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91.
S Kangsadalampai G Chelvanayagam RT Baker P Yenchitsomanus P Pung-amritt C Mahasandana PG Board 《Canadian Metallurgical Quarterly》1998,92(2):481-487
We re-evaluated three schemes of liver organization: the classic lobule, the portal lobule, and Rappaport's liver acinus. The lobular angioarchitecture of normal rat liver and the three-dimensional structure of pseudolubules found in rat livers with fibrosis induced by swine serum were compared with the classic lobule of the pig. Normal and fibrotic rat livers and pig livers were perfused, injected with either India ink or 0.75% OsO4 through the portal and/or hepatic vein, and immersionfixed. Whole lobes and hand-cut thick sections were made transparent with a solution of benzyl benzoate and methyl salicylate. The angioarchitecture of normal rat liver differs from pig liver. In the former, terminal portal branches and central veins interdigitate, and in the latter, numerous terminal portal branches that arise from interlobular portal veins establish a vascular basket surrounding one central vein and forming classic lobule. The structure of liver acinus is never found in the pig liver. The terminal portal branch, together with the terminal hepatic artery and bile duct, are present inside each pseudolobule of fibrotic rat livers. Blood from the terminal portal branch flows through inlet venules into radiating sinusoids, and, at the periphery converges into newly formed septal and angular outlet venules; these venules terminate in fibrotic central veins located at each corner. Pseudolobules are not rugby ball-like as Rappaport's liver acini are but are polyhedron in shape. The rat pseudolobules are comparable with the portal lobule; its structure and microcirculation are the reverse of the pig classic lobule. Rat pseudolobules are different from liver acini, as shown by the following: 1) their three-dimensional shape is different; and 2) they have a reverse relationship to classic lobules while acini are defined to subdivide classic lobules. In normal and fibrotic rat livers, the liver unit is the portal lobule with a terminal portal branch as the axial branch and central veins at the periphery. The co-existence of liver acini and classic lobules is doubtful. 相似文献
92.
JS Chang DY Noh IA Park MJ Kim H Song SH Ryu PG Suh 《Canadian Metallurgical Quarterly》1997,57(24):5465-5468
Phospholipase C-gamma1 (PLC-gamma1) mediates signals from various extracellular origins to evoke cellular events such as mitogenesis. Previously, we reported that PLC-gamma1 was highly expressed in colorectal cancer and familial adenomatous polyposis, suggesting that PLC-gamma1 might be oncogenic. In this study, we have established rat 3Y1 fibroblasts that overexpress whole PLC-gamma1 and src homology 2 (SH2)-SH2-SH3 domain of PLC-gamma1. These cells showed a transformed phenotype and were tumorigenic when transplanted into nude mice. These results indicate that overexpression of PLC-gamma1 could transform rat fibroblasts, and the transformation is mediated by SH2-SH2-SH3 domain of PLC-gamma1. 相似文献
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94.
An antibody generated to an alpha-keto amide containing hapten 1 catalyzes the cis-trans isomerization of peptidyl-prolyl amide bonds in peptides and in the protein RNase T1. The antibody-catalyzed peptide isomerization reaction showed saturation kinetics for the cis-substrate, Suc-Ala-Ala-Pro-Phe-pNA, with a kcat/Km value of 883 s-1.M-1; the reaction was inhibited by the hapten analog 13 (Ki = 3. 0 +/- 0.4 microM). Refolding of denatured RNase T1 to its native conformation also was catalyzed by the antibody, with the antibody-catalyzed folding reaction inhibitable both by the hapten 1 and hapten analog 13. These results demonstrate that antibodies can catalyze conformational changes in protein structure, a transformation involved in many cellular processes. 相似文献
95.
A time-domain version of the uniform geometrical theory of diffraction (TD-UTD) is developed to describe, in closed form, the transient electromagnetic scattering from a perfectly conducting, arbitrarily curved wedge excited by a general time impulsive astigmatic wavefront. This TD-UTD impulse response is obtained by a Fourier inversion of the corresponding frequency domain UTD solution. An analytic signal representation of the transient fields is used because it provides a very simple procedure to avoid the difficulties that result when inverting frequency domain UTD fields associated with rays that traverse line or smooth caustics. The TD-UTD response to a more general transient wave excitation of the wedge may be found via convolution. A very useful representation for modeling a general pulsed astigmatic wave excitation is also developed which, in particular, allows its convolution with the TD-UTD impulse response to be done in closed form. Some numerical examples illustrating the utility of these developments are presented 相似文献
96.
97.
98.
AR Young CS Potten O Nikaido PG Parsons J Boenders JM Ramsden CA Chadwick 《Canadian Metallurgical Quarterly》1998,111(6):936-940
Epidemiology shows a relationship between solar exposure and all types of skin cancer. Understanding the mechanisms of skin cancer requires knowledge of the photomolecular events that occur within the relevant epidermal cell types in vivo. Studies to date have focused on UVR-induced DNA lesions in keratinocytes, the majority epidermal cell population which gives rise to most skin cancers. Malignant melanoma, arising from melanocytes (5%-10% of epidermal cells), accounts for most skin cancer deaths. We report on new techniques to detect DNA photolesions in human epidermal melanocytes in situ. Previously nonexposed buttock skin of volunteers of skin types I/II was exposed to clinically relevant doses of narrow bandwidth UVB (300 nm) and UVA (320 nm, 340 nm, 360 nm) radiation. Biopsies were taken immediately afterwards and processed for routine histology. Microscope sections were prepared and double-stained with fluorescent-tagged monoclonal antibodies for thymine dimers and melanocytes. UVR dose-response curves for dimer levels within melanocyte nuclei were determined by image analysis and compared with dimer levels in adjacent basal cell keratinocytes. Our data show that UVB and UVA readily induce thymine dimers in melanocytes at levels that are comparable with those found in adjacent keratinocytes. This new technique will enable melanocyte specific studies, such as DNA repair kinetics, to be done in vivo. 相似文献
99.
100.
PG Reitnauer 《Canadian Metallurgical Quarterly》1976,17(3):138-142
The lumbar-spine radiographs of 67 patients with idiopathic chondrocalcinosis articularis were reviewed for disc calcification and other changes. Calcification was present in 21 (31%) of the patients, seen most frequently at the L 2-3 disc space. The 21 patients as a group were significantly older than the 46 patients without disc calcification, and also had a much higher incidence of chondrocalcinosis in peripheral joints. There was no association with back pain or spinal stiffness. The 21 patients with disc calcification included six patients with a destructive peripheral arthropathy, and three of them had destructive changes affecting the lumbar spine. Three patients with a destructive peripheral arthropathy were also included in the group without disc calcification, and one of these had a destructive arthritis of the lumbar spine. For comparison, there was a 55% incidence of spinal chondrocalcinosis in nine patients with primary hyperparathyroidism and peripheral joint chondrocalcinosis, and a 6% incidence in 100 anteroposterior lumbar spine radiograph 'controls', taken before intravenous urography, although in this latter group the changes were minimal and confined to the margin of a single disc in each case. 相似文献