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1.
To investigate the internal structure changes in virgin black human hair keratin fibers due to aging, the structure of cross-sections at various depths of virgin black human hair (sections of new growth hair: 2 mm from the scalp) from a group of eight Japanese females in their twenties and another group of eight Japanese females in their fifties were analyzed using Raman spectroscopy. For the first time, we have succeeded in recording the Raman spectra of virgin black human hair, which had been impossible due to high melanin granule content. The key points of this method are to cross-section hair samples to a thickness of 1.50-microm, to select points at various depths of the cortex with the fewest possible melanin granules, and to optimize laser power, cross slit width as well as total acquisition time. The reproducibility of the Raman bands, namely the alpha-helix (alpha) content, the beta-sheet and/or random coil (beta/R) content, the disulfide (--SS--) content, and random coil content of two adjoining cross-sections of a single hair keratin fiber was clearly good. The --SS-- content of virgin black human hair from the Japanese females in their fifties for the cortex region decreased compared with that of the Japanese females in their twenties. On the other hand, the beta/R and alpha contents of the cortex region did not change. 相似文献
2.
MA Henson RS Larsen SN Lawson I Pérez-Otaño N Nakanishi SA Lipton BD Philpot 《PloS one》2012,7(8):e42327
Glutamatergic synapse maturation is critically dependent upon activation of NMDA-type glutamate receptors (NMDARs); however, the contributions of NR3A subunit-containing NMDARs to this process have only begun to be considered. Here we characterized the expression of NR3A in the developing mouse forebrain and examined the consequences of NR3A deletion on excitatory synapse maturation. We found that NR3A is expressed in many subcellular compartments, and during early development, NR3A subunits are particularly concentrated in the postsynaptic density (PSD). NR3A levels dramatically decline with age and are no longer enriched at PSDs in juveniles and adults. Genetic deletion of NR3A accelerates glutamatergic synaptic transmission, as measured by AMPAR-mediated postsynaptic currents recorded in hippocampal CA1. Consistent with the functional observations, we observed that the deletion of NR3A accelerated the expression of the glutamate receptor subunits NR1, NR2A, and GluR1 in the PSD in postnatal day (P) 8 mice. These data support the idea that glutamate receptors concentrate at synapses earlier in NR3A-knockout (NR3A-KO) mice. The precocious maturation of both AMPAR function and glutamate receptor expression are transient in NR3A-KO mice, as AMPAR currents and glutamate receptor protein levels are similar in NR3A-KO and wildtype mice by P16, an age when endogenous NR3A levels are normally declining. Taken together, our data support a model whereby NR3A negatively regulates the developmental stabilization of glutamate receptors involved in excitatory neurotransmission, synaptogenesis, and spine growth. 相似文献
3.
NRSF regulates the fetal cardiac gene program and maintains normal cardiac structure and function 总被引:1,自引:0,他引:1
4.
In rodents an intravenous administration of viableCryptococcus (C.) neoformans cells frequently resulted in attachment of intravascular cryptococcal granulomas to inner walls of the large to medium-sized
veins of various organs, including the lungs, liver and spleen. In order to elucidate the pathogenesis of granulomatous changes,
the cells composing the intravascular granulomas were observed by electron microscopic peroxidase (PO) cytochemistry. The
granuloma composing cells could be divided into the following four types according to the pattern of endogenous peroxidase
activity: exudate macrophage (Mφ, type I), PO-negative Mφ (type II), resident Mφ (type III) and other inflammatory cells (type
IV). In the intravenous granulomas of the lung, the percentages of composed cells were 39.0% for type I, 57.9% for type II,
0% for type III and 3.1% for type IV. By contrast, in the interstitial granulomas in the lung, type III Mφs, possibly derived
from alveolar Mφs, played a significant role in granuloma formation. This may indicate that the intravascular granuloma is
almost composed of macrophages derived from monocytes rather than alveolar macrophages. The expression of ICAM-1 on endothelia
of the pulmonary veins was examined by immunoelectron microscopy. An immunogold labeling index was significantly augmented
on the surface of endothelia in response to intravenous challenge ofC. neoformans. The intravascular granuloma demonstrates that the monocytes develop into the granuloma-composing macrophages and suppress
the cryptococcal activities even hi the peripheral blood resulting in an assistance of endothelial functions. 相似文献
5.
Murata S Mochizuki K Nakazawa T Kondo T Nakamura N Yamashita H Urata Y Ashihara T Katoh R 《Cytometry》2002,49(3):91-95
BACKGROUND: Aspiration biopsy cytology of thyroid tumors has been used more frequently in recent times to differentiate between malignant and benign lesions. Chromatin patterns of the tumor cell nuclei are one of most important factors for cytologic diagnosis. The interpretation of nuclear chromatin patterns is subjective and more difficult than that of nuclear size or shape. In the present report, we investigated how to detect underlying chromatin characteristics of benign and malignant thyroid tumor cells by means of texture and factor analyses. METHODS: We employed a computer-aided system in which light microscopy was combined with an image processor and monochrome camera. Using this system, 100 randomly selected cells in a Papanicolaou stained, aspiration biopsy cytologic smear in each case of 39 benign and malignant thyroid tumor cases were digitized. We applied two-dimensional and higher texture analyses with the use of co-occurrence and run-length matrices to analyze the chromatin patterns. Factor analysis was used to determine whether a large number of independent variables actually measured one or more underlying common variables. RESULTS: According to parameters with high factor-loading values, the morphologic chromatin characters were classified into three categories according to heterogeneity, contrast, and homogeneity of chromatin patterns. On the basis of analyses with these morphologic categories, nuclei of papillary carcinoma showed higher contrast of chromatin patterns than did those of the benign group. Moreover, there was a variety of contrasting chromatin patterns among cells in each papillary carcinoma case in comparison with the benign group. In contrast, follicular carcinomas showed a significant difference in the standard deviation of factor 3, which indicated more monotonous chromatin patterns among cells in each follicular carcinoma case than in each benign case. CONCLUSION: We believe that this technique, using texture and factor analyses, is useful in the detection of underlying characteristics of nuclear chromatin patterns in aspiration biopsy cytology. 相似文献
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In this article, membrane perforation of endothelial cells with attached microbubbles caused by exposure to single-shot short pulsed ultrasound is described, and the mechanisms of membrane damage and repair are discussed. Real-time optical observations of cell-bubble interaction during sonoporation and successive scanning electron microscope observations of the membrane damage with knowledge of bubble locations revealed production of micron-sized membrane perforations at the bubble locations. High-speed observations of the microbubbles visualized production of liquid microjets during nonuniform contraction of bubbles, indicating that the jets are responsible for cell membrane damage. The resealing process of sonoporated cells visualized using fluorescence microscopy suggested that Ca2+-independent and Ca2+-triggered resealing mechanisms were involved in the rapid resealing process. In an experimental condition in which almost all cells have one adjacent bubble, 25.4% of the cells were damaged by exposure to single-shot pulsed ultrasound, and 15.9% (∼60% of the damaged cells) were resealed within 5 s. These results demonstrate that single-shot pulsed ultrasound is sufficient to achieve sonoporation when microbubbles are attached to cells. 相似文献
8.
In previous experimental studies on the visual processing in vertebrates, higher-order visual functions such as the object
segregation from background were found even in the retinal stage. Previously, the “linear–nonlinear” (LN) cascade models have
been applied to the retinal circuit, and succeeded to describe the input-output dynamics for certain parts of the circuit,
e.g., the receptive field of the outer retinal neurons. And recently, some abstract models composed of LN cascades as the
circuit elements could explain the higher-order retinal functions. However, in such a model, each class of retinal neurons
is mostly omitted and thus, how those neurons play roles in the visual computations cannot be explored. Here, we present a
spatio-temporal computational model of the vertebrate retina, based on the response function for each class of retinal neurons
and on the anatomical inter-cellular connections. This model was capable of not only reproducing the spatio-temporal filtering
properties of the outer retinal neurons, but also realizing the object segregation mechanism in the inner retinal circuit
involving the “wide-field” amacrine cells. Moreover, the first-order Wiener kernels calculated for the neurons in our model
showed a reasonable fit to the kernels previously measured in the real retinal neuron in situ. 相似文献
9.
Shinji Ohsawa Takeshi Saito Shin Yoshikawa Hideo Mawatari Makoto Yamada Kazuhiro Amita Nobuki Takamatsu Yasuaki Sudo Tsuneomi Kagiyama 《Limnology》2010,11(3):207-215
One feature of volcanic lakes influenced by subaqueous fumaroles existing at lake bottoms (called active crater lakes) is
the remarkable color of their waters: turquoise or emerald green. The active crater lake named Yudamari at Mt. Nakadake of
Aso volcano, Japan, takes on a milky pale blue-green. The particular blue component of the lake water color results from Rayleigh
scattering of sunlight by very fine aqueous colloidal sulfur particles; the green component is attributable to absorption
of sunlight by dissolved ferrous ions. An objective color observation conducted during 2000–2007 revealed that the lake water
color changed from blue-green to solid green. The disappearance of the blue ingredient of the water color will result in diminution
of aqueous colloidal sulfur from chemical analyses of lake waters sampled simultaneously. The aqueous sulfur is produced by
the reaction of sulfur dioxide and hydrogen sulfide supplied from subaqueous fumaroles. However, its production efficiency
decreases by domination of sulfur dioxide in the subaqueous fumarolic sulfur gas species with increasing subaqueous fumarolic
temperature. The disappearance of blue ingredients from the blue-green color of the lake water may be attributed to activation
of subaqueous fumarole activity. 相似文献
10.
Nobuki Hayase Yui Fujikawa Katsuhiko Nakagawa Kazutoshi Ushio 《Bioscience, biotechnology, and biochemistry》2016,80(8):1663-1665
A bacterial strain (strain 224), which has the ability to utilize sulfanilic acid as a sole source of carbon, was isolated from soil. 16S rRNA gene sequence obtained from strain 224 exhibited 100% identical to that of species in the genus Bradyrhizobium. Strain 224 degraded 4.7 mM of sulfanilic acid and released almost the same molar concentration of sulfate ion 相似文献