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71.
Noise-induced effects within the inner ear have been well investigated for several years. However, this peripheral damage cannot fully explain the audiological symptoms in noise-induced hearing loss (NIHL), e.g. tinnitus, recruitment, reduced speech intelligibility, hyperacusis. There are few reports on central noise effects. Noise can induce an apoptosis of neuronal tissue within the lower auditory pathway. Higher auditory structures (e.g. medial geniculate body, auditory cortex) are characterized by metabolic changes after noise exposure. However, little is known about the microstructural changes of the higher auditory pathway after noise exposure. The present paper was therefore aimed at investigating the cell density in the medial geniculate body (MGB) and the primary auditory cortex (AI) after noise exposure. Normal hearing mice were exposed to noise (10 kHz center frequency at 115 dB SPL for 3 h) at the age of 21 days under anesthesia (Ketamin/Rompun, 10:1). After 1 week, auditory brainstem response recordings (ABR) were performed in noise exposed and normal hearing animals. After fixation, the brain was microdissected and stained (Kluever-Barrera). The cell density in the MGB subdivisions and the AI were determined by counting the cells within a grid. Noise-exposed animals showed a significant ABR threshold shift over the whole frequency range. Cell density was significantly reduced in all subdivisions of the MGB and in layers IV-VI of AI. The present findings demonstrate a significant noise-induced change of the neuronal cytoarchitecture in central key areas of auditory processing. These changes could contribute to the complex psychoacoustic symptoms after NIHL. 相似文献
72.
Lisa Werner Ernst Winkelmann Annelore Koglin J?rg Neser Heiko Rodewohl 《Anatomy and embryology》1989,180(6):583-597
Summary The morhological features of 298 neurons impregnated according to Golgi-Kopsch in areas 17 and 18 of Macaca mulatta were analyzed, and the same neurons were deimpregnated to visualize structural details of the somata in different types of neurons. The following cell types were investigated: Pyramidal and pyramid-like cells, spiny stellate cells, double bouquet cells, bipolar cells, chandelier cells, neurogliaform cells, basket and related cells. This procedure allows the evaluation of the nuclear-cytoplasmic proportion and the position of the nucleus besides shape and size of the cell body. Pyramidal and pyramid-like cells (N=43), spiny stellate cells (N=26), basket and related cells (N=126) are variable in these features. A positive correlation between soma size and width of the cytoplasm is found in pyramidal, pyramid-like cells and spiny stellate cells. With the exception of some large somata in both these types of neurons the nucleus is found in a central position. Double bouquet cells (N=6), bipolar cells (N=13) and chandelier cells (N=11) exhibit small cytoplasmic rims and centrally located nuclei. The small somata of neurogliaform cells (N=37), however, and the small to very large somata of basket and related cells show broad cytoplasmic portions surrounding the eccentrically located nuclei. These findings allow the identification of different neuronal types in Nisslstained sections on the basis of these soma features. This is a prerequisite for further detailed quantitative studies on the laminar distribution of different neuronal types in the visual cortex of the monkey. 相似文献
73.
Defective antigen presentation by Mycobacterium tuberculosis-infected monocytes. 总被引:4,自引:1,他引:4 下载免费PDF全文
In this study we investigated the effect of an in vitro infection with Mycobacterium tuberculosis on the ability of human monocytes to present the soluble antigen tetanus toxoid to T cells. We observed that tetanus toxoid-specific T-cell proliferation was markedly reduced when monocytes were infected with large numbers (bacterium-to-monocyte ratio, 50:1) of both viable and heat-killed mycobacteria. The level of antigen-induced gamma interferon release also was decreased when M. tuberculosis-containing monocytes were used as antigen-presenting cells. However, mycobacterium-infected monocytes did not show or trigger suppressive activity, because the presence of mycobacterium-infected monocytes did not affect the T-cell response induced by tetanus toxoid-pulsed control monocytes. When M. tuberculosis-infected monocytes were fixed with paraformaldehyde, they were not able to serve as antigen-presenting cells even in the presence of untreated accessory monocytes. Moreover, the uptake of both viable and heat-killed M. tuberculosis cells reduced the expression of human leukocyte antigen DR on monocytes. With regard to accessory function, monocytes infected with large numbers of mycobacteria were less efficient as accessory cells than were control monocytes in cultures of T cells activated with pokeweed mitogen. These results indicate that infection with large numbers of M. tuberculosis cells impairs the ability of monocytes to process and/or present soluble antigen and to serve as accessory cells in T-cell activation. 相似文献
74.
Tumor cell growth fractions in human malignant melanomas and the correlation to histopathologic tumor grading. 总被引:1,自引:1,他引:1 下载免费PDF全文
P. Kaudewitz O. Braun-Falco M. Ernst M. Landthaler W. Stolz J. Gerdes 《The American journal of pathology》1989,134(5):1063-1068
The growth fraction (GF) of 72 human malignant melanomas was determined by immunostaining with monoclonal antibody Ki-67. A positive correlation of GF and histopathologically-assessed prognostic variables, such as tumor thickness, mitotic rate, and prognostic index, was found. Individual Ki-67 values were considerably scattered in all histologically defined groups of malignancy. Thus, GF as determined by Ki-67 was used to calculate a modified prognostic index. In contrast to the histologically defined prognostic index, the Ki-67 based prognostic index allows further subdivision of thin malignant melanomas with no or few mitotic figures. This may be of help in identifying tumors with a high recurrence potential. 相似文献
75.
Children seen in a multispecialty medical clinic for abdominalpain were divided into three groups: 21 with confirmed organicfindings related to the abdominal pain, 14 with confirmed organicfindings unrelated to the pain, and 108 whose physical examinationswere negative (the functional pain group). For children withfunctional abdominal pain (but not for the others) the numberof symptoms of somatization disorder (Briquet's syndrome) wassignificantly related to the chronicity of the child's condition.Children with functional pain and no prior complaint had a meanof 1.95 symptoms; those with complaints of less than 1 year'sduration, 2.21 symptoms; those with complaints of more thana year since age 6, 4.04 symptoms; and those with complaintsfor more than a year with onset prior to age 6 years, 4.55 symptomsfrom the Somatization Disorder list. Findings were interpretedas preliminary evidence for a distinct, chronic, polysymptomatichysterical disorder beginning in childhood. 相似文献
76.
77.
Wolf Singer Ernst Pöppel Otto Creutzfeldt 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1972,14(2):210-226
Summary Spike activities of optic tract fibers and corresponding relay cells were recorded simultaneously in layers A and A1 of the dorsal lateral geniculate nucleus of the cat. Light stimuli of various diameters were shone into the receptive field center of these unit pairs and their input/output ratios were determined. An increase of the stimulus size leads to an impairment of the input/output ratio in on-center and off-center relay cells. This suppressive effect has approximately the same latency as the excitatory response.Intracellular recordings suggest that the inhibitory effect of the surround is due to a postsynaptic process. Inhibitory postsynaptic potentials occur during and — under certain stimulus conditions —before the excitatory response. The short latency of these IPSPs suggests that they result from the activity of adjacent units with the same RF characteristics as the recorded neuron. This inhibitory input is not restricted to the RF periphery but may also be activated by stimulation within the RF center. Most neurons are also inhibited by units with antagonistic center responses.During the period of this research Ernst Pöppel held a training grant of the Stiftung Volkswagenwerk, Az. 11 1015. 相似文献
78.
J Anthony R Near S L Wong E Iida E Ernst M Wittekind E Haber S C Ng 《Molecular immunology》1992,29(10):1237-1247
We have created a bacterial expression-export system and have used it to express (14 mg l-1) the variable region fragment (Fv) of an anti-digoxin antibody (26-10) in Escherichia coli. The expression-export plasmid contains a T7 promoter and the E. coli signal sequences ompA [Movva et al., J. biol. Chem. 255, 27-29 (1980)] and phoA [Inouye et al., J. Bacteriol. 149, 434-439 (1982)] fused to heavy chain (VH) and light chain (VL) variable region sequences to generate an artificial cistron. The 26-10 Fv protein made using this system was soluble, unlike many other expression systems which produce insoluble proteins in the form of inclusion bodies. The 26-10 VH and VL proteins were cleaved at their mature N-termini and exported into the bacterial periplasm where they could be easily extracted and affinity purified on ouabain-Sepharose. 26-10 Fv bound to digoxin with similar affinity and specificity as the whole 26-10 antibody (Ka for Fv, 1.3 x 10(9) M-1, Ka for IgG, 7 x 10(9) M-1). 26-10 Fv appears to be remarkably stable in comparison with other Fv fragments. The half-life for chain dissociation of 26-10 Fv was 48 hr compared to the reported 1.5 hr half-life of McPC603 Fv. We present the proton NMR spectra of the 26-10 Fv as preliminary evidence that this expression-export system can be used to facilitate the analysis of the solution structure of 26-10 Fv by NMR. 相似文献
79.
Pepe C Foley S Shannon J Lemiere C Olivenstein R Ernst P Ludwig MS Martin JG Hamid Q 《The Journal of allergy and clinical immunology》2005,116(3):544-549
BACKGROUND: Airway remodeling in asthma comprises a range of structural changes. Several studies have suggested an association between these changes and disease severity. The relationship between the extent of remodeling and lung function is not well defined. OBJECTIVE: We sought to contrast the structural changes in the airways of well-defined groups of subjects with severe and moderate asthma and to correlate the extent of remodeling with disease severity. METHODS: Endobronchial biopsy specimens were obtained from 15 subjects with severe and 13 subjects with moderate asthma. Epithelial integrity, cell-layer areas, subepithelial fibrosis, and the distance between epithelial and airway smooth muscle (ASM) layers were measured by means of image analysis. Collagen was identified by using Van Giesen stain, and ASM was defined by using smooth muscle alpha-actin immunostaining. Specific immunostains were performed for the evaluation of RANTES, IL-8, and eotaxin expression as markers of ASM phenotype. RESULTS: ASM area was greater in subjects with severe (0.24+/- 0.03 mm(2)) than in subjects with moderate (0.05+/- 0.01 mm(2)) asthma (P<.001). The distance between the epithelial and ASM layers was less in the severe group (0.12+/- 0.01 mm) than in the moderate group (0.24+/- 0.02, P<.001). A trend toward greater subepithelial fibrosis in subjects with severe asthma did not reach statistical significance. IL-8 and eotaxin expression, but not RANTES expression, were increased in the ASM of subjects with severe asthma compared with in subjects with moderate asthma. CONCLUSION: Smooth muscle alteration is the key structural change that distinguishes severe from moderate asthma, and phenotypic change in ASM might contribute to the difficulty in obtaining adequate control in some subjects with severe asthma. 相似文献
80.
Hortense Dodo Damien Marsic Monique Callender Ernst Cebert Olga Viquez 《Food and Agricultural Immunology》2002,14(2):147-154
Peanut is one of the most allergenic foods and reports of accidental ingestion of peanuts in unsuspected food are increasing. No information is available on the allergen content of peanut germplasm grown commercially and used in the food and confectionery industry. The objectives of this study were: (1) to determine the allergen contents of 34 peanut introductions (PI); and (2) to identify naturally occurring allergen-free and/or low or hypoallergenic peanuts germplasm. A basic ELISA protocol was utilized to detect the presence of antigens in the peanut lines using a pool of human sera from patients with documented history of peanut allergy. Two naturally occurring low, or hypo-allergenic germplasm were identified as PI 261942 and PI 338386. Both are Valencia market types with total allergen content significantly lower (P ≤0.05) than that of PI 119880 (0.550), PI 119876 (0.415) and PI 118991 (0.410) three Valencia market types and PI 262111 (0.485), a Virginia market type. No allergen-free PI was found. Allergen content of peanut lines from Bolivia and Paraguay were significantly (P ≤0.05) different to those from Venezuela. No significant difference was observed in the allergen content of the four market types. 相似文献