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Biomedical subjects

I Hatta

Publications and source records attributed to I Hatta.

33 records · Page 2Linked to original sources
PubMed1993

[A case of acute hepatitis A associated with acute renal failure from the onset].

A 42-year-old female was admitted to a hospital, because of acute hepatitis A. Laboratory data were GOT 8210mU/ml. GPT 4650mU/ml, LDH 11860mU/ml, total bilirubin 4.7mg/dl, BUN 19.5mg/dl and creatinine 1.9mg/dl. Urinalysis showed proteinuria 3+ and occult blood 1+. Soon after admission, she suffered from anuric acute renal failure and was transferred to our hospital for hemodialysis. Her urine-volume was under 20 ml per day. Urinalysis showed proteinuria 4+, occult blood 1+ and casts. Laboratory data showed BUN 58.2mg/dl and creatinine 8.5mg/dl. She was treated by hemodialysis for 35 days, before recovering from renal failure. However, her renal function did not recover perfectly and her 24-hour creatinine clearance remained at 50ml/min after 6 months. Renal biopsy was performed on the 17th day after admission. Examination by light microscopy revealed the findings of acute tubular necrosis and examination by immunofluorescence antibody method was negative. Urinalysis of 8 patients with acute hepatitis A showed that all patients had proteinuria at the onset. Patients with acute hepatitis A have symptoms of appetite-loss, nausea, vomiting and/or diarrhea. These symptoms cause hypovolemia, and hepatic dysfunction causes discontrol of vasoactive hormones, which gives rise to disturbance of renal circulation. Subsequently, acute tubular necrosis and acute renal failure occur.

Acute Disease↗
PubMed1992

Effects of poly(L-lysine) on the structural and thermotropic properties of dipalmitoylphosphatidylglycerol bilayers.

The effects of poly(L-lysine) on the structural and thermotropic properties of dipalmitoylphosphatidylglycerol (DPPG) bilayers were studied with differential scanning calorimetry (DSC), X-ray diffraction and freeze-fracture electron microscopy. For thermal behavior, in the DPPG/poly(L-lysine) system the main transition temperature rises to 45.7 degrees C and the pretransition disappears in opposition to pure DPPG vesicles. An additional transition appears approximately at 36 degrees C for the DPPG/poly(L-lysine) system after incubation at 4 degrees C for two months. The incubated sample gives a X-ray diffraction pattern having several additional reflections in the range of 0.2-0.9 nm at 15 degrees C. These results suggest that even in the presence of poly(L-lysine) the DPPG bilayers form the subgel (Lc) phase after the long incubation at a low temperature. The X-ray diffraction measurements indicate that the structure of the Lc phase for DPPG/poly(L-lysine) system is different from that of pure DPPG bilayers. On the other hand, in the gel (L beta') phase, the wide-angle X-ray diffraction pattern suggests that the presence of poly(L-lysine) hardly affects the packing of hydrocarbon chains in the DPPG bilayers. The small-angle X-ray diffraction and freeze-fracture electron microscopy exhibit that the DPPG/poly(L-lysine) system forms a tightly packed multilamellar structure in which the poly(L-lysine) is intercalated between the subsequent DPPG bilayers.

Calorimetry, Differential Scanning↗
PubMed1991

Electrostatic interaction of poly(L-lysine) with dipalmitoylphosphatidic acid studied by X-ray diffraction.

Structure of dipalmitoylphosphatidic acid (DPPA) bilayers in the presence of poly(L-lysine) is proposed from the results of X-ray diffraction obtained by a storage phosphor detector with a high resolution called an imaging plate. The small-angle X-ray diffraction pattern exhibits that DPPA/poly(L-lysine) complex forms a highly ordered multilamellar structure. The electron density profile of the DPPA/poly(L-lysine) complex draws that only one poly(L-lysine) layer is intercalated between the neighboring DPPA bilayers. The wide-angle X-ray diffraction pattern suggests that the presence of poly(L-lysine) hardly affects the nature of hydrocarbon chain packing in the DPPA bilayers. The X-ray reflection from the DPPA/poly(L-lysine) complex indicates that the poly(L-lysine) molecules adopt a beta-sheet conformation on the surface of the DPPA bilayers. The both surface areas occupied by a headgroup of the DPPA and by a lysine residue in poly(L-lysine) are estimated from the observed spacings. The number ratio of lysine residues to DPPA headgroups per unit area is greater than unity. Therefore, one DPPA headgroup interacts with more than one lysine residue electrostatically, i.e., the electric charge distributions in both the surface of a DPPA bilayer and the poly(L-lysine) beta-sheet are incommensurate.

Electrons↗
PubMed1990

Ethanol induces interdigitated gel phase (L beta I) between lamellar gel phase (L beta') and ripple phase (P beta') in phosphatidylcholine membranes: a scanning density meter study.

Effects of ethanol on dipalmitoylphosphatidylcholine (DPPC) and distearoylphosphatidylcholine (DSPC) dispersions were investigated with an automated scanning density meter and a differential scanning calorimeter (DSC). The temperature-dependent profile of specific volume measured by the density meter clearly exhibited phase transitions of the DPPC and the DSPC dispersions as drastic changes in the thermal expansion coefficients. On increasing the ethanol concentration in the DPPC dispersions, the pretransition temperature was reduced faster than the main transition temperature was. An interdigitated gel phase (L beta I) appeared as a region of lower specific volume at the pretransition temperature when the ethanol concentration reached 40 mg/ml. The L beta I phase spread both its ends in an ethanol-dependent fashion, and the high-temperature end merged to the main transition at 50 mg/ml of ethanol. The temperature-ethanol phase diagram has been determined for DPPC. The transitions L beta' to L beta I and from L beta I to P beta' were also observed on the thermograms of DSC measurements. In the DSPC dispersions, the L beta I phase was induced between the L beta' and the P beta' phases by a lower ethanol concentration (about 20 mg/ml).

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1990

Temperature dependence of the ripple structure in dimyristoylphosphatidylcholine studied by synchrotron X-ray small-angle diffraction.

The ripple structure of 1,2-dimyristoyl-L-phosphatidylcholine (DMPC) multibilayer containing excess water (60 wt%) was studied by synchrotron X-ray small-angle diffraction. The (0,1) spacing which corresponds to the ripple repeat distance depends on temperature: At 13 degrees C the (0,1) spacing is 14.15 nm, the spacing decreases at higher temperatures and reaches 12.1 nm at 23.5 degrees C, just below the main transition temperature. The spacing is in good agreement between heating process and cooling process except for the supercooling region. The result suggests that the rearrangement of the ripple structure takes place during temperature change successively. The Landau-de Gennes free energy equation explains well the temperature dependence of the ripple repeat distance.

Dimyristoylphosphatidylcholine↗
PubMed1988

ESR studies on the ripple phase in multilamellar phospholipid bilayers.

The structure of the ripple phase in multilamellar DPPC liposomes was studied by measuring electron spin resonance (ESR) spectra of the stearic acid spin probe (16-SASL). The spectrum observed in the P beta' phase is explained in terms of the superposition of ordered- and disordered-type spectra. This fact suggests the existence of a nonhomogeneous structure in the P beta' phase, i.e., the coexistence of the ordered region present in the L beta' phase and the disordered region present in the L alpha phase. The fluidity of acyl chains in both regions and the intensity ratio of the disordered-type spectra to the total intensity were estimated from the ESR spectra at various temperatures. The fluidity of both regions did not exhibit remarkable temperature dependence. On the other hand, the intensity ratio showed almost similar temperature dependence of the partitioning of the TEMPO observed by ESR measurement and of the enthalpy curve by DSC measurement, that is, the intensity ratio value increases slowly near the pretransition temperature, is almost constant in the P beta' phase, and increases abruptly at the main transition temperature with temperature. The proportion of the disordered region is estimated to be about one-fifth to the total region in the P beta' phase. Based upon the above results, a model for the ripple structure is proposed.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1988

Stiffness changes in frog skeletal muscle during contraction recorded using ultrasonic waves.

1. A technique has been developed with which the stiffness changes in frog skeletal muscle can be continuously recorded by measuring the propagation velocity of ultrasonic waves (3-7 MHz) with negligibly small perturbations to the contractile system. 2. The resting muscle stiffness was 2.256 +/- 0.002 x 10(9) N/m2 (S.D.) at 1-2 degrees C (n = 10) and 2.480 +/- 0.007 x 10(9) N/m2 at 19-20 degrees C (n = 12) in the longitudinal direction, and 2.223 +/- 0.008 x 10(9) N/m2 at 1-2 degrees C (n = 8) and 2.437 +/- 0.007 x 10(9) N/m2 at 19-20 degrees C (n = 9) in the transverse direction. 3. The resting muscle stiffness measured with ultrasonic waves was virtually insensitive to the resting force development, i.e. the extension of the parallel elastic component. 4. The longitudinal muscle stiffness increased during isometric contraction at a rate faster than the force development. The amount of increase of the longitudinal stiffness in an isometric tetanus at 2.2 microns sarcomere length was 2.4 +/- 0.1 x 10(7) N/m2 at 1-2 degrees C (n = 10) and 6.5 +/- 1.3 x 10(7) N/m2 at 19-20 degrees C (n = 12). 5. On the other hand, the transverse muscle stiffness decreased during isometric contraction at a rate faster than the force development. The amount of decrease of the transverse stiffness in an isometric tetanus at 2.2 microns sarcomere length was 5.6 +/- 0.1 x 10(7) N/m2 at 1-2 degrees C (n = 8) and 6.4 +/- 0.3 x 10(7) N/m2 at 19-20 degrees C (n = 9). 6. The amount of both the longitudinal and the transverse stiffness changes during an isometric tetanus decreased linearly with increasing sarcomere length, indicating that the stiffness changes during contraction reflect the formation of cross-links between the myofilaments. 7. Both the longitudinal and the transverse stiffness increased when resting muscle was put into rigor state. The rigor muscle stiffness was insensitive to small stretches, i.e. the strain of the rigor cross-links. 8. These results are discussed in connection with the behaviour of cross-bridges during isometric contraction and in rigor.

Animals↗
PubMed1988

Sarcomere length dependence of muscle stiffness changes during contraction recorded using ultrasonic waves.

We have developed a technique with which muscle stiffness changes during isometric contraction can be continuously recorded by measuring the propagation velocity of ultrasonic waves with negligibly small perturbations to the contractile system, and obtained an unexpected result that, during isometric contraction, muscle stiffness decreased in the transverse direction while it increased in the longitudinal direction. In the present study, we measured the stiffness of frog skeletal muscle with ultrasonic waves at various sarcomere lengths from 2.2 to more than 3.6 microns, and found that (1) the resting muscle stiffness is insensitive to the resting force development in both the longitudinal and the transverse directions, and (2) the absolute amount of both the longitudinal and the transverse stiffness changes during isometric tetanus decreased linearly with increasing sarcomere length, approaching zero at 3.6-3.8 microns sarcomere lengths. These results indicate that the stiffness changes measured with ultrasonic waves reflect the changes in the number of cross-links between the myofilaments.

Animals↗
PubMed1987

Dynamics of appearance and disappearance of the ripple structure in multilamellar liposomes of dipalmitoylphosphatidylcholine.

The physical properties of the pretransition (P beta'----L beta') of dipalmitoylphosphatidylcholine liposomes were investigated using freeze-fracture electron microscopy. The kinetics of pretransition examined in the previous paper using TEMPO spin probe (Tsuchida, K., et al. (1985) Biochim. Biophys. Acta 812, 249-254) was extensively studied by observing the ripple structures in the freeze-fractured surfaces at different time intervals. When the temperature is decreased from 38 degrees C to 30 degrees C, the ripple structure disappears in the following steps. The intervals between ripples begin to expand with the decrease of ripple density upon the temperature shift, and this process continues for several tens minutes. Then, each ripple disappears gradually and changes into a completely smooth surface at 3 h after the temperature shift. The comparison of relaxation times between the previous ESR measurement and the present experiment suggests that the fast relaxation observed in the previous study corresponds to the expansion of the intervals between ripples. On the other hand, the ripple structure of regular intervals appears rapidly in some places and then spreads over the whole area of fractured surface when the temperature is increased from 23 degrees C to 35 degrees C. The results obtained in this work and the previous ESR work strongly suggest that the formation and disappearance of ripple structure is closely related to the relaxation processes near the pretransition temperature.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1984

Muscle stiffness changes during isometric contraction in frog skeletal muscle as studied by the use of ultrasonic waves.

In order to measure muscle stiffness changes with a high time resolution and with minimal disturbance to the contractile mechanism per se, we constructed an apparatus with which the propagation velocity of ultrasonic waves (MHz region) in the longitudinal or transverse direction was measured to serve as a measure of muscle stiffness. The longitudinal muscle stiffness started to increase on stimulation before the onset of isometric force, and reached a maximum before the peak twitch force. Analysis of experimental data indicated that, during an isometric tetanus, the increment of muscle longitudinal stiffness was about 6 X 10(7)N/m2, a value similar to those obtained by Truong (1974) and Ford et al. (1981) with sinusoidal vibrations (3 kHz) and length steps respectively. This suggests that the increment of muscle longitudinal stiffness during the activation of the contractile system results from the recruitment of an almost non-dispersive elastic component. In the case of transverse muscle stiffness, on the other hand, it started to decrease on stimulation before the onset of isometric force, and reached a minimum before the peak twitch force. Possible causes of this unexpected result is discussed in relation to the molecular mechanism of muscle contraction.

Animals↗
PubMedDate not supplied

Structure and phase behaviour of dimyristoylphosphatidic acid/poly(L-lysine) systems.

Differential scanning calorimetry (DSC) and X-ray diffraction studies on (DMPA)/poly(L-lysine) systems are reported. DSC studies revealed that addition of poly(L-lysine) to DMPA bilayers raises the gel to liquid-crystalline phase transition of the systems, and that this effect depends on the molecular weight of the poly(L-lysine). Small-angle X-ray diffraction measurements showed that, in the liquid-crystalline phase, the lamellar spacing of a DMPA/short-poly(L-lysine) (approximately 4000 mol. wt.) system is shorter than that of a DMPA/long-poly(L-lysine) (approximately 22000 mol. wt.). In this connection wide-angle X-ray diffraction measurements indicate that the long-poly(L-lysine) adopts a beta-sheet conformation on the DMPA bilayers in both the gel and the liquid-crystalline phases, but the short-poly(L-lysine) adopts this conformation only on gel phase DMPA bilayers. We found that the spacings of the hydrocarbon chain packing in a DMPA bilayer in the gel phase increases with temperature, while the spacing between neighbouring polypeptide chains in long-poly(L-lysine) in the beta-sheet conformation remains almost constant. These observations indicate that the positively charged lysine residues are structurally independent of the negatively charged head groups of the phospholipid. On the basis of the present results we propose a model to explain the elementary behaviour of extrinsic membrane proteins in biomembranes.

Calorimetry, Differential Scanning↗