-40 
    ISSN: 1432-1920
    Keywords: Cerebellopontine angle ; Choroid plexus papilloma ; Magnetic resonance imaging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We present a cerebellopontine angle choroid plexus papilloma that originated from the tuft of choroid plexus of the fourth ventricle protruding from the foramen of Luschka. MRI and CT did not establish the diagnosis, but the tumor was shown histopathologically to be a choroid plexus papilloma. Distinct features of the tumor on MRI are described and the differential diagnosis of other cerebellopontine angle tumors is discussed.
    Type of Medium: Electronic Resource
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