299 research outputs found
Inhibitory Effects of Anti-VEGF Antibody on the Growth and Angiogenesis of Estrogen-induced Pituitary Prolactinoma in Fischer 344 Rats: Animal Model of VEGF-targeted Therapy for Human Endocrine Tumors
Estrogen-induced pituitary prolactin-producing tumors (PRLoma) in F344 rats express a high level of vascular endothelial growth factor (VEGF) associated with marked angiogenesis and angiectasis. To investigate whether tumor development in E2-induced PRLoma is inhibited by anti-VEGF monoclonal antibody (G6-31), we evaluated tumor growth and observed the vascular structures. With simultaneous treatment with G6-31 for the latter three weeks of the 13-week period of E2 stimulation (E2+G6-31 group), the following inhibitory effects on the PRLoma were observed in the E2+G6-31 group as compared with the E2-only group. In the E2+G6-31 group, a tendency to reduction in pituitary weight was observed and significant differences were observed as (1) reductions in the Ki-67-positive anterior cells, (2) increases in TUNEL-positive anterior cells, and (3) repair of the microvessel count by CD34-immunohistochemistry. The characteristic âblood lakesâ in PRLomas were improved and replaced by repaired microvascular structures on 3D observation using confocal laser scanning microscope. These inhibitory effects due to anti-VEGF antibody might be related to the autocrine/paracrine action of VEGF on the tumor cells, because VEGF and its receptor are co-expressed on the tumor cells. Thus, our results demonstrate that anti-VEGF antibody exerted inhibitory effects on pituitary tumorigenesis in well-established E2 induced PRLomas
SAXS STUDY ON THE STRUCTURE AND CRYSTALLIZATION OF AMORPHOUS METALLIC ALLOYS
The change in structure of several amorphous alloys as Fe-P-C, Fe-B, Pd-Si and Pd-Au-Si alloys during isothermal ageing was examined using small angle X-ray scattering measurement and transmission electron microscopy. The SAXS intensity was related to two different types of scattering sources depending on ageing time and temperature. For the as-splatted amorphous alloys and the specimens aged for short period at the temperature below their crystallization temperatures, the week and spreaded SAXS intensity was observed. This indicates the existence of electron density fluctuation in the amorphous state. The average size of their scattering regions was 1.8 to 2.4 nm for Fe-P-C alloys and 1.2 to 0.8 nm for Fe-B alloys. The origin of its fluctuation has been discussed based on one dimensional model. When the amorphous alloys was aged for longer period, the fine crystalline particles precipitate ; those are the two phase lamellar structure of Fe_3P and α Fe for Fe-P-C alloys, the α iron phase for Fe-B alloys and the α phase for Pd-Au-Si alloys, respectively. Their size and structure were determined from the analysis of SAXS intensity and TEM observation
Experts' opinion: Recommendations for retesting breast cancer metastases for HER2 and hormone receptor status
Abstract The human epidermal growth factor receptor 2 (HER2) and hormone receptor status of recurrent breast cancer may change between the tumor and metastases from negative to positive and vice versa, potentially affecting the treatment regimen. Retesting of metastases may therefore be crucial to allow appropriate selection of patients for whom targeted therapy is indicated; however, retesting is not routinely performed. This article recommends that metastases be retested for HER2 and hormone receptor status and provides practical guidance on when and how to retest, as agreed by a panel of expert pathologists with extensive experience of HER2 and hormone receptor testing
Mechanism for the uniaxial strain dependence of the critical current in practical REBCO tapes
Clinical Pathological Analysis of Surgically Resected Superficial Esophageal Carcinoma to Determine Criteria for Deciding on Treatment Strategy
We performed a clinical pathological study of conventionally resected superficial esophageal carcinomas since this type of lesion has been increasing, in order to develop criteria of determination for therapeutic strategies. Pathological studies were performed on specimens obtained by radical surgical resection in 133 cases of superficial esophageal cancer. Evaluation was performed in terms of the gross classification of the lesion type, depth of invasion, lymph node metastasis, vascular invasion, size of the lesion, outcome, etc. In 0-I, 0-IIc+0-IIa, and 0-III type submucosal cancer lesions the rate of metastasis to lymph nodes was more than 40%, but in 0-IIa and 0-IIb mucosal cancer cases no lymph node metastasis was observed. 0-IIc type lesions showed a wide range of invasiveness, ranging from m1 to sm3. In cases with m1 or m2 invasion, no lymph node or lymph-vessel invasion was recognized, but in m3, sm1, sm2, and sm3 cases lymph node metastasis was recognized in 12.5%, 22.2%, 44.0% and 47.4%, respectively. In 47% of lesions with a greatest dimension of less than 30 mm invasion was limited to the mucosa. Seventy-two percent of m1 and m2 cases were 30 mm in size or less. Lymph node metastasis was recognized in only 16.7% of cases less than 30 mm in size, but in cases of lesions 30 mm or more the rate of lymph node metastasis was 35.8%. 0-IIb and 0-IIa type lesions are indications for endoscopic esophageal mucosal resection (EEMR), while 0-I, 0-IIc+0-IIa, and 0-III lesions should be candidates for radical surgical resection. In the 0-IIc category, lesions in which the depression is relatively flat and with a finely granular surface are indications for EEMR, but those cases in which the surface of depression shows granules of varying sizes should be treated with radical surgical resection. Cases of 0-IIa type 30 mm or larger in greatest dimension which have a gently sloping protruding margin shoulder or reddening should be treated with caution, but EEMR can be performed first and subsequent therapeutic strategy decided on, based on the pathological findings of the specimen
Pathology, Pathogenesis and Therapy of Growth Hormone (GH)-producing Pituitary Adenomas: Technical Advances in Histochemistry and Their Contribution
Growth hormone (GH)-producing adenomas (GHomas) are one of the most frequently-occurring pituitary adenomas. Differentiation of hormone-producing cells in the pituitary gland is regulated by transcription factors and co-factors. The transcription factors include Pit-1, Prop-1, NeuroD1, Tpit, GATA-2, SF-1. Aberrant expression of transcription factors such as Pit-1 results in translineage expression of GH in adrenocorticotropic hormone-producing adenomas (ACTHomas). This situation has been substantiated by GFP-Pit-1 transfection expression in the AtT20 cell line. Experimentally, GHomas have been induced in GH-releasing hormone (GHRH) or Prop-1 transgenic animals. Immunohistochemical detection of somatostatin receptor (SSTR2a) has recently emphasized their role in the response of GHomas to somatostatin analogue therapy. In this review, the advances in technology and their contribution to cell biology and medical practice are discussed
Two-dimensional Distributions and Column Densities of Gaseous Molecules in Protoplanetary Disks II
We have investigated the two-dimensional (R,Z) distribution of deuterated
molecular species in circumstellar disks around young stellar objects. The
abundance ratios between singly deuterated and normal molecules (``D/H
ratios'') in disks evolve in a similar way as in molecular clouds.
Fractionation is caused by rapid exchange reactions that are exothermic because
of energy differences between deuterated and normal species. In the midplane
region, where molecules are heavily depleted onto grain surfaces, the D/H
ratios of gaseous molecules are higher than at larger heights. The D/H ratios
for the vertical column densities of NH3, H2O, and HCO+ are sensitive to the
temperature, and decrease significantly with decreasing radial distance for R <
300 AU. The analogous D/H ratios for CH4 and H2CO, on the other hand, are not
very sensitive to the temperature in the range (T=10-50 K) we are concerned
with, and do not decrease with decreasing R at R > 50 AU. The D/H
column-density ratios also depend on disk mass. In a disk with a larger mass,
the ratios of deuterated species to normal species are higher, because of
heavier depletion of molecules onto grains. In the second part of the paper, we
report molecular column densities for disks embedded in ambient cloud gas. Our
results suggest that CN and HCO+ can be tracers of gaseous disks, especially if
the central object is a strong X-ray source. Our results also suggest that the
radial distributions of CN, C2H, HCN, and H2CO may vary among disks depending
on the X-ray luminosity of the central star.Comment: 13 page
Strain Effects on Point Defects and Chain-Oxygen Order-Disorder Transition in 123-Structure Cuprate Superconductors
The energetics of Schottky defects in 123 cuprate superconductor series, (where RE = lanthandies) and (AE =
alkali-earths), were found to have unusual relations if one considers only the
volumetric strain. Our calculations reveal the effect of non-uniform changes of
interatomic distances within the RE-123 structures, introduced by doping
homovalent elements, on the Schottky defect formation energy. The energy of
formation of Frenkel Pair defects, which is an elementary disordering event, in
123 compounds can be substantially altered under both stress and chemical
doping. Scaling the oxygen-oxygen short-range repulsive parameter using the
calculated formation energy of Frenkel pair defects, the transition temperature
between orthorhombic and tetragonal phases is computed by quasi-chemical
approximations (QCA). The theoretical results illustrate the same trend as the
experimental measurements in that the larger the ionic radius of RE, the lower
the orthorhombic/tetragonal phase transition temperature. This study provides
strong evidence of the strain effects on order-disorder transition due to
oxygens in the CuO chain sites.Comment: In print Phys Rev B (2004
Warm Molecular Layers in Protoplanetary Disks
We have investigated molecular distributions in protoplanetary disks,
adopting a disk model with a temperature gradient in the vertical direction.
The model produces sufficiently high abundances of gaseous CO and HCO+ to
account for line observations of T Tauri stars using a sticking probability of
unity and without assuming any non-thermal desorption. In regions of radius R >
10 AU, with which we are concerned, the temperature increases with increasing
height from the midplane. In a warm intermediate layer, there are significant
amounts of gaseous molecules owing to thermal desorption and efficient
shielding of ultraviolet radiation by the flared disk. The column densities of
HCN, CN, CS, H2CO, HNC and HCO+ obtained from our model are in good agreement
with the observations of DM Tau, but are smaller than those of LkCa15.
Molecular line profiles from our disk models are calculated using a
2-dimensional non-local-thermal-equilibrium (NLTE) molecular-line radiative
transfer code for a direct comparison with observations. Deuterated species are
included in our chemical model. The molecular D/H ratios in the model are in
reasonable agreement with those observed in protoplanetary disks.Comment: 11 pages, Latex (aa.cls), to be published in Astronomy and
Astrophysic
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