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61.
There exists a class of two-dimensional figures (including cumulative gaussian waveforms) whose contours have a limited range of orientations. These figures can appear as highly nonrigid if they undergo pure translation in the image plane. In the case of the cumulative gaussian waveform, it is the region around the inflection point that appears as nonrigid. Motivated by Hildreth's (1984) proposal, we made 5 predictions which were confirmed by the data: (0), rigidity of a figure can be dramatically increased if one attaches line terminators to the figure; (1), moving terminators "on" the figure increase rigidity far more than such terminators "off" the figure; (2) decreasing the velocity of the terminator decreases rigidity; (3) decreasing the distance between the terminator and the inflection point increases rigidity; (4) the effect of a moving terminator can be blocked by interposing a stationary terminator between it and a nonrigidly moving portion of the curve. 相似文献
62.
Occlusion and the solution to the aperture problem for motion 总被引:5,自引:0,他引:5
The "aperture problem" indicates that a local reading of the velocity of an oriented contour is inherently ambiguous, insufficient by itself to recover the velocity of image points. In Wallach's "barber pole" display consisting of moving diagonal lines within an elongated rectangular aperture, it has been suggested that the unambiguous motion of edge-terminators along the longer edges of the aperture propagates towards the motion-ambiguous center part of drifting stripes. This results in the perception of a surface moving in the direction of the longer axis of the aperture. By manipulating the stereoscopic disparity of a striped pattern relative to the aperture plane, we found that the disambiguating effects of terminators could be abolished if the striped pattern was in uncrossed disparity relative to the aperture plane. Also, the motion in 3 separate horizontally oriented, and vertically aligned apertures which would otherwise be seen as moving horizontally, was seen as "linked" together and moving vertically. This occurred only when the horizontally oriented segments separating these apertures were stereoscopically coded so that they appeared as occluders in front. These findings suggest that accidental or "extrinsic" terminators created by occluding edges are treated differently from real or "intrinsic" terminators, and that the real-world constraint of occlusion is thus implemented in the ambiguity-solving processes for motion. 相似文献
63.
Nishimura T Nishida N Itoh T Komeda T Fukuda Y Ikai I Yamaoka Y Nakao K 《Genes, chromosomes & cancer》2005,42(1):34-43
Recurrent chromosomal gain at 1q is one of the most common features of human hepatocellular carcinoma (HCC), but how the gain at 1q contributes to hepatocarcinogenesis is still unclear. To identify the target genes, precise determination of the shortest region of overlap (SRO) and of breakpoints is necessary. Similarly, the role of loss at 1p, which is also a major cytogenetic aberration in HCC, needs to be determined. Fifty HCCs were examined with the aid of 59 microsatellite markers distributed throughout both arms of chromosome 1. To detect allelic gain effectively, the cutoff value of the allelic imbalance index was set at 0.70. Alleles showing imbalance were subjected to multiplex PCR, using a retained allele as an internal control, to determine whether the imbalance was the result of chromosomal gain or loss. The SRO of the gains was defined as D1S2878-D1S2619 (1q23.-q25.3, 16.9 Mb), which involved 36 cases (72%). Gains in the number of copies of certain oncogenes within this region seemed to be critical for the pathogenesis of HCC. In contrast, the centromeric breakpoints of these gains varied, but they tended to occur mainly in the pericentromeric region (26 of 50 cases, 52%). Rearrangement of specific genes associated with the gains is unlikely. On the other hand, the SRO of deletion was defined as D1S2893-D1S450 (1p36.32-p36.22, 5.1 Mb). Four known putative tumor-suppressor genes (TP73, RIZ1, NBL1/DAN, and CDKN2C) were outside the SRO, suggesting the presence of other candidate genes with critical roles in hepatocarcinogenesis. 相似文献
64.
Motoko Yanase Hideto Tanaka Teruo Nakayama 《European journal of applied physiology》1989,58(4):446-451
Summary In female rats, rectal temperature (T
re), tail vasomotor response, oxygen uptake
, and carbon dioxide production
were measured in proestrus and estrus stages during treadmill running at two different speeds at an ambient temperature (T
a) of 24° C. Experiments were performed at 2.00–6.00 a.m., when the difference inT
re was greatest between the two stages;T
re at rest in the estrus stage was 0.54° C higher than in the proestrus stage. In a mild warm environment, thresholdT
re for a rise in tail skin temperature (T
tail) was also higher in the estrus stage than in the proestrus stage. In contrast, no difference was seen in the thresholdT
re and steady stateT
re at the end of exercise between proestrus and estrus stages. These values were higher at the higher work intensity.
was also similar between the two stages, except in the second 5 min after the beginning of exercise, when
was greater andT
re rose more steeply in the proestrus stage. These data indicate that deep body temperature during exercise is regulated at a certain level depending on the work intensity and is not influenced by the estrus cycle.This study was supported in part by a Grant-in Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan (Grant No. 62480114) 相似文献
65.
Aonuma M Saeki Y Akimoto T Nakayama Y Hattori C Yoshitake Y Nishikawa K Shibuya M Tanaka NG 《International journal of experimental pathology》1999,80(5):271-281
To elucidate the role of vascular endothelial growth factor (VEGF), an endothelial cell-specific mitogen, in tumour angiogenesis and malignant progression, an expression vector harboring human VEGF cDNA was stably transfected into three human cancer cell lines with poor VEGF productivity. Though their in vitro growth rate and intrinsic productivity of another angiogenic factor, basic fibroblast growth factor (bFGF), were not changed by transfection, those clones with higher VEGF production were endowed with tumorigenic and angiogenic potentials as follows: firstly, nontumorigenic, lung carcinoma QG90 cells having lower bFGF productivity acquired tumorigenicity as well as significant in vivo angiogenesis-inducing ability, secondly, tumorigenic colorectal carcinoma RPMI4788 cells having higher potency for bFGF production could form more vascularized solid tumour with faster growth rate and thirdly, oestrogen-dependent breast carcinoma MCF-7 cells, which did not produce detectable bFGF, acquired tumorigenicity even in the absence of oestrogen and the solid tumour growth rate was remarkably enhanced, accompanied with increased vascularization, in the presence of oestrogen. These results suggest that tumour progression closely depends on angiogenesis, and VEGF significantly contributes to malignant progression of a variety of tumour cells through its potent angiogenic activity, independent on the bFGF productivity of tumour cells. 相似文献
66.
Alipov G Nakayama T Ito M Kawai K Naito S Nakashima M Niino D Sekine I 《Histopathology》2005,47(2):202-208
AIMS: The high incidence of clinically diagnosed prostatic cancer is exceeded by the frequency of tumours detected at autopsy. The Ets-1 proto-oncogene is expressed by a variety of malignant and normal tissues. Therefore, in this study, expression of Ets-1 protein was investigated in 'latent' prostatic cancer detected at autopsy, compared with benign prostatic hyperplasia, normal prostatic tissues and clinical prostatic cancer. METHODS AND RESULTS: Using immunohistochemistry, we analysed Ets-1 expression in 95 prostatic specimens including 19 cases of latent prostatic carcinoma (LPC) and 55 cases of clinical prostatic carcinoma (CPC), 11 cases of benign prostatic hyperplasia (BPH) and 10 cases of normal prostate (NP). Differences in the incidence of LPC and CPC suggest different courses for the biological progression of prostatic cancer. There was a significant difference in the degree of Ets-1 expression in CPC and LPC (P < 0.05). Ets-1 was not expressed in BPH and NP, but in malignant cases (57 of 74; 77.0%) commonly demonstrated immunoreactivity in the tumour cells. In our study the expression of Ets-1 between benign and malignant, and well, moderately and poorly differentiated adenocarcinomas of prostatic cancer showed significant differences. The presence of Ets-1 mRNA was confirmed by in-situ hybridization in human prostatic tissues. CONCLUSION: Our results suggest that Ets-1 might play an important role in carcinogenesis and/or the progression of human prostatic carcinomas. 相似文献
67.
68.
Ebihara T Endo R Ishiguro N Nakayama T Sawada H Kikuta H 《Journal of clinical microbiology》2004,42(12):5944-5946
Human metapneumovirus (hMPV) is one of the major pathogens of respiratory illness. Reinfection with hMPV occurs frequently throughout life. We describe an infant who was infected with two different hMPV strains during a period of only 1 month. 相似文献
69.
Kiyoshi A Ishikawa T Hayashi K Iwatsuki Y Ishii K Nakayama K 《Pflügers Archiv : European journal of physiology》2003,447(2):142-149
Rhythmical contractions accompanied by an increase in cytosolic Ca2+ concentrations were produced in ring preparations of endothelium-denuded pulmonary arteries from monocrotaline-treated rats, but not in those from vehicle-treated rats, 2-3 h after a resting tension of 15 mN (150-180% of the initial wall length of the artery) was applied. The rhythmical contractions were abolished by nicardipine and ryanodine. Cyclopiazonic acid reduced the relaxation phase of the rhythmical contractions, finally leading to a sustained contraction. Similarly, apamin caused a sustained contraction, whereas charybdotoxin increased the amplitude of the rhythmical contractions. Glibenclamide had no apparent effects on them. Indomethacin and the prostaglandin H2/thromboxane A2 receptor antagonist SQ29548 abolished the rhythmical contractions and reduced the tension, but the thromboxane synthase inhibitor ozagrel had no effect. These results suggest that optimal stretch induces rhythmical contractions in the pulmonary arteries of monocrotaline-induced pulmonary hypertensive rats, to which both Ca2+ influx through voltage-operated Ca2+ channels and Ca2+ release from the endoplasmic reticulum seem to contribute. It is also suggested that small-conductance Ca(2+)-activated K+ channels participate in the relaxation phase of rhythmical contractions. Furthermore, prostaglandin H2 released from nonendothelial cells is likely to play a pivotal role in the induction of rhythmical contractions. 相似文献
70.
Osamu Sakai Yasuhide Nakayama Yasushi Nemoto Yoshihiro Okamoto Taiji Watanabe Keiichi Kanda Hitoshi Yaku 《Journal of artificial organs》2005,8(2):119-124
A novel sutureless vascular connecting system, an assembly with a delivery rod, an introducing sheath, and a connecting device, was developed for easy implantation of small-caliber vascular grafts less than 2 mm in internal diameter. A microporous stainless tube (length 2 mm, external diameter 1.6 mm, wall thickness 65 µm, pore diameter 400 µm, pore-to-pore distance 500 µm) was designed to serve as a connecting device. The feasibility of the system was tested using two types of preliminary animal experiments. One animal model consisted of graft implantation into the rat abdominal aorta (1.5 mm in diameter). The connecting device was inserted into the proximal and distal ends of the aorta through the introducing sheath by pushing the delivery rod with the connecting device placed over it. Subsequently, the aortic segments were inserted into both ends of model grafts made of segmented polyurethane (1.8 mm in internal diameter) and were fixed with banding silk threads from the exterior. The procedure was completed within 20 min without requiring specialized microsurgery techniques. Blood leakage and obstruction did not occur. The second model consisted of an end-to-end anastomosis between rabbit common carotid arteries (2 mm in diameter), which was performed within several minutes of blood flow interruption. Scanning electron microscopy demonstrated that the luminal surface of the device was fully covered with endothelial cells (ECs) after 1 week as a result of transluminal ingrowth of native ECs through the micropores in the device. This endothelialization may prevent early thrombus-induced occlusion. This simple and “easy-to-learn” technique will promote the development of small-caliber arterial grafts, and furthermore, it may have potential for clinical application. 相似文献