Biomedical subjects

T Handa

Publications and source records attributed to T Handa.

At least 19 recordsLinked to original sources

PubMed1992

Resonance Raman study on the active-site structure of a cooperative hemerythrin.

Resonance Raman spectra were observed for the oxy and azidomet forms of a cooperative hemerythrin (Hr) isolated from Lingula unguis and a noncooperative Hr from Siphonosoma cumanense. The O-O stretching frequency of the oxy derivative of the L. unguis Hr was lower in the high-affinity form generated at pH 7.6 than in the low-affinity form generated at pH 6.2, while that of the S. cumanense Hr did not change at those two pH values. The Fe-O-Fe symmetric stretching mode of L. unguis azidomet-Hr exhibited a frequency shift between pH 7.6 and 6.2, while that of S. cumanense was not shifted. However, the corresponding band of the oxy form did not show a pH-dependent frequency change. Therefore, it is noted that the azidomet form is not a suitable model for studying a mechanism of cooperativity, contrary to the structural similarity between the oxy and azidomet forms. The Fe-O2 as well as Fe-N3 stretching frequencies were found to have no relation with the oxygen affinity. Upon exchange of solvent from H2O to D2O, the O-O and Fe-O2 stretching modes of L. unguis Hr were shifted to higher and lower frequencies, respectively, and their magnitudes were the same for the high- and low-affinity forms. The same frequency shifts were observed for S. cumanense Hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Monolayer-bilayer equilibrium of phospholipid: stabilization of neutral lipid droplets in aqueous medium and catabolism of plasma lipoproteins.

Phospholipid spreads as monolayer at air/water and oil/water interfaces. Interfacial pressure of the monolayer in equilibrium with a definite bulk phase of the lipid, (equilibrium) spreading pressure, depends on lyotropic and thermotropic polymorphic state of the lipid bulk phase. Phosphatidylcholine (PC) in hydrated liquid crystalline state (bilayers in L alpha state) gives an appreciably large value of spreading pressure, 45-46 mN/m. Monolayer-bilayer equilibrium of a neutral lipid-phospholipid mixture is determined by miscibilities of the lipids in mixed monolayer, PC bilayer and bulk (liquid or solid) phase of the neutral lipid. A neutral lipid of limited solubility in PC bilayer forms a separate phase in aqueous medium. The phase is stabilized as small particles in the medium by PC monolayer at the particle surface. The monolayer is in equilibrium with the bilayer. This sort of equilibrium plays important roles in formation and catabolism of triglyceride- and cholesteryl ester-rich lipoprotein particles in animal plasma. The equilibrium is a critical factor also in stabilization of aqueous dispersion of lipophilic vitamin (neutral lipid). Coexistence of emulsion particles (neutral lipid core covered with PC monolayer) and vesicles made of PC bilayer are observed in a stable dispersion.

Animals↗

PubMed1992

Lateral interactions of pig apolipoprotein A-1 with egg yolk phosphatidylcholine and with cholesterol in mixed monolayers at the triolein-saline interface.

Interfacial tensions of egg yolk phosphatidylcholine (PC) and cholesterol monolayers adsorbed at the triolein-saline interface were measured in the presence and absence of pig apolipoprotein A-1 (apoA-1) in the saline phase. In the absence of apoA-1, the adsorptions of PC and cholesterol at the interface from the triolein phase are cooperative, showing large lateral attractive interactions between the PC molecules and the cholesterol molecules in the monolayer. In the presence of apoA-1, the PC adsorption is anti-cooperative, indicating strong lateral attractive interactions between the PC and the apoA-1 molecules, i.e., apparently, repulsive lateral interactions between the PC molecules. On the other hand, lateral interactions of very low magnitude are observed between the cholesterol and apoA-1 molecules in the monolayer. Values of the lateral interaction energy are evaluated from the adsorption data by the Defay-Prigogine-Flory theory of monolayers. The large difference in lateral interaction energy with apoA-1 between PC and cholesterol in a mixed monolayer is discussed in connection with current problems in lipoprotein catabolism: reverse cholesterol transport, alterations in affinity of lipid particles to apoA-1, and formation of high-density lipoproteins and abnormal lipoproteins.

Adsorption↗

PubMed1992

Histopathological study of balloon embolization: silicone versus latex.

Bilateral, symmetrical, experimental aneurysms were produced with anastomosed vein flap in the carotid arteries of 24 mongrel dogs. Aneurysms were occluded with latex or silicone balloons on each side and observed angiographically from 2 weeks to 2 months. A histopathological study was performed subsequently using light and scanning electron microscopy. Rupture after balloon embolization occurred in five aneurysms; all of which were incompletely occluded by a silicone balloon. On subsequent angiograms, four silicone balloons and one latex balloon were found to have migrated into the aneurysm, resulting in aneurysmal expansion. Parent artery occlusion was more common with latex balloons than silicone balloons. Histopathologically, residual fresh thrombi, decreased proliferation of fibroblasts within the aneurysmal cavity, and poor endothelialization were present around the silicone balloon. These results suggest that the intra-aneurysmal organization, as seen in the aneurysm occluded by the silicone balloon, will be delayed because the balloon is not fixed within the aneurysm, and that this free-floating and rotating balloon causes repeated trauma to the aneurysm wall, contributing to subsequent enlargement and rupture of the aneurysm. The superior antithrombogenic nature of silicone may be responsible for the bias of such phenomena toward the silicone balloon.

Aneurysm↗

PubMed1992

Computer-assisted gait training (CAGT) of hemiparetic stroke patients: whose recovery is most predictable?

Maximum walking speed for 10 m distance of 109 hemiparetic stroke patients was examined every week for 7 weeks after starting computer-assisted gait training (CAGT), and the relation between the time since stroke onset (x) and the maximum walking speed (y) was approximated by a hyperbolic function, y = A-B/x. The patients were divided into two groups, 91 cases with a significant fit of the function (fit group) and 18 without fit (non-fit). The gain of maximum walking speed during 7 weeks was larger in the fit group, compared to the non-fit. Computed tomography examination revealed that the significant fit was mostly expected in patients with the caspular lesion without the cortical involvements except the frontal. The time at which the maximum walking speed of the patients belonging to the fit group would reach the midst of the estimated full recovery of gait can be predicted at the start of CAGT (R2 = 0.955), using two variables: the time since stroke onset and the maximum walking speed.

Brain↗

PubMed1992

Vascular endoscopy for intravascular surgery--an experimental study.

A combination of endoscope and high-pressure saline irrigation system was tested in the occlusion of experimental aneurysms, and angioplasty and fibrinolysis of vascular occlusive lesions in canine femoral arteries. Endoscopy provided detailed information about the aneurysmal orifice and lumen and aided balloon placement and detachment. Endoscopy visualized the dynamic changes accompanying thrombolysis and the fine intimal injury due to angioplasty invisible on angiography. Vascular endoscopy is valuable for pre-, intra-, and postoperative evaluation of intravascular interventions.

Angiography↗

PubMed1992

Isolated intramedullary spinal artery aneurysm presenting with quadriplegia. Case report.

The case is presented of an isolated intramedullary posterior spinal artery aneurysm at the C-2 level in a 3-year-old girl. Quadriplegia related to probable intramedullary hemorrhage was the presenting symptom. Magnetic resonance imaging revealed findings consistent with an intramedullary vascular lesion, and vertebral angiography confirmed this to be an aneurysm of the posterior spinal artery. No associated vascular abnormalities were noted, and the aneurysm was successfully resected. Previous reports of isolated spinal aneurysms are reviewed.

Aneurysm↗

PubMed1992

[A case report of adenoid cystic carcinoma of the nasal septum].

A 50-year-old woman with adenoid cystic carcinoma of the nasal septum is presented. Her chief complaint was recurrent epistaxis. Surgery was originally performed to remove a nasal polyp, but during resection, the surgeon discovered that the mass had arisen from the nasal septum, so only a biopsy was done. The pathological report was adenoid cystic carcinoma, so she was referred and admitted to our hospital. A flat 1.5 x 1.5 cm tumor was recognized on the left side of the nasal septum. Nasal septectomy was performed. The tumor was dissected with nasal septal cartilage, and the defect was covered with a free skin flap from the thigh. The incidence of malignant tumors from the nasal septum is very low, composing from 2.7% to 8.4% of nasal and paranasal malignant tumors. Therefore the incidence of adenoid cystic carcinoma in particular is very low.

Carcinoma, Adenoid Cystic↗

PubMed1992

[Diagnosis on Mycoplasma pneumoniae infections by DNA-probe assay in comparison with serological tests].

To evaluate the usefulness of DNA diagnosis as a diagnostic approach to Mycoplasma pneumoniae infections, we compared the DNA-probe assay with serological tests in 32 patients who were clinically suspected of having Mycoplasma pneumonia. The DNA-probe assay was carried out using the Gen-probe kit. Serological tests included complement fixation and passive hemagglutination tests. At first visit 10 patients were positive for the DNA-probe assay, while only 2 of them were positive for serological tests. The other 3 patients became positive for serological tests during the clinical course. In accordance with clinical improvement, these patients became negative for the DNA-probe assay. Three patients were negative for DNA-probe assay while they were positive for the serological tests. However, these patients had already received antibiotics; therefore, their conditions were considered to have been improved at the time of the study. The other 19 patients were negative for both the DNA-probe assay and serological tests. These patients might have suffered from respiratory tract infections of pathogenic organisms other than M. pneumoniae or the number of M. pneumoniae might have been too small to be detected by the DNA-probe assay. The results of the present work demonstrate that the DNA-probe assay was valuable in the diagnosis of mycoplasmal infections at the early stage, which indicates that DNA diagnosis provides useful information to determine the most appropriate therapeutic regimen.

Child↗

PubMed1992

Effect of recombinant human granulocyte colony-stimulating factor (rh G-CSF) on murine resistance against Listeria monocytogenes.

Recombinant human granulocyte colony-stimulating factor (rh G-CSF) enhanced resistance of mice against Listeria monocytogenes (LM) as determined by survival and bacterial growth. Mice pretreated with rh G-CSF twice daily for 5 days survived better than untreated animals to the challenge with LM. Number of bacteria in peritoneal cavity (PC) and spleen was lower in treated mice than that in the control group. Rh G-CSF increased mainly polymorphonuclear cells (PMN) in blood and spleen. After LM inoculation, a larger number of PMN and monocyte-macrophages accumulated in PC and spleen of tested mice. In addition, PMN primed in vivo with rh G-CSF released more superoxide anions when stimulated with phorbol myristate acetate. The inhibition of bacterial growth in PC and spleen could be ascribed to the accumulation of phagocytic cells at the infection sites and the increased oxidative metabolism. The results provided further evidence of the important contribution of G-CSF and neutrophils, as target cells, to the host defence against the intracellular bacteria.

Animals↗

PubMed1992

Functional electrical stimulation (FES) systems for restoration of motor function of paralyzed muscles--versatile systems and a portable system.

Multichannel functional electrical stimulation (FES) systems were developed to restore the motor functions of the paralyzed muscles, i.e. two kinds of versatile systems for laboratory use and a practical portable system were developed. The first microcomputer-based FES system was composed of an 8 bit microcomputer (PC-8801mkII) with a voice recognition board and 30 stimulation outputs, in which the voice commands were used for selecting a motion pattern, and for executing (start), (hold), (restart) and (stop) commands. In combination with the voice commands, a proportional control command detected from a head angle sensor was used for volitional control of motion. The second microcomputer-based FES system was composed of a 16 bit microcomputer (PC-9801 UV or compatible) with flexible control capabilities (e.g. respiratory sensors) for volitional control and with 64 stimulation outputs. An originally designed practical portable FES system was 89 x 145 x 31 mm in dimension and 380 g in weight. This paper describes the system configurations, the control methods of these FES systems and three examples of the clinical applications of the FES systems.

Electric Stimulation Therapy↗

PubMed1992

Difference in the functional maturation of T cells against Listeria monocytogenes in lymph nodes and spleen.

After subcutaneous immunization of mice with viable Listeria monocytogenes (LM), we evaluated the function of T cells induced in draining lymph nodes (LN) and spleen as determined by the local transfer of delayed-type hypersensitivity (DTH), acquired cellular resistance (ACR) and in vitro lymphokine production. LN cells could transfer specifically DTH but not ACR. In contrast, spleen cells from the same donor mice evoked the DTH response as well as bacterial clearance at the reaction site. Comparison of bacterial counts in spleen and in LN upon subcutaneous inoculation of mice with LM suggested that the lack of bacterial proliferation in LN underlay the failure to induce protective T cells in this lymphoid tissue. Spleen and LN T cells expressed CD4 and CD8 surface antigens equally and DTH response was solely dependent on CD4+ cells. Another major difference between LN and spleen cells was the profile of lymphokines produced in vitro. Upon the in vitro restimulation with killed Listeria, immune spleen cells produced macrophage chemotactic factor (MCF), interleukin-2 (IL-2) and interferon-gamma (IFN-gamma). In contrast, LN cells could produce all of the measured lymphokines but not IFN-gamma. The results provided strong evidence for the dissociation of DTH and ACR. Listerial growth appeared to be the requirement for full maturation of anti-listerial immunity that may coincide with the generation of IFN-gamma-producing T cells.

Animals↗

PubMed1991

[Evaluation of DNA-probe assay for the clinical diagnosis of Mycoplasma pneumoniae infections].

DNA probe-assay using the Gen-Probe kit was carried out to detect Mycoplasma pneumoniae infections. Fifteen children visited Ota General Hospital complaining of dry cough and high grade fever. Throat swabs of the patients were examined to detect M. pneumoniae ribosomal RNA by Gen-Prove kit. Five out of 15 patients were positive for DNA probe assay of M. pneumoniae. Clinical and laboratory data including serological examinations were compatible with M. pneumoniae infection in these cases. Following the improvement of clinical symptoms and signs by receiving erythromycin or minocycline, the positivity for DNA probe assay turned to negative. Among the ten patients, who were negative for DNA probe assay, 2 cases were suspected of M. pneumoniae infection on the basis of clinical and laboratory findings. One patient had already taken antibiotics. Therefore, in these two patients, there was a possibility that the bacterial numbers were too small to be detected by DNA-probe assay. The data described above support that DNA-probe assay is useful for the diagnosis of M. pneumoniae infections in the early stage. DNA-probe assay is also valuable to follow up the clinical course of the patients.

Child↗

PubMed1991

[Effects of heavy metal ions in endocochlear DC potential and cochlear microphonics in the guinea pig--the influence of calcium on the cochlea].

Endocochlear DC potential (EP) and cochlear microphonics (CM) in the guinea pig under the influence of the divalent heavy metal cations of manganese, nickel, cobalt and cadmium, and the trivalent cation of lanthanum were investigated. The area from the scala tympani to the scala vestibuli was perfused with control and test solutions. CM decreased gradually to 50-80%, but EP showed no change after perfusion with a solution containing 1 mM of metal ions. At a concentration of 10 mM, EP decreased from 80 mV to 10-20 mV and CM decreased to 15-55%. At 100 mM, EP increased by about 10 mV at the beginning of perfusion, remained steady for 1 min, and then rapidly decreased to 0-10 mV. Meanwhile, CM continued to decrease, finally sustaining a 10-56% reduction. The decrease in EP and CM were irreversible, and perfusion of the area with the standard solution for 20 min had no effect. The osmolarity of the artificial perilymph containing 100 mM of metal ions was twice as high as that of the normal physiological solution. The effects of osmolarity, however, were excluded because perfusion with an artificial perilymphatic solution made hypertonic by either NaCl or sucrose changed neither EP nor CM. The application of 100 mM of metal ions topically to the round window membrane caused no change in EP. The alkali metal ions are known to inhibit inward Ca2+ current. Therefore, the present results suggest that Ca2+ ions play a role in maintaining EP generation in the stria vascularis and CM generation in the organ of Corti.

Animals↗

PubMed1991

A dissociated induction of MCF-producing and MAF-producing T cells specific for Listeria monocytogenes in the in vitro primary culture system.

Using an in vitro primary culture system which we had previously established, the induction phase of Listeria monocytogenes-specific effector cells was analysed with respect to their abilities to produce effector lymphokines, macrophage chemotactic factor (MCF) and macrophage-activating factor (MAF). Listeria-specific effector cells generated after in vitro culture of normal spleen cells with viable L. monocytogenes for 5 days conveyed L3T4+, Lyt-2-, Thy-1+ surface antigens and produced MCF and MAF in response to the secondary stimulation with heat-killed L. monocytogenes. The cells required for the induction of Listeria-specific effector cells, which produce effector lymphokines, MCF and MAF, were L3T4+, Lyt-2-, Thy-1+ cells. The kinetic analysis revealed that the ability of these effector cells to produce MCF was generated earlier than that to produce MAF. Furthermore, using passive transfer of cells, the effector cells producing only MCF, which were generated early in culture, conferred delayed-type hypersensitivity (DTH) alone, but MCF- and MAF-producing effector cells generated late in culture conferred sufficient levels of DTH and acquired cellular resistance (ACR). These results indicate a dissociated production of MCF and MAF by L. monocytogenes-specific T cells generated in the primary in vitro culture system.

Animals↗

PubMed1990

Phospholipid monolayers at the triolein-saline interface: production of microemulsion particles and conversion of monolayers to bilayers.

Interfacial tensions of phospholipid monolayer at the triolein (TO)-saline interface were measured. The adsorption isotherms and the interfacial pressure-molecular area curves were evaluated on the basis of the measurements. Phosphatidylcholine (PC) forms a highly condensed monolayer, with a large lateral attractive interaction; phosphatidylethanolamine (PE) and phosphatidylserine (PS) form expanded monolayers with smaller lateral interaction energies. At the lowest interfacial tension (the highest interfacial pressure), the mole fractions of PC, PE, and PS in the monolayers are estimated as 0.95, 0.73, and 0.88, respectively. Therefore, PC forms the most stable monolayer at the interface. These results are consistent with the finding that the stable TO particles in aqueous solution were produced by using PC as an emulsifier, and PE and PS did not stabilize the particles. The phase diagram of TO and PC mixtures in saline obtained from theoretical considerations predicts the equilibrium conversion of the monolayers on TO particles to bilayers. This process may be closely related to the transformations of very low density lipoproteins and chylomicrons to high-density lipoproteins in plasma. The particle sizes of the emulsion are calculated theoretically as a function of PC mole fraction in the TO-PC mixture and compared with the experimental values obtained from quasi-elastic light scattering (QLS) measurements.

Adsorption↗

PubMed1990

Interactions of lecithin and pig apolipoproteins of high density lipoproteins at the surface monolayer of reconstituted very small particles.

Cosonication of egg yolk lecithin and triolein with apolipoproteins isolated from pig high density lipoprotein (apoHDL) gave us reconstituted high density lipoprotein particles (r-HDLs) of 9 nm in average diameter. They were smaller than microemulsion particles (MEs) composed of the lipids (35 nm). The protein/egg yolk lecithin ratio in the fractionated r-HDLs was higher in the smaller particles. Binding of a hydrophobic probe, 2-p-toluidinylnaphthalene-6-sulfonate (TNS), to MEs, r-HDLs and apoHDL were evaluated on the basis of Halfman and Nishida's method. The reconstitution of apoHDL into MEs led to a 68% reduction in the binding of TNS and a small increase in the alpha-helix content as compared with free apoHDL. The binding experiments also showed the condensation of lecithin molecules at the r-HDL surface. The amphipathic helixes of apoHDL are located in the surface monolayer of egg yolk lecithin surrounding the triolein core. The intercalation of the hydrophobic residues of apoHDL between egg yolk lecithin molecules brings about a pronounced curvature of the surface and a decrease in the particle diameter.

Animals↗

PubMed1990

Determinants of maximum walking speed in hemiparetic stroke patients.

The time necessary to walk 10 m with the fastest speed, the sway path of the center of feet pressure in station, and the isokinetic strength for knee extension of each side were examined in 29 hemiparetic stroke patients. The maximum walking speed of the patients was related to the sway path and the isokinetic muscle strength of affected side. The patients could be divided into two groups based on their sway path. The determinants of the maximum walking speed in the unstable group were the sway path and the isokinetic muscle strength of the both sides, whereas that in the stable group was only the isokinetic muscle strength of affected side.

Adult↗