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31.
Light and electron microscopic study of the thyroid gland and an enlarged cervical lymph node in a 75-year-old woman with Hashimoto''s thyroiditis disclosed immunoblastic proliferation in the lymph node, marked by collections of striking round cells positive to periodic acid-Schiff (PAS) staining, immunoblasts and plasmacytoid elements in a vascular, fibrous framework. The PAS-positive cells ("macaroni cells") were distended with whorls of angulated tubular material resembling endoplasmic reticulum. Parafollicular-cell hyperplasia and an atypical plasmacytoid focus were noted in the thyroid. Hashimoto''s disease is known to be associated with malignant lymphoma, as are autoimmune and malignant diseases with immunoblastic lymphadenopathy. This is the first report of the association of Hashimoto''s disease and immunoblastic lymphadenopathy. The atypical plasma cells have not previously been described.  相似文献   
32.
Candidatus Magnetoglobus multicellularis (CMm) is a multicellular organism in which each constituent cell is a magnetotactic bacterium. It has been observed that disaggregation of this organism provokes the death of the individual cells. The observed flagellar movement of the CMm indicates that the constituent cells move in a coordinated way, indicating a strong correlation between them and showing that this aggregate could be considered as an individual. As every constituent cell is a magnetotactic bacterium, every cell contributes with a magnetic moment vector to the resultant magnetic moment of the CMm organism that can be calculated through the vectorial sum of all the constituent magnetic moments. Scanning electron microscopy images of CMm organisms have shown that the constituent cells are distributed on a helix convoluted on a spherical surface. To analyze the magnetic properties of the distribution of magnetic moments on this curve, we calculated the magnetic energy numerically as well as the vectorial sum of the magnetic moment distribution as a function of the number of cells, the sphere radius and the number of spiral loops. This distribution proposes a magnetic organization not seen in any other living organism and shows that minimum energy configurations of magnetic moments are in spherical meridian chains, perpendicular to the helix turns. We observed that CMm has a high theoretical degree of magnetic optimization, showing that its geometrical structure is important to the magnetic response. Our results indicate that the helical structure must have magnetic significance.  相似文献   
33.
There are few clearly established prognostic factors available to guide the use of adjuvant chemotherapy in early stage colon cancer patients. Some of the most promising candidates include the invasion of extramural blood vessels by tumour cells and the densities of FOXP3+ T regulatory cells (Tregs) in tumour and adjacent normal colonic mucosal tissue. The aim of our study was to evaluate the prognostic significance of these markers in AJCC stage II colon cancer, with particular reference to lymphoid follicles in the mucosa. Histopathological review for the presence of vascular and serosal invasion was conducted on a series of 165 stage II colon cancers treated by surgery alone. Immunohistochemical staining for FOXP3 was performed on tumour tissue and histologically normal colonic mucosa from the surgical margin. Image analysis software was used to evaluate the density of FOXP3+ cells in the tumour core, invading margin and lymphoid follicles from the colonic mucosa. For survival analysis, cases were classified into high- or low-density of FOXP3+ cells according to the median value. The mean density of FOXP3+ Tregs in lymphoid follicles was twofold and fivefold higher than in the invading margin and tumour core, respectively. Multivariate analysis identified extramural vascular invasion (HR, 2.47; 95% CI: 1.00-6.07; P?=?0.05) and high FOXP3+ cell density in lymphoid follicles (HR, 4.22; 95% CI: 1.49-11.91; P?=?0.007) as independent factors for worse survival, whereas a high frequency of lymphoid follicles in histologically normal colonic mucosa was associated with better survival (HR, 0.31; 95% CI: 0.12-0.79; P?=?0.014). Our data suggest that host factors related to the immune system have major prognostic significance in early stage colon cancer. The density of FOXP3+ cells within lymphoid follicles and the frequency of these structures in normal colonic mucosa represent novel and independent prognostic factors.  相似文献   
34.
Cervical cancer is known to metastasize primarily by the lymphatic system. Dissemination through lymphatic vessels represents an early step in regional tumor progression, and the presence of lymphatic metastasis is associated with a poor prognosis. In patients who have undergone a radical hysterectomy, lymphovascular space invasion (LVSI), assessed on hematoxylin and eosin-stained slides, is a major factor for adjuvant therapy in patients with cervical cancer. With the advent of a lymphatic endothelial cell-specific marker, such as D2-40, it is now possible to distinguish between blood and lymphatic space invasion (LSI). In this study, the utility of D2-40 was assessed for the detection of lymphatic vessel density (LVD) and identification of LSI. The expressions of vascular endothelial growth factor receptor-3 (VEGFR-3), VEGF-C, tyrosine receptor kinase-2, and angiopoietin-1 were assessed by immunohistochemical methods on 50 patients with squamous cell carcinoma of the cervix. Clinicopathologic characteristics, including pelvic lymph node metastasis, were correlated with the above histochemical findings. We found that lymphangiogenesis, measured by an increase in peritumoral LVD, was significantly associated with positive lymph node status (P < .005). VEGFR-3 expression was significantly associated with LVD (P < .05). D2-40 staining verified LSI (P = .03) and surpassed that of hematoxylin and eosin-identified LVSI (P = .54). In conclusion, lymphangiogenic markers, specifically LVD quantified by D2-40 and VEGFR-3, are independently associated with LSI and lymph node metastasis in patients with early squamous cell carcinoma of the cervix treated with radical hysterectomy and pelvic lymphadenectomy.  相似文献   
35.
36.
Previous studies proposed that N-ethylmaleimide (NEM) alkylates 3 classes of thiols on skeletal muscle ryanodine receptors (RyRs) producing 3 phases of channel modification, as function of time and concentration. NEM (5 mm) decreased, increased, and then decreased the open probability (P(o)) of the channel by thiol alkylation, a reaction not reversed by reducing agents. We now show that low NEM concentrations (20-200 microm) elicit Ca(2+) release from sarcoplasmic reticulum (SR) vesicles, but contrary to expectations, the effect was fully reversed by reducing agents or by washing SR vesicles. In bilayers, NEM (0.2 mm) increased P(o) of RyRs within seconds when added to the cis (not trans) side, and dithiothreitol (DTT; 1 mm) decreased P(o) in seconds. High (5 mm) NEM concentrations elicited SR Ca(2+) release that was not reversed by DTT, as expected for an alkylation reaction. A non-sulfhydryl reagent structurally related to NEM, N-ethylsuccinimide (0.1-0.5 mm), also elicited SR Ca(2+) release that was not reversed by DTT (1 mm). Other alkylating agents elicited SR Ca(2+) release, which was fully (N-methylmaleimide) or partially (iodoacetic acid) reversed by DTT and inhibited by ruthenium red. Nitric oxide (NO) donors at concentrations that did not activate RyRs inhibited NEM-induced Ca(2+) release, most likely by an interaction of NO with NEM rather than an inactivation of RyRs by NO. Thus, at low concentrations, NEM does not act as a selective thiol reagent and activates RyRs without alkylating critical thiols indicating that the multiple phases of ryanodine binding are unrelated to RyR activity or to NEM alkylation of RyRs.  相似文献   
37.
A 106 kD protein was isolated from skeletal sarcoplasmic reticulum (SR) vesicles and shown to have the properties of SR Ca2+ release channels, including blockade by 5 nM ryanodine. In view of extensive reports that the ryanodine-receptor complex consists of four 565 kD junctional feet proteins (JFPs) and is the 'physiological' Ca2+ release channel, we prepared ryanodine-affinity columns to isolate its receptor site(s). Conditions known to maximize the association and dissociation of ryanodine to SR proteins were respectively used to link, then elute, the receptor(s) from ryanodine-affinity columns. The method purified a protein at about 100 kD from both rabbit skeletal and canine cardiac SR vesicles. The skeletal and cardiac proteins isolated by ryanodine-affinity chromatography were identified as the low molecular weight Ca2+ release channel through their antigenic reaction with an anti-106 kD monoclonal antibody. Upon reconstitution in planar bilayers, both skeletal and cardiac proteins revealed the presence of functional SR Ca2+ release channels. Surprisingly, ryanodine-affinity columns did not retain JFPs but purified 106 kD Ca2+ release channels which are a minor component (0.1-0.3%) of SR proteins.  相似文献   
38.
Analyses of the haemolymph of the larvae ofSpodoptera littoralis Boisduval with an amino acid analyser indicated the presence of a group of amino acids, some of which showed an obvious quantitative decrease as a result of treatment withBacillus thuringiensis Berliner such as threonine, serine, asparagine, alanine, valine, methionine, isoleucine, leucine, phenyl alanine and ornithine. Glutamic acid, cystine, β-alanine, γ-butyric acid and histidine contents of the haemolymph of diseased larvae were higher than those in the haemolymph of normal individuals. This increase in the content of some amino acids in infested larvae may be attributed to the possible dissolution of protein crystals ofBacillus thuringiensis. The activity of proteolytic enzymes in the gut may be partly involved in the reaction. B. thuringiensis was found to affect the concentration of some ions of the haemolymph ofS. littoralis. So, a marked decrease in sodium and potassium concentration was observed 4–5 days after treatment withB. thuringiensis. The change in Na+/K+ ratio in healthy and treated larvae possibly indicate their interference, in the larval toxicity withB. thuringiensis. An obvious decrease in the concentration of magnesium and zinc was also observed in the larval haemolymph after feeding on a diet containing theB. thuringiensis preparations. The pH value of the haemolymph however showed no change after treatment withB. thuringiensis.
Résumé L'analyse de l'hémolymphe des chenilles deSpodoptera littoralis Boisduval à l'aide d'un analyseur d'acides aminés montre une diminution significative de la quantité de certains acides aminés à la suite d'un traitement parBacillus thuringiensis Berliner, tels que: thréonine, sérine, asparagine, alanine, valine, methionine, isoleucine, leucine, phenylalanine et ornithine. La teneur en acide glutamique, cystine, β alanine, γ acide butyrique et histidine de l'hémolymphe des larves traitées est plus élevée que celle des chenilles témoins. Cette augmentation est peut-être liée à la dissolution des protéines du cristal deB. thuringiensis. B. thuringiensis affecte également la concentration de certains ions dans l'hémolymphe deS. littoralis. On observe une nette réduction du taux de sodium et de potassium 4 à 5 jours après le traitement. Il est possible que cette modification du rapport Na+/K+ chez les larves malades traduise l'interférence de ces deux ions dans les phénomènes de toxicité deB. thuringiensis. Une diminution nette de la concentration en magnésium et en zinc est également notée dans l'hémolymphe des chenilles après alimentation sur un milieu traité parB. thuringiensis. Le pH de l'hémolymphe n'est pas affecté.
  相似文献   
39.
Specific inherent optical properties (SIOP) of the Berau coastal waters were derived from in situ measurements and inversion of an ocean color model. Field measurements of water-leaving reflectance, total suspended matter (TSM), and chlorophyll a (Chl a) concentrations were carried out during the 2007 dry season. The highest values for SIOP were found in the turbid waters, decreasing in value when moving toward offshore waters. The specific backscattering coefficient of TSM varied by an order of magnitude and ranged from 0.003 m2 g−1, for clear open ocean waters, to 0.020 m2 g−1, for turbid waters. On the other hand, the specific absorption coefficient of Chl a was relatively constant over the whole study area and ranged from 0.022 m2 mg−1, for the turbid shallow estuary waters, to 0.027 m2 mg−1, for deeper shelf edge ocean waters. The spectral slope of colored dissolved organic matter light absorption was also derived with values ranging from 0.015 to 0.011 nm−1. These original derived values of SIOP in the Berau estuary form a corner stone for future estimation of TSM and Chl a concentration from remote sensing data in tropical equatorial waters.  相似文献   
40.
In this study conservation of Castilleja levisecta Greenm., a globally endangered species was addressed through in vitro cryopreservation of shoot tips. In vitro cultures were successfully established using seedlings received from British Columbia, Canada. Shoot tips excised from in vitro propagated plants were cryopreserved using a droplet-vitrification method following optimization of individual protocol steps such as pre-culture, treatment with vitrification solutions, and unloading. The highest plant regrowth after cryopreservation (66%) was achieved when shoot tips were pre-cultured in 0.3 M sucrose for 17 h followed by 0.5 M sucrose for 4 h, incubated in an osmo-protectant solution (17.5% [v/v] glycerol and 17.5% [w/v] sucrose) for 20 min, exposed to vitrification solution A3 (37.5% [v/v] glycerol plus 15% [v/v] dimethylsulfoxide (DMSO) plus 15% [v/v] ethylene glycol (EG) plus 22.5% [w/v] sucrose) on ice for 40 min, and unloaded in 0.8 M sucrose solution for 30 min. Healthy plants were developed from cryopreserved shoot tips and propagated in vitro using nodal segments. Plants derived from in vitro culture and from cryopreserved tissues were successfully rooted and acclimated in a greenhouse with 100% survival rate. Acclimatized plants were reintroduced in a naturalized propagation area at the Conservation Nursery at Fort Rodd Hill, Canada. Twenty of 94 reintroduced plants (21%) survived the transit from lab to field and some had started to flower. This is the first report for cryopreservation of C. levisecta, an important step in conserving and re-introducing this critically imperiled species in nature.  相似文献   
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