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Biomedical subjects

A Okada

Publications and source records attributed to A Okada.

At least 541 records · Page 30Linked to original sources

Preparation and disposition of asialofetuin-labelled liposome.

A liposome labelled with asialofetuin(AF-liposome) was prepared by the detergent dialysis method. Asialofetuin in the amount of 34-68 micrograms were imposed among the 1 microM of phospholipids constituting the outer surface of liposome. The AF-liposome containing [14C]-cholesterol in the lipid layer and [3H]-sucrose in the aqueous layer was intravenously administered to rats. Both radioactivities were biphasically cleared from systemic circulation at rates faster than that of the fetuin-labelled liposome. These radioactivities were recovered in the liver by about 90 per cent within 60 min, and per gram of tissue, were highest in this organ. In an in vitro experiment using isolated rat hepatocytes, the high affinity of the AF-liposome toward hepatocytes was observed from scanning electron micrographs. Based on these findings, the AF-liposome may possibly be stable in circulation and function as a carrier of encapsulated drugs to hepatocytes.

Animals↗

Specific incorporation of asialofetuin-labeled liposomes into hepatocytes through the action of galactose-binding protein.

Asialofetuin-labelled liposomes (AF-liposomes) having mean diameters of 0.13 micron ([S]) and 0.35 micron ([L]) were obtained by the subsequent extrusion method in combination with dialysis. Intravenously administered AF-liposomes [S] were rapidly cleared from the systemic circulation. By pre- and post-treatment of the rats with free asialofetuin (AF), the rate of elimination decreased to that of non-labelled liposomes (N-liposomes) [S]. The liver uptake of AF-liposomes [S] (60 per cent of dose in 30 min) was about twice that of N-liposomes [S]. Forty-seven per cent of the AF-liposomes [S] incorporated into the liver were found in the parenchymal cell fraction as against 20 per cent in the non-parenchymal cell fraction. In contrast, N-liposomes [S] were taken up primarily by non-parenchymal cells as was also the case for AF- or N-liposomes [L]. Both the lipid and aqueous markers of AF-liposomes [S] were detected in subcellular fractions of the liver, but their distribution was noted to change differently with the lapse of time. Intravenously administered AF-liposomes [S] were specifically recognized by galactose-binding protein and underwent disruption in the cell after being taken up by hepatocytes. AF-liposomes [S] may possibly be utilized to deliver drugs into hepatocytes.

Animals↗

Influence of paramagnetic contrast on single-shot MRCP image quality.

To assess the ability of gadolinium enhancement to suppress the overlapping vessel signals that diminish the image quality of magnetic resonance cholangiopancreatography (MRCP), we obtained MRCP before and after intravenous injection of gadolinium. Signal intensity ratio of the common bile duct to the main pancreatic duct was significantly improved after the injection of contrast media. The image quality of the postcontrast MRCP was better than that of the precontrast one.

Adolescent↗

Prenatal diagnosis of congenital diaphragmatic hernia and perinatal care: assessment of lung hypoplasia.

To assess the severity of lung hypoplasia, we have attempted to measure the lung thorax transverse area ratio (L/T) by using ultrasonic echography and to select immediate surgery after delivery by caesarean section. The evaluation of L/T for an index of lung hypoplasia was made by arterial blood gas data and clinical courses. Of 14 fetuses diagnosed, 13 had left sided CDH and one right sided case, from 11 to 38 weeks of pregnancy, 10 cases survived. The L/T in 14 fetuses with CDH was from 0.08 to 0.36 (mean 0.2 +/- 0.073) and was significantly lower than that of the controls. L/T was correlated best with data of arterial pH, PCO2, preductal A-aDO2 before operation and the duration of mechanical ventilation in survivors. Although L/T was also significantly low in the cases with severe grade, diaphragmatic patch closure and ECMO therapy, no significant differences were noted in L/T between survivors and non-survivors. These results indicated that L/T may predict the severity of lung hypoplasia in CDH and that the combination of perinatal management bases on prenatal diagnosis of CDH and ECMO support may improve the outcome of fatal CDH with severe lung hypoplasia.

Cesarean Section↗

Morphometric development of the human fetal auditory system: inferior collicular nucleus.

The development of the human inferior collicular nucleus was studied on serial sections of the brains of 9 fetuses at 12-34 weeks of gestation and an adult of 63 years using an electronic planimeter with a computer. Morphometric analysis of the development of the inferior collicular nucleus showed that its development accelerates after 18 weeks of gestation in terms of the columnar volume and length, size of neurons and circularity ratio. Large-sized neurons 2-3 times the area of small-sized neurons appeared after 18 weeks of gestation. The ratio of large neurons to the total ranged between 3 and 6% in the inferior collicular nucleus. The development of the inferior collicular nucleus was similar to that of the ventral cochlear nucleus and the medial superior olivary nucleus.

Age Factors↗

Hyperactivation of human spermatozoa: measurement of motility before and after incubation.

The motility rate of sperm during capacitation process was determined by calculating a sperm motile efficiency index (SMEI) using a hemocytometer. The SMEI values for the sperm from 100% of normal fertile men and 64% of infertile patients increased significantly by the fourth hour of incubation, while for 36% of infertile patients there was no increase. A correlation between the increase of SMEI and original motility, original SMEI and original semen amount was not possible. In addition, a decrease of the SMEI value was observed after sperm incubated for 3 hours were added to the seminal plasma of the donor. It is concluded that in human spermatozoa "hyperactivation and dehyperactivation" can be measured by SMEI.

Adult↗

Augmentation of water-immersion stress- induced gastric mucosal lesions in BALB/c mice infected with Helicobacter felis.

BACKGROUND AND AIMS: Inoculation of Helicobacter felis into the murine stomach has been reported to induce chronic gastric inflammation and may be a model of Helicobacter pylori-induced chronic gastritis. In this study, to characterize H. felis-induced gastritis, the gastric production of interleukin-1beta (IL-1beta) and hepatocyte growth factor (HGF) was measured in mice. METHODS: Gastric mucosal lesions were induced in H. felis-infected BALB/c mice by water-immersion stress. The severity score of gastric erosions per stomach was measured as the sum of the length of erosions. Gene expression of IL-1beta and HGF were analyzed by Northern blot analysis and production of HGF was examined using the enzyme immunoassay method. RESULTS: Water-immersion stress induced gastric mucosal lesions accompanied by increased expression of IL-1beta mRNA. H. felis infection evoked enhanced expression of IL-1beta and HGF genes. When H. felis-infected mice were stressed by water immersion, the mucosal lesions were more severe than those in non-infected mice. Moreover, IL-1beta gene expression as well as HGF production was further increased. CONCLUSIONS: Although H. felis inoculation did not cause gastric mucosal erosions by itself, it augmented the stress-induced erosions.

Animals↗

Lipoprotein(a) phenotypes in patients with vascular dementia.

We tried to examine if there is a particular distribution pattern of lipoprotein(a) [Lp(a)] phenotypes specific for patients with vascular dementia (VD). Fourteen cases of VD (9 males and 5 females), 18 cases of dementia of the Alzheimer type (DAT)(7 males and 11 females), 29 cases of cerebrovascular disease (CVD) in the chronic phase (18 males and 11 females) and 47 healthy individuals as controls (25 males and 22 females) were examined for serum Lp(a). Serum concentrations and phenotypes of Lp(a) were assessed by ELISA and a test kit for the Lp(a) phenotype, respectively. Serum concentrations of Lp(a) were significantly higher in patients with VD (p < 0.05) as well as patients with CVD (p < 0.01) compared with those in healthy individuals. Serum concentrations of Lp(a) did not significantly differ between patients with DAT and healthy individuals. The incidences of Lp(a) phenotypes containing relatively low-molecular-weight apolipoprotein(a) isoforms were significantly higher in patients with CVD in the chronic phase (p < 0.05) or those with VD (p < 0.01) compared with those in healthy individuals. Distribution patterns of Lp(a) phenotypes did not differ between patients with DAT and healthy individuals. Thus, high serum levels of Lp(a) could be considered a clinical hallmark to distinguish VD from DAT. Abnormally high serum levels of Lp(a) in patients with CVD and VD seemed to be due to specific increases in low-molecular-weight apolipoprotein(a) isoforms in Lp(a).

Aged↗

The expression of presenilin 1 mRNA in skin fibroblasts and brains from sporadic Alzheimer's disease.

We examined the expression of presenilin 1 (PS-1) mRNA in cultured skin fibroblasts taken from living patients with Alzheimer's disease (AD) and human brains taken postmortem from AD patients by RT-PCR analysis. The donors of fibroblasts consisted of 28 cases with AD and 19 neurological patient without dementia (CTL). The brains came from 17 cases with AD and 23 cases with CTL. We found that PS-1 mRNA levels in skin fibroblasts of AD patients were significantly higher than those of CTL patients (p < 0.0001). Moreover, we found that PS-1 mRNA levels in human brains with AD were significantly higher than in those with CTL (p < 0.0001). These findings suggest that high levels of PS-1 mRNA in AD may play an important role in developing AD and that the examination of PS-1 mRNA in skin fibroblasts may be helpful for the diagnosis of AD.

Aged↗

Bilateral diaphragmatic hernia followed by fetal ultrasonography. A report of two cases.

Two cases of bilateral congenital diaphragmatic hernia (CDH) followed by fetal ultrasonography were described. Although many cases of CDH are diagnosed by fetal ultrasonography, it is difficult to diagnose bilateral CDH in utero, which is a relatively rare and fatal condition. Two fetuses were diagnosed as having left CDH associated with severe anomalies. However, a retrospective review of fetal ultrasonography indicated elevation of the liver in the right posterior chest. Both patients died shortly after surgical repair for left CDH despite the use of extracorporeal membrane oxygenation. Diagnosis of bilateral CDH by fetal ultrasonography and the evaluation of its prognosis were discussed.

Fatal Outcome↗