Modal characteristics of ferrimagnetic tridisk-coupled resonator

The eigenvalue characteristics of a ferrimagnetic tridisk-coupled (TDC) resonator are described first. A TDC resonator is made of three AlYIG ferrite disks partially scraped and mutually attached on a center conductor. The EM field is treated with a consistent theory. The eigenvalue characteristics computed with stress on the mode of ν=1 are represented by the Z₁₀ versus Z₀ and Z₁ versus κ/μ relationships, where Z₁₀ is a degenerate eigenvalue, Z₀ is a wavenumber-eccentric radius product, and Z₁ is a continuously varying eigenvalue dependent on κ/μ with a given value of Z₀. Z₁₀ is distinguished by either a single- or double-value region as a function of Z₀. The computed Z₁ versus κ/μ graph belonging to the double-value region demonstrates a contradiction to the physical reality, which is resolved by introducing an equivalent circular resonant mode. The equivalent resonant mode is definitely identified by a degenerate eigenvalue and its modal curve with large modal separation. Experiments were carried out with various center conductors. The experimental results support the equivalent resonant mode. Finally, discussions are presented     

The effect of PTA on cerebral vessels in experimental vasospasm: a histopathological study

Although the percutaneous transluminal angioplasty (PTA) is an useful procedure for the treatment of symptomatic vasospasm after subarachnoid hemorrhage, the morphological changes in spastic intracranial vessels after PTA are not yet clear. The purpose of this study was to evaluate the effects of PTA angiographically and histologically. Chronic cerebral vasospasm was induced by producing a blood clot in the subarachnoid space around the top of internal carotid siphon in Japanese monkey. After angiographic recognition of vasospasm, PTA was carried out with silicone microballoon at 1 atmosphere, 3 times for 10 seconds. Angiography after PTA disclosed significant dilatation at the site of PTA, without any significant dilatation of distal spastic vessels. Papaverine hydrochloride was then infused intra-arterially, which resulted in significant dilatation of distal spastic vessels. Upon histological examination, deformation and some denudation of endothelial cells were noted in the intimal layer. At the site of denudation, attachment of platelets was observed despite generalized heparinization. Internal elastic lamina and the media were also stretched and myocytes were deformed and arranged irregularly. These changes were not uniform all over the vascular walls. We conclude that the prolonged effect of PTA may be caused by mechanical damage of endothelial cells and myocytes, and the nonuniformity of histological changes in vascular wall may be a leading cause of its rupture during PTA.     

A new aspect of the carotid body function controlling hypoxic ventilatory decline in humans

Ventilatory response to eucapnic sustained mild hypoxia was measured in one patient with unilateral and three patients with bilateral carotid body (CB) resection (defined UR and BR, respectively). The profile of ventilatory response in UR patient was initially augmented then gradually declined (biphasic pattern) as generally seen in normal subjects although the absolute magnitude was substantially low. On the other hand, biphasic pattern was disappeared in all three BRs. Lack of hypoxic ventilatory decline (HVD) in the late period of sustained hypoxia was in marked contrast to that reported in the anaesthetized and CB-denervated animals whose ventilation was severely depressed lower than the pre-hypoxic control level. In view of recent knowledge that the analogous mild hypoxia in normal animals and humans elicits an useful adaptation to economize energy expenditure with maintaining reversible excitability in control of respiration, BR patients were considered to have lost this ability. We conclude that in awake humans the CB not only stimulates ventilation but also controls the degree of subsequent HVD during sustained hypoxia.     

Application of non-radioactive europium (Eu3+) release assay to a measurement of human natural killer activity of healthy and patient populations

Europium (Eu3+) release assay is a non-radioactive method for a measurement of cytotoxicity of lymphocytes and has several advantages compared with a conventional 51Cr release assay. However, the Eu3+ release assay has not been applied to a natural killer (NK) activity measurement of a large number of the human population mainly due to a lack of comparability with the 51Cr release assay. With some modifications of the procedures and careful manipulation of cells, constant and reproducible results were obtained by the Eu3+ release assay. NK activity of several individuals was measured by the Eu3+ release assay and was compared with data obtained by 51Cr release assay performed simultaneously. The obtained values by the two methods were almost identical. We applied the Eu3+ method to measure NK activity of a large number of individuals, including 68 apparently healthy donors and 36 autoimmune and 21 cancer patients. Some of these diseases are known to show abnormal NK activity. The obtained cytotoxicities were mostly consistent with the previously reported data obtained by the 51Cr release assay. These results indicated that the Eu3+ release assay could be used as an alternative method for a measurement of human NK activity of mass population including patients.     

Scanning electron microscopy studies of wheat protein fractions from doughs mixed with oxidants at high temperature

Protein from flour and doughs mixed with a Do-Corder at high temperatures in the presence and absence of oxidants (potassium bromate, potassium iodate and L-ascorbic acid) was fractionated according to solubility into water-, salt-, alcohol-, acetic acid-soluble protein fractions and insoluble residue protein. All fractions were freeze-dried and subjected to scanning electron microscopy to observe visually the changes in protein structure. Acetic acid-soluble and insoluble residue protein are alike in structure, but the former was thermally denatured easily, while the latter was very stable to heat treatment. Salt- and alcohol-soluble protein were not deformed, but the water-soluble protein was deformed by heat treatment in the absence of oxidant. Oxidants generally promoted deformation of protein structure with the exception that bromate partly protected acetic acid-soluble protein from deformation.     

Polymorphism of murine Fas ligand that affects the biological activity

Fas ligand (FasL) is a member of the tumor necrosis factor family and induces apoptosis in Fas (CD95)-bearing target cells. In this study, we generated several mAbs that react with mouse FasL (mFasL) and characterized their functional properties. One of these mAbs, K10, specifically reacted with mFasL derived from C57BL/6 (B6) mice, but not that from BALB/c mice as estimated by surface staining and blocking of cytotoxic activities of mFasL transfectants, suggesting a polymorphism of mFasL. Sequence analysis of mFasL cDNA from several strains revealed that BALB/c and DBA/2 mice have three nucleotide differences from the known B6 and C3H sequences, which result in two amino acid substitutions (Thr-184 --> Ala-184 and Glu-218 --> Gly-218) in the extracellular region. Analysis of the K10 reactivity and genotyping by PCR-restriction fragment length polymorphism revealed that inbred mice segregate into the following two allotypes: mFasL.1 (B6, C3H, MRL, SJL, NOD, NZB, NZW) and mFasL.2 (BALB/c, DBA/1, DBA/2). Interestingly, COS7 cells expressing BALB/c FasL lysed Fas-bearing target cells more efficiently than those expressing B6 FasL. Furthermore, BALB/c-derived CD8-FasL fusion protein, which is composed of the extracellular domains of human CD8alpha and mFasL, exhibited 9-fold higher specific activity than did B6-derived CD8-FasL. These results suggest that in mFasL.2 mice the Fas/FasL system works more effectively than in mFasL.1 mice.