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Biomedical subjects

K Kusaka

Publications and source records attributed to K Kusaka.

At least 19 recordsLinked to original sources
PubMed2001

Commensurate structure of Ca(2)CoSi(2)O(7), a new twinned orthorhombic structure.

The crystal structure of the commensurate phase of Ca(2)CoSi(2)O(7), dicalcium cobalt disilicate, has been derived from the modulated structure described in (3 + 2)-dimensional space. The structure is orthorhombic P2(1)2(1)2; a = 23.510 (4), b = 23.510 (4), c = 5.025 (1) A (at 170 K), Z = 18. Since the crystal is twinned and the apparent diffraction symmetry is 4/mmm, the parameters were refined by a newly developed least-squares program for the refinement of twinned crystals. The structure is essentially similar to the known structure of the melilite group, but with regular arrangement of the bundles along [001] formed with four arrays of the sixfold coordinated Ca polyhedra and an array of CoO(4) tetrahedra. The distribution of the bundles found in the present structure is different from that reported by Riester et al. [(2000), Z. Kristallogr. 215, 102-109].

Journal Article↗
PubMed2000

Two-dimensional incommensurately modulated structure of (Sr0.13Ca0. 87)2CoSi2O7 crystals.

The incommensurate structure of (Sr(0.13)Ca(0.87))(2)CoSi(2)O(7) at room temperature has been determined from single-crystal X-ray diffraction data. The compound has a non-centrosymmetric tetragonal basic cell of a = 7.8743 (4) and c = 5.0417 (2) A with the space group P4;2(1)m. The refinements of the basic structure converged to R = 0.038 for 757 main reflections. The two-dimensional incommensurate structure is characterized by the wavevectors q(1) = 0.286 (3)(a* + b*) and q(2) = 0.286 (3)(-a* + b*), where a*, b* are the reciprocal lattice vectors of the basic structure. With the (3 + 2)-dimensional superspace group P(p4mg)(P4;2(1)(m)), the refinements converged to R = 0.071 for 1697 observed reflections (757 main and 940 satellite reflections). The structure is described in terms of displacement of the atoms, rotation, distortion of CoO(4) and SiO(4) tetrahedra, and the partial ordering of the Sr and Ca atoms accompanied with the modulation. Correlated evolution of these features throughout the crystal gives rise to various oxygen coordination around Ca/Sr. Comparison of the derived modulated structure to that of Ca(2)CoSi(2)O(7) clarified that the partial substitution of Ca by large alkaline-earth atoms such as Sr should decrease the distortion of the polyhedra around the cations.

Journal Article↗
PubMed2000

Objective evaluation of liver consistency to estimate hepatic fibrosis and functional reserve for hepatectomy.

BACKGROUND: The empiric evaluation of liver consistency is currently used to plan the surgical strategy. The aim of this study was to verify the feasibility of the objective measurement of liver consistency and to check its correlation with liver fibrosis and liver functional reserve. STUDY DESIGN: Fifty-two consecutive patients who underwent hepatic resections in our department were enrolled. The indications for liver resection were hepatocellular carcinoma in 36 patients, metastatic liver tumors in 12 patients, and other conditions in 4 patients. Liver consistency was measured with a new tactile sensor. A fibrosis index was calculated as an expression of the percentage of fibrotic tissue. Liver consistency was compared with the degree of liver fibrosis observed in histologic specimens (fibrosis index) and with liver function parameters. RESULTS: Liver stiffness showed a significant positive correlation with fibrosis index (r = 0.887, p < 0.0001). Liver stiffness also showed significant positive correlation with the indocyanine green test (r = 0.631, p < 0.0001) by a univariate analysis. The indocyanine green test and platelet count were independently and significantly associated with liver stiffness by a multiple regression analysis. In five patients, the liver stiffness values measured intraoperatively differed markedly from those expected from the indocyanine green test values. In these patients, the operative procedures were finally selected based on the liver stiffness measured with the tactile sensor and good clinical outcomes were obtained. CONCLUSIONS: These results show for the first time that liver stiffness can be clinically assessed quantitatively by means of the tactile sensor. The tactile sensor adequately estimates liver stiffness and this estimation is well correlated with liver fibrosis and functional reserve. Liver consistency determined objectively in this manner may be useful for optimizing surgical decision making.

Adult↗
PubMed2000

Celiac plexus block in cancer pain management.

The neurolytic celiac plexus block (NCPB) has been recommended for pain relief in patients with upper abdominal cancer by the WHO Cancer Pain Relief Program. In this article, we review the indications, techniques, and adverse effects of NCPB based on the previous findings in the literature and our own experience of 142 NCPBs during the past 11 years. No well-validated indication criteria for the NCPB have been available from invasive trials or non-invasive pain evaluations. Thus, the procedure has been employed using comprehensive pain assessment. Several modified approaches have been described for NCPB with differences in the target space where the alcohol is injected (precrural and retrocrural) and the insertion route of the needle (posterolateral and transdiscal). We have used the retrocrural transdiscal approach because of its simplicity and safety. The efficacy of the resultant pain relief does not differ among these techniques. Therefore, whether a distinction exists between blocks of the celiac plexus and those of the splanchnic nerves is controversial. The term "peri-aortic nerve block" may better describe the feature of this neurolytic intervention. The noteworthy adverse effects of alcoholic neurolysis include regional pain, hypotension, diarrhea, hypoxemia, and acute alcoholic intoxication. Most of them are transient and controllable. The diarrhea may counteract the morphine-induced constipation. NCPB relieves visceral pain in upper abdominal cancer with no serious adverse effects. We recommend this procedure to improve the quality of life of the patients suffering from abdominal cancer pain.

Abdominal Neoplasms↗