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Biomedical subjects

C Oshio

Publications and source records attributed to C Oshio.

At least 19 recordsLinked to original sources
PubMed2001

Direct measurement of erythrocyte deformability in diabetes mellitus with a transparent microchannel capillary model and high-speed video camera system.

To measure erythrocyte deformability in vitro, we made transparent microchannels on a crystal substrate as a capillary model. We observed axisymmetrically deformed erythrocytes and defined a deformation index directly from individual flowing erythrocytes. By appropriate choice of channel width and erythrocyte velocity, we could observe erythrocytes deforming to a parachute-like shape similar to that occurring in capillaries. The flowing erythrocytes magnified 200-fold through microscopy were recorded with an image-intensified high-speed video camera system. The sensitivity of deformability measurement was confirmed by comparing the deformation index in healthy controls with erythrocytes whose membranes were hardened by glutaraldehyde. We confirmed that the crystal microchannel system is a valuable tool for erythrocyte deformability measurement. Microangiopathy is a characteristic complication of diabetes mellitus. A decrease in erythrocyte deformability may be part of the cause of this complication. In order to identify the difference in erythrocyte deformability between control and diabetic erythrocytes, we measured erythrocyte deformability using transparent crystal microchannels and a high-speed video camera system. The deformability of diabetic erythrocytes was indeed measurably lower than that of erythrocytes in healthy controls. This result suggests that impaired deformability in diabetic erythrocytes can cause altered viscosity and increase the shear stress on the microvessel wall.

Adult↗
PubMed2000

Image correlation method for measuring blood flow velocity in microcirculation: correlation 'window' simulation and in vivo image analysis.

To elucidate the function of the microcirculation system, it is very important to know the blood flow velocity and its distribution in the microvessels. We have developed an automated system for measuring blood flow velocity in microcirculation by image correlation. The 'window' in the image correlation method is equivalent to the sensors in various other measurement methods. We performed simulations with virtual blood flow images consisting of random dots before measuring actual ones, and examined the optimum window shape and size. We found that by reducing the size of a circular window to the size of erythrocytes we could measure in vivo blood flow images with high accuracy. We recorded them with a high-speed video camera system at high temporal resolution, and measured the velocity in microvessels of normal Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). SHR had higher blood velocity than WKY even though the vessel diameters were the same. Using this method to measure the blood flow velocity profile at the bent corner of SHR's arteriole at the heart systole, we found that erythrocytes flow faster at the inner side of the bend, so the vessel wall was exposed locally to higher shear stress in the hypertensive condition.

Animals↗
PubMed1993

Oxyradical generation from leukocytes during endotoxin-induced microcirculatory disturbance in rat mesentery--attenuating effect of cetraxate.

By using the intravital microscope equipped with digital imaging processor, we investigated the granulocyte-mediated oxidative burst during the endotoxin-induced microvascular derangement in rat mesentery. The leukocyte behavior after the injection of acridine orange was detected by using a silicon-intensified target camera, the erythrocyte velocity was measured by using a high-speed video camera system, and the luminol-dependent photoemission was visualized by an ultrasensitive photon-counting camera in lipopolysaccharide (LPS)-treated microvascular beds. At 60 min after the LPS administration, a significant leakage of FITC-labeled albumin was observed along mesenteric venules under a fluorescence microscopy. The number of sticking leukocytes increased in association with the decrease in erythrocyte velocity after starting the LPS infusion. The luminol-dependent chemiluminescence in microvascular beds gradually increased over that recorded prior to LPS exposure and was fourfold higher 60 min after the start of LPS infusion. The distribution of the photoemission clearly corresponded to the venular endothelium, to which leukocytes adhered. In blood samples taken from the mesenteric vein at 60 min after the LPS administration, a decrease in the number of granulocytes and increases of total and individual chemiluminescence activities were observed. These results suggest that LPS induces oxidative burst from granulocytes on the venular endothelium. Cetraxate, an inhibitor of proteases including plasmin, significantly inhibited the leukocyte activation and prevented alterations in microvascular hemodynamics induced by LPS in vivo, whereas it had no effect on the LPS-induced oxyradical generation from adherent leukocytes in vitro. The present study demonstrates that proteases such as plasmin may play an important role in the pathogenesis of endotoxin-induced microvascular disturbances.

Animals↗
PubMed1991

Intralobular heterogeneity of carbon tetrachloride-induced oxidative stress in perfused rat liver visualized by digital imaging fluorescence microscopy.

Spatial and temporal alterations in carbon tetrachloride-induced oxidative stress were studied in perfused hepatic microcirculatory units of the rat by digital imaging microscopic fluorography using dichlorofluorescin diacetate, a hydroperoxide-sensitive fluorogenic probe. The surface of the liver loaded with dichlorofluorescin was microscopically visualized, and the fluorescence of dichlorofluorescin (DCF), a highly fluorescent molecule generated by hydroperoxide-mediated oxidation of dichlorofluorescin, was digitally processed. After completing the experiments, fluorescein-labeled albumin was injected into the perfusate to confirm the state of sinusoidal perfusion and the topography of hepatic microangioarchitecture in the area studied. During transportal infusion of carbon tetrachloride, DCF fluorescence was observed predominantly in the pericentral area and was attenuated by pretreatment with SKF-525A, suggesting the involvement of cytochrome P-450. After peaking at the maximum level, the pericentral DCF fluorescence gradually decreased in parallel to the loss of viability, implicating the causal role of intracellular hydroperoxide formation in hepatocellular injury. In retrogradely perfused liver, in which intralobular O2 gradient was reversed, no significant activation of DCF fluorescence was observed among hepatic lobules. It is therefore conceivable that the zonal heterogeneity of carbon tetrachloride-induced lipid peroxidation may depend on at least two factors, sinusoidal oxygenation and the intralobular distribution of cytochrome P-450. Furthermore, development of the current technique will provide a useful method to investigate the microtopography of oxidative stress in organ microcirculatory units.

Animals↗
PubMed1989

Effects of serine protease inhibitors on oxyradical burst from phagocytizing neutrophils--analysis by chemiluminescence counting and its microscopic imaging.

Reaction difference of oxyradical generation and luminol-dependent photoemission of zymosan- and phorbol ester-treated neutrophils were investigated using a conventional photomultiplier and ultrasensitive photonic imaging technique. Zymosan-treated cells released a concentrated photonic burst corresponding to the cellular distribution. In contrast, phorbol ester-treated cells produced a negligible level of photoemission, and the additional application of Ca2+ ionophore enhanced the photonic burst, which was gradually spread out into extracellular space. Serine protease inhibitors did not attenuate PMA-induced chemiluminescence but did attenuate zymosan-induced chemiluminescence. This suggests the involvement of serine protease in the respiratory burst of phagocytizing neutrophils.

Free Radicals↗
PubMed1988

Luminol-dependent photoemission from single neutrophil stimulated by phorbol ester and calcium ionophore--role of degranulation and myeloperoxidase.

Luminol-dependent photonic burst from phorbol ester-treated single neutrophil was visually investigated by using an ultrasensitive photonic image intensifier microscope. Neutrophils stimulated by phorbol myristate acetate (0.1 microgram/ml) alone produced a negligible level of photonic activities in the presence of luminol (10 micrograms/ml). The additional application of 0.1 microM Ca2+ ionophore A23187 induced explosive changes of photonic burst corresponding to the distribution of neutrophils, and these photonic activities were gradually spread to extracellular space. Sodium azide, which prevents myeloperoxidase activity, inhibited Ca2+ ionophore-induced photonic burst from phorbol ester-treated neutrophil. These findings suggest a prerequisite role of degranulation and myeloperoxidase release in luminol-dependent photoemission from stimulated neutrophils.

Azides↗
PubMed1988

Child-environment relationships: a cross-cultural study of educable mentally retarded children and their families.

A cross-cultural study was conducted to determine the generality of child-environment relationships in Japanese and American families with educable mentally retarded (EMR) children. A total of 90 families with EMR children in Japan and 93 families with EMR children in America participated. The Henderson Environment Learning and Process Scale, Family Environment Scale, and Home Quality Rating Scale were employed in home interviews and observations. The AAMD Adaptive Behavior Scale was used to measure social competency and psychosocial adjustment of the children. The results indicated that the relation between cognitive opportunities at home and the child's social competency appeared similar between the two cultures. However, the relation between the affective aspects of home environment and the child's psychosocial adjustment appeared to differ between the two cultures.

Activities of Daily Living↗
PubMed1988

Microcirculatory disturbances in endotoxin-induced disseminated intravascular coagulation. The effects of heparin and gabexate mesilate on locomotive and metabolic changes of neutrophils.

Neutrophil-mediated oxidative stress on the rat mesenteric microcirculation was studied in the experimental model of endotoxin-induced disseminated intravascular coagulation (DIC) by using an intravital fluorescent technique and luminol-dependent chemiluminescence (ChL) analysis. Leukocytes sticking to the venules were visualized by the injection of acridine orange, a fluorochrome tracer which shows high affinity to white cells. Endotoxin (E coli, O-111B4, Difco, USA) was infused intravenously at a dose of 2 mg/kg/hr. After starting the infusion of endotoxin, the number of sticking cells were gradually increased on the venular endothelium followed by a transient neutropenia. In order to investigate the distribution of infused endotoxin in the microvasculature, FITC-labeled endotoxin (Sigma, USA) was used. After administration of FITC-endotoxin, multiple patches of fluorescence along the venular walls were observed, while no fluorescent conjugates were found at the sticking neutrophils and along the arteriolar walls. ChL activities of neutrophils were also dramatically elevated, which may reflect the enhanced ability to generate oxyradical species. To investigate the inhibitory effects of heparin sodium and gabexate mesilate which was a synthetic protease inhibitor on locomotive and metabolic changes of neutrophils induced by endotoxemia, both agents were administered prior to endotoxin infusion. Gabexate mesilate attenuated these changes, but heparin sodium did not show any improving effects. It was concluded that endotoxin primarily affects the venular endothelial cells, resulting in the activation of neutrophils. Gabexate mesilate was more likely to attenuate neutrophil-mediated oxidative stress on microvasculature in endotoxin-induced DIC than heparin sodium.

Animals↗
PubMed1988

5-lipoxygenase inhibitor (AA-861) attenuates neutrophil-mediated oxidative stress on the venular endothelium in endotoxemia.

Neutrophil-mediated oxidative stress on the rat mesenteric microcirculation was studied in the experimental model of endotoxin-induced disseminated intravascular coagulation (DIC) by using an intravital fluorescent microscope equipped with a Silicon Intensifier Target Image Tube camera and luminol-dependent chemiluminescence (ChL) analysis. Leukocytes adhering to the venules were visualized by the injection of acridine orange, a fluorochrome tracer which shows high affinity to white cells. Endotoxin (E. coli, O-111 B4) was administered intravenously at a dose of 2 mg/kg/hour. After starting the infusion of endotoxin, the number of adherent cells gradually increased in the venular endothelium and was followed by a transient neutropenia. ChL activities from neutrophils were also significantly elevated, which may reflect the enhanced ability to generate oxygen-radicals. To elucidate the role of 5-lipoxygenase products in the locomotive and metabolic changes of neutrophils, the effects of AA-861, a specific inhibitor of 5-lipoxygenase was tested. In addition prednisolone and indomethacin were evaluated. AA-861 and prednisolone reduced neutropenia, leukocyte adhesion to the venular walls and ChL activities from neutrophils. It was concluded that 5-lipoxygenase may modulate neutrophil-mediated oxidative stress on microvasculature in endotoxin-induced DIC.

Acridine Orange↗
PubMed1987

Real-time visualization of oxyradical burst from single neutrophil by using ultrasensitive video intensifier microscopy.

Dynamics of oxyradical burst from single human neutrophils stimulated by opsonized zymosan was visualized by using an ultrasensitive video intensifier microscopy in the presence of chemiluminescence probe. Luminol-dependent photonic burst activities were clearly corresponding to the distribution of zymosan-treated neutrophils. Heterogeneity of photon-bursting period and the maximum photonic intensity among reactive cells was demonstrated. This may reflect functional heterogeneity of the ability to release oxyradicals among neutrophils.

Free Radicals↗
PubMed1987

Increased lymphocyte transport by lipid absorption in rat mesenteric lymphatics.

The effect of olive oil administration on lymphocyte transport through mesenteric lymphatics was examined to see the possible involvement of nutritional absorption in lymphocyte traffic from the intestinal mucosa. After the olive oil administration to rats, remarkable increase in lymphocyte flux was observed within 2 h in lymph samples collected from rats with lymphatic fistula. The use of a high-speed microscopic video system made it possible to analyze accurately the lymphocyte transport in rapid movement that could not be detected by any of the ordinary video systems. The direct observation of mesenteric collecting lymphatics by this system showed an increment of lymphocyte transport from the intestinal mucosa by lipid absorption in 2 h. The contraction frequency of intestinal collecting lymphatics was also enhanced by olive oil administration. The densitometric analysis on video image was applied to estimate the extent of lipid absorption. The combination of a high-speed video system and the densitometric analysis revealed that the increase in lymphocyte flux occurred before lipid absorption reached its maximum and also demonstrated that the lymphocyte transport returned to control levels under the maximal absorptive condition. The results suggest that the fat absorption could be an important factor influencing the lymphocyte transport in the lymphatic system of intestine.

Absorption↗
PubMed1987

Sulfasalazine and its metabolites attenuate respiratory burst of leukocytes--a possible mechanism of anti-inflammatory effects.

The effects of sulfasalazine and its metabolites, 5-amino salicylic acid and sulfapyridine on respiratory burst of polymorphonuclear leukocytes were investigated by determining not only luminol-dependent chemiluminescence for the detection of myeloperoxidase-mediated active oxidants, but also lucigenin-dependent chemiluminescence for the detection of superoxide anion. The present study showed that sulfasalazine, 5-amino salicylic acid and sulfapyridine attenuated active oxygen species from polymorphonuclear leukocytes at the concentrations comparable to clinical doses. Therefore, it was concluded that anti-inflammatory effects of sulfasalazine can be explained by the ability of sulfasalazine and its degraded compounds to scavenge active oxidants from polymorphonuclear leukocytes.

Aminosalicylic Acids↗
PubMed1987

Homes of TMR children: comparison between American and Japanese families.

A cross-cultural study was conducted to examine the extent to which certain environment-child development relationships can be generalized across two cultures. Participants were 103 trainable mentally retarded (TMR) children and their families in Japan and 88 TMR children and their families in the United States. The relation between cognitive stimulation and cultural opportunities at home and the children's social competence appeared to generalize across both cultures; however, the relation between affective and emotional aspects of parental behavior and the children's emotional adjustment appeared to be culture-specific. The cross-cultural difference in home environment was interpreted in terms of qualitative difference in parental values and expectations regarding the children's behavior.

Adolescent↗
PubMed1985

Colchicine effect on bile canalicular motility: long-term study using isolated cultured hepatocytes and time-lapse cinephotomicrography.

The effect of colchicine on spontaneous in vitro contractions of bile canaliculi was assessed using time-lapse cinephotomicrography. Colchicine 2.5 microM and/or taurocholate 5 microM were added to the culture medium. The experiment was long-term, lasting for 13 h. Frame-by-frame analysis revealed that colchicine, after a lag period of 4 h, suppressed the number of contractions over the remainder of the 13-h experimental period, even in the presence of taurocholate (p less than 0.001). The number of contractions per hour decreased in both the colchicine and combined colchicine-plus-taurocholate-treated groups compared to untreated and taurocholate-treated controls. These results do not necessarily mean that colchicine has an effect on the contractile process per se, since the contractions, when they occurred, appeared normal. It is likely that the canalicular motility events are related to bile secretion. The reduction in contractions after a lag period likely indicates that secretion is impaired, and hence the need for contractions is reduced. These results support the view that for normal canalicular bile secretory function, microtubules as well as a normal microfilament system are required.

Animals↗
PubMed1985

Coordination of the contractile activity of bile canaliculi. Evidence from spontaneous contractions in vitro.

Rat hepatocytes, when isolated and maintained in primary culture, are capable of producing forceful contractions of their bile canaliculi, with contractions occurring on a regular basis once every 5.5 minutes. To determine whether the contraction of one bile canaliculus affected the contraction of a neighboring canaliculus, cinephotomicrographic studies of pairs of contiguous canaliculi were undertaken. The activity of 10 pairs of contiguous canaliculi, and 10 pairs of noncontiguous canaliculi which served as a control group, was recorded for a period of 12.5 hours at the rate of 1 frame every 15 seconds. Using frame-by-frame analysis of this period of observation, we determined the time of contraction of each of the canaliculi in the pairs. Cross-correlations were obtained for the contraction times of each of the 10 pairs of contiguous canaliculi and 10 control pairs. A peak in activity was found, with that peak occurring five frames or 75 seconds from the midline, whereas the noncontiguous controls showed no correlation in contractile activity. This finding indicates that, when one bile canaliculus contracts, a neighboring canaliculus is likely to contract after an interval of 1.25 minutes. That there is coordination of contractile activity of bile canaliculi suggests that, within the intact liver lobule, ordered motility function of the bile canaliculi may facilitate bile flow.

Animals↗