A study of interference of three parallel cracks

This paper describes the priority of propagation among three parallel cracks. The treated object is an infinite elastic body with three parallel cracks subjected to uniform tension or antiplane shear at infinity. The results make it clear that the longest crack does not always have the biggest value relating to fracture, e.g. the biggest tangential stress at crack tip or the biggest stress intensity factor, because of the interaction among the cracks.     

The relationship between cell proliferation activity and secretory activity in pituitary adenoma--a review of 63 cases

Determination of the cell proliferation activity of neoplasm is useful in making a prognosis. Immunohistochemical detection using MIB-1 monoclonal antibody has recently allowed us to assess tumor cell proliferation easily, because it can be performed on paraffin-embedded specimens and the results have been demonstrated to be positively correlated with the results of PCNA staining. In this study, surgical specimens of 63 pituitary adenomas were examined by immunohistochemical staining with MIB-1 monoclonal antibody. Twenty-nine cases were non-functioning pituitary adenomas, 20 were prolactin (PRL)-producing pituitary adenomas, and 14 were growth hormone (GH)-producing pituitary adenomas. The MIB-1 positive rates of the pituitary adenomas ranged from 0% to 6.46%. In the non-functioning pituitary adenomas, the MIB-1 positive rates ranged from 0% to 4.55% (mean : 0.76%), in the PRL-producing pituitary adenomas the MIB-1 positive rates ranged 0% to 6.46% (mean : 0.91%), and in the GH-producing pituitary adenomas the MIB-1 positive rates ranged 0% to 1.28% (mean: 0.58%). There were no significant differences between these values according to the results of the Wilcoxon signed-rank test. Although the size of the non-functioning pituitary adenomas was not correlated with their MIB-1 positive rate, tumor size was closely correlated with the interval between the onset of the initial symptoms and the date of surgery. In the PRL-producing pituitary adenomas, the MIB-1 positive rate was not correlated with serum PRL levels as an index of secretory activity, but was correlated with the PRL staining positive rate. Preoperative bromocriptine therapy proved effective in reducing tumor size and serum PRL levels, but had no effect on the MIB-1 positive rate. In the GH-producing pituitary adenomas, the MIB-1 positive rate was not correlated with serum GH levels as an index of secretory activity, but was closely correlated with the GH staining positive rate. All three groups included both invasive and noninvasive tumor types, but there were no close statistical correlations between the three tumor types.     

A case report of pneumonia due to Chlamydia trachomatis with pleural effusion

A 64-year-old male consulted our hospital with a 6-day history of malaise, body temperature to 38 degrees C, anorexia, and light headedness. The chest radiograph showed consolidation in the left lower lung area. Chest CT and ultrasonography revealed left pleural fluid. The pleural fluid was exudative (yellowish in color, protein 3.0 g/dl, Rivalta reaction positive, adenosine deaminase 19.4 U/L), and had a total cell count of 4.7 x 10(6)/ml with 45% lymphocytes, 40% histiocytes, and 15% polymorphonuclear leukocytes. He had kept a budgerigar, but we could not isolate Chlamydia from the pleural fluid or the pet bird. Transbronchial lung biopsy from left S10 revealed an increase of mononuclear leukocytes within the interstitial spaces, and the alveolar spaces contained polymorphonuclear leukocytes, fibrin, and organized alveolar exudate. Bronchoalveolar lavage cellular constituents were 50% lymphocytes, 27% neutrophils, and 23% macrophages. Serologic studies demonstrated C. trachomatis specific IgM antibody titers at 1:20 in a serum sample and at 1:10 in pleural fluid. We report a case of community-acquired pneumonia caused by C. trachomatis diagnosed by serologic studies.     

Increase in serum vascular endothelial growth factor levels during altitude training

Atlantoaxial transarticular fixation is a proven stabilization technique used to augment conventional sublaminar fusion. Along with its superior biomechanical profile comes the inherent risk of neurovascular injury and potential compromised fixation during its application. This article presents a detailed systematic guide to this procedure including preoperative evaluation, positioning, and the more subtle aspects of the surgical technique. A new instrumentation design that has enhanced the ease and accuracy of screw placement with less operative frustration and potential morbidity of previous systems also is presented.     

Structure-function study on gastric proton pump

H+, K(+)-ATPase is a proton pump responsible for gastric acid secretion. It actively transport proton and K+ coupled with the hydrolysis of ATP, resulting in the formulation of a 10(6) fold proton gradient across the plasma membrane of parietal cells. The pump belongs to a family of P-type ATPases which include the Na+ pump (Na+, K(+)-ATPase) and the Ca2+ pump (Ca(2+)-ATPase). This review focuses on the structure-function relationship of this proton pump by using functional antibodies, specific inhibitor(s), a fluorescent reagent and site-directed mutants. First we prepared monoclonal antibodies which modified the functions of the H+, K(+)-ATPase . One of the antibodies, HK2032 inhibited the H+, K(+)-ATPase activity and the chloride conductance in gastric vesicles opened by S-S cross-linking, suggesting that the chloride pathway is in the H+, K(+)-ATPase molecule, and that the H+, K(+)-ATPase is a multi-functional molecule. Other antibody, HK4001 inhibited the H+, K(+)-ATPase activity by inhibiting its phosphorylation step. By using this antibody we found an H+, K(+)-ATPase isoform in the rabbit distal colon. Second we found that scopadulcic acid B, a main ingredient of Paraguayan traditional herb, is an inhibitor specific for the H+, K(+)-ATPase. This compound inhibited the H+, K(+)-ATPase activity by stabilizing the K(+)-form of the enzyme. Third we studied the conformational changes of the H+, K(+)-ATPase by observing the fluorescence of FITC-labeled enzyme. H+, K(+)-ATPase did not utilize acetylphosphate instead the ATP as an energy source of active transport, suggesting that the energy transduction system is not common among P-type ATPases. Finally we constructed a functional expression system of the H+, K(+)-ATPase in human kidney cells. By using this functional expression system in combination with site-directed mutagenesis, we studied the significance of amino acid residues in the catalytic centers (a phosphorylation site and an ATP binding site) and the putative cation binding sites. We newly found the sites determining the affinity for cations.     

Thermochemical study of vaporization of LiTiO by a mass spectrometric Knudsen effusion method

The vaporization of Li₄TiO₄ has been studied by a mass spectrometric Knudsen effusion method in the temperature range 1082–1582 K. Identified vapors are Li(g), LiO(g), Li₂O(g) and Li₃O(g). When the vaporization proceeds, the content of Li₂O in the Li₄TiO₄ sample decreases and the condensed phase of the sample changes to β-Li₄TiO₄ plus l-Li₂TiO₃ below 1323 K, to β-Li₄TiO₄ plus h-Li₂TiO₃ in the range 1323–1473 K and to h-Li₂TiO₃ plus liquid above 1473 K. On the basis of the partial pressure data, the enthalpies of formation for β-Li₄TiO₄ from elements and from constituent oxides have been determined to be ΔH_f,298^°(β-Li₄TiO₄,s) = −2247.8 ± 14.3 kJ mol⁻¹ and Δ_fox,298^°(β-Li₄TiO₄, s) = −107.3 ± 14.3 kJ mol⁻¹, respectively.     

A novel vascular relaxing agent, N-(6--aminohexyl)-5-chloro-1-naphthalensulfonamide which affects vascular smooth muscle actomyosin

The relaxing effect and possible mechanism of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7) on isolated rabbit artery were investigated. The addition of W-7 in concentrations ranging from 1 X 10(-6) to 3 X 10(-4) M caused a significant relaxation of isolated rabbit vascular strips contracted by KCl, prostaglandin F2alpha, norepinephrine, histamine, CaCl2, serotonin or angiotensin II. W-7 also caused a shift to the right of the dose-response curves for all agonists tested. Propranolol and atropine did not affect W-7 induced relaxation, suggesting that this drug does not act through beta adrenergic or cholinergic receptors. Superprecipitation of actomyosin from bovine aorta smooth muscle was inhibited by the addition of W-7 in a dose-dependent fashion. The concentration of W-7 which inhibited superprecipitation of bovine aorta smooth muscle actomyosin was in good agreement with the dose producing relaxation of isolated vascular strips. These facts suggest that W-7 produces relaxation of isolated vascular strips by inhibiting actin and myosin interaction.     

Fabrication of dense silicon carbide through aqueous slurries containing well-dispersed carbon as a sintering aid

Tetramethyl ammonium hydroxide (TMAOH) has no fluidizing effect on carbon particles, because of their hydrophobic surface properties. On the other hand, styrene/maleic copolymer (SM) enhanced the fluidity of two kinds of carbon slurries in the basic pH range, where the particle diameters of carbon {#}2650 and MA100 were 13 and 22 nm, respectively. High-density sintered bodies of silicon carbide containing carbon and boron carbide as sintering aids were obtained by controlling the pH of 10–11 with TMAOH and by addition of SM: i.e., 9.5 and 5.5 wt% of SM were added to #2650 and MA100, respectively, in the dry weight base of the carbon. The highest sintered density product with more than 98% was obtained by intimate dispersion of the finer carbon particles in the silicon carbide slurries.